Acquisitions HNH (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 12 Months Ended 11 Months Ended 0 Months Ended 2 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 1 Months Ended 8 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2011
BNS
SWH
Feb. 02, 2011
BNS
SWH
May 31, 2012
HNH
Zaklad [Member]
Dec. 31, 2012
HNH
Zaklad [Member]
Nov. 05, 2012
HNH
Zaklad [Member]
Dec. 31, 2012
HNH
Hickman
Jul. 05, 2011
HNH
DGT
Jul. 31, 2011
HNH
DGT
May 31, 2010
HNH
DGT
Mar. 23, 2011
HNH
Tiger Claw
May 31, 2010
SPH
HNH
Dec. 31, 2010
SPH
HNH
May 07, 2010
SPH
HNH
May 07, 2010
HNH
SPH
Business Acquisition [Line Items]                                  
Business Combination, Pro Forma Information, Acquired Manufacturing Profit in Inventory Included in Continuing Operations                             $ 7,825    
Purchase price         50,463     4,000 8,400       8,500        
Business Acquisition, Purchase Price Allocation, Working Capital               3,100 2,700                
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment               2,200 1,200                
Business Acquisition, Purchase Price Allocation, Noncurrent Liabilities, Long-term Debt               1,600                  
Revenues since acquisition date, pro forma       32,984     1,700                    
Pretax income from continuing operations since acquisition date, pro forma       4,536     100                    
Business Combination, Pro Forma Information, Intercompany Sales Since Acquisition Date, Actual             1,200                    
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets                 1,500                
Goodwill, Period Increase (Decrease)                 3,300                
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High                 1,500                
Business Acquisition, Contingent Consideration, at Fair Value                 200                
Additional shares of common stock acquired (in shares)                   193,305       57,801      
Acquisition price, portion paid in cash                   1,933              
Investment owned (in shares)                   1,977,023           6,123,876 6,066,075
Noncontrolling interest (as a percent)           100.00%       51.10%       50.30%      
Fair value basis upon acquisition of controlling interest in DGT                   13,500              
Acquisition-date fair value of previously held equity interest                   21,389             26,084
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net                             8,670    
Net investment gains                       8,177          
Fair value of net assets acquired by SPH                   32,687              
Investments in associated companies 35,096 128,218               23,709              
Bargain purchase gain 0 8,978 0               8,978            
Noncontrolling interest, parent ownership (as a percent)                               49.80%  
Business Combination, Pro Forma Information, Acquired Manufacturing Profit in Inventory                             $ 9,538