Earnings per Share (EPS) - Reconciliation of Net Income and Weighted Average Common Shares Outstanding (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 135,648	$ 149,523
Basic weighted average shares outstanding (in shares)	112,016	97,949
Dilutive effect of nonvested shares (in shares)	362	377
Diluted weighted average shares outstanding (in shares)	112,378	98,326
Basic earnings per share (in dollars per share)	$ 1.21	$ 1.53
Diluted earnings per share (in dollars per share)	$ 1.21	$ 1.52