AFS Securities (Amortized cost and fair value of AFS securities, with gross unrealized gains and losses) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 585,579	$ 654,348
Gross Unrealized Gains	17,423	9,816
Gross Unrealized Losses	539	4,028
AFS securities	602,463	660,136
Government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,362	24,407
Gross Unrealized Gains	9	13
Gross Unrealized Losses	0	75
AFS securities	10,371	24,345
States and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	215,874	224,752
Gross Unrealized Gains	10,187	7,511
Gross Unrealized Losses	14	46
AFS securities	226,047	232,217
Auction rate money market preferred [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,200	3,200
Gross Unrealized Gains	0	0
Gross Unrealized Losses	81	334
AFS securities	3,119	2,866
Preferred stocks [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,800	3,800
Gross Unrealized Gains	0	0
Gross Unrealized Losses	394	501
AFS securities	3,406	3,299
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	235,480	264,109
Gross Unrealized Gains	4,715	1,156
Gross Unrealized Losses	0	1,881
AFS securities	240,195	263,384
Collateralized mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	116,863	134,080
Gross Unrealized Gains	2,512	1,136
Gross Unrealized Losses	50	1,191
AFS securities	$ 119,325	$ 134,025