Acquisitions - Narrative (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended							0 Months Ended	12 Months Ended			12 Months Ended
	Dec. 31, 2013 Service_Center	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Trade name	Dec. 31, 2013 Customer relationships	Dec. 31, 2013 Non-compete agreements	Dec. 31, 2013 Developed technology	Dec. 31, 2011 Tube Supply	Dec. 31, 2013 Tube Supply Service_Center	Dec. 31, 2011 Tube Supply	Dec. 15, 2011 Tube Supply	Dec. 31, 2013 Tube Supply Trade name	Dec. 31, 2013 Tube Supply Customer relationships	Dec. 31, 2013 Tube Supply Non-compete agreements	Dec. 31, 2013 Tube Supply Developed technology
Business Acquisition [Line Items]
Business Acquisition, Percentage of Outstanding Common Shares Acquired											100.00%
Service centers	46								2
Total purchase price		$ 184,385
Business Acquisition, Cost of Acquired Entity, Transaction Costs								4,260		4,260
Acquired Intangible Assets, Weighted Average Useful Life	10 years 10 months 5 days			9 years 6 months 29 days	11 years 3 months 15 days	3 years	3 years		11 years 5 months
Intangible assets useful lives						3 years	3 years					10 years	12 years	3 years	3 years
Off-market lease unfavorable noncurrent	1,465	2,168
Off-market Lease, Current	703	645
Business combination, sales of acquiree since acquisition date, actual								7,648
Business combination, earnings or loss of acquiree since acquisition date, actual								901
Loss on extinguishment of debt	(2,606)	0	(6,153)							(6,153)
Interest Expense										$ 7,366