Goodwill & Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 118,238	$ 108,755
Accumulated Impairment losses	(15,417)	(15,417)
Total	102,821	93,338
Acquisitions	13,606	8,566
Purchase adjustments	(79)
Foreign currency translation	643	925
Other	(4)	(8)
Goodwill	132,404	118,238
Accumulated impairment losses	(15,417)	(15,417)
Total	116,987	102,821
Learning Solutions [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	48,240	39,109
Accumulated Impairment losses	(2,079)	(2,079)
Total	46,161	37,030
Acquisitions	13,606	8,226
Purchase adjustments	(196)
Foreign currency translation	620	913
Other	(4)	(8)
Goodwill	62,266	48,240
Accumulated impairment losses	(2,079)	(2,079)
Total	60,187	46,161
Professional and Technical Services [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	45,520	45,520
Accumulated Impairment losses	(7,830)	(7,830)
Total	37,690	37,690
Acquisitions	0	0
Purchase adjustments	0
Foreign currency translation	0	0
Other	0	0
Goodwill	45,520	45,520
Accumulated impairment losses	(7,830)	(7,830)
Total	37,690	37,690
Sandy Training and Marketing [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	6,161	6,161
Accumulated Impairment losses	(5,508)	(5,508)
Total	653	653
Acquisitions	0	0
Purchase adjustments	0
Foreign currency translation	0	0
Other	0	0
Goodwill	6,161	6,161
Accumulated impairment losses	(5,508)	(5,508)
Total	653	653
Performance Readiness Group [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	9,795	9,795
Accumulated Impairment losses	0	0
Total	9,795	9,795
Acquisitions	0	0
Purchase adjustments	0
Foreign currency translation	0	0
Other	0	0
Goodwill	9,795	9,795
Accumulated impairment losses	0	0
Total	9,795	9,795
Energy Services [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	8,522	8,170
Accumulated Impairment losses	0	0
Total	8,522	8,170
Acquisitions	0	340
Purchase adjustments	117
Foreign currency translation	23	12
Other	0	0
Goodwill	8,662	8,522
Accumulated impairment losses	0	0
Total	$ 8,662	$ 8,522