Equity - Summary of Class A Common Stock Issuances (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Shares issued	25,875,000	10,842,746	10,535,842	14,568,431
Net proceeds		$ 278,322	$ 372,337	$ 476,420
Class A Common Stock [Member]
Class of Stock [Line Items]
Shares issued		10,840,696	10,534,628	14,566,743
Gross share issue price		$ 27.79	$ 35.75	$ 33.16
Net share issue price		$ 27.52	$ 35.38	$ 32.76
Net proceeds		$ 297,599	$ 372,341	$ 476,420