Schedule II Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Activity of the allowance for doubtful accounts
Balance at Beginning of Year	$ 531	$ 596	$ 623
Additions Charged to Expense	520	290	400
Deductions	(277)	(355)	(427)
Balance at End of Year	$ 774	$ 531	$ 596