Annual report pursuant to Section 13 and 15(d)

Debt (Junior Subordinated Debentures Outstanding) (Details)

v3.8.0.1
Debt (Junior Subordinated Debentures Outstanding) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Debt Instrument [Line Items]    
Outstanding Amount $ 70,384 $ 69,044
Junior subordinated debenture, purchase accounting adjustment 40,400 41,800
Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount 70,384 69,044
Initial Equity In Trust $ 3,327 [1] $ 3,327 [2]
Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate   4.85%
BST I [Member]    
Debt Instrument [Line Items]    
Issue Date Mar. 15, 2005 Mar. 15, 2005
Beginning Optional Redemption Date Mar. 30, 2010 Mar. 30, 2010
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR+ 4.90% 3-month LIBOR + 4.90%
Interest Rate 6.59% 5.90%
Debt Instrument, Maturity Date Mar. 30, 2035 Mar. 30, 2035
BST I [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 14,703 $ 14,422
Initial Equity In Trust $ 696 [1] $ 696 [2]
BST I [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate 4.90% 4.90%
BST II [Member]    
Debt Instrument [Line Items]    
Issue Date May 04, 2005 May 04, 2005
Beginning Optional Redemption Date Jul. 30, 2010 Jul. 30, 2010
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR + 4.85% 3-month LIBOR + 4.85%
Interest Rate 6.23% 5.74%
Debt Instrument, Maturity Date Jul. 30, 2035 Jul. 30, 2035
BST II [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 16,472 $ 16,164
Initial Equity In Trust $ 774 [1] $ 774 [2]
BST II [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate 4.85%  
BST III [Member]    
Debt Instrument [Line Items]    
Issue Date May 10, 2005 May 10, 2005
Beginning Optional Redemption Date Jul. 30, 2010 Jul. 30, 2010
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR + 4.85% 3-month LIBOR + 4.85%
Interest Rate 6.23% 5.74%
Debt Instrument, Maturity Date Jul. 30, 2035 Jul. 30, 2035
BST III [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 6,670 $ 6,550
Initial Equity In Trust $ 310 [1] $ 310 [2]
BST III [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate   4.85%
BST IV [Member]    
Debt Instrument [Line Items]    
Issue Date Apr. 24, 2006 Apr. 24, 2006
Beginning Optional Redemption Date Jun. 30, 2011 Jun. 30, 2011
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR+ 4.85% 3-month LIBOR + 4.85%
Interest Rate 6.54% 5.85%
Debt Instrument, Maturity Date Jun. 30, 2036 Jun. 30, 2036
BST IV [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 9,802 $ 9,614
Initial Equity In Trust $ 464 [1] $ 464 [2]
BST IV [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate 4.85% 4.85%
BST V [Member]    
Debt Instrument [Line Items]    
Issue Date Jul. 21, 2006 Jul. 21, 2006
Beginning Optional Redemption Date Sep. 30, 2011 Sep. 30, 2011
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR+ 4.85% 3-month LIBOR + 4.85%
Interest Rate 6.54% 5.85%
Debt Instrument, Maturity Date Sep. 30, 2036 Sep. 30, 2036
BST V [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 9,802 $ 9,614
Initial Equity In Trust $ 464 [1] $ 464 [2]
BST V [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate 4.85% 4.85%
BST VI [Member]    
Debt Instrument [Line Items]    
Issue Date Feb. 26, 2007 Feb. 26, 2007
Beginning Optional Redemption Date Apr. 30, 2012 Apr. 30, 2012
Interest Rate Following Beginning Optional Redemption Date 3-month LIBOR+ 4.80% 3-month LIBOR + 4.80%
Interest Rate 6.18% 5.69%
Debt Instrument, Maturity Date Apr. 30, 2037 Apr. 30, 2037
BST VI [Member] | Junior Subordinated Debentures [Member]    
Debt Instrument [Line Items]    
Outstanding Amount $ 12,935 $ 12,680
Initial Equity In Trust $ 619 [1] $ 619 [2]
BST VI [Member] | Junior Subordinated Debentures [Member] | LIBOR [Member]    
Debt Instrument [Line Items]    
Basis spread on rate 4.80% 4.80%
[1] Amounts include purchase accounting adjustments which reduced the carrying value by $40.4 million.
[2] Amounts include purchase accounting adjustments which reduced the carrying value by $41.8 million.