Earnings Per Share - Computation Of Basic And Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income	$ 22,337	$ 55,463
Income allocated to participating securities	(110)	(317)
Net income available to common shareholders	$ 22,227	$ 55,146
Denominator:
Weighted average shares of common stock outstanding – basic (in shares)	55,263	55,343
Basic earnings per share (in dollars per share)	$ 0.40	$ 1.00
Numerator:
Income allocated to participating securities	$ (110)	$ (316)
Net income available to common shareholders	$ 22,227	$ 55,147
Denominator:
Weighted average shares of common stock outstanding – basic (in shares)	55,263	55,343
Diluted effect of stock options and PVRSUs (in shares)	398	334
Weighted average shares of common stock outstanding – diluted (in shares)	55,661	55,677
Diluted earnings per share (in dollars per share)	$ 0.40	$ 0.99