Guarantor and Non-Guarantor Financial Statements - Condensed Consolidated Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Supplemental Cash Flow Information [Line Items]
Operating activities	$ 65,767	$ (94,948)
Investing activities	(112,423)	(38,074)
Financing activities	43,207	116,021
Increase (decrease) in cash	(3,449)	(17,001)
Effect of exchange rate on cash	(5,839)	2,246
Cash - beginning of period	46,127	56,202
Cash - end of period	36,839	41,447
MRC Global Inc [Member]
Supplemental Cash Flow Information [Line Items]
Operating activities	(333,300)	(800)
Investing activities	(200)	(100)
Financing activities	333,400
Increase (decrease) in cash	(100)	(900)
Cash - beginning of period	100	1,100
Cash - end of period		200
Issuer [Member]
Supplemental Cash Flow Information [Line Items]
Operating activities	346,000	(91,300)
Investing activities	(51,600)	3,700
Financing activities	(299,400)	90,200
Increase (decrease) in cash	(5,000)	2,600
Effect of exchange rate on cash	7,300	3,200
Cash - beginning of period	4,800	4,400
Cash - end of period	7,100	10,200
Guarantors [Member]
Supplemental Cash Flow Information [Line Items]
Operating activities	8,800	5,800
Investing activities	(9,000)	(5,800)
Increase (decrease) in cash	(200)
Cash - beginning of period	200
Non-Guarantors [Member]
Supplemental Cash Flow Information [Line Items]
Operating activities	44,300	(8,600)
Investing activities	(97,100)	(35,900)
Financing activities	54,700	25,800
Increase (decrease) in cash	1,900	(18,700)
Effect of exchange rate on cash	(13,200)	(1,000)
Cash - beginning of period	41,000	50,700
Cash - end of period	29,700	31,000
Elim [Member]
Supplemental Cash Flow Information [Line Items]
Operating activities	0
Investing activities	45,500
Financing activities	$ (45,500)