Shareholders' Equity	9 Months Ended
Sep. 30, 2018
Stockholders Equity Note [Abstract]
Shareholders' Equity	Note 6—Shareholders’ Equity The Company functions as the sole managing member of the operating company. As a result, the Company: (i) consolidates the financial results of the operating company and reflects the membership interest in it that it does not own as a non-controlling interest in its consolidated financial statements; and (ii) recognizes income generated from its economic interest in the operating company’s net income. Class A and Class B units of the operating company have the same economic rights per unit. As of September 30, 2018, the holders of Class A common stock of the Company and the holders of Class B units of the operating company held approximately 25.0% and 75.0%, respectively, of the economic interests in the operations of the business. As of December 31, 2017, the holders of Class A common stock of the Company and the holders of Class B units of the operating company held approximately 26.3% and 73.7%, respectively, of the economic interests in the operations of the business. Each Class B unit of the operating company is issued with a corresponding share of the Company’s Class B common stock, par value $0.000001 per share. Holders of Class B common stock have the right to receive the par value of the Class B common stock held by them upon our liquidation, dissolution or winding up, but do not share in dividends. Each share of the Company’s Class B common stock entitles its holder to five votes, until the first time that the number of shares of Class B common stock outstanding constitutes less than 20% of the number of all shares of the Company’s common stock outstanding. From such time and thereafter, each share of the Company’s Class B common stock entitles its holder to one vote. When a Class B unit is exchanged for a share of the Company’s Class A common stock or forfeited, a corresponding share of the Company’s Class B common stock will automatically be redeemed and canceled. Conversely, to the extent that the Company causes the operating company to issue additional Class B units to employees pursuant to its equity incentive plan, these additional holders of Class B units would be entitled to receive a corresponding number of shares of the Company’s Class B common stock (including if the Class B units awarded are subject to vesting). All holders of the Company’s Class B common stock have entered into a stockholders’ agreement, pursuant to which they agreed to vote all shares of Class B common stock then held by them, with the majority of votes of Class B common stockholders taken in a preliminary vote of the Class B common stockholders. The outstanding shares of the Company’s Class A common stock represent 100% of the rights of the holders of all classes of the Company’s capital stock to receive distributions, except that holders of Class B common stock will have the right to receive the class’s par value upon the Company’s liquidation, dissolution or winding up. Pursuant to the operating agreement of the operating company, each vested Class B unit is exchangeable for a share of the Company’s Class A common stock, subject to certain exchange timing and volume limitations. These acquisitions of additional operating company membership was treated as a reorganization of entities under common control as required by the Business Combinations Topic of the FASB ASC. The Company’s share repurchase program was announced on April 24, 2012. The Board of Directors authorized the Company to repurchase up to an aggregate of $10 million of the Company’s outstanding Class A common stock and the operating company’s Class B units on the open market and in private transactions in accordance with applicable securities laws. On February 11, 2014, the Company announced that its Board of Directors approved an increase of $20 million in the aggregate amount authorized under the program. On April 19, 2018, the Company announced that its Board of Directors approved an additional increase of $30 million in the aggregate amount authorized under the program. The timing, number and value of common shares and units repurchased are subject to the Company’s discretion. The Company’s share repurchase program is not subject to an expiration date and may be suspended, discontinued, or modified at any time, for any reason. During the nine months ended September 30, 2018, the Company purchased and retired 742,255 shares of Class A common stock and 3,870 Class B units under the current repurchase authorization at a weighted average price per share of $10.10 and $10.67, respectively. During the nine months ended September 30, 2017, the Company purchased and retired 79,717 shares of Class A common stock and 2,897 Class B units under the repurchase authorization at a weighted average price per unit of $8.88 and $11.11, respectively. The Company records the repurchase of shares and units at cost based on the trade date of the transaction.

Note 6—Shareholders’ Equity

The Company functions as the sole managing member of the operating company. As a result, the Company: (i) consolidates the financial results of the operating company and reflects the membership interest in it that it does not own as a non-controlling interest in its consolidated financial statements; and (ii) recognizes income generated from its economic interest in the operating company’s net income. Class A and Class B units of the operating company have the same economic rights per unit. As of September 30, 2018, the holders of Class A common stock of the Company and the holders of Class B units of the operating company held approximately 25.0% and 75.0%, respectively, of the economic interests in the operations of the business. As of December 31, 2017, the holders of Class A common stock of the Company and the holders of Class B units of the operating company held approximately 26.3% and 73.7%, respectively, of the economic interests in the operations of the business.

Each Class B unit of the operating company is issued with a corresponding share of the Company’s Class B common stock, par value $0.000001 per share. Holders of Class B common stock have the right to receive the par value of the Class B common stock held by them upon our liquidation, dissolution or winding up, but do not share in dividends. Each share of the Company’s Class B common stock entitles its holder to five votes, until the first time that the number of shares of Class B common stock outstanding constitutes less than 20% of the number of all shares of the Company’s common stock outstanding. From such time and thereafter, each share of the Company’s Class B common stock entitles its holder to one vote. When a Class B unit is exchanged for a share of the Company’s Class A common stock or forfeited, a corresponding share of the Company’s Class B common stock will automatically be redeemed and canceled. Conversely, to the extent that the Company causes the operating company to issue additional Class B units to employees pursuant to its equity incentive plan, these additional holders of Class B units would be entitled to receive a corresponding number of shares of the Company’s Class B common stock (including if the Class B units awarded are subject to vesting).

All holders of the Company’s Class B common stock have entered into a stockholders’ agreement, pursuant to which they agreed to vote all shares of Class B common stock then held by them, with the majority of votes of Class B common stockholders taken in a preliminary vote of the Class B common stockholders.

The outstanding shares of the Company’s Class A common stock represent 100% of the rights of the holders of all classes of the Company’s capital stock to receive distributions, except that holders of Class B common stock will have the right to receive the class’s par value upon the Company’s liquidation, dissolution or winding up.

Pursuant to the operating agreement of the operating company, each vested Class B unit is exchangeable for a share of the Company’s Class A common stock, subject to certain exchange timing and volume limitations. These acquisitions of additional operating company membership was treated as a reorganization of entities under common control as required by the Business Combinations Topic of the FASB ASC.

The Company’s share repurchase program was announced on April 24, 2012. The Board of Directors authorized the Company to repurchase up to an aggregate of $10 million of the Company’s outstanding Class A common stock and the operating company’s Class B units on the open market and in private transactions in accordance with applicable securities laws. On February 11, 2014, the Company announced that its Board of Directors approved an increase of $20 million in the aggregate amount authorized under the program. On April 19, 2018, the Company announced that its Board of Directors approved an additional increase of $30 million in the aggregate amount authorized under the program. The timing, number and value of common shares and units repurchased are subject to the Company’s discretion. The Company’s share repurchase program is not subject to an expiration date and may be suspended, discontinued, or modified at any time, for any reason.

During the nine months ended September 30, 2018, the Company purchased and retired 742,255 shares of Class A common stock and 3,870 Class B units under the current repurchase authorization at a weighted average price per share of $10.10 and $10.67, respectively. During the nine months ended September 30, 2017, the Company purchased and retired 79,717 shares of Class A common stock and 2,897 Class B units under the repurchase authorization at a weighted average price per unit of $8.88 and $11.11, respectively. The Company records the repurchase of shares and units at cost based on the trade date of the transaction.