Stockholders' Deficit - Dividends declared and paid per share (Details) - $ / shares			3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 03, 2020	Jan. 10, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Equity [Abstract]
Dividends declared per common share (USD per share)			$ 0	$ 0.76	$ 0.69	$ 0.76	$ 2.07	$ 0.69
Dividends paid per common share (USD per share)	$ 0.76	$ 0.69	$ 0		$ 0.69	$ 1.45	$ 2.01