Derivative and Other Fair Value Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 18,712	$ 1,523
Fair Value Of Serp Investments	83,845	70,655
Other Assets, Fair Value Disclosure		2,214
Assets, Fair Value Disclosure	102,557	74,392
Derivative liability, fair value		44,050
Other Liabilities, Fair Value Disclosure	83,845	70,655
Liabilities, Fair Value Disclosure	83,845	114,705
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	363,144	398,372
Fair Value, Inputs, Level 1 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	0	0
Fair Value Of Serp Investments	83,845	70,655
Other Assets, Fair Value Disclosure		2,214
Assets, Fair Value Disclosure	83,845	72,869
Derivative liability, fair value		0
Other Liabilities, Fair Value Disclosure	83,845	70,655
Liabilities, Fair Value Disclosure	83,845	70,655
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	18,712	1,523
Fair Value Of Serp Investments	0	0
Other Assets, Fair Value Disclosure		0
Assets, Fair Value Disclosure	18,712	1,523
Derivative liability, fair value		44,050
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	44,050
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	363,144	398,372
Fair Value, Inputs, Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	0	0
Fair Value Of Serp Investments	0	0
Other Assets, Fair Value Disclosure		0
Assets, Fair Value Disclosure	0	0
Derivative liability, fair value		0
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Redeemable Noncontrolling Interest Operating Partnership Liability Fair Value Disclosure	$ 0	$ 0