Investments (Details 2) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	$ 134,988	$ 773,925
Fair Value, Less than 12 Months	(423)	(33,356)
Gross Unrealized Losses, 12 Months or More	305,449	5,032
Fair Value, 12 Months or More	(8,340)	(189)
Gross Unrealized Losses, Total	440,437	778,957
Fair Value, Total	(8,763)	(33,545)
Government agency and government-sponsored enterprise pass through securities [Member] | Residential Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	954	148,662
Fair Value, Less than 12 Months	(2)	(2,767)
Gross Unrealized Losses, 12 Months or More	42,325	32
Fair Value, 12 Months or More	(443)	(1)
Gross Unrealized Losses, Total	43,279	148,694
Fair Value, Total	(445)	(2,768)
Government agency and government-sponsored enterprise pass through securities | Residential Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	95,351	179,938
Fair Value, Less than 12 Months	(374)	(4,486)
Gross Unrealized Losses, 12 Months or More	42,971	4,383
Fair Value, 12 Months or More	(1,135)	(98)
Gross Unrealized Losses, Total	138,322	184,321
Fair Value, Total	(1,509)	(4,584)
Covered private label collateralized mortgage obligation [Member] | Residential Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	0	1,640
Fair Value, Less than 12 Months	0	(60)
Gross Unrealized Losses, 12 Months or More	1,088	617
Fair Value, 12 Months or More	(100)	(90)
Gross Unrealized Losses, Total	1,088	2,257
Fair Value, Total	(100)	(150)
Collateralized Mortgage Obligations [Member] | Residential Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	6,809
Fair Value, Less than 12 Months	(8)
Gross Unrealized Losses, 12 Months or More	0
Fair Value, 12 Months or More	0
Gross Unrealized Losses, Total	6,809
Fair Value, Total	(8)
Municipal securities
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	9,655	337,208
Fair Value, Less than 12 Months	(10)	(24,273)
Gross Unrealized Losses, 12 Months or More	206,241
Fair Value, 12 Months or More	(6,600)	0
Gross Unrealized Losses, Total	215,896	337,208
Fair Value, Total	(6,610)	(24,273)
Corporate Debt Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	22,219	72,636
Fair Value, Less than 12 Months	(29)	(1,483)
Gross Unrealized Losses, 12 Months or More	2,795	0
Fair Value, 12 Months or More	(38)	0
Gross Unrealized Losses, Total	25,014	72,636
Fair Value, Total	(67)	(1,483)
US Government-sponsored Enterprises Debt Securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	0	9,872
Fair Value, Less than 12 Months	0	(174)
Gross Unrealized Losses, 12 Months or More	0	0
Fair Value, 12 Months or More	0	0
Gross Unrealized Losses, Total	0	9,872
Fair Value, Total	0	(174)
Other securities [Member]
Investment Securities, Available-for-Sale:
Gross Unrealized Losses, Less Than 12 Months	0	23,969
Fair Value, Less than 12 Months	0	(113)
Gross Unrealized Losses, 12 Months or More	10,029	0
Fair Value, 12 Months or More	(24)	0
Gross Unrealized Losses, Total	10,029	23,969
Fair Value, Total	$ (24)	$ (113)