Note 2 - Sales/Mergers/Acquisitions - Bates Companies (Details) - USD ($)		1 Months Ended	12 Months Ended
	Oct. 01, 2018	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 12, 2019	Dec. 31, 2016
Business Acquisition [Line Items]
Cash paid				$ 9,834,000	$ 7,803,000
Common stock consideration				81,637,000	30,880,000
Interest rate (as a percent)						5.375%
Business acquisition related costs				1,795,000	1,069,000
Intangibles				10,064,000	2,698,000
Goodwill		$ 74,748,000	$ 74,748,000	77,832,000	$ 28,334,000		$ 13,111,000
Bates Companies [Member]
Business Acquisition [Line Items]
Assets under management	$ 704,000,000
Voting interests acquired (as a percent)	100.00%
Cash paid	$ 3,000,000			$ 1,435,595
Cash consideration paid from operating cash	$ 1,500,000
Stock issued during period (in shares)				23,501
Stock consideration		3,000,000	$ 3,000,000
Number of shares expecting to issue based on 10-day volume weighted average of the closing stock price of the Company ending five days prior to closing			47,003
Business acquisition related costs				$ 394,000
Goodwill		3,700,000	$ 3,700,000
Other Liabilities. | Bates Companies [Member]
Business Acquisition [Line Items]
Business combination, contingent consideration		2,000,000	2,000,000
Customer Lists [Member] | Bates Companies [Member]
Business Acquisition [Line Items]
Intangibles		$ 1,600,000	$ 1,600,000
Promissory Note [Member] | Bates Companies [Member]
Business Acquisition [Line Items]
Repayment period (in years)	5 years
Frequency of installments	annual installments
Periodic payment of principal amount	$ 300,000
Interest rate (as a percent)	2.18%
Promissory Note [Member] | Other Liabilities. | Bates Companies [Member]
Business Acquisition [Line Items]
Promissory note	$ 1,500,000
Maximum | Bates Companies [Member]
Business Acquisition [Line Items]
Common stock consideration	$ 3,000,000
Common Stock [Member] | Bates Companies [Member]
Business Acquisition [Line Items]
Stock issued during period (in shares)		9,400	9,400