Equity - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Feb. 28, 2018	Aug. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	May 04, 2018	May 31, 2013
Class of Stock [Line Items]
Cash dividends declared per share of common stock			$ 0.10	$ 0.10	$ 0.20	$ 0.20
Cash dividends per common share, date of dividend payable	Apr. 18, 2018	Oct. 18, 2017
Cash dividends per common share, date of record for dividend	Mar. 14, 2018	Sep. 13, 2017
Subsequent Event [Member]
Class of Stock [Line Items]
Remaining authorized amount under stock repurchase program							$ 429,000,000
Class A Common Stock [Member]
Class of Stock [Line Items]
Aggregate amount of shares authorized to be repurchased								$ 500,000,000
Number of shares repurchased					0
Cash dividends declared per share of common stock	$ 0.10	$ 0.10
Class A Common Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Number of shares repurchased							5,200,000
Value of shares purchased in the period							$ 71,000,000
Class B Common Stock [Member]
Class of Stock [Line Items]
Cash dividends declared per share of common stock	$ 0.10	$ 0.10