Earnings Per Share - Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 154,352	$ 110,690	$ 84,396	$ 36,760	$ 265,042	$ 121,156
Less: distributed earnings allocated to participating securities	(133)		(121)		(291)	(256)
Less: undistributed earnings allocated to participating securities	(589)		(363)		(1,067)	(465)
Net income attributable to common stockholders (numerator for basic earnings per share)	153,630		83,912		263,684	120,435
Add back: undistributed earnings allocated to participating securities	589		363		1,067	465
Less: undistributed earnings reallocated to participating securities	(569)		(357)		(1,032)	(455)
Numerator for diluted earnings per share under two class method	$ 153,650		$ 83,918		$ 263,719	$ 120,445
Weighted-average common shares outstanding (in shares)	70,291,057		68,057,093		70,044,326	67,775,735
Denominator for diluted earnings per share under two class method (in shares)	72,715,273		69,207,415		72,754,141	69,701,942
Basic Earnings Per Common Share (in dollars per share)	$ 2.19		$ 1.23		$ 3.76	$ 1.78
Diluted Earnings Per Common Share (in dollars per share)	$ 2.11		$ 1.21		$ 3.62	$ 1.73
Add: dilutive effect of stock options
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted-average common shares outstanding, dilutive effect of stock options and performance share units (in shares)	2,424,216		1,150,322		2,394,887	1,614,428
Add: dilutive effect of performance share units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted-average common shares outstanding, dilutive effect of stock options and performance share units (in shares)	0		0		314,928	311,779