Capital Stock	6 Months Ended
Jun. 30, 2018
Equity [Abstract]
Capital Stock	Capital Stock The Company had 34,200,792 shares of Class A common stock and 22,559,402 shares of Class B common stock outstanding as of June 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. During the six months ended June 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 six months ended June 30, 2018, the Company did not repurchase any shares of its Class A common stock. All other stock repurchases during the six months ended June 30, 2018 and 2017 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

6 Months Ended

Jun. 30, 2018

The Company had 34,200,792 shares of Class A common stock and 22,559,402 shares of Class B common stock outstanding as of June 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.

During the six months ended June 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 six months ended June 30, 2018, the Company did not repurchase any shares of its Class A common stock. All other stock repurchases during the six months ended June 30, 2018 and 2017 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.