Capital and Financing Transactions Interest Rate Swaps (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative [Line Items]
Fair market value liability	$ (6,393,000)	$ (15,039,000)
Swap 1 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	12,088,000
Maturity date	Nov. 18, 2015
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	4.10%
Fair market value liability	0	(541,000)
Swap 2 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	30,000,000
Maturity date	Feb. 01, 2016
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	2.30%
Fair market value liability	0	(1,666,000)
Swap 3 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	50,000,000
Maturity date	Sep. 27, 2017
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	2.40%
Swap 3 | Receivables and Other Assets
Derivative [Line Items]
Fair market value assets	695,000	26,000
Swap 4 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	75,000,000
Maturity date	Sep. 27, 2017
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	2.40%
Swap 4 | Receivables and Other Assets
Derivative [Line Items]
Fair market value assets	1,049,000	39,000
Swap 5 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	33,875,000
Maturity date	Nov. 18, 2017
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	4.70%
Fair market value liability	(1,864,000)	(3,113,000)
Swap 11 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	1,875,000
Maturity date	Jan. 25, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	4.94%
Fair market value liability	(56,000)	0
Swap 6 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	22,000,000
Maturity date	Jan. 25, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	4.50%
Fair market value liability	(1,015,000)	(1,804,000)
Swap 7 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	45,000,000
Maturity date	Jan. 25, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	4.71%
Fair market value liability	(377,000)	(1,447,000)
Swap 12 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	120,000,000
Maturity date	Jun. 11, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	3.30%
Fair market value liability	(1,033,000)	0
Swap 8 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	9,250,000
Maturity date	Sep. 30, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	5.20%
Fair market value liability	(679,000)	(1,140,000)
Swap 9 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	22,500,000
Maturity date	Oct. 08, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	5.40%
Fair market value liability	(1,781,000)	(2,935,000)
Swap 13 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	13,500,000
Maturity date	Oct. 08, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	3.30%
Swap 13 | Receivables and Other Assets
Derivative [Line Items]
Fair market value assets	65,000	0
Swap 10 | Accounts Payable and Other Liabilities
Derivative [Line Items]
Notional amount	22,100,000
Maturity date	Nov. 18, 2018
Reference rate (in hundredths)	1-month LIBOR
Rate at which reference rate is fixed	5.00%
Fair market value liability	$ (1,397,000)	$ (2,458,000)