Computation of Basic and Diluted Net Income Per Share Attributable to Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income	$ 1,518,131	$ 71,848
Weighted average common shares outstanding, basic	78,592	79,860
Dilutive effect of potential common stock	436	827
Total shares, diluted	79,028	80,687
Net income per share, basic	$ 19.32	$ 0.90
Net income per share, diluted	$ 19.21	$ 0.89
Retained Earnings
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income	$ 1,518,131	$ 71,848