Mortgages and Notes Payable (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				15 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended			9 Months Ended
	Sep. 30, 2010	Sep. 30, 2012 Line of Credit [Member]	Jan. 13, 2012 Secured Term Loan [Member]	Sep. 30, 2012 Secured Term Loan 1 [Member]	Mar. 31, 2012 Secured Term Loan 2 [Member]	Sep. 30, 2012 Secured Term Loan 2 [Member]	Jan. 13, 2012 Secured Revolving Credit Facility [Member]	Sep. 30, 2012 6.00% Convertible Guaranteed Note [Member]	Sep. 30, 2011 6.00% Convertible Guaranteed Note [Member]	Sep. 30, 2012 6.00% Convertible Guaranteed Note [Member]	Sep. 30, 2011 6.00% Convertible Guaranteed Note [Member]	Dec. 31, 2011 6.00% Convertible Guaranteed Note [Member]	Mar. 31, 2011 6.00% Convertible Guaranteed Note [Member]	Sep. 30, 2012 5.45% Exchangeable Guaranteed Note [Member]	Sep. 30, 2011 5.45% Exchangeable Guaranteed Note [Member]	Sep. 30, 2012 5.45% Exchangeable Guaranteed Note [Member]	Sep. 30, 2011 5.45% Exchangeable Guaranteed Note [Member]	Dec. 31, 2011 5.45% Exchangeable Guaranteed Note [Member]	Dec. 31, 2007 5.45% Exchangeable Guaranteed Note [Member]	Jan. 31, 2012 5.45% Exchangeable Guaranteed Note [Member]	Sep. 30, 2012 Other Debt Obligations [Member]	Sep. 30, 2011 Other Debt Obligations [Member]	Jan. 13, 2012 Condition One [Member] Secured Term Loan [Member]	Jan. 13, 2012 Condition One [Member] Secured Revolving Credit Facility [Member]	Jan. 13, 2012 Condition Four [Member] Secured Term Loan [Member]	Jan. 13, 2012 Condition Four [Member] Secured Revolving Credit Facility [Member]	Sep. 30, 2012 Secured Revolving Credit Facility, Expiring January 2015 [Member] Secured Term Loan [Member]	Jan. 13, 2012 Secured Revolving Credit Facility, Expiring January 2015 [Member] Secured Revolving Credit Facility [Member]	Jan. 13, 2012 Secured Revolving Credit Facility, Expiring January 2014 [Member] Secured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 215,000	$ 25,000		$ 35,551		$ 115,000		$ 115,000		$ 115,000	$ 115,000	$ 0		$ 0		$ 62,150	$ 450,000									$ 300,000	$ 300,000
Debt Instrument, Basis Spread on Variable Rate																							2.00%	1.625%	2.85%	2.375%
Debt Instrument, Interest Rate, Stated Percentage			1.49%																5.45%
Line of Credit Facility, Amount Outstanding		93,000																									215,000
Line of Credit Facility, Remaining Borrowing Capacity		203,256																									215,000
Debt Instrument, Increase in Credit Facility							225,000
Debt Instrument, Aggregate Credit Facility Amount							525,000
Letters of Credit Outstanding, Amount		3,744
Gains (Losses) on Extinguishment of Debt From Continuing Operations					1,578														44
Debt Instrument, Maturity Date										Jan. 31, 2030
Percent Of Notes Required To Be Repurchased At The Option Of The Holders On Set Dates	100.00%
Debt Instrument, Convertible, Conversion Ratio										144.2599
Debt Instrument, Convertible, Conversion Price (dollars per share)								$ 6.93		$ 6.93
Debt Instrument, Prepaid Amount																		387,850
Debt Instrument, Repurchased and Satisfied Amount																				62,150
Unamortized discount								(8,398)		(8,398)		(9,851)		0		0		(48)
Carrying amount of debt component								106,602		106,602		105,149		0		0		62,102
Carrying amount of equity component								13,134		13,134		13,134		0		0		20,293
Effective interest rate								8.10%		8.10%		8.10%		0.00%		0.00%		7.00%
Aggregate if-converted value in excess of aggregate principal amount										45,258		7,907				0		0
Coupon interest								1,725	1,725	5,175	5,175			0	847	188	2,540
Discount amortization								484	484	1,453	1,453			0	166	34	498
Interest Expense								2,209	2,209	6,628	6,628			0	1,013	222	3,038
Extinguishment of Debt, Gain (Loss), Net of Tax																					$ (17)	$ 3