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Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Incremental Costs of Obtaining a Contract, Deferred During Period		$ 2,600,000
Capitalized Contract Cost, Amortization		2,500,000
Capitalized Computer Software, Additions		4,000,000	$ 3,000,000
Asset Impairment Charges, Total		0	0	$ 0
Impairment of Intangible Assets (Excluding Goodwill), Total		0	0	0
Goodwill, Impairment Loss		0	0	0
Income Tax Credits and Adjustments		0	4,000	$ 77,000
Cash Equivalents, at Carrying Value, Total		1,800,000	$ 34,500,000
Loss Contingency Accrual, Ending Balance		0
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 2,735,000
Common Class A [Member]
Stock Options Excluded from Computation of Earnings Per Share, Amount		93,346	104,647	546,910
Common Class B [Member]
Stock Options Excluded from Computation of Earnings Per Share, Amount			1,858	83,440
Direct Operating Costs [Member]
Capitalized Contract Cost, Amortization		$ 83,000
Selling, General and Administrative Expenses [Member]
Capitalized Contract Cost, Amortization		2,300,000
Capitalized Contract Cost, Impairment Loss		$ 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
Accounting Standards Update 2016-02 [Member] \| Minimum [Member] \| Scenario, Forecast [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 2,300,000
Accounting Standards Update 2016-02 [Member] \| Maximum [Member] \| Scenario, Forecast [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 3,000,000