Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic and Diluted Earnings:
Net income	$ 29,306	$ 21,317	$ 34,091	$ 27,074	$ 21,554	$ 3,953	$ 84,714	$ 52,581
Basic weighted-average shares outstanding (in shares)	32,465			33,047			32,641	33,250
Add: Stock awards (in shares)	91			51			118	81
Diluted weighted-average shares outstanding (in shares)	32,556			33,098			32,759	33,331
Basic earnings per share:
Earnings per common share - basic (in dollars per share)	$ 0.90			$ 0.82			$ 2.60	$ 1.58
Diluted earnings per share:
Earnings per common share - diluted (in dollars per share)	$ 0.90			$ 0.82			$ 2.59	$ 1.58
Antidilutive securities excluded from calculating earnings
Number of antidilutive options (in shares)	462			835			288	811