Stockholders' Equity	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	11. Stockholders’ Equity As of December 31, 2017 and 2016, the Company was authorized to issue two classes of stock: common stock and preferred stock. Common Stock Each holder of common stock has one vote per share of common stock held on all matters that are submitted for stockholder vote. At December 31, 2017 and 2016, there were 500,000,000 shares of common stock authorized. At December 31, 2017 and 2016, there were 86,790,624 and 85,692,333 shares of common stock issued and outstanding, respectively. The Company did not hold any shares as treasury shares as of December 31, 2017 and 2016. On January 22, 2016, the Company’s Board of Directors approved a program that authorizes the repurchase of up to $100 million of the Company’s common stock exclusive of any fees, commissions or other expenses relating to such repurchases through open market purchases or privately negotiated transactions at the prevailing market price at the time of purchase. The repurchase program was announced on January 25, 2016. Repurchased stock may be retired or held as authorized but unissued treasury shares. The repurchase authorizations do not obligate the Company to acquire any particular amount of common stock or adopt any particular method of repurchase and may be modified, suspended or terminated at any time at management’s discretion. Repurchased and retired shares will result in an immediate reduction of the outstanding shares used to calculate the weighted-average common shares outstanding for basic and diluted net income per share at the time of the transaction. During the year ended December 31, 2017, the Company did not repurchase any shares of its common stock. During the year ended December 31, 2016, the Company repurchased and retired 724,473 shares of its common stock at a weighted-average share price of $20.37, or an aggregate of $14.8 million. Preferred Stock The Company was authorized to issue 25,000,000 shares of preferred stock as of December 31, 2017 and 2016. There were no issued or outstanding shares of preferred stock as of December 31, 2017 and 2016.

11. Stockholders’ Equity

As of December 31, 2017 and 2016, the Company was authorized to issue two classes of stock: common stock and preferred stock.

Common Stock

Each holder of common stock has one vote per share of common stock held on all matters that are submitted for stockholder vote. At December 31, 2017 and 2016, there were 500,000,000 shares of common stock authorized. At December 31, 2017 and 2016, there were 86,790,624 and 85,692,333 shares of common stock issued and outstanding, respectively. The Company did not hold any shares as treasury shares as of December 31, 2017 and 2016.

On January 22, 2016, the Company’s Board of Directors approved a program that authorizes the repurchase of up to $100 million of the Company’s common stock exclusive of any fees, commissions or other expenses relating to such repurchases through open market purchases or privately negotiated transactions at the prevailing market price at the time of purchase. The repurchase program was announced on January 25, 2016. Repurchased stock may be retired or held as authorized but unissued treasury shares. The repurchase authorizations do not obligate the Company to acquire any particular amount of common stock or adopt any particular method of repurchase and may be modified, suspended or terminated at any time at management’s discretion. Repurchased and retired shares will result in an immediate reduction of the outstanding shares used to calculate the weighted-average common shares outstanding for basic and diluted net income per share at the time of the transaction. During the year ended December 31, 2017, the Company did not repurchase any shares of its common stock. During the year ended December 31, 2016, the Company repurchased and retired 724,473 shares of its common stock at a weighted-average share price of $20.37, or an aggregate of $14.8 million.

Preferred Stock

The Company was authorized to issue 25,000,000 shares of preferred stock as of December 31, 2017 and 2016. There were no issued or outstanding shares of preferred stock as of December 31, 2017 and 2016.