Note 1 - Summary of Significant Accounting Policies (Details Textual)		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Jan. 01, 2019 USD ($)
Cumulative Effect on Retained Earnings, Net of Tax, Total			$ 2,735,000
Incremental Costs of Obtaining a Contract, Deferred During Period		$ 3,600,000	2,600,000
Capitalized Contract Cost, Net, Noncurrent		4,204,000	3,484,000
Capitalized Computer Software, Additions		4,100,000	4,000,000
Asset Impairment Charges, Total		0	0	$ 0
Impairment of Intangible Assets (Excluding Goodwill), Total		0	0	0
Goodwill, Impairment Loss		0	0	0
Goodwill, Ending Balance		57,935,000	57,831,000	58,021,000
Income Tax Credits and Adjustments		24,000	0	$ 4,000
Cash Equivalents, at Carrying Value, Total		3,700,000	1,800,000
Operating Lease, Right-of-Use Asset		1,628,000			$ 2,287,000
Accrued Liabilities and Prepaid Expenses, Net					43,000
Sales and Excise Tax Payable		775,000
Excess Loss Coverage Per Person		150,000
Self Insurance Reserve, Current		$ 270,000
Common Class B [Member]
Percent of Amount of Dividend or Other Distribution Payable on each Share of Common Stock			0.1666%
Stock Options Excluded from Computation of Earnings Per Share, Amount | shares				1,858
Common Class A [Member]
Stock Options Excluded from Computation of Earnings Per Share, Amount | shares		16,221	93,346	104,647
Other Current Liabilities and Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Total		$ 1,663,000			$ 2,331,000
Canadian Subsidiary [Member]
Goodwill, Ending Balance		$ 2,300,000
Number of Customers		1
Selling, General and Administrative Expenses [Member]
Capitalized Contract Cost, Impairment Loss		$ 22,000	$ 51,000
Minimum [Member]
Capitalized Contract Cost, Amortization Period			3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] | Computer Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] | Software and Software Development Costs [Member]
Property, Plant and Equipment, Useful Life			1 year
Minimum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life			7 years
Maximum [Member]
Capitalized Contract Cost, Amortization Period			5 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life			10 years
Maximum [Member] | Computer Equipment [Member]
Property, Plant and Equipment, Useful Life			5 years
Maximum [Member] | Software and Software Development Costs [Member]
Property, Plant and Equipment, Useful Life			5 years
Maximum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life			40 years
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 2,700,000
Cumulative Effect on Retained Earnings, Tax	814,000
Accounting Standards Update 2014-09 [Member] | Changes Related to Contract Costs [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	2,600,000
Cumulative Effect on Retained Earnings, Tax	776,000
Cumulative Effect on Retained Earnings, before Tax	$ 3,400,000