Stockholders' Equity	12 Months Ended
Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY The Company’s charter provides that it can issue up to 500,000,000 shares of common stock, $0.01 par value per share and 50,000,000 shares of preferred stock, $0.01 par value per share. As of December 31, 2018, 127,103,750 shares of common stock were issued and outstanding, and no shares of preferred stock were issued or outstanding. All holders of the Company's common stock are entitled to receive dividends and to one vote on all matters submitted to a vote of stockholders. The transfer agent and registrar for the Company’s common stock is American Stock Transfer & Trust Company. On August 28, 2015, the Company filed a $400,000 “at the market” equity program with the Securities and Exchange Commission, and entered into separate equity distribution agreements with five sales agents. On May 6, 2016, the Company filed its current $400,000 "at the market" equity program with the Securities and Exchange Commission using a new shelf registration statement on Form S-3, and entered into separate equity distribution agreements with five sales agents. Under the terms of the current equity distribution agreements, the Company may from time to time offer and sell shares of common stock, up to the aggregate offering price of $400,000, through its sales agents. The current equity distribution agreements, dated May 6, 2016, replaced and superseded the previous equity distribution agreements, dated August 28, 2015. During the year ended December 31, 2018, the Company sold 933,789 shares of common stock under its "at the market" equity program at an average sales price of $97.93 per share, resulting in net proceeds of $90,531. At December 31, 2018, the Company had $257,929 available for issuance under the current equity distribution agreements. During July 2016, the Company sold 550,000 shares of common stock under the current “at the market” equity program at an average sales price of $92.04 per share, resulting in net proceeds of $50,062. From January 1, 2016, through May 6, 2016, the Company sold 831,300 shares of common stock under the previous “at the market” equity program at an average sales price of $89.66 per share, resulting in net proceeds of $73,360.

STOCKHOLDERS’ EQUITY

The Company’s charter provides that it can issue up to 500,000,000 shares of common stock, $0.01 par value per share and 50,000,000 shares of preferred stock, $0.01 par value per share. As of December 31, 2018, 127,103,750 shares of common stock were issued and outstanding, and no shares of preferred stock were issued or outstanding.

All holders of the Company's common stock are entitled to receive dividends and to one vote on all matters submitted to a vote of stockholders. The transfer agent and registrar for the Company’s common stock is American Stock Transfer & Trust Company.

On August 28, 2015, the Company filed a $400,000 “at the market” equity program with the Securities and Exchange Commission, and entered into separate equity distribution agreements with five sales agents. On May 6, 2016, the Company filed its current $400,000 "at the market" equity program with the Securities and Exchange Commission using a new shelf registration statement on Form S-3, and entered into separate equity distribution agreements with five sales agents. Under the terms of the current equity distribution agreements, the Company may from time to time offer and sell shares of common stock, up to the aggregate offering price of $400,000, through its sales agents. The current equity distribution agreements, dated May 6, 2016, replaced and superseded the previous equity distribution agreements, dated August 28, 2015.

During the year ended December 31, 2018, the Company sold 933,789 shares of common stock under its "at the market" equity program at an average sales price of $97.93 per share, resulting in net proceeds of $90,531. At December 31, 2018, the Company had $257,929 available for issuance under the current equity distribution agreements.

During July 2016, the Company sold 550,000 shares of common stock under the current “at the market” equity program at an average sales price of $92.04 per share, resulting in net proceeds of $50,062.

From January 1, 2016, through May 6, 2016, the Company sold 831,300 shares of common stock under the previous “at the market” equity program at an average sales price of $89.66 per share, resulting in net proceeds of $73,360.