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 receivable
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	$ 1,499	$ 799	$ 930
Additions	(346)	724	(129)
Deductions	(129)	(24)	(2)
Balance at End of Year	1,024	1,499	799
Allowance for doubtful employee advances and miscellaneous receivables
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	292	500	681
Additions	(48)	1,665	2,184
Deductions	(68)	(1,873)	(2,365)
Balance at End of Year	176	292	500
Deferred tax valuation allowance
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	34,776	50,114	45,565
Additions	(3,179)	(15,338)	4,549
Deductions	0	0	0
Balance at End of Year	$ 31,597	$ 34,776	$ 50,114