Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Principles of Consolidation - Statement of Operations (Details)

v3.10.0.1
Basis of Presentation and Principles of Consolidation - Statement of Operations (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]        
Net sales $ 429.9 $ 359.4 $ 1,361.1 $ 1,153.7
Cost of sales (387.0) (315.8) (1,211.3) (1,015.3)
Gross profit 42.9 43.6 149.8 138.4
Selling, general and administrative expenses (22.0) (19.4) (68.5) (61.6)
Operating income 20.9 24.2 81.3 76.8
Interest expense (4.1) (4.4) (12.7) (13.9)
Loss on extinguishment of debt 0.0 (0.2) (0.5) (0.2)
Other (expense) income, net 0.0 (0.6) (1.0) 3.6
Income before provision for income taxes 16.8 19.0 67.1 66.3
Provision for income taxes (1.9) (6.6) (15.2) (20.4)
Net income 14.9 12.4 51.9 45.9
Net income attributable to noncontrolling interest (0.1) (0.1) (0.3) (0.4)
Net income attributable to Global Brass and Copper Holdings, Inc. $ 14.8 $ 12.3 $ 51.6 $ 45.5
Net income attributable to Global Brass and Copper Holdings, Inc. per common share:        
Basic (in usd per share) $ 0.67 $ 0.56 $ 2.35 $ 2.10
Diluted (in usd per share) $ 0.66 $ 0.56 $ 2.31 $ 2.06
Weighted average common shares outstanding:        
Basic (in shares) 22.1 21.8 22.0 21.7
Diluted (in shares) 22.4 22.1 22.3 22.1
Previously Reported [Member]        
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]        
Net sales   $ 378.6   $ 1,149.3
Cost of sales   (334.8)   (1,010.9)
Gross profit   43.8   138.4
Selling, general and administrative expenses   (19.4)   (61.6)
Operating income   24.4   76.8
Interest expense   (4.4)   (13.9)
Loss on extinguishment of debt   (0.2)   (0.2)
Other (expense) income, net   (0.6)   3.6
Income before provision for income taxes   19.2   66.3
Provision for income taxes   (6.7)   (20.4)
Net income   12.5   45.9
Net income attributable to noncontrolling interest   (0.1)   (0.4)
Net income attributable to Global Brass and Copper Holdings, Inc.   $ 12.4   $ 45.5
Net income attributable to Global Brass and Copper Holdings, Inc. per common share:        
Basic (in usd per share)   $ 0.57   $ 2.10
Diluted (in usd per share)   $ 0.56   $ 2.06
Weighted average common shares outstanding:        
Basic (in shares)   21.8   21.7
Diluted (in shares)   22.1   22.1
Restatement Adjustment [Member] | Accounting Standards Update 2014-09 [Member]        
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]        
Net sales   $ (19.2)   $ 4.4
Cost of sales   19.0   (4.4)
Gross profit   (0.2)   0.0
Selling, general and administrative expenses   0.0   0.0
Operating income   (0.2)   0.0
Interest expense   0.0   0.0
Loss on extinguishment of debt   0.0   0.0
Other (expense) income, net   0.0   0.0
Income before provision for income taxes   (0.2)   0.0
Provision for income taxes   0.1   0.0
Net income   (0.1)   0.0
Net income attributable to noncontrolling interest   0.0   0.0
Net income attributable to Global Brass and Copper Holdings, Inc.   $ (0.1)   $ 0.0
Net income attributable to Global Brass and Copper Holdings, Inc. per common share:        
Basic (in usd per share)   $ (0.01)   $ 0.00
Diluted (in usd per share)   $ 0.00   $ 0.00
Weighted average common shares outstanding:        
Basic (in shares)   0.0   0.0
Diluted (in shares)   0.0   0.0