Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands	Jun. 30, 2011
Total carrying value at period end
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	$ 31,996
Derivative liabilities	(1,692)
Total	30,304
Quoted prices in active markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	31,996
Derivative liabilities	0
Total	31,996
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	0
Derivative liabilities	(1,692)
Total	(1,692)
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	0
Derivative liabilities	0
Total	$ 0