Net Income per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 61,922	$ 62,092
Less distributed and undistributed earnings allocated to participating securities	197	462
Net Income (Loss) Available to Common Stockholders, Basic	$ 61,725	$ 61,630
Weighted average common shares outstanding basic (in shares)	38,216	38,802
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	623	266
Weighted Average Number of Shares Outstanding, Diluted	38,839	39,068