Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax rate, at federal statutory income tax rate, percent	21.00%		35.00%
Maximum measurement period to finalize accounting of tax	1 year
Income tax provision	$ 46.5	$ 61.7
Effective income tax rate, percent	24.90%	34.50%
Tax cuts and jobs act of 2017, reduction in federal tax rate, percent	14.00%
Effective income tax rate, offset by domestic production activities, percent	3.20%
Effective income tax rate, federal benefit of state tax deductions, percent	0.80%
Cash paid for taxes, net of refunds received	$ 10.3	$ 9.7