SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 25,649		$ 15,119		$ 6,638
Charged to Cost and Expenses	(38)		13,047		9,892
Due to Currency Translation Adjustments	(320)		(1,585)		(969)
Other	(13,491)	[1]	(932)		(442)
Balance at End of Period	11,800		25,649		15,119
Deferred Tax Assets - Valuation Allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	110,680		131,422		127,164
Charged to Cost and Expenses	38,490		13,175		24,332
Due to Currency Translation Adjustments	(6,323)		(11,519)		(9,254)
Other	3,250		(22,398)	[2]	(10,820)
Balance at End of Period	$ 146,097		110,680		$ 131,422
Pension adjustments
Movement in Valuation Allowances and Reserves [Roll Forward]
Non-cash tax expense			(16,100)
Infrastructure Transaction
Movement in Valuation Allowances and Reserves [Roll Forward]
Non-cash tax expense			(13,200)
UK tax rate changes
Movement in Valuation Allowances and Reserves [Roll Forward]
Non-cash tax expense			$ 6,300

[1] Includes the write-off of previously reserved accounts receivable balances.

[2] Includes a decrease of $16.1 million related to pension adjustments recorded through Accumulated other comprehensive loss and a $6.3 million decrease related to a U.K. tax rate change.