Earnings Per Common Share - Narrative (Details) - shares	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive potential common shares - forward equity agreements (in shares)		0	0	(1,901,000)	0
Down REIT
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of anti-dilutive securities excluded from earnings per share calculation (in shares)		7,000,000	7,000,000	7,000,000	7,000,000
Employee stock option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of anti-dilutive securities excluded from earnings per share calculation (in shares)		1,000,000	1,000,000	1,000,000	1,000,000
Convertible Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of anti-dilutive securities excluded from earnings per share calculation (in shares)		19,000,000		18,000,000
Forward Equity Offering
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Maximum shares issuable under forward equity sales agreement (in shares)	15,250,000
Option indexed to issuers equity, term	1 year			1 year
Forward Contract Indexed to Issuer's Equity, Remainder Outstanding, Shares		10,150,000		10,150,000
Issuance of common stock, net (in shares)		3,600,000		5,100,000
At-The-Market Program 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share settlement (in shares)		5,500,000		5,500,000
Forward Contract Indexed to Issuer's Equity, Remainder Outstanding, Shares		9,300,000		9,300,000
Issuance of common stock, net (in shares)						5,400,000