Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			1 Months Ended		3 Months Ended								12 Months Ended
	Dec. 31, 2020	May 09, 2018	Dec. 31, 2020	Oct. 31, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 09, 2020
Equity [Abstract]
Common stock issued (in shares)			13.0	9.6
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01	$ 0.01	$ 0.01				$ 0.01				$ 0.01	$ 0.01		$ 0.01
Common stock, price per share (in dollars per share)	$ 76.65		$ 76.65	$ 60.00	76.65								76.65
Proceeds from sale of stock	$ 868,600		$ 994,600	$ 557,400
Common stock dividends declared (in dollars per share)					$ 0	$ 0	$ 0	$ 0.78	0.78	$ 0.78	$ 0.70	$ 0.70	$ 0.78	$ 2.96	$ 2.60
Common stock, dividends paid (in dollars per share)							$ 0.78	$ 0.78	$ 0.78	$ 0.70	$ 0.70
Term of stock repurchase program		24 months
Treasury stock, shares acquired (in shares)														0.9
Total cost of treasury stock, acquired during the period													$ 0	$ 99,582	$ 575,039