SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful receivables
Allowance for doubtful receivables
Beginning Balance	$ 1,459,000	$ 1,189,000	$ 88,000
Additions	7,590,000	10,201,000	2,032,000
Reductions	(5,942,000)	(9,931,000)	(931,000)
Ending Balance	3,107,000	1,459,000	1,189,000
Valuation allowance for deferred tax assets
Allowance for doubtful receivables
Beginning Balance	14,180,000	10,804,000	4,764,000
Additions	23,370,000	3,783,000	7,248,000
Reductions	(5,027,000)	(407,000)	(1,208,000)
Ending Balance	32,523,000	14,180,000	$ 10,804,000
As Previously Reported | Allowance for doubtful receivables
Allowance for doubtful receivables
Beginning Balance	0
Additions	14,562,000
Reductions	0
Ending Balance	$ 14,562,000	$ 0