SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts, sales returns and cash discounts
Changes to valuation allowance
Balance at beginning of period	$ 1,248	$ 1,704	$ 2,926
Charged to cost and expenses	7,389	8,407	2,652
Deductions	(7,516)	(8,863)	(3,874)
Balance at end of period	1,121	1,248	1,704
Allowance on Deferred Tax Assets and Unrecognized Tax Benefits
Changes to valuation allowance
Balance at beginning of period	17,846	19,786	24,130
Charged to cost and expenses	8,240	(1,940)	(4,344)
Balance at end of period	$ 26,086	$ 17,846	$ 19,786