Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income tax provision and effective tax rate
Income tax provision	$ 12,918	$ 711	$ 19,800	$ 12,780
Effective income tax rate (as a percent)	39.90%	13.40%	22.70%	35.20%
Other information
Increase in income tax expense	$ 12,207
Stock-based compensation, options	1,833		$ 14,874
Decrease related to settlement with IRS			337
Decrease in effective tax rate due to settlement of prior period tax positions		$ 1,300	660
Decrease related to tax returns filed during the period	481		481
RowdMap
Other information
Restricted stock, nondeductible	$ 2,358		$ 2,358