Investment Securities - Unrealized Loss Position (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014 position	Dec. 31, 2013 position
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 549,482	$ 684,499
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	112,421	128,670
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	(313)	(557)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(12,452)	(15,430)
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	37	64
Investment Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions In Loss Position Greater than Twelve Months	9	7
Available-for-Sale Securities Gross Unrealized Losses	12,765	15,987
Available-for-sale securities in a loss position for more than 12 months, qualitative disclosure, percent of amortized cost	90.00%
Standard & Poor's, A- Rating [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	2	2
Standard & Poor's, BBB+ Rating [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		1
Floating Interest Rate [Member] | Floating rate auction-rate certificates backed by Government guaranteed student loans
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	40,773	65,285
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(5,827)	(8,815)
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	5,826	8,815
Floating Interest Rate [Member] | Asset-backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	25,703	50,129
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,988	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	(23)	(59)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(1)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	24	59
Floating Interest Rate [Member] | Corporate Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		19,982
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses		(18)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	0	18
Floating Interest Rate [Member] | Government/GSE Guaranteed Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	149,196	161,960
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	6,275	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	(269)	(435)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(9)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	279	435
Floating Interest Rate [Member] | GSE Subordinated Debt [Member}
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	63,385	63,385
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	(6,615)	(6,615)
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	6,615	6,615
Floating Interest Rate [Member] | Taxable Municipal Bonds [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses		3
Floating Interest Rate [Member] | US Treasury Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	0
Fixed Interest Rate [Member] | Corporate Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		10,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses		(4)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	0	4
Fixed Interest Rate [Member] | Government/GSE Guaranteed Mortgage Backed Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	0	0
Fixed Interest Rate [Member] | Taxable Municipal Bonds [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		8,041
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses		(3)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	0
Fixed Interest Rate [Member] | Preferred Stock [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	78,500
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	(17)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	17	0
Fixed Interest Rate [Member] | Senior Agency Debt Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		316,273
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses		(30)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses		30
Fixed Interest Rate [Member] | US Treasury Securities [Member]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	296,083	118,056
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract]
Available-for-Sale Continuous Unrealized Loss Position Less than 12 Months, Aggregate Losses	(4)	(8)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-Sale Securities Gross Unrealized Losses	$ 4	$ 8