Income Taxes - Quarterly (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Effective Income Tax Rate, Percent	6.32%	24.77%
Statutory rate, Percent	35.00%	35.00%
Undistributed Earnings of Foreign Subsidiaries	$ 3.2		$ 0.8
Tax Liabilities, Undistributed Foreign Earnings	0.5		$ 0.1
Convergex Group [Member]
Income Tax Contingency [Line Items]
Taxes Payable	$ 5.3