Components of Lease Expense (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 18,079
Variable and short term lease cost	8,046	[1]
Total lease cost	26,125
Finance lease cost:
Amortization of right-of-use-assets	481
Interest on lease liabilities	484
Total finance lease cost	$ 965

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