Revenues - Impact of Adopting New Revenue Recognition Standard (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts and notes receivable, net	$ 130,579	$ 84,979	$ 56,064
Contract assets, net	13,960	5,512	0
Prepaid expenses and other current assets	30,391	23,699	21,696
Total current assets	558,155	114,190	205,192
Deferred income tax assets, net	19,347	10,597	15,755
Long-term notes receivable	40,230	23,900	36,877
Other assets	22,999	20,689	15,366
Total assets	719,540	169,376	338,112
Accrued liabilities	41,092	26,014	23,502
Contract with customer, liability, current	107,016	71,264	70,401
Total current liabilities	166,011	97,278	107,950
Deferred revenue, net of current portion	74,417	56,130	54,881
Total liabilities	252,216	153,408	170,668
Retained earnings	171,383	142,179	123,185
Total stockholders’ equity	467,324	142,179	167,444	$ 150,888	$ 157,004
Total liabilities and stockholders’ equity	719,540	295,587	338,112
December 31, 2017 (As reported)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts and notes receivable, net			56,064
Contract assets, net			0
Prepaid expenses and other current assets			21,696
Total current assets			77,760
Deferred income tax assets, net			15,755
Long-term notes receivable			36,877
Other assets			15,366
Total assets			145,758
Accrued liabilities			23,502
Contract with customer, liability, current			70,401
Total current liabilities			93,903
Deferred revenue, net of current portion			54,881
Total liabilities			148,784
Retained earnings			123,185
Total stockholders’ equity			123,185
Total liabilities and stockholders’ equity			$ 271,969
Impact of Adoption of Topic 606 on Opening Balance Sheet | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts and notes receivable, net		28,915
Contract assets, net		5,512
Prepaid expenses and other current assets		2,003
Total current assets		36,430
Deferred income tax assets, net		(5,158)
Long-term notes receivable		(12,977)
Other assets		5,323
Total assets		23,618
Accrued liabilities		2,512
Contract with customer, liability, current		863
Total current liabilities		3,375
Deferred revenue, net of current portion		1,249
Total liabilities		4,624
Retained earnings	$ 19,000	18,994
Total stockholders’ equity		18,994
Total liabilities and stockholders’ equity		$ 23,618