Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Segment Information - Reconciliation of Adjusted EBITDA to Income Before Provision for Income Taxes and Equity Income (Detail) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Segment Reporting Information [Line Items]                      
Revenues $ 404.3 $ 429.9 $ 459.4 $ 471.8 $ 424.9 $ 359.4 $ 374.8 $ 419.5 $ 1,765.4 $ 1,578.6 $ 1,338.3
Depreciation expense                 (21.1) (18.5) (14.8)
Amortization of intangible assets                 (0.4) (0.1) (0.1)
Interest expense, net                 (16.8) (17.6) (26.2)
Net income attributable to noncontrolling interest                 0.4 0.6 0.6
Unrealized gain (loss) on derivative contracts                 (2.8) (0.8) 3.1
LIFO liquidation (loss)/gain (0.1)       (1.0)       (0.1) (1.0) (1.9)
Refinancing Costs                 (1.6) (0.9) (23.4)
Specified legal / professional expenses                 (0.4) (1.3) (1.2)
Lower of cost or market adjustment to inventory (2.8) (1.2) 0.2 0.9 2.8 0.7 (0.7) 0.8 (2.9) 3.6 1.7
Share-based compensation expense                 (6.7) (8.2) (6.9)
Restructuring and other business transformation charges                 0.0 (0.4) 0.0
Inventory step-up costs from acquisition accounting                 (0.2) (0.3) 0.0
Income before provision for income taxes and equity income $ 8.8 $ 16.8 $ 29.1 $ 21.2 $ 19.3 $ 19.0 $ 24.6 $ 22.7 75.9 85.6 49.5
Unusual or Infrequent Item, or Both, Insurance Proceeds                   7.4  
Operating Segments [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 1,765.4 1,578.6 1,338.3
Adjusted EBITDA                 146.6 139.2 136.3
Intersegment [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 87.7 79.2 76.5
Corporate [Member]                      
Segment Reporting Information [Line Items]                      
Adjusted EBITDA                 (18.1) (8.7) (17.7)
Interest expense, net                 (16.6) (17.3) (25.9)
LIFO liquidation (loss)/gain                 0.0 0.0 (0.1)
Olin Brass [Member] | Operating Segments [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 679.8 664.1 553.9
Adjusted EBITDA                 57.2 51.2 49.9
Interest expense, net                 (0.1) (0.3) (0.3)
LIFO liquidation (loss)/gain                 (0.2) (1.0) (1.6)
Olin Brass [Member] | Intersegment [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 87.5 79.0 75.5
Chase Brass [Member] | Operating Segments [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 612.1 591.0 501.7
Adjusted EBITDA                 66.3 73.2 68.0
LIFO liquidation (loss)/gain                 0.0 0.0 (0.3)
Chase Brass [Member] | Intersegment [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 0.0 0.1 1.0
A.J. Oster [Member] | Operating Segments [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 473.5 323.5 282.7
Adjusted EBITDA                 23.1 14.8 18.4
Interest expense, net                 (0.1) 0.0 0.0
LIFO liquidation (loss)/gain                 0.1 0.0 0.1
A.J. Oster [Member] | Intersegment [Member]                      
Segment Reporting Information [Line Items]                      
Revenues                 $ 0.2 $ 0.1 $ 0.0