Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Elements [Abstract]
Accrued property and equipment purchases	$ 501	$ 83
Increase to goodwill from measurement period adjustments related to business combinations	4	1,766
Decrease in accrued financing costs related to 2021 Notes	0	196
Consideration for asset acquisitions or business combinations	500	0
Settlement of escrow related to asset acquisition	2,519	0
Settlement of indemnification asset	1,004	0
Tax benefit related to Accordion intangible technology	0	2,042
Effects of Class B Exchanges
Decrease in deferred tax liability as a result of securities offerings	25,334	168,883
Decrease in deferred tax liability as a result of securities offerings	$ 908	$ 12,992