Related-Party Transactions - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Feb. 10, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
PE Shay Holdings, LLC
Related Party Transaction [Line Items]
Liability for estimated payment to platinum stockholder		$ 4.7
Affiliated Entity | Advisory Services
Related Party Transaction [Line Items]
Related party transaction expenses	$ 15.0	$ 15.8	$ 5.1	$ 5.0
Affiliated Entity | Advisory Services | Selling, General and Administrative Expenses
Related Party Transaction [Line Items]
Related party transaction expenses	$ 0.8