Financial Instruments: Derivatives and Hedging (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financial Instruments: Derivatives and Hedging
Interest rate swap agreements (included in accrued interest payable and other liabilities	$ (1,329,000)	$ (1,959,000)
Loss from settlement of hedges included in accumulated other comprehensive loss	(16,000)	(770,000)	(66,000)
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months	2,700,000
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months	5,000,000
Amount of Gain or (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	6,485,000	(10,549,000)	(15,972,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	7,005,000	12,676,000	12,626,000
Amount of Gain or (Loss) or Recognized into Income (Ineffective Portion)	3,000	3,000	(16,000)
Derivative, Fair Value, Net	1,322,000
Interest Rate Swap
Financial Instruments: Derivatives and Hedging
Amount of Gain or (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	(68,000)	(912,000)	(5,699,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	1,933,000	1,865,000	1,554,000
Amount of Gain or (Loss) or Recognized into Income (Ineffective Portion)	3,000	3,000	(16,000)
Interest Rate Cap expiring in November, 2015
Financial Instruments: Derivatives and Hedging
Notional Value	263,426,000
Strike Rate (as a percent)	6.00%
Derivative Asset, Fair Value, Gross Asset	9,000
Interest Rate Cap Expiring in September 2015
Financial Instruments: Derivatives and Hedging
Notional Value	137,500,000
Strike Rate (as a percent)	4.00%
Derivative Asset, Fair Value, Gross Asset	7,000
Interest Rate Cap expiring in June, 2016
Financial Instruments: Derivatives and Hedging
Notional Value	30,000,000
Strike Rate (as a percent)	2.295%
Interest rate swap agreements (included in accrued interest payable and other liabilities	(1,293,000)
Interest Rate Swap expiring in February, 2015
Financial Instruments: Derivatives and Hedging
Notional Value	8,500,000
Strike Rate (as a percent)	0.74%
Interest rate swap agreements (included in accrued interest payable and other liabilities	(45,000)
Level 2 | Interest Rate Swap expiring in February, 2015
Financial Instruments: Derivatives and Hedging
Loss from settlement of hedges included in accumulated other comprehensive loss		(700,000)
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of Gain or (Loss) Recognized in Other Comprehensive Loss (Effective Portion)	6,553,000	(9,637,000)	(10,273,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	5,072,000	10,811,000	11,072,000
Amount of Gain or (Loss) or Recognized into Income (Ineffective Portion)	$ 0	$ 0	$ 0