Investment Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014 item	Dec. 31, 2013 item	Mar. 31, 2013 item
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	106	178	125
Less than 12 months, Fair Value	$ 130,064	$ 202,228	$ 74,031
Less than 12 months, Gross Unrealized Holding Losses	(1,898)	(4,925)	(737)
12 months or more, Number	13	1	27
12 months or more, Fair Value	17,358	12,607	1,031
12 months or more, Gross Unrealized Holding Losses	(856)	(913)	(217)
Total, Number	119	179	152
Total, Fair Value	147,422	214,835	75,062
Total, Gross Unrealized Holding Losses	(2,754)	(5,838)	(954)
Municipal bonds
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	74	133	122
Less than 12 months, Fair Value	36,765	61,524	53,773
Less than 12 months, Gross Unrealized Holding Losses	(476)	(1,850)	(387)
12 months or more, Number	12
12 months or more, Fair Value	5,046
12 months or more, Gross Unrealized Holding Losses	(110)
Total, Number	86	133	122
Total, Fair Value	41,811	61,524	53,773
Total, Gross Unrealized Holding Losses	(586)	(1,850)	(387)
Mortgage-backed securities
Investment Securities Available-for-Sale, Total temporary impaired securities
Less than 12 months, Number	32	45	3
Less than 12 months, Fair Value	93,299	140,704	20,258
Less than 12 months, Gross Unrealized Holding Losses	(1,422)	(3,075)	(350)
12 months or more, Number	1	1	27
12 months or more, Fair Value	12,312	12,607	1,031
12 months or more, Gross Unrealized Holding Losses	(746)	(913)	(217)
Total, Number	33	46	30
Total, Fair Value	105,611	153,311	21,289
Total, Gross Unrealized Holding Losses	$ (2,168)	$ (3,988)	$ (567)