QUARTERLY RESULTS (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Sales	$ 371.5	$ 356.5	$ 367.3	$ 332.8	$ 354.6	$ 327.7	$ 323.4	$ 296.6		$ 1,428.1	$ 1,302.3	$ 1,132.9
Gross profit	144.1	140.4	140.7	123.8	131.7	122.8	119.3	107.7		549.0	481.5	414.6
Net earnings	$ 10.3	$ 17.5	$ 21.7	$ 18.0	$ 24.6	$ 20.3	$ 13.1	$ 15.3		$ 67.5	$ 73.3	$ 80.2
Earnings per share—Basic (in dollars per share)	$ 0.21	$ 0.36	$ 0.44	$ 0.37	$ 0.50	$ 0.42	$ 0.27	$ 0.31		$ 1.38	$ 1.51	$ 1.66
Earnings per share—Diluted (in dollars per share)	$ 0.21	$ 0.35	$ 0.44	$ 0.37	$ 0.50	$ 0.41	$ 0.27	$ 0.31		$ 1.36	$ 1.49	$ 1.63
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pension settlement charges	$ (10.5)	$ (9.8)	$ (0.5)	$ (0.2)	$ 0.5	$ 0.6	$ 4.6			$ 21.0	$ 5.7	$ 2.2
Restructuring charges	0.6	$ 0.1		$ 0.1						0.8	2.6	2.2
Write-off of property, plant, and equipment	$ 6.5									0.0	0.0	16.3
Results include impact of Tax Cuts and Jobs Act					1.7				$ 26.6		1.7
Corporate
Quarterly Financial Information Disclosure [Abstract]
Sales										0.0	0.0	0.0
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Acquisition costs					0.2	0.2	0.5	$ 1.0			1.3
Office
Quarterly Financial Information Disclosure [Abstract]
Sales										873.8	797.1	733.3
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Pension settlement charges										21.0	5.7	2.2
Restructuring charges					$ 0.1	$ 1.2	$ 0.8	$ 0.5		$ 0.8	$ 2.6	2.2
Write-off of property, plant, and equipment												$ 16.3