Quarterly report pursuant to Section 13 or 15(d)

Segment Information - Reconciliation of Adjusted EBITDA to Income Before Provision for Income Taxes (Detail)

v3.10.0.1
Segment Information - Reconciliation of Adjusted EBITDA to Income Before Provision for Income Taxes (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Segment Reporting Information [Line Items]        
Net sales $ 429.9 $ 359.4 $ 1,361.1 $ 1,153.7
Depreciation expense (5.3) (4.5) (15.6) (13.5)
Amortization expense (0.1) (0.1) (0.3) (0.1)
Interest expense, net (4.1) (4.2) (12.7) (13.6)
Net income attributable to noncontrolling interest 0.1 0.1 0.3 0.4
Unrealized (loss) gain on derivative contracts (b) (0.7) 0.3 (1.3) (1.1)
Refinancing costs (c) 0.0 (0.9) (1.6) (0.9)
Specified legal / professional expenses (d) 0.0 (0.5) 0.0 (0.5)
Lower of cost or market adjustment to inventory (e) (1.2) 0.7 (0.1) 0.8
Share-based compensation expense (f) (1.5) (2.0) (4.6) (6.3)
Step-up costs from acquisition accounting 0.0 0.0 (0.2) 0.0
Income before provision for income taxes 16.8 19.0 67.1 66.3
Insurance recoveries       7.4
Intersegment [Member]        
Segment Reporting Information [Line Items]        
Net sales 22.4 17.6 66.3 61.8
Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Adjusted EBITDA 33.7 33.7 116.6 105.7
Corporate and Other [Member]        
Segment Reporting Information [Line Items]        
Adjusted EBITDA (4.1) (3.6) (13.4) (4.6)
Olin Brass [Member]        
Segment Reporting Information [Line Items]        
Net sales 163.5 137.7 518.0 487.3
Olin Brass [Member] | Intersegment [Member]        
Segment Reporting Information [Line Items]        
Net sales 22.4 17.6 66.2 61.6
Olin Brass [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Adjusted EBITDA 11.4 11.8 45.5 38.7
Chase Brass [Member]        
Segment Reporting Information [Line Items]        
Net sales 149.0 144.8 480.1 439.9
Chase Brass [Member] | Intersegment [Member]        
Segment Reporting Information [Line Items]        
Net sales 0.0 0.0 0.0 0.1
Chase Brass [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Adjusted EBITDA 16.0 18.3 53.0 56.6
A.J. Oster [Member]        
Segment Reporting Information [Line Items]        
Net sales 117.4 76.9 363.0 226.5
A.J. Oster [Member] | Intersegment [Member]        
Segment Reporting Information [Line Items]        
Net sales 0.0 0.0 0.1 0.1
A.J. Oster [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Adjusted EBITDA $ 6.3 $ 3.6 $ 18.1 $ 10.4