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 receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 2,243	$ 1,996	$ 1,693
Additions, Charge (Credit) to Costs and Expenses	(1,311)	253	303
Deductions, Credit to the respective receivable	(2)	(6)	0
Balance at End of Year	930	2,243	1,996
Allowance for doubtful employee advances and miscellaneous receivables [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	692	402	538
Additions, Charge (Credit) to Costs and Expenses	1,294	1,125	1,176
Deductions, Credit to the respective receivable	(1,305)	(835)	(1,312)
Balance at End of Year	681	692	402
Deferred tax valuation allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	52,002	48,453	48,489
Additions, Charge (Credit) to Costs and Expenses	(6,437)	3,549	(36)
Deductions, Credit to the respective receivable	0	0	0
Balance at End of Year	$ 45,565	$ 52,002	$ 48,453