Fair Value Measurements (Details) (USD $)			9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Recurring Basis [Member]		Dec. 31, 2013 Recurring Basis [Member]		Sep. 30, 2014 Recurring Basis [Member] Interest Rate Swap [Member]	Dec. 31, 2013 Recurring Basis [Member] Interest Rate Swap [Member]	Sep. 30, 2014 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Recurring Basis [Member]		Dec. 31, 2013 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Recurring Basis [Member]		Sep. 30, 2014 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Recurring Basis [Member] Interest Rate Swap [Member]	Dec. 31, 2013 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Recurring Basis [Member] Interest Rate Swap [Member]	Sep. 30, 2014 Significant Other Observable Inputs (Level 2) [Member] Recurring Basis [Member]		Dec. 31, 2013 Significant Other Observable Inputs (Level 2) [Member] Recurring Basis [Member]		Sep. 30, 2014 Significant Other Observable Inputs (Level 2) [Member] Recurring Basis [Member] Interest Rate Swap [Member]	Dec. 31, 2013 Significant Other Observable Inputs (Level 2) [Member] Recurring Basis [Member] Interest Rate Swap [Member]	Sep. 30, 2014 Significant Unobservable Inputs (Level 3) [Member] Recurring Basis [Member]		Dec. 31, 2013 Significant Unobservable Inputs (Level 3) [Member] Recurring Basis [Member]		Sep. 30, 2014 Significant Unobservable Inputs (Level 3) [Member] Recurring Basis [Member] Interest Rate Swap [Member]	Dec. 31, 2013 Significant Unobservable Inputs (Level 3) [Member] Recurring Basis [Member] Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of Real Estate			$ 11,700,000
Available-for-sale securities				169,000	[1]	250,000	[1]			169,000	[1]	250,000	[1]			0	[1]	0	[1]			0	[1]	0	[1]
Interest rate swaps								10,040,000	13,030,000					0	0					10,040,000	13,030,000					0	0
Long-term debt, aggregate fair value	2,174,000,000	2,299,000,000
Long-term debt, aggregate carrying amount	2,147,970,000	2,198,149,000
Assets Held-for-sale, Long Lived, Fair Value Disclosure			$ 2,000,000

[1] (a) Available-for-sale securities are included in Other assets, net on the Condensed Consolidated Balance Sheets.