Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure
Balance at beginning of year		$ 3,615
Balance at end of year		3,108	$ 3,615
Allowance for Doubtful Accounts and Returns
Valuation and Qualifying Accounts Disclosure
Balance at beginning of year		3,615	3,936	$ 4,526
Charged to costs and expenses		561	1,087	999
Reclassification	[1]	0	172	0
Charged to other accounts	[2]	(19)	(159)	(319)
Deductions	[3]	(1,049)	(1,421)	(1,270)
Balance at end of year		3,108	3,615	3,936
Inventory Reserves
Valuation and Qualifying Accounts Disclosure
Balance at beginning of year		3,540	3,272	3,250
Charged to costs and expenses		1,455	1,728	622
Charged to other accounts	[2]	(50)	(160)	(194)
Deductions	[4]	(1,301)	(1,300)	(406)
Balance at end of year		3,644	3,540	3,272
Valuation Allowance for Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure
Balance at beginning of year		5,884	5,699	7,243
Charged to costs and expenses		1,295	734	(636)
Charged to other accounts	[2]	(314)	(549)	(908)
Balance at end of year		$ 6,865	$ 5,884	$ 5,699

[1] Includes amount reclassified from Other Current Liabilities to Allowance for Doubtful Accounts to properly classify a customer's open receivables balance.

[2] Primarily includes impact from foreign currency fluctuations

[3] Includes accounts determined to be uncollectible and charged against reserves, net of collections on accounts previously charged against reserves.

[4] Includes inventory identified as excess, slow moving or obsolete and charged against reserves.