Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Statement of Cash Flows [Abstract]
Net income	$ 31.2	$ 31.2
Adjustments to reconcile net income to net cash provided by operating activities:
Gain from discontinued operations and disposal	0.0	(3.9)
Depreciation and amortization	21.3	13.0
Deferred financing costs	0.2	0.5
Deferred gain	(1.5)	(1.4)
Stock-based compensation expense	3.5	3.4
Pension expense, net of funding	(4.2)	(4.2)
Provision for doubtful accounts	0.5	0.3
Deferred income taxes	3.3	9.6
Changes in operating assets and liabilities, net of effects of acquisitions and discontinued operations	(2.2)	(31.4)
Net cash provided by continuing operating activities	52.1	17.1
Net cash (used for) provided by discontinued operating activities	(0.5)	0.8
Net cash provided by operating activities	51.6	17.9
Investing activities:
Purchases of properties and equipment	(5.3)	(4.8)
Payments for acquisitions, net of cash acquired	(269.2)	(102.6)
Other, net	0.2	(0.5)
Collection of cash provided to customer	0.0	6.0
Net cash used for continuing investing activities	(274.3)	(101.9)
Net cash (used for) provided by discontinued investing activities	(1.1)	88.0
Net cash used for investing activities	(275.4)	(13.9)
Financing activities:
Increase in revolving lines of credit, net	214.1	64.8
Payments on long-term borrowings	0.0	(43.4)
Payments of debt financing fees	(0.2)	(1.1)
Purchases of treasury stock	0.0	(33.8)
Redemptions of common stock to satisfy withholding taxes related to stock-based compensation	(2.5)	(2.6)
Cash dividends paid to stockholders	(12.6)	(12.8)
Proceeds from stock-based compensation activity	1.5	0.4
Other, net	(0.3)	(0.4)
Net cash provided by (used for) continuing financing activities	200.0	(28.9)
Net cash provided by discontinued financing activities	0.0	0.7
Net cash provided by (used for) financing activities	200.0	(28.2)
Effects of foreign exchange rate changes on cash and cash equivalents	1.3	(1.0)
Decrease in cash and cash equivalents	(22.5)	(25.2)
Cash and cash equivalents at beginning of year	50.7	76.0
Cash and cash equivalents at end of period	$ 28.2	$ 50.8