Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Class A Cumulative Redeemable Preferred Shares [Member]
Class Of Stock [Line Items]
Cumulative redeemable preferred shares	$ 175,000	$ 175,000	$ 0
Preferred stock dividend rate	6.375%	6.375%
Cumulative redeemable preferred shares, liquidation value	$ 500.00	$ 500.00
Shares issuance costs	$ 6,100
Class A Depositary Share [Member]
Class Of Stock [Line Items]
Cumulative redeemable preferred shares, liquidation value	$ 25.00	$ 25.00