Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ 960	$ 27,305	$ 29,472	$ 70,273
Income Tax Disclosure [Line Items]
Effective income tax rate	(49.60%)	36.30%	42.00%	31.60%
Valuation allowance	$ 14,200		$ 14,200			$ 9,900
Unrecognized tax benefits	1,500		1,500			$ 1,300
Unrecognized tax benefits that would impact the Company's effective tax rate	1,300		1,300
Unrecognized tax benefits that would impact goodwill	$ 200		$ 200
Forecast
Income Tax Disclosure [Line Items]
Effective income tax rate					41.70%