Debt (Schedule of Debt) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Debt payable, net to 2038	[1]	$ 1,921,852	$ 1,656,083
Unsecured notes payable under credit facilities		73,000	189,000
Debt service guaranty liability		72,105	72,105
Obligations under capital leases		21,000	21,000
Total	[2]	$ 2,087,957	$ 1,938,188
Debt stated interest rate		3.50%	7.40%
Debt Payable To 2038 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt stated interest rate		1.734%	3.40%
Debt Payable To 2038 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt stated interest rate		8.57%	8.60%
Debt Payable To 2038 [Member] | Weighted Average [Member]
Debt Instrument [Line Items]
Debt stated interest rate		4.20%	4.80%

[1] At June 30, 2015, interest rates ranged from 1.7% to 8.6% at a weighted average rate of 4.2%. At December 31, 2014, interest rates ranged from 3.4% to 8.6% at a weighted average rate of 4.8%.

[2] * Consolidated variable interest entities' assets held as collateral and debt included in the above balances (see Note 16):