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
Changes in valuation and qualifying accounts
Balance at Beginning of Period		$ 7,858	$ 8,398	$ 8,654
Additions: Charged to Costs and Expenses		1,969	2,064	2,671
Additions: Charged to Other Accounts	[1]	(1,046)	(867)	49
Deductions	[2]	1,482	1,737	2,976
Balance at End of Period		$ 7,299	$ 7,858	$ 8,398

[1] Currency translation adjustment.

[2] Uncollectible accounts written-off, net of recoveries.