Total Unrecognized Compensation Costs Related to Unvested Liability Awards and Equity Awards and Period over which they are Expected to be Recognized (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011 Year
Liability Awards
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Compensation Expense	$ 3,355
Weighted Average Period (in years)	1.5
Equity Awards
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Compensation Expense	$ 15,175
Weighted Average Period (in years)	3.2