Stockholders' Equity and EPS - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017		Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Related tax expense (benefit)	$ (51,405)	[1]	$ (53,584)
Net income available to common stockholders	101,483	[1]	79,174
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	(608)		746
Related tax expense (benefit)	248		(304)
Net income available to common stockholders	$ (360)		$ 442

[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 months ended March 31, 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.