Related Party Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Nov. 19, 2015	Dec. 31, 2016	Dec. 31, 2014
Related Party Transaction [Line Items]
Stock repurchased during period (in shares)		211,790	691,000
Stock repurchased and retired during period, value		$ 27.6	$ 61.6
Number of days for average common stock repurchase price	20 days
The Duchossois Group
Related Party Transaction [Line Items]
Stock repurchased during period (in shares)	945,000
Stock repurchased and retired during period, value	$ 138.1
Repurchase price (in dollars per share)	$ 146.13