Long-Term Debt - Outstanding Debt Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total debt	$ 275,971	$ 372,394
Less: debt discount, net of accretion		(2,735)
Total debt, net of unaccreted discount	275,971	369,659
Less current portion of long-term debt	(384)	(43,690)
Total long-term debt, net of unaccreted discount	275,587	325,969
2015 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total debt	262,915	313,620
Convertible Notes [Member]
Debt Instrument [Line Items]
Total debt		45,656
Mortgages and Other [Member]
Debt Instrument [Line Items]
Total debt	12,833	12,755
Capital Leases [Member]
Debt Instrument [Line Items]
Total debt	$ 223	$ 363