Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Provisions for doubtful accounts	$ 1,304	$ 2,104	$ 1,465
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	5,500	5,700	4,800
Provisions for doubtful accounts	1,304	2,104	1,465
Deductions - returns and write-offs	1,604	2,304	565
Balance at end of year	$ 5,200	$ 5,500	$ 5,700