Schedule II - Valuation And Qualifying Accounts And Reserves Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 5,199	$ 5,039	$ 5,342
Additions charged to costs and expenses	785	1,191	3,562
Deductions and net write-offs	(2,211)	(1,031)	(3,865)
Balance at end of period	$ 3,773	$ 5,199	$ 5,039