Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets-
Accounts receivable and allowance for doubtful accounts	$ 1,660	$ 1,445
Stock-based compensation	2,561	2,538
Accrued liabilities and expenses	25,569	19,449
Lease liabilities	20,873
Net operating loss carryforwards	2,750	3,242
Intangible assets	7,988	5,071
Other	525	550
Subtotal	61,926	32,295
Valuation allowances	(369)	(648)
Total deferred tax assets	61,557	31,647
Deferred tax liabilities-
Property and equipment	(11,286)	(10,488)
Lease right-of-use asset	(20,873)
Long-term contracts	(876)	(688)
Goodwill	(6,020)	(3,864)
Other	(2,004)	(360)
Total deferred tax liabilities	(41,059)	(15,400)
Net deferred tax assets	20,498	16,247
Deferred income tax assets
Deferred tax assets	21,923	17,634
Deferred income tax liabilities
Deferred tax liabilities	$ 1,425	$ 1,387