Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2015
Class Of Stock [Line Items]
Repurchase authorization, shares			5,000,000
Cash dividends paid to common stockholders	$ 19,000,000	$ 14,000,000
Cash dividend paid per share	$ 0.30	$ 0.22
Noncontrolling interest dividends declared	$ 7,000,000	$ 9,000,000
Dividends paid to noncontrolling interests	$ 0
January 2015 Share Repurchase Authorization [Member]
Class Of Stock [Line Items]
Common stock shares repurchased	2,429,176
Shares remaining available for repurchase under the current authorization	2,570,824