Common Stock and Other Equity Related Transactions - Common Stock, OP Units, and Distributions (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock Outstanding [Roll Forward]
Shares outstanding at January 1, (in shares)	182,089,595	179,842,036	177,170,320
Common stock issued through the ATM Equity Offering Program and its predecessor (in shares)	0	1,010,472	1,722,282
Common stock issued through conversion of OP Units (in shares)	12,028	997,750	176,268
Common stock issued through exercise of options (in shares)	0	5,600	405,600
Common stock issued through restricted stock grants (in shares)	151,104	193,262	385,010
Common stock forfeitures (in shares)	0	0	0
Common stock issued through ESPP and Dividend Reinvestment Plan (in shares)	32,099	41,589	45,144
Common stock repurchased and retired (in shares)	(54,195)	(1,114)	(62,588)
Shares outstanding at December 31, (in shares)	182,230,631	182,089,595	179,842,036