Net Income per Share (Details) - USD ($) 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 [Abstract]
Net income	$ 25,154	$ 51,851	$ 87,076	$ 113,943
Less distributed and undistributed earnings allocated to participating securities	37	276	193	724
Net Income (Loss) Available to Common Stockholders, Basic	$ 25,117	$ 51,575	$ 86,883	$ 113,219
Weighted average common shares outstanding basic (in shares)	38,591	38,567	38,410	38,684
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	232	79	427	173
Weighted Average Number of Shares Outstanding, Diluted	38,823	38,646	38,837	38,857