Acquisitions (Details Textual) - USD ($) $ in Thousands						3 Months Ended	12 Months Ended
	Aug. 31, 2017	Apr. 01, 2017	Feb. 01, 2017	Oct. 01, 2016	Mar. 01, 2016	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life							3 years 4 months
Goodwill						$ 144,835	$ 144,835	$ 127,772	$ 121,975
Accounts payable and accrued liability						2,700	2,700	3,600
Business acquisition contingent consideration, other long term liability						1,500	$ 1,500	$ 1,700
YouTrain [Member]
Business Acquisition [Line Items]
Cash purchase price	$ 4,898
Consideration transferred, completion accounts payment						$ 200
Fair value of contingent consideration	0
Goodwill	3,268
Business Combination, Consideration Transferred, Estimated Completion Accounts Payment	180
Business Combination, Consideration Transferred	5,078
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	673
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	234
Fixed assets	215
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	5,703
Accrued expenses	348
Billings in excess of costs and estimated earnings on uncompleted contracts	28
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	249
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	625
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	5,078
YouTrain [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	0
YouTrain [Member] | Customer-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	1,313
YouTrain [Member] | Marketing-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	0
CLS [Member] [Member]
Business Acquisition [Line Items]
Cash purchase price	436
Fair value of contingent consideration	888
Goodwill	1,090
Business Combination, Consideration Transferred, Estimated Completion Accounts Payment	0
Business Combination, Consideration Transferred	1,324
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	0
Fixed assets	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	1,343
Accrued expenses	19
Billings in excess of costs and estimated earnings on uncompleted contracts	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	19
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	1,324
CLS [Member] [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	0
CLS [Member] [Member] | Customer-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	253
CLS [Member] [Member] | Marketing-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 0
Emantras [Member]
Business Acquisition [Line Items]
Cash purchase price		$ 3,191
Fair value of contingent consideration		220
Goodwill		3,156
Business Combination, Consideration Transferred, Estimated Completion Accounts Payment		0
Business Combination, Consideration Transferred		3,411
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables		0
Fixed assets		50
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		4,024
Accrued expenses		558
Billings in excess of costs and estimated earnings on uncompleted contracts		55
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		613
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		3,411
Emantras [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		0
Emantras [Member] | Customer-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		818
Emantras [Member] | Marketing-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 0
Jencal Training [Member]
Business Acquisition [Line Items]
Cash purchase price					$ 2,500
Additional consideration contingent on achieving certain earnings targets					200
Goodwill					1,800
Jencal Training [Member] | Intangible Assets [Member]
Business Acquisition [Line Items]
Amortizable intangible assets					$ 1,400
Acquired finite-lived intangible assets, weighted average useful life					4 years
Maverick Solutions [Member]
Business Acquisition [Line Items]
Cash purchase price				$ 4,639
Fair value of contingent consideration				5,166
Additional consideration contingent on achieving certain earnings targets				10,000
Goodwill				8,111
Business Combination, Consideration Transferred				9,805
Fixed assets				63
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				10,166
Accrued expenses				38
Billings in excess of costs and estimated earnings on uncompleted contracts				323
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				361
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net				$ 9,805
Maverick Solutions [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life				3 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 649
Maverick Solutions [Member] | Marketing-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life				2 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$ 124
McKinney Rogers [Member]
Business Acquisition [Line Items]
Cash purchase price			$ 3,259
Fair value of contingent consideration			4,505
Goodwill			5,196
Business Combination, Consideration Transferred, Estimated Completion Accounts Payment			0
Business Combination, Consideration Transferred			7,764
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables			0
Fixed assets			0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets			8,674
Accrued expenses			44
Billings in excess of costs and estimated earnings on uncompleted contracts			866
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent			0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			910
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			7,764
McKinney Rogers [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			2,704
McKinney Rogers [Member] | Customer-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			653
McKinney Rogers [Member] | Marketing-Related Intangible Assets [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			$ 121