Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic EPS [Abstract]
Net income	$ 104,388	$ 121,021	$ 112,566
Weighted average shares, basic (in shares)	43,693	43,815	43,701
Basic EPS (in dollars per share)	$ 2.39	$ 2.76	$ 2.58
Diluted earnings per share [Abstract]
Net income	$ 104,388	$ 121,021	$ 112,566
Dilutive effect of stock based compensation (in shares)	296	309	319
Weighted average shares, diluted (in shares)	43,989	44,124	44,020
Diluted EPS (in dollars per share)	$ 2.37	$ 2.74	$ 2.56