Subsequent Events - Additional Information (Detail) - $ / shares	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Dividends Payable [Line Items]
Dividend declared, per share	$ 0.34	$ 0.34
Dividend Declared [Member]
Dividends Payable [Line Items]
Dividend declared, declaration date	Jul. 13, 2015
Dividend declared, payable date	Sep. 10, 2015
Dividend declared, record date	Aug. 20, 2015