Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net sales	$ 463.6	$ 328.3	$ 817.9	$ 657.5
Cost of sales	373.2	279.9	659.1	545.9
Gross profit	90.4	48.4	158.8	111.6
Operating costs and expenses:
Engineering, selling and administrative expenses	63.6	49.7	121.3	105.6
Amortization of intangible assets	0.1	0.1	0.2	0.2
Restructuring (income) expense	0.0	0.2	(0.1)	1.7
Total operating costs and expenses	63.7	50.0	121.4	107.5
Operating income (loss)	26.7	(1.6)	37.4	4.1
Other income (expense):
Interest expense	(7.3)	(7.2)	(14.4)	(14.4)
Amortization of deferred financing fees	(0.3)	(0.3)	(0.7)	(0.7)
Other income (expense) - net	2.8	(2.9)	0.7	(6.9)
Total other expense - net	(4.8)	(10.4)	(14.4)	(22.0)
Income (loss) before income taxes	21.9	(12.0)	23.0	(17.9)
Provision for income taxes	4.0	0.7	8.2	2.6
Net income (loss)	$ 17.9	$ (12.7)	$ 14.8	$ (20.5)
Per Share Data
Basic income (loss) per common share	$ 0.51	$ (0.37)	$ 0.42	$ (0.59)
Diluted income (loss) per common share	$ 0.50	$ (0.37)	$ 0.42	$ (0.59)
Weighted average shares outstanding - basic	34,903,657	34,519,889	34,856,950	34,827,582
Weighted average shares outstanding - diluted	35,602,042	34,519,889	35,460,779	34,827,582