Quarterly report pursuant to Section 13 or 15(d)

Document And Entity Information

v3.19.1
Document And Entity Information - shares
3 Months Ended
Mar. 31, 2019
Apr. 25, 2019
Document Information [Line Items]    
Entity Registrant Name GLOBAL BRASS & COPPER HOLDINGS, INC.  
Entity Central Index Key 0001533526  
Trading Symbol brss  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Small Business false  
Entity Common Stock, Shares Outstanding (in shares)   21,952,777
Document Type 10-Q  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Amendment Flag false