Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Operating activities:
Net income	$ 32.8		$ 26.9	$ 50.3	$ 39.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization				19.3	17.6
Deferred financing costs				0.2	0.2
Deferred gain				0.0	(0.9)	$ (1.9)
Stock-based compensation expense				4.2	4.0
Pension expense, net of funding				(0.1)	(3.2)
Changes in fair value of contingent consideration and deferred payment				0.8	0.6
Deferred income taxes				4.0	2.0
Changes in operating assets and liabilities				(52.9)	(22.3)
Net cash provided by operating activities				25.8	37.8
Investing activities:
Purchases of properties and equipment				(9.4)	(7.0)
Proceeds from acquisition-related activity				0.0	3.0
Other, net				0.0	0.1
Net cash used for investing activities				(9.4)	(3.9)
Financing activities:
Decrease in revolving lines of credit, net				(3.1)	(26.6)
Purchases of treasury stock				(1.0)	0.0
Redemptions of common stock to satisfy withholding taxes related to stock-based compensation				(1.6)	(0.3)
Cash dividends paid to stockholders	(4.8)	$ (4.8)	(4.8)	(9.6)	(9.0)
Proceeds from stock-based compensation activity				0.0	0.9
Other, net				(0.1)	0.1
Net cash used for financing activities				(15.4)	(34.9)
Effects of foreign exchange rate changes on cash and cash equivalents				0.2	(0.5)
Increase (decrease) in cash and cash equivalents				1.2	(1.5)
Cash and cash equivalents at beginning of year		$ 37.4		37.4	37.5	37.5
Cash and cash equivalents at end of period	$ 38.6		$ 36.0	$ 38.6	$ 36.0	$ 37.4