Other Long Term Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Long Term Liabilities [Line Items]
Intangible lease liability	$ 6,191	$ 6,578
Accrued workers' compensation	19,518	14,726
Accrued deferred compensation	10,208	9,850
Lease financing obligation	15,530	18,832
Other	1,583	1,856
Other liabilities	$ 53,030	$ 51,842