Fair Value of Financial Instruments , Measurement Inputs (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Assets
Derivative instruments	$ 0	$ 0
Total Fair Value [Member]
Assets
Derivative instruments	0
Total assets	0
Liabilities
Derivative instruments	847
Debt	1,193,100
Total liabilities	1,193,947
Level 1 [Member]
Assets
Derivative instruments	0
Total assets	0
Liabilities
Derivative instruments	0
Debt	0
Total liabilities	0
Level 2 [Member]
Assets
Derivative instruments	0
Total assets	0
Liabilities
Derivative instruments	847
Debt	1,193,100
Total liabilities	1,193,947
Level 3 [Member]
Assets
Derivative instruments	0
Total assets	0
Liabilities
Derivative instruments	0
Debt	0
Total liabilities	$ 0