Summary Of Changes In RSUs Outstanding (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2012 Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs granted, weighted-average remaining contractual term	1.6
Target Amount | Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	400,000
Minimum | Target Amount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual number of RSUs that will ultimately be granted	0.00%
Maximum | Target Amount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual number of RSUs that will ultimately be granted	200.00%
Executive Officer | Performance Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	700,000
Non-Executive | Service Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	300,000