Stockholders' Equity	3 Months Ended
Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock As of March 31, 2019 and December 31, 2018, the Company had 83.8 million and 76.1 million shares of Common Stock outstanding, respectively, excluding unvested restricted stock units in respect of shares of Common Stock ("RSUs") and long-term incentive plan units of limited partner interest in the OP ("LTIP Units"). LTIP Units may be convertible into shares of Common Stock in the future. ATM Program — Common Stock The Company has an “at the market” equity offering program (the “ATM Program”) pursuant to which the Company may sell shares of Common Stock, from time to time through its sales agents. During the three months ended March 31, 2019, the Company sold 7,759,322 shares of Common Stock through the ATM Program for gross proceeds of $152.8 million, before commissions paid of $1.5 million and additional issuance costs of $1.2 million. Following these sales, the Company had raised all $175.0 million contemplated by its existing equity distribution agreement related to the ATM Program. In February 2019, the Company terminated its existing equity distribution agreement and entered into a new equity distribution agreement with substantially the same sales agents on substantially the same terms. The Company did not sell any shares of common stock during the three months ended March 31, 2018. In May 2019, the Company amended the equity distribution agreement for the ATM Program to add a new agent. For additional information, see Note 14 - Subsequent Events. Preferred Stock The Company is authorized to issue up to 16,670,000 shares of Preferred Stock, of which it has classified and designated 13,409,650 as authorized shares of its Series A Preferred Stock as of March 31, 2019 and December 31, 2018. The Company had 5,484,994 and 5,416,890 shares of Series A Preferred Stock issued and outstanding, as of March 31, 2019 and December 31, 2018, respectively. ATM Program — Series A Preferred Stock In March 2018, the Company established an “at the market” equity offering program for its Series A Preferred Stock (the "Preferred Stock ATM Program") pursuant to which the Company may raise aggregate sales proceeds of $200.0 million through sales of shares of Series A Preferred Stock from time to time through its sales agents. During the three months ended March 31, 2019, the Company sold 68,104 shares of Series A Preferred Stock through the Preferred Stock ATM Program for gross proceeds of $1.7 million, before commissions paid of approximately $25,000 and additional issuance costs of approximately $59,000. During the three months ended March 31, 2018, the Company sold 1,676 shares of Series A Preferred Stock through the Preferred Stock ATM Program for net proceeds of $41,000, after commissions paid of $623 and additional issuance costs of $0.5 million. Dividends Common Stock Dividends Historically, and through March 31, 2019, the Company generally paid dividends on Common Stock on the 15th day of each month (or, if not a business day, the next succeeding business day) to Common Stock holders of record on the applicable record date during the month at an annualized rate of $2.13 per share or $0.1775 per share on a monthly basis. Prior to July 2018, the record date for the Company’s regular dividend was generally the 8thday of the applicable month. On April 5, 2019, the Company's board of directors approved a change in the Company's Common Stock dividend policy. Accordingly, consistent with its peers, the Company anticipates paying future dividends authorized by its board of directors on shares of its Common Stock on a quarterly basis in arrears on the 15th day of the first month following the end of each fiscal quarter (unless otherwise specified) to common stock holders of record on the record date for such payment. This change will affect the frequency of dividend payments only, and will have no impact on the annualized dividend rate on Common Stock of $2.13. Following the payment of the dividend declared with respect to the month of March 2019 on April 15, 2019, in accordance with the new policy, the next dividend to holders of Common Stock will not be declared and paid until July 2019 with respect to the fiscal quarter ending June 30, 2019. The Company's board of directors may alter the amounts of dividends paid or suspend dividend payments at any time prior to declaration and therefore dividend payments are not assured. For purposes of the presentation of information herein, the Company may refer to distributions by the OP on OP Units and LTIP Units as dividends. In addition, see Note 5 — Credit Facilities for additional information on the restrictions on the payment of dividends and other distributions imposed by the Credit Facility. Preferred Stock Dividend Dividends on Series A Preferred Stock accrue in an amount equal to $0.453125 per share per quarter to Series A Preferred Stock holders, which is equivalent to 7.25% of the $25.00 liquidation preference per share of Series A Preferred Stock per annum. Dividends on the Series A Preferred Stock are payable quarterly in arrears on the 15th day of January, April, July and October of each year (or, if not on a business day, on the next succeeding business day) to holders of record at the close of business on the record date set by the Company's board of directors, which must be not more than 30 nor fewer than 10 days prior to the applicable payment date.

Stockholders' Equity

Common Stock

As of March 31, 2019 and December 31, 2018, the Company had 83.8 million and 76.1 million shares of Common Stock outstanding, respectively, excluding unvested restricted stock units in respect of shares of Common Stock ("RSUs") and long-term incentive plan units of limited partner interest in the OP ("LTIP Units"). LTIP Units may be convertible into shares of Common Stock in the future.

ATM Program — Common Stock

The Company has an “at the market” equity offering program (the “ATM Program”) pursuant to which the Company may sell shares of Common Stock, from time to time through its sales agents. During the three months ended March 31, 2019, the Company sold 7,759,322 shares of Common Stock through the ATM Program for gross proceeds of $152.8 million, before commissions paid of $1.5 million and additional issuance costs of $1.2 million. Following these sales, the Company had raised all $175.0 million contemplated by its existing equity distribution agreement related to the ATM Program. In February 2019, the Company terminated its existing equity distribution agreement and entered into a new equity distribution agreement with substantially the same sales agents on substantially the same terms. The Company did not sell any shares of common stock during the three months ended March 31, 2018.

In May 2019, the Company amended the equity distribution agreement for the ATM Program to add a new agent. For additional information, see Note 14 - Subsequent Events.

Preferred Stock

The Company is authorized to issue up to 16,670,000 shares of Preferred Stock, of which it has classified and designated 13,409,650 as authorized shares of its Series A Preferred Stock as of March 31, 2019 and December 31, 2018. The Company had 5,484,994 and 5,416,890 shares of Series A Preferred Stock issued and outstanding, as of March 31, 2019 and December 31, 2018, respectively.

ATM Program — Series A Preferred Stock

In March 2018, the Company established an “at the market” equity offering program for its Series A Preferred Stock (the "Preferred Stock ATM Program") pursuant to which the Company may raise aggregate sales proceeds of $200.0 million through sales of shares of Series A Preferred Stock from time to time through its sales agents. During the three months ended March 31, 2019, the Company sold 68,104 shares of Series A Preferred Stock through the Preferred Stock ATM Program for gross proceeds of $1.7 million, before commissions paid of approximately $25,000 and additional issuance costs of approximately $59,000. During the three months ended March 31, 2018, the Company sold 1,676 shares of Series A Preferred Stock through the Preferred Stock ATM Program for net proceeds of $41,000, after commissions paid of $623 and additional issuance costs of $0.5 million.

Dividends

Common Stock Dividends

Historically, and through March 31, 2019, the Company generally paid dividends on Common Stock on the 15th day of each month (or, if not a business day, the next succeeding business day) to Common Stock holders of record on the applicable record date during the month at an annualized rate of $2.13 per share or $0.1775 per share on a monthly basis. Prior to July 2018, the record date for the Company’s regular dividend was generally the 8thday of the applicable month. On April 5, 2019, the Company's board of directors approved a change in the Company's Common Stock dividend policy. Accordingly, consistent with its peers, the Company anticipates paying future dividends authorized by its board of directors on shares of its Common Stock on a quarterly basis in arrears on the 15th day of the first month following the end of each fiscal quarter (unless otherwise specified) to common stock holders of record on the record date for such payment. This change will affect the frequency of dividend payments only, and will have no impact on the annualized dividend rate on Common Stock of $2.13. Following the payment of the dividend declared with respect to the month of March 2019 on April 15, 2019, in accordance with the new policy, the next dividend to holders of Common Stock will not be declared and paid until July 2019 with respect to the fiscal quarter ending June 30, 2019. The Company's board of directors may alter the amounts of dividends paid or suspend dividend payments at any time prior to declaration and therefore dividend payments are not assured. For purposes of the presentation of information herein, the Company may refer to distributions by the OP on OP Units and LTIP Units as dividends. In addition, see Note 5 — Credit Facilities for additional information on the restrictions on the payment of dividends and other distributions imposed by the Credit Facility.

Preferred Stock Dividend

Dividends on Series A Preferred Stock accrue in an amount equal to $0.453125 per share per quarter to Series A Preferred Stock holders, which is equivalent to 7.25% of the $25.00 liquidation preference per share of Series A Preferred Stock per annum. Dividends on the Series A Preferred Stock are payable quarterly in arrears on the 15th day of January, April, July and October of each year (or, if not on a business day, on the next succeeding business day) to holders of record at the close of business on the record date set by the Company's board of directors, which must be not more than 30 nor fewer than 10 days prior to the applicable payment date.