Subsequent Event - Additional Information (Detail) (USD $)	3 Months Ended			12 Months Ended	0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2014	Feb. 18, 2015
Subsequent Event [Line Items]
Cash dividends declared per share	$ 0.45	$ 0.45	$ 0.45	$ 1.35
Dividend, record date				Jan. 30, 2015
Dividend, to be paid date				Feb. 13, 2015
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash dividends declared per share					$ 0.45
Dividend, record date					Apr. 30, 2015
Dividend, to be paid date					May 13, 2015