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Note 6 - Related-party Transactions (Details Textual)			3 Months Ended				5 Months Ended	6 Months Ended			7 Months Ended	9 Months Ended		12 Months Ended
Note 6 - Related-party Transactions (Details Textual)	May 23, 2018 USD ($)	Sep. 08, 2016 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	May 31, 2016	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Aug. 31, 2018 USD ($)
Related Party Transaction, Expenses from Transactions with Related Party			$ 3,000,000		$ 8,631,000							$ 19,406,000	$ 24,111,000
Payments for Cash Collateral Deposits												$ 965,000
Merhold Property Trust [Member]
Number Of Vehicles Subleased												20
Number Of Vehicles Leased												172
Lessee, Operating Lease, Term of Contract			4 years					4 years				4 years
SBS [Member]
Number of Merchandising Specialists												3,900	3,900
Number of National, Regional, and District Administrators												54	60
Withheld Final Mark-up Compensation Due to Related Party	$ 125,000
Additional Funding for Field Specialist Payments												$ 11,000
Estimated Additional Field Specialist Payments	$ 120,000
Related Party Transaction, Reimbursement of Legal Expenses from Transaction with Related Party				$ 44,000		$ 93,000			$ 104,000	$ 179,000		105,000	$ 218,000
Payments for Cash Collateral Deposits, Allocated to Related Party												379,000
SBS [Member] \| Post-termination Expenses [Member]
Loss Contingency, Estimate of Possible Loss			$ 105,000					$ 105,000				105,000			$ 120,000
SBS [Member] \| Domestic Merchandising Specialists Field Force [Member]
Payments for Related Party Services												$ 15,400,000	$ 19,600,000	$ 25,900,000
Percent Of Service Provided By Related Party												36.00%	75.00%	77.00%
SBS [Member] \| Domestic Field Management [Member]
Payments for Related Party Services												$ 2,700,000	$ 3,200,000
Percent Of Service Provided By Related Party												68.00%	90.00%
Related Party Transaction, Expenses from Transactions with Related Party												$ 18,200,000	$ 22,800,000
SBS [Member] \| Cost Plus Fees [Member]
Related Party Transaction, Rate							4.00%				2.00%	2.96%
SAS [Member] \| Post-termination Expenses [Member]
Loss Contingency, Estimate of Possible Loss			$ 42,000					$ 42,000				$ 42,000			$ 45,000
NRS [Member]
Majority Interest Ownership Percentage By Parent			51.00%					51.00%				51.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			49.00%					49.00%				49.00%
Resource Plus, Inc [Member]
Majority Interest Ownership Percentage By Parent			51.00%					51.00%				51.00%
Mr. Justus [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			49.00%					49.00%				49.00%
C M R Meridien [Member]
Majority Interest Ownership Percentage By Parent			51.00%					51.00%				51.00%
Mr. Brian Mason Mr. Garry Bristow And Mr. Adrian Wingfield [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			49.00%					49.00%				49.00%
Mr. Mason [Member] \| Merhold Property Trust [Member]
Related Party Ownership Percentage												50.00%
Mr. Mason [Member] \| Merhold Holding Trust [Member]
Related Party Ownership Percentage												46.70%
Mr. Mason and Mr. Bristow [Member] \| Merhold Cape Property Trust [Member]
Related Party Ownership Percentage												50.00%
Mr. Bristow [Member] \| Merhold Holding Trust [Member]
Related Party Ownership Percentage												20.00%
Mr. Wingfield [Member] \| Merhold Holding Trust [Member]
Related Party Ownership Percentage												33.30%
NDS [Member]
Majority Interest Ownership Percentage By Parent			51.00%					51.00%				51.00%
Mr And Ms Yilmaz [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			49.00%					49.00%				49.00%
Mr. Juan F. Medina Domenzain [Member] \| CON [Member]
Related Party Ownership Percentage												90.00%
SMF [Member]
Payments for Cash Collateral Deposits, Allocated to Related Party												$ 296,000
All Others [Member]
Payments for Cash Collateral Deposits, Allocated to Related Party												290,000
SAS, SBS, and SMF [Member] \| Affinity Insurance [Member]
Estimated Reimbursement on Advances												$ 675,000
Robert G. Brown and William H. Bartels [Member]
Related Party Ownership Percentage												59.00%
SBS And SAS [Member]
Due from Related Parties, Total			$ 675,000	675,000				$ 675,000	$ 675,000			$ 675,000
Reserve for Related-party Receivables, Amount Recorded During Period				$ 675,000				$ 675,000
SPAR InfoTech, Inc. [Member] \| Assistance Provided in Connection to Brazilian Acquisition [Member]
Related Party Transaction, Amounts of Transaction		$ 49,000