Shareholders' Equity (Details) - USD ($)		3 Months Ended				6 Months Ended
	Feb. 01, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Oct. 30, 2018
Distribution Made to Limited Partner [Line Items]
Repurchase aggregate cost			$ 193,900,000		$ 27,900,000
October 2018 Stock Repurchase Program
Distribution Made to Limited Partner [Line Items]
Authorized stock repurchase amount								$ 300,000,000.0
Remaining unused authorization for stock repurchase program		$ 147,100,000				$ 147,100,000
Repurchase of common stock (in shares)		0		0		0	235,590
Repurchase aggregate cost							$ 27,900,000
Stock Repurchase Agreement with The Duchossois Group, Inc Affiliate
Distribution Made to Limited Partner [Line Items]
Repurchase of common stock (in shares)	1,000,000
Repurchase aggregate cost	$ 193,900,000
Price per common stock (in dollars per share)	$ 193.94