CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Common stock, shares authorized	248,125,000
Class K Common Stock
Common stock, par value per share (in dollars per share)	$ 0.01			$ 0.01
Common stock, shares authorized	55,500,000			55,500,000
Common stock, shares issued	3,399,505			2,680,845
Common Stock, shares outstanding	3,399,505	3,278,238	3,301,738	2,680,845	2,372,121	1,983,883	1,663,570	1,364,918
Class K-I Common Stock
Common stock, par value per share (in dollars per share)	$ 0.01			$ 0.01
Common stock, shares authorized	55,500,000			55,500,000
Common stock, shares issued	644,990			491,718
Common Stock, shares outstanding	644,990	631,699	631,699	491,718	388,618	213,321	66,517	12,243
Class K-T Common Stock
Common stock, par value per share (in dollars per share)	$ 0.01			$ 0.01
Common stock, shares authorized	116,000,000			116,000,000
Common stock, shares issued	47,989			45,616
Common Stock, shares outstanding	47,989	47,989	47,989	45,616	33,562	6,050	510	510
Class A Common Stock
Common stock, par value per share (in dollars per share)	$ 0.01			$ 0.01
Common stock, shares authorized	21,000,000			21,000,000
Common stock, shares issued	537,410			537,410
Common Stock, shares outstanding	537,410	537,410	537,410	537,410	537,410	537,410	468,410	468,410
Class B Common Stock
Common stock, par value per share (in dollars per share)	$ 0.01			$ 0.01
Common stock, shares authorized	125,000			125,000
Common stock, shares issued	125,000			125,000
Common Stock, shares outstanding	125,000	125,000	125,000	125,000	125,000	125,000	125,000	125,000