Proceeds from Issuance of Common Stock, Net of Offering Costs

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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 percentage rate used to calculate dividend payments on preferred stock.

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Aggregate dividends declared during the period for each share of preferred stock outstanding.

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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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The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. The redemption features of this preferred stock are solely within the control of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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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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Per share or per unit amount of equity securities issued.

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Number of shares issued during the period as a result of the conversion of convertible securities.

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Number of new stock issued during the period.

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The gross value of stock issued during the period upon the conversion of convertible securities.

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Number of stock bought back by the entity at the exercise price or redemption price.

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Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			2 Months Ended		3 Months Ended			6 Months Ended
	Jun. 10, 2019	Aug. 02, 2018	Jun. 10, 2019	Sep. 30, 2018	Jun. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common stock, shares authorized (in shares)					450,000,000			450,000,000	450,000,000
Common stock, par value (in dollars per share)					$ 0.01			$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)					50,000,000			50,000,000	50,000,000
Preferred stock, par value (in dollars per share)					$ 0.01			$ 0.01	$ 0.01
Common stock, shares issued (in shares)					153,531,597			153,531,597	133,853,565
Proceeds from issuance of common stock net of offering costs					$ 314,800		$ 275,900
Increase to additional paid in capital as a result of conversion of 2019 Notes						$ 33,778
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					6,770,393			6,770,393	6,770,393
Preferred stock, shares outstanding (in shares)					6,770,393			6,770,393	6,770,393
Preferred stock dividend percentage								8.00%
Unpaid dividends (in USD per share)					$ 0.50	$ 0.50
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)					0			0	6,900,000
Preferred stock, shares outstanding (in shares)					0			0	6,900,000
Redemption of preferred stock (in shares)	6,900,000
Preferred stock dividend percentage	8.00%
Redemption price (in USD per share)	$ 25.00		$ 25.00
Unpaid dividends (in USD per share)			$ 0.2223		$ 0.2223	$ 0.50
Common Stock
Class of Stock [Line Items]
Issuance of common stock (in shares)					17,250,000		15,525,000
Conversions of convertible senior notes for common stock (in shares)						1,967,361
Increase to additional paid in capital as a result of conversion of 2019 Notes						$ 20
2019 Notes \| Convertible Debt \| Common Stock
Class of Stock [Line Items]
Shares issued, price per share (in dollars per share)						$ 17.17
Conversions of convertible senior notes for common stock (in shares)		10,020,328		2,775,509		1,967,361
Increase to additional paid in capital as a result of conversion of 2019 Notes						$ 33,800
Follow On Public Offering \| Common Stock
Class of Stock [Line Items]
Issuance of common stock (in shares)					17,250,000		15,525,000
Shares issued, price per share (in dollars per share)					$ 18.27		$ 17.77	$ 18.27