Segment Information Segment Information (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Segment Reporting Information [Line Items]                      
Revenue $ 174,893 $ 195,616 $ 215,272 $ 175,673 $ 156,448 $ 164,454 $ 189,897 $ 168,585 $ 761,454 $ 679,384 $ 406,395
Income (loss) from continuing operations before income taxes                 70,977 13,270 19,324
Income tax provision (benefit)                 (17,647) 65,119 (2,522)
Net income from continuing operations 6,568 7,953 (7,140) 45,949 53,004 (8,549) 21,146 12,788 53,330 78,389 16,802
(Loss) Income from equity method investments                 5,875 (29,566) 7,085
Diversified Industrial
                     
Segment Reporting Information [Line Items]                      
Revenue                 629,396 634,964 367,124
Income (loss) from continuing operations before income taxes                 41,610 46,568 28,874
(Loss) Income from equity method investments                 1,796 8,712 21,178
Energy
                     
Segment Reporting Information [Line Items]                      
Revenue                 92,834 32,984 0
Income (loss) from continuing operations before income taxes                 25,034 6,558 0
(Loss) Income from equity method investments                 13,139 0 0
Financial Services
                     
Segment Reporting Information [Line Items]                      
Revenue                 21,155 14,921 10,803
Income (loss) from continuing operations before income taxes                 12,913 6,165 4,381
Corporate
                     
Segment Reporting Information [Line Items]                      
Revenue                 18,069 (3,485) 28,468
Income (loss) from continuing operations before income taxes                 (8,580) (46,021) (13,931)
(Loss) Income from equity method investments                 $ (9,060) $ (38,278) $ (14,093)