Stockholders' Equity and EPS - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Related tax expense (benefit)	[1]	$ (54,974)	$ (35,928)	$ (118,040)	[2]	$ (97,224)
Net income available to common stockholders	[1]	86,143	50,953	174,659	[2]	141,903
Reclassification out of Accumulated Other Comprehensive Income | Gains on investment securities, net
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification adjustment for (gains) losses included in net income		(141)	16,480	(2,737)		16,421
Related tax expense (benefit)		57	(6,653)	1,105		(6,630)
Net income available to common stockholders		$ (84)	$ 9,827	$ (1,632)		$ 9,791

[1] Prior period amounts have been revised to reflect the retrospective application of new accounting guidance adopted in the first quarter of 2015 related to our investments in qualified affordable housing projects (ASU 2014-01). See Note 1— "Basis of Presentation" of the "Notes to Interim Consolidated Financial Statements" under Part I, Item 1 in this report.

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