Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Basic and Diluted Earnings:
Net income	$ 21,317	$ 34,091	$ 21,554	$ 3,953	$ 55,408	$ 25,507
Basic weighted-average shares outstanding (in shares)	32,632		33,016		32,730	33,353
Add: Stock awards (in shares)	167		67		130	92
Diluted weighted-average shares outstanding (in shares)	32,799		33,083		32,860	33,445
Basic earnings per share:
Earnings per common share - basic (in dollars per share)	$ 0.65		$ 0.65		$ 1.69	$ 0.76
Diluted earnings per share:
Earnings per common share - diluted (in dollars per share)	$ 0.65		$ 0.65		$ 1.69	$ 0.76
Antidilutive securities excluded from calculating earnings
Number of antidilutive options (in shares)	3		860		231	813