Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) shares	Jul. 31, 2015 shares
Equity [Line Items]
Common stock, shares, issued	254,770,719	235,008,554
Proceeds from issuance of common shares | $	$ 197,643,000	$ (2,818,000)	$ 16,804,000
Preferred shares outstanding (in shares)	1,935,400	1,935,400
Shares issued, net of forfeitures (in shares)	896,807	965,932	835,234
Remaining authorized repurchase amount | $	$ 10,306,255
OP unit equivalent in common shares (in unit per share)	1.13
Shares issued for units redeemed (in shares)	391,993	53,388	140,746
Partners' capital account, exchanges and conversions | $	$ 1,655,000	$ 189,000	$ 584,000
OP units outstanding (in units)	2,829,000
Unsettled repurchases | $		$ 2,641,000
Common Stock
Equity [Line Items]
Number of shares authorized to be repurchased (in shares)		10,000,000		10,000,000
Repurchase of common shares (in shares)	441,581	5,851,252	0
Average cost per share (usd per share) | $ / shares	$ 8.13	$ 8.05
Series C
Equity [Line Items]
Preferred shares outstanding (in shares)	1,935,400
Dividend rate (usd per share) | $ / shares	$ 3.25
Preferred shares, liquidation preference | $	$ 96,770,000
Preferred shares to common shares conversion ratio	2.4339
Series C | Minimum
Equity [Line Items]
Common share closing price percent of conversion price	125.00%
At The Market
Equity [Line Items]
Common stock, shares, issued	9,668,748	0	1,593,603
Proceeds from issuance of common shares | $	$ 102,299,000		$ 17,362,000
Sale of stock, amount available for issuance | $	$ 296,076,000
Underwritten Offering
Equity [Line Items]
Common stock, shares, issued	10,000,000
Proceeds from issuance of common shares | $	$ 100,749,000
Underwritten Offering | Common Stock
Equity [Line Items]
Shares issued, price per share | $ / shares	$ 10.09