Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 24,073	[1]	$ 21,491	[1]	$ 20,351	[1]
Additions Charged to Cost and Expenses	17,817	[1]	17,412	[1]	22,148	[1]
Additions Charged to Other Accounts— Acquisitions and Related Adjustments	(443)	[1]	79	[1]	(36)	[1]
Deductions From Reserve	(15,978)	[1]	(14,909)	[1]	(20,972)	[1]
Balance at End of Year	25,469	[1]	24,073	[1]	21,491	[1]
Deferred tax asset valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	18,058	[2]	17,975	[2]	17,686	[2]
Additions Charged to Cost and Expenses	1,366	[2]	2,352	[2]	3,257	[2]
Additions Charged to Other Accounts— Acquisitions and Related Adjustments	(996)	[2]	0	[2]	(657)	[2]
Deductions From Reserve	(3,050)	[2]	(2,269)	[2]	(2,311)	[2]
Balance at End of Year	$ 15,378	[2]	$ 18,058	[2]	$ 17,975	[2]

[1] Deductions from reserve represent accounts written off and recoveries.

[2] Deductions from reserve result from the expiration or utilization of net operating losses and foreign tax credits previously reserved.