Stockholders' Equity and EPS - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Related tax (benefit) expense	$ (71,656)	[1]	$ (65,047)	$ (123,061)	[1]	$ (118,631)
Net income available to common stockholders	123,193	[1]	92,964	224,676	[1]	172,138
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 losses (gains) included in net income	123		(12,328)	(485)		(11,582)
Related tax (benefit) expense	(50)		5,017	198		4,713
Net income available to common stockholders	$ 73		$ (7,311)	$ (287)		$ (6,869)

[1] Included in income tax expense, net income available to common shareholders, earnings per common share-basic and earnings for common share-diluted, for the three and six months ended June 30, 2017, are tax benefits recognized associated with the adoption of Accounting Standards Update (“ASU”) 2016-09, Improvements to Employee Share-Based Payment Accounting in the first quarter of 2017. This guidance was adopted on a prospective basis with no change to prior period amounts.