Earnings Per Share - Reconciliation of Numerators and Denominators of Basic and Diluted Earnings Per Computations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator / net income
Income and shares used in basic calculations	$ 255,697	$ 249,104	$ 62,434
Denominator / shares
(Loss) income and shares used in basic calculations (in shares)	84,405	100,437	112,854
(Loss) income and shares used in diluted calculations (in shares)	86,160	102,922	116,534
Income and shares used in basic calculations	$ 255,697	$ 249,104	$ 61,102
Basic earnings per share (in dollars per share)	$ 3.03	$ 2.48	$ 0.54
Diluted earnings per share (in dollars per share)	$ 2.97	$ 2.42	$ 0.52
Restricted awards
Denominator / shares
Effect of dilutive stock based awards (in shares)	876	1,955	3,579
Stock options and SARs
Denominator / shares
Effect of dilutive stock based awards (in shares)	490	316	101
Warrants
Denominator / shares
Effect of dilutive stock based awards (in shares)	389	214	0