Securities, Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Available-for-sale, amortized cost [Abstract]
Due in one year or less	$ 43,386
Due after one through five years	189,343
Due after five through ten years	86,596
Due after ten years	46,774
U.S. government sponsored agency mortgage-backed securities	202,282
Amortized cost	568,381	$ 613,395
CRA investment funds	25,000
Amortized cost	593,381	638,395
Available-for-sale, fair value [Abstract]
Due in one year or less	43,403
Due after one through five years	189,131
Due after five through ten years	88,577
Due after ten years	47,498
U.S. government sponsored agency mortgage-backed securities	201,576
Total debt securities	570,185	615,297
CRA investment funds	24,751
Total securities	594,936
Held-to-maturity, amortized cost [Abstract]
Due in one year or less	0
Due after one through five years	1,181
Due after five through ten years	480
Due after ten years	0
U.S. government sponsored agency mortgage-backed securities	0
Amortized cost	1,661	1,662
CRA investment funds	0
Total securities	1,661
Held-to-maturity, fair value [Abstract]
Due in one year or less	0
Due after one through five years	1,183
Due after five through ten years	468
Due after ten years	0
U.S. government sponsored agency mortgage-backed securities	0
Total debt securities	1,651	1,644
CRA investment funds	0
Total securities	1,651
Net loss realized on sales and calls of AFS securities	(106)	(211)	$ (45)
Realized pre-tax gain on sale of securities	839
Realized pre-tax loss on sale of securities	945
Securities pledged as collateral to secure public deposit and for other purposes	228,200	267,100
Amortized cost of securities sold under agreements to repurchase	$ 285,500	$ 280,900
Percentage of total investment with unrealized losses	62.80%	44.10%
CRA Investments Funds [Member]
Schedule of Available for Sale Securities [Line Items]
Severity of impairment in percentage of fair value less than cost	1.00%