Investment Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014 item	Dec. 31, 2013 item
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	42	178
Less than 12 months, Fair Value	$ 42,482	$ 202,228
Less than 12 months, Gross Unrealized Holding Losses	(222)	(4,925)
12 months or more, Number	20	1
12 months or more, Fair Value	25,352	12,607
12 months or more, Gross Unrealized Holding Losses	(565)	(913)
Total, Number	62	179
Total, Fair Value	67,834	214,835
Total, Gross Unrealized Holding Losses	(787)	(5,838)
Municipal bonds
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	35	133
Less than 12 months, Fair Value	18,129	61,524
Less than 12 months, Gross Unrealized Holding Losses	(117)	(1,850)
12 months or more, Number	16
12 months or more, Fair Value	6,510
12 months or more, Gross Unrealized Holding Losses	(56)
Total, Number	51	133
Total, Fair Value	24,639	61,524
Total, Gross Unrealized Holding Losses	(173)	(1,850)
Mortgage-backed securities
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	7	45
Less than 12 months, Fair Value	24,353	140,704
Less than 12 months, Gross Unrealized Holding Losses	(105)	(3,075)
12 months or more, Number	4	1
12 months or more, Fair Value	18,842	12,607
12 months or more, Gross Unrealized Holding Losses	(509)	(913)
Total, Number	11	46
Total, Fair Value	43,195	153,311
Total, Gross Unrealized Holding Losses	$ (614)	$ (3,988)