Components of Lease Expense (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease cost		$ 18,260	$ 36,339
Variable and short term lease cost	[1]	8,275	16,321
Total lease cost		26,535	52,660
Finance lease cost:
Amortization of right-of-use-assets		482	963
Interest on lease liabilities		474	958
Total finance lease cost		$ 956	$ 1,921

[1] Includes equipment, month-to-month and leases with a maturity of less than 12 months.