Summary of Significant Accounting Policies - Net Income per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Common stock excluded from calculation of EPS (in shares)	33	41	43
Computation of Basic and Diluted Net Income Per Common Share [Abstract]
Net income	$ 327,388	$ 70,665	$ 113,988
Net income - diluted	$ 327,388	$ 70,665	$ 113,988
Net income per common share - basic (in dollars per share)	$ 6.87	$ 1.49	$ 2.44
Net income per common share - diluted (in dollars per share)	$ 6.81	$ 1.48	$ 2.40
Weighted average common shares outstanding - basic (in shares)	47,685	47,424	46,704
Plus dilutive effect of potential common shares (in shares)	360	266	889
Weighted average common shares outstanding - diluted (in shares)	48,045	47,690	47,593