Earnings per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Net income	$ 20,875	$ 2,085	$ 53,478	$ 2,923
Net income allocated to unvested restricted stock awards	0	(3)	(30)	0
Net income allocated to common shares	$ 20,875	$ 2,082	$ 53,448	$ 2,923
Weighted average shares outstanding	29,390	29,187	29,359	29,237
Average unvested restricted stock awards	0	(38)	(16)	(53)
Denominator for basic earnings per share—weighted-average shares outstanding	29,390	29,149	29,343	29,184
Effect of dilutive securities—employee stock options and restricted stock units	140	15	136	35
Denominator for diluted earnings per share—adjusted weighted-average shares outstanding	29,530	29,164	29,479	29,219
Basic earnings per share	$ 0.71	$ 0.07	$ 1.82	$ 0.10
Diluted earnings per share	$ 0.71	$ 0.07	$ 1.81	$ 0.10
Average antidilutive options and restricted stock units excluded from computation of diluted earnings per share	283	705	287	451