CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Preferred stock, authorized (shares)	16,670,000	16,670,000
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, authorized (shares)	150,000,000	100,000,000
Common stock, issued (shares)	83,839,947	76,080,625
Common stock, outstanding (shares)	83,839,947	76,080,625
Redeemable Preferred Stock
Preferred stock, dividend rate	7.25%	7.25%
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (usd per share)	$ 25	$ 25
Preferred stock, authorized (shares)	13,409,650	13,409,650
Preferred stock, issued (shares)	5,484,994	5,416,890
Preferred stock, outstanding (shares)	5,484,994	5,416,890

Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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