Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012
Quoted prices in active markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	$ 33,519
Derivative liabilities	0
Total	33,519
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	(1,793)
Total	(1,793)
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
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities - restricted	33,519
Derivative liabilities	(1,793)
Total	$ 31,726