Fair Value Measurements (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, aggregate fair value		$ 2,172,000	$ 2,166,000
Long-term debt, aggregate carrying amount, net of unamortized discounts		2,126,729	2,146,599
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of Real Estate		1,900
Property, Plant, and Equipment, Fair Value Disclosure		2,000
Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	[1]	115	187
Recurring Basis [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps		10,284	10,254
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	[1]	115	187
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Basis [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps		0	0
Significant Other Observable Inputs (Level 2) [Member] | Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	[1]	0	0
Significant Other Observable Inputs (Level 2) [Member] | Recurring Basis [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps		10,284	10,254
Significant Unobservable Inputs (Level 3) [Member] | Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	[1]	0	0
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]
Interest rate swaps		$ 0	$ 0

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