Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets - Gross carrying amounts included in goodwill and intangible assets related to accumulated amortization and weighted average amortization periods (Details)

v3.8.0.1
Goodwill and Intangible Assets - Gross carrying amounts included in goodwill and intangible assets related to accumulated amortization and weighted average amortization periods (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Schedule Of Intangible Assets [Line Items]    
Gross Carrying Amount $ 124,028 $ 124,028
Accumulated Amortization (69,127) (37,895)
Net Carrying Amount 54,901 86,133
License    
Schedule Of Intangible Assets [Line Items]    
Indefinite-lived   4,427
Customer relationships    
Schedule Of Intangible Assets [Line Items]    
Gross Carrying Amount 120,000 120,000
Accumulated Amortization (66,866) (36,593)
Net Carrying Amount $ 53,134 $ 83,407
Weighted - Average Amortization Period (Years) 6 years 6 years
License    
Schedule Of Intangible Assets [Line Items]    
Gross Carrying Amount $ 3,368 $ 3,368
Accumulated Amortization (1,601) (807)
Net Carrying Amount $ 1,767 $ 2,561
Weighted - Average Amortization Period (Years) 5 years 7 months 6 days 5 years 7 months 6 days
Non-compete agreements    
Schedule Of Intangible Assets [Line Items]    
Gross Carrying Amount $ 660 $ 660
Accumulated Amortization (660) (495)
Net Carrying Amount $ 0 $ 165
Weighted - Average Amortization Period (Years) 1 year 1 year