Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average warrant strike price (in USD per share)		$ 94.62
Numerator:
Net income	$ 181,222	$ 110,348
Denominator:
Denominator for basic net earnings per share - weighted-average shares outstanding (shares)	124,737,000	131,483,000
Effect of dilutive employee stock awards (shares)	2,840,000	2,834,000
Effect of dilutive Convertible Notes (shares)	0	5,016,000
Effect of dilutive warrants (shares)	0	1,692,000
Denominator for net diluted earnings per share - weighted-average shares outstanding (shares)	127,577,000	141,025,000
Basic earnings per share (in dollars per share)	$ 1.45	$ 0.84
Diluted earnings per share (in dollars per share)	$ 1.42	$ 0.78
Senior Notes Due 2019 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stated interest rate percentage			0.50%