Investment Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015 item	Dec. 31, 2014 item	Mar. 31, 2014 item
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	58	42	106
Less than 12 months, Fair Value	$ 42,675	$ 42,482	$ 130,064
Less than 12 months, Gross Unrealized Holding Losses	(245)	(222)	(1,898)
12 months or more, Number	6	20	13
12 months or more, Fair Value	16,184	25,352	17,358
12 months or more, Gross Unrealized Holding Losses	(387)	(565)	(856)
Total, Number	64	62	119
Total, Fair Value	58,859	67,834	147,422
Total, Gross Unrealized Holding Losses	(632)	(787)	(2,754)
Municipal bonds
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	48	35	74
Less than 12 months, Fair Value	20,818	18,129	36,765
Less than 12 months, Gross Unrealized Holding Losses	(179)	(117)	(476)
12 months or more, Number	3	16	12
12 months or more, Fair Value	1,073	6,510	5,046
12 months or more, Gross Unrealized Holding Losses	(13)	(56)	(110)
Total, Number	51	51	86
Total, Fair Value	21,891	24,639	41,811
Total, Gross Unrealized Holding Losses	(192)	(173)	(586)
Mortgage-backed securities
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	10	7	32
Less than 12 months, Fair Value	21,857	24,353	93,299
Less than 12 months, Gross Unrealized Holding Losses	(66)	(105)	(1,422)
12 months or more, Number	3	4	1
12 months or more, Fair Value	15,111	18,842	12,312
12 months or more, Gross Unrealized Holding Losses	(374)	(509)	(746)
Total, Number	13	11	33
Total, Fair Value	36,968	43,195	105,611
Total, Gross Unrealized Holding Losses	$ (440)	$ (614)	$ (2,168)