Equity and Noncontrolling Interests (Common stock) - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Stock repurchase program, authorized amount			$ 200,000,000
Stock repurchase program, last date to repurchase	2017-12
Repurchased shares of common stock, shares	599,000	582,000
Repurchased shares of common stock, aggregate cost	$ 32,744,000	$ 32,336,000
Repurchased shares of common stock, average gross price	$ 54.67	$ 55.55
Common stock reserved for future issuance	4,000,000