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
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 1,526	$ 1,328	$ 1,362
Additions Charged to Costs and Expenses	1,402	1,426	488
Deductions Returns and Write-Offs	(1,253)	(1,228)	(522)
Balance at End of Year	1,675	1,526	1,328
Income tax valuation allowance
Valuation and Qualifying Accounts
Balance at Beginning of Year	2,576	988	1,146
Additions Charged to Costs and Expenses	183		988
Charged to Other Accounts		1,616
Deductions Returns and Write-Offs	(77)	(28)	(1,146)
Balance at End of Year	$ 2,682	$ 2,576	$ 988