Securities, Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Debt Securities [Abstract]
Amortized cost	$ 568,381	$ 613,395
Gross unrealized gains	5,582	7,358
Gross unrealized losses	(3,778)	(5,456)
Fair value	570,185	615,297
Securities Available-for-Sale [Abstract]
Amortized cost	593,381	638,395
Gross unrealized gains	5,582	7,358
Gross unrealized losses	(4,027)	(5,567)
Fair value	594,936	640,186
Securities Held-to-Maturity [Abstract]
Amortized cost	1,661	1,662
Gross unrealized gains	2	1
Gross unrealized losses	(12)	(19)
Fair value	1,651	1,644
U.S. Treasury and Government Agencies [Member]
Available-for-sale Debt Securities [Abstract]
Amortized cost	240,434	190,563
Gross unrealized gains	311	509
Gross unrealized losses	(1,351)	(2,140)
Fair value	239,394	188,932
State and Political Subdivisions [Member]
Available-for-sale Debt Securities [Abstract]
Amortized cost	125,665	133,951
Gross unrealized gains	3,707	3,973
Gross unrealized losses	(157)	(466)
Fair value	129,215	137,458
U.S. Government Sponsored Agency Mortgage-backed Securities [Member]
Available-for-sale Debt Securities [Abstract]
Amortized cost	202,282	288,881
Gross unrealized gains	1,564	2,876
Gross unrealized losses	(2,270)	(2,850)
Fair value	201,576	288,907
CRA Investments Funds [Member]
Available-for-sale Equity Securities [Abstract]
Amortized cost	25,000	25,000
Gross unrealized gains	0	0
Gross unrealized losses	(249)	(111)
Fair value	24,751	24,889
U.S. Treasury and Government Agencies [Member]
Securities Held-to-Maturity [Abstract]
Amortized cost	480	480
Gross unrealized gains	0	0
Gross unrealized losses	(12)	(19)
Fair value	468	461
State and Political Subdivisions [Member]
Securities Held-to-Maturity [Abstract]
Amortized cost	1,181	1,182
Gross unrealized gains	2	1
Gross unrealized losses	0	0
Fair value	$ 1,183	$ 1,183