Net Income per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 20,009	$ 25,859	$ 133,952	$ 130,704
Less distributed and undistributed earnings allocated to participating securities	104	284	792	1,546
Net Income (Loss) Available to Common Stockholders, Basic	$ 19,905	$ 25,575	$ 133,160	$ 129,158
Weighted average common shares outstanding basic (in shares)	38,507	40,168	38,625	40,481
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	234	149	193	143
Weighted Average Number of Shares Outstanding, Diluted	38,741	40,317	38,818	40,624