Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Option to extend lease	options to extend the leases for up to 30 years
Option to terminate lease	options to terminate the leases within one year
Operating leases primarly for equipment and land	$ 1.7
Lease expenses for operating lease		$ 122.5
Total royalties		$ 52.5
Minimum
Lessee Lease Description [Line Items]
Financing lease term	1 year
Estimated incremental percentage on interest rate	3.50%
Lease terms	2 years
Maximum
Lessee Lease Description [Line Items]
Financing lease term	54 years
Estimated incremental percentage on interest rate	5.50%
Lease terms	10 years