Schedule II Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance, Beginning Balance	$ 22,379	$ 18,844	$ 13,070
Charged to Cost and Expenses	21,983	20,340	18,501
Charged to Other Accounts	6,410	4,561	3,967
Charge-off Against Allowances	(22,910)	(21,366)	(16,694)
Valuation Allowances and Reserves, Balance, Ending Balance	$ 27,862	$ 22,379	$ 18,844