Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for Doubtful Accounts, Balance at beginning of year		$ 52,256	$ 49,659	$ 59,188
Allowance for doubtful accounts, Charged to Income		12,887	8,336	(8)
Valuation Allowances and Reserves, Additions for Charges to Other Accounts	[1]	2,831	(392)	(383)
Allowance for Doubtful Accounts, Write-down		11,683	5,347	9,138
Allowance for Doubtful Accounts, Balance at end of year		$ 56,291	$ 52,256	$ 49,659

[1] "Other" primarily includes the effect of fluctuations in foreign currencies and the allowance for doubtful accounts of the businesses acquired by the company.