Securities - Summary of Held-to-Maturity and Available-for-Sale Securities Having Continuous Unrealized Loss Position (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	$ 115,915	[1]	$ 305,241	[2]
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value	20,257		132,805
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss	229		6,076
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value	65,806		5,856
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	3,538		1,674
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	86,063		138,661
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	3,767		7,750
Debt Securities
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	491,330		5,479,134
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	2,025		296,255
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	2,870,347		37,181
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	113,890		8,986
Temporarily Impaired Held-to-Maturity, Total Fair Value	3,361,677		5,516,315
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	115,915		305,241
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value	11,360		56,919
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss	58		1,881
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value	51,022		5,856
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	3,029		1,674
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	62,382		62,775
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	3,087		3,555
Debt Securities | GSE debentures
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	129,894		2,777,417
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	75		208,506
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	2,150,525
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	86,785
Temporarily Impaired Held-to-Maturity, Total Fair Value	2,280,419		2,777,417
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	86,860		208,506
Debt Securities | GSE certificates
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	269,519		1,684,793
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	1,606		61,280
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	493,289
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	12,286
Temporarily Impaired Held-to-Maturity, Total Fair Value	762,808		1,684,793
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	13,892		61,280
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value			110
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss			1
Temporarily Impaired Available-for-Sale Securities, Total Fair Value			110
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss			1
Debt Securities | GSE CMOs
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	52,932		936,691
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	93		22,520
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	147,839
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	3,259
Temporarily Impaired Held-to-Maturity, Total Fair Value	200,771		936,691
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	3,352		22,520
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value			44,725
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss			1,861
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value	45,456
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	1,167
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	45,456		44,725
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	1,167		1,861
Debt Securities | Municipal bonds
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	14,078		55,333
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	158		3,849
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	42,456
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	1,617
Temporarily Impaired Held-to-Maturity, Total Fair Value	56,534		55,333
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	1,775		3,849
Debt Securities | Capital trust notes
Schedule of Investments [Line Items]
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Fair Value	24,907		24,900
Temporarily Impaired Held-to-Maturity, Less than Twelve Months Unrealized Loss	93		100
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Fair Value	36,238		37,181
Temporarily Impaired Held-to-Maturity, Twelve Months or Longer Unrealized Loss	9,943		8,986
Temporarily Impaired Held-to-Maturity, Total Fair Value	61,145		62,081
Temporarily Impaired Held-to-Maturity, Total Unrealized Loss	10,036		9,086
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value	1,993		1,992
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss	8		8
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value	5,566		5,746
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	1,862		1,673
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	7,559		7,738
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	1,870		1,681
Debt Securities | Private label CMOs
Schedule of Investments [Line Items]
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value	9,367		10,202
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss	50		12
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	9,367		10,202
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	50		12
Equity securities
Schedule of Investments [Line Items]
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Fair Value	8,897		75,886
Temporarily Impaired Available-for-Sale Securities, Less than Twelve Months Unrealized Loss	171		4,195
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Fair Value	14,784
Temporarily Impaired Available-for-Sale Securities, Twelve Months or Longer Unrealized Loss	509
Temporarily Impaired Available-for-Sale Securities, Total Fair Value	23,681		75,886
Temporarily Impaired Available-for-Sale Securities, Total Unrealized Loss	$ 680		$ 4,195

[1] Held-to-maturity securities are reported at a carrying amount equal to amortized cost less the non-credit portion of OTTI recorded in AOCL. At September 30, 2014, the non-credit portion of OTTI recorded in AOCL was $8.9 million (before taxes).

[2] Held-to-maturity securities are reported at a carrying amount equal to amortized cost less the non-credit portion of OTTI recorded in AOCL. At December 31, 2013, the non-credit portion of OTTI recorded in AOCL was $9.2 million (before taxes).