SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts receivable and revenue adjustments
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	$ 5,731	$ 4,533	$ 5,249
Additions, Charged to Costs and Expenses	998	1,941	2,065
Additions, Charged to Other Accounts	(144)	2,363	39
Deductions	1,760	3,106	2,820
Balance at End of Period	4,825	5,731	4,533
Allowance for other accounts receivable
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	1,701	1,422	1,334
Additions, Charged to Costs and Expenses	(672)	279	88
Balance at End of Period	1,029	1,701	1,422
Allowance for deferred tax assets
Changes in valuation and qualifying accounts and reserves
Balance at Beginning of Period	332	1,028	2,511
Additions, Charged to Costs and Expenses	22
Deductions		696	1,483
Balance at End of Period	$ 354	$ 332	$ 1,028