Commitments and Contingencies - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2017
Operating Leased Assets [Line Items]
Operating lease costs	$ 64,200,000
Rent expense		$ 46,800,000	$ 42,800,000
Operating lease liabilities, payments	44,100,000
Right-of-use assets obtained in exchange for operating lease liabilities	$ 115,000,000.0
Weighted-average remaining lease term	9 years 8 months 12 days
Weighted-average discount rate	3.70%
Undiscounted cash flows	$ 445,700,000
Unrecognized tax benefits	6,100,000
Letters of credit	22,900,000
2022 Notes
Operating Leased Assets [Line Items]
Principal	$ 782,491,000	$ 782,500,000		$ 782,500,000
Minimum
Operating Leased Assets [Line Items]
Operating lease terms	3 years
Maximum
Operating Leased Assets [Line Items]
Operating lease terms	15 years