Net Income per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 51,851	$ 28,556	$ 113,943	$ 104,845
Less distributed and undistributed earnings allocated to participating securities	276	309	724	1,183
Net Income (Loss) Available to Common Stockholders, Basic	$ 51,575	$ 28,247	$ 113,219	$ 103,662
Weighted average common shares outstanding basic (in shares)	38,567	40,771	38,684	40,640
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	79	145	173	140
Weighted Average Number of Shares Outstanding, Diluted	38,646	40,916	38,857	40,780