Condensed Consolidated Statements of Operations (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Non-cash profits interest expense	$ 29,271	$ 19,517	$ 29,271	$ 19,517

The noncash expense attributable to profits interest shares granted to certain employees as compensation.

No definition available.

Name:	brss_ProfitsInterestCompensationExpense
Namespace Prefix:	brss_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration