Schedule II - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Allowance for doubtful accounts [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Valuation Allowances beginning balance $ 860 $ 1,040 $ 315
Additions 979 466 992
Deductions (899) (646) (267)
Valuation Allowances ending balance 940 860 1,040
Deferred income tax valuation allowance [Member]      
Movement in Valuation Allowances and Reserves [Roll Forward]      
Valuation Allowances beginning balance 32,212 12,004 5,653
Additions 23,630 20,208 6,351
Deductions 0 0 0
Valuation Allowances ending balance $ 55,842 $ 32,212 $ 12,004