Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts
Balance at beginning of period	$ 11,453	$ 4,217	$ 5,063
Charge to expenses	(2,275)	7,375	1,752
Additions/(deductions)	(5,414)	(139)	(2,598)
Balance at end of period	3,764	11,453	4,217
Valuation Allowance for Deferred Tax Assets [Member]
Balance at beginning of period	713	393	393
Charge to expenses	7,648	320
Balance at end of period	$ 8,361	$ 713	$ 393