Fair Value Measurements And Disclosures Fair Value Measurements and Disclosures - Financial Instruments Required to be Carried at Fair Value (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost method investments, expected liquidation period, minimum	1 year
Cost method investments, expected liquidation period, Maximum	4 years
Assets:
Short-term investments	$ 13,160	$ 37,405
Securitized assets	5,938	3,721
Liabilities:
Interest rate swap contracts (recorded in accrued expenses)	1,619	3,387
Level 1 [Member]
Assets:
Short-term investments	13,160	37,405
Securitized assets	0	0
Liabilities:
Interest rate swap contracts (recorded in accrued expenses)	0	0
Level 2 [Member]
Assets:
Short-term investments	0	0
Securitized assets	0	0
Liabilities:
Interest rate swap contracts (recorded in accrued expenses)	1,619	3,387
Level 3 [Member]
Assets:
Short-term investments	0	0
Securitized assets	5,938	3,721
Liabilities:
Interest rate swap contracts (recorded in accrued expenses)	$ 0	$ 0