Fair Value Of Financial Instruments (Narrative) (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]
Notes payable	$ 290,519,000	$ 300,822,000
Other comprehensive (loss) income - change in value of interest rate swaps	(2,098,000)	10,971,000	(8,448,000)
Interest expense	93,941,000	104,977,000	113,336,000
Accumulated Other Comprehensive Loss
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other comprehensive (loss) income - change in value of interest rate swaps	(2,098,000)	10,971,000	(8,448,000)
Accumulated Other Comprehensive Loss | Reclassification out of Accumulated Other Comprehensive Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest expense	4,300,000
Notes Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	290,519,000	300,822,000
Term loan | Notes Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	1.72%
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of interest rate swap agreements	2
Interest Rate Swap | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap liability	3,515,000	1,417,000
Interest Rate Swap | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount	$ 275,000,000