Equity - Additional Information (Details) - USD ($)				3 Months Ended	12 Months Ended
	Oct. 15, 2019	Sep. 03, 2019	Jan. 29, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 28, 2018
Stockholders Equity Note [Line Items]
Issuance of common stock (in shares)		14,375,000	11,500,000			7,187,500
Net proceeds from issuance of common stock					$ 450,710,000	$ 142,601,000	$ 302,000
Outstanding for future offerings, amount				$ 117,000,000		117,000,000
Issuance of common stock		$ 228,000,000	$ 177,000,000		442,172,000	142,228,000
Share-based compensation, vesting period (in years)	2 years
Direct stock purchase and dividend reinvestment plan					6,307,000	$ 1,706,000
Share Repurchase Plan, February 2018
Stockholders Equity Note [Line Items]
Stock repurchase program, authorized amount								$ 100,000,000
Stock repurchase program, remaining authorized repurchase amount					$ 100,000,000
Convertible debt securities
Stockholders Equity Note [Line Items]
Securities excluded in the calculation of diluted earnings per share					0	0	0
Equity awards
Stockholders Equity Note [Line Items]
Securities excluded in the calculation of diluted earnings per share					10,051	7,230	5,843
ATM Offerings | Common Stock
Stockholders Equity Note [Line Items]
Aggregate value of common stock issuable				$ 150,000,000		$ 150,000,000
Issuance of common stock (in shares)				1,550,819	2,259,758
Net proceeds from issuance of common stock					$ 36,000,000	$ 25,000,000
Outstanding for future offerings, amount					$ 88,000,000
Common Stock
Stockholders Equity Note [Line Items]
Issuance of common stock (in shares)					28,724,645	8,738,319
Issuance of common stock					$ 288,000	$ 88,000
Direct stock purchase and dividend reinvestment plan (in shares)					399,838	113,004
Direct stock purchase and dividend reinvestment plan					$ 4,000	$ 1,000
CoreVest LLC
Stockholders Equity Note [Line Items]
Restricted stock awards (in shares)	588,260
Shares issued (in usd per share)	$ 16.48
Restricted stock awards	$ 10,000,000