Components Of Equity - Additional Information (Detail) (Dividend Declared [Member], USD $)	3 Months Ended
	Mar. 31, 2012
Dividend Declared [Member]
Class of Stock [Line Items]
Date of declaration of dividends	May 02, 2012
Dividend declared per share	$ 0.28
Date of dividend payment	Jun. 15, 2012
Dividends payable to shareholders date of record	Jun. 01, 2012