Stockholders' Equity - Additional Information (Details) - $ / shares		1 Months Ended	9 Months Ended
	Mar. 31, 2020	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Common stock, shares authorized			248,125,000
Class K Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			55,500,000	55,500,000
Common stock, par value per share (in dollars per share)			$ 0.01	$ 0.01
Common stock, voting rights			one vote
Rate of cumulative cash distributions	6.00%		7.00%
Base distribution per share			$ 10.00
Percentage of excess cash available for distribution			50.00%
Percentage of remaining liquidation cash distribution on pro rata basis			50.00%
Class K-I Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			55,500,000	55,500,000
Common stock, par value per share (in dollars per share)			$ 0.01	$ 0.01
Common stock, voting rights			one vote
Rate of cumulative cash distributions		6.00%	7.00%
Base distribution per share			$ 10.00
Percentage of excess cash available for distribution			50.00%
Percentage of remaining liquidation cash distribution on pro rata basis			50.00%
Class K-T Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			116,000,000	116,000,000
Common stock, par value per share (in dollars per share)			$ 0.01	$ 0.01
Common stock, voting rights			one vote
Rate of cumulative cash distributions		6.00%	7.00%
Base distribution per share			$ 10.00
Percentage of excess cash available for distribution			50.00%
Percentage of remaining liquidation cash distribution on pro rata basis			50.00%
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			21,000,000	21,000,000
Common stock, par value per share (in dollars per share)			$ 0.01	$ 0.01
Common stock, voting rights			one vote
Rate of cumulative cash distributions			7.00%
Base distribution per share			$ 10.00
Percentage of excess cash available for distribution			37.50%
Percentage of remaining liquidation cash distribution on pro rata basis			37.50%
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			125,000	125,000
Common stock, par value per share (in dollars per share)			$ 0.01	$ 0.01
Percentage of excess cash available for distribution			12.50%
Percentage of remaining liquidation cash distribution on pro rata basis			12.50%