Debt Obligations (Outstanding Unsecured Notes in Series of Transactions) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Schedule of principal payments of debt obligations
Repurchase Amount	$ 16,476
Principal	14,693
Loss	(1,499)
Deferred Financing Amortization	16
2012 5.750% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	309
Principal	301
Loss	(2)
Deferred Financing Amortization	0
Debt instrument stated interest rate	5.75%
2014 5.400% Notes
Schedule of principal payments of debt obligations
Repurchase Amount	4,630
Principal	4,302
Loss	(264)
Deferred Financing Amortization	7
Debt instrument stated interest rate	5.40%
2015 7.500% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	11,537
Principal	10,090
Loss	(1,233)
Deferred Financing Amortization	$ 9
Debt instrument stated interest rate	7.50%