Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended
	May 31, 2020	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 07, 2020	Aug. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			300,000,000	300,000,000
Preferred stock, shares authorized (in shares)			100,000,000	100,000,000
Preferred stock, shares issued (in shares)			0	0
Preferred stock, shares outstanding (in shares)			0	0
Issuance of common stock in public offering of common stock, shares (in shares)	2,587,500	2,985,575
Issuance of common stock in public offering of common stock, net	$ 1,700,000,000	$ 1,200,000,000
Dividends distributions			$ 936,269,000	$ 825,893,000	$ 727,448,000
Short term dividend payable			10,873,000	9,029,000
Long term dividend payable			7,947,000	7,108,000
Special Distribution
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Short term dividend payable			10,900,000	9,000,000.0
Long term dividend payable			$ 7,900,000	$ 7,100,000
2017 ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in public offering of common stock, shares (in shares)					930,934
Issuance of common stock in public offering of common stock, net					$ 388,200,000
Sale of stock, equity offering agreement, authorized							$ 750,000,000.0
2018 ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in public offering of common stock, shares (in shares)			415,512	903,555
Issuance of common stock in public offering of common stock, net			$ 298,300,000	$ 447,500,000
Sale of stock, equity offering agreement, authorized			$ 750,000,000.0
2020 ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, equity offering agreement, authorized						$ 1,500,000,000
Series A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			25,000,000
Series A-1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			25,000,000
Undesignated
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			50,000,000