Goodwill and Other Intangibles, Net - Reconciliation (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Gross Goodwill	$ 176,149	$ 91,170	$ 91,131
Accumulated impairments	(45,219)	(45,219)	(3,769)
Goodwill [Roll Forward]
Balance at beginning of year	45,951	87,362
Acquisitions	85,204	0
Impairment	0	(41,450)
Currency translation adjustment	0	(37)
Other adjustments	(225)	76
Balance at end of year	130,930	45,951
Diversified
Goodwill [Line Items]
Gross Goodwill	111,278	26,299	26,260
Accumulated impairments	0	0	0
Goodwill [Roll Forward]
Balance at beginning of year	26,299	26,260
Acquisitions	85,204	0
Impairment	0	0
Currency translation adjustment	0	(37)
Other adjustments	(225)	76
Balance at end of year	111,278	26,299
Energy
Goodwill [Line Items]
Gross Goodwill	64,790	64,790	64,790
Accumulated impairments	(45,219)	(45,219)	(3,769)
Goodwill [Roll Forward]
Balance at beginning of year	19,571	61,021
Acquisitions	0	0
Impairment	0	(41,450)
Currency translation adjustment	0	0
Other adjustments	0	0
Balance at end of year	19,571	19,571
Corporate
Goodwill [Line Items]
Gross Goodwill	81	81	81
Accumulated impairments	0	0	$ 0
Goodwill [Roll Forward]
Balance at beginning of year	81	81
Acquisitions	0	0
Impairment	0	0
Currency translation adjustment	0	0
Other adjustments	0	0
Balance at end of year	$ 81	$ 81