Income Taxes - Schedule of Components of Company's Net Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued liabilities	$ 17,563	$ 19,393
Depreciation and amortization	980	1,787
Foreign operating loss carryforward	246	246
U.S. federal tax credits and carryforward	8,152	0
U.S. state and local tax credits and carryforward	1,799	385
Other	667	1,209
Valuation allowance	(2,394)	(987)
Total deferred tax assets	27,013	22,033
Deferred tax liabilities:
Depreciation and amortization	(20,117)	(33,436)
Prepaid expenses	(572)	(310)
Other	(541)	(220)
Total deferred tax liabilities	(21,230)	(33,966)
Net deferred tax asset	$ 5,783
Net deferred tax (liability)		$ (11,933)