Debt Schedule of Long-Term Debt Repayments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Debt Instrument [Line Items]
Repayments of Long-term Debt			$ 67,502	$ 55,630
Secured Debt [Member] | 2011 Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	3,752	0	7,502	0
Secured Debt [Member] | 2007 Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	0	2,711	0	55,630
Secured Debt [Member] | Credit Facilities [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	53,752	2,711	67,502	55,630
Line of Credit [Member] | Secured Debt [Member] | 2011 Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 50,000	$ 0	$ 60,000	$ 0