Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Telephone support and software repair services provided free in certain instances, period	3 months
Allowance for doubtful accounts and estimated sales returns	$ 231	$ 435	$ 735
Weighted average common shares excluded from dilutive shares outstanding	2,852,028	2,628,862
Unamortized capitalized software	$ 18,100	$ 15,400
Amounts of software under development	5,800	1,800
Total other intangibles - accumulated amortization	68,734	63,685	$ 57,194
Samples cost	400	900
Advertising expenses	1,400	1,200
Accounting Standards Update 2015-03 | New Accounting Pronouncement Early Adoption Effect
Significant Accounting Policies [Line Items]
Reclassification of unamortized debt issuance costs from other assets to reduction in long-term debt		2,300
Product Revenue
Significant Accounting Policies [Line Items]
Prior period reclassification adjustment	1,400
Goodwill and Other Intangible Assets
Significant Accounting Policies [Line Items]
Total other intangibles - accumulated amortization	21,900	20,600
Acquired Curriculum and Technology
Significant Accounting Policies [Line Items]
Total other intangibles - accumulated amortization	$ 22,100	19,600
Acquired Publishing Rights
Significant Accounting Policies [Line Items]
Expected economic life of product	10 years
Total other intangibles - accumulated amortization	$ 24,700	23,400
Pre-Publication Costs
Significant Accounting Policies [Line Items]
Expected economic life of product	5 years
Total other intangibles - accumulated amortization	$ 19,300	15,700
Interest capitalized	$ 200	$ 100
Minimum
Significant Accounting Policies [Line Items]
Subscription period	12 months
Minimum | Goodwill and Other Intangible Assets
Significant Accounting Policies [Line Items]
Expected economic life of product	7 years
Minimum | Software and Software Development Costs
Significant Accounting Policies [Line Items]
Expected economic life of product	3 years
Minimum | Acquired Curriculum and Technology
Significant Accounting Policies [Line Items]
Expected economic life of product	6 years
Maximum | Goodwill and Other Intangible Assets
Significant Accounting Policies [Line Items]
Expected economic life of product	15 years
Maximum | Software and Software Development Costs
Significant Accounting Policies [Line Items]
Expected economic life of product	5 years
Maximum | Acquired Curriculum and Technology
Significant Accounting Policies [Line Items]
Expected economic life of product	7 years