Fair Value Measurements (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of goodwill	$ 0		$ 1,183,000		$ 0
Impairment of land held for development	11,739,000		0		10,066,000
Aggregate fair value	2,166,000,000		2,299,000,000
Aggregate carrying amount	2,146,599,000		2,198,148,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of land held for development	11,700,000				10,100,000
Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	187,000	[1]	250,000	[1]
Recurring Basis [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	10,254,000		13,030,000
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	187,000	[1]	250,000	[1]
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	0	[1]	0	[1]
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	10,254,000		13,030,000
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	0	[1]	0	[1]
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
Reno, Nevada [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of land held for development	11,700,000
Property, Plant, and Equipment, Fair Value Disclosure	$ 2,000,000

[1] Available-for-sale securities are included in other assets in the accompanying Consolidated Balance Sheets.