Equity - Summary of Class A Common Stock Issuances (Parenthetical) (Detail) - $ / shares	1 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares Issued	25,875,000	10,535,842	14,568,431	12,421,401
Class A Common Stock [Member] | At The Market [Member]
Shares Issued		1,900,000	7,700,000
Weighted Average Price Per Share		$ 34.63	$ 33.66