Capital Stock	9 Months Ended
Sep. 30, 2018
Equity [Abstract]
Capital Stock	Capital Stock The Company had 38,107,555 shares of Class A common stock and 22,501,994 shares of Class B common stock outstanding as of September 30, 2018. The Company had 33,560,202 shares of Class A common stock and 22,905,357 shares of Class B common stock outstanding as of December 31, 2017. On August 16, 2018, the Company issued 3,837,540 shares of its Class A common stock with an aggregate value of $173.3 million as consideration for the acquisition of Northwest. In addition, during the nine months ended September 30, 2018, the Company issued 11,389 shares of its Class A common stock to directors for their annual service on the Company’s board of directors. The aggregate value of the shares issued to directors of $0.5 million is included in stock-based compensation expense in the accompanying consolidated statements of changes in stockholders’ equity. During the nine months ended September 30, 2018 and 2017, the Company did not repurchase any shares of its Class A common stock other than stock repurchases which were redemptions of vested restricted shares tendered in lieu of cash for payment of income tax withholding amounts by participants in the Company’s equity compensation plans.

Capital Stock

The Company had 38,107,555 shares of Class A common stock and 22,501,994 shares of Class B common stock outstanding as of September 30, 2018. The Company had 33,560,202 shares of Class A common stock and 22,905,357 shares of Class B common stock outstanding as of December 31, 2017.

On August 16, 2018, the Company issued 3,837,540 shares of its Class A common stock with an aggregate value of $173.3 million as consideration for the acquisition of Northwest. In addition, during the nine months ended September 30, 2018, the Company issued 11,389 shares of its Class A common stock to directors for their annual service on the Company’s board of directors. The aggregate value of the shares issued to directors of $0.5 million is included in stock-based compensation expense in the accompanying consolidated statements of changes in stockholders’ equity.

During the nine months ended September 30, 2018 and 2017, the Company did not repurchase any shares of its Class A common stock other than stock repurchases which were redemptions of vested restricted shares tendered in lieu of cash for payment of income tax withholding amounts by participants in the Company’s equity compensation plans.