Amount of revenue, fees and commissions earned per month from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

No definition available.

RELATED PARTY TRANSACTIONS (Details)				3 Months Ended		6 Months Ended		12 Months Ended
RELATED PARTY TRANSACTIONS (Details)	Mar. 01, 2018 USD ($)	Feb. 01, 2017 USD ($)	Mar. 01, 2015 USD ($) Office	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
BKF Capital
RELATED PARTY TRANSACTIONS
Revenue from related parties				$ 750	$ 750	$ 3,000	$ 2,250
Costs paid to related party				2,465		7,395		$ 0
Receivable from related party				0		0		0
Payable to related party				0		0
BKF Capital \| Westlake Village, CA office
RELATED PARTY TRANSACTIONS
Number of offices leased out \| Office			1
Revenue from related parties per month		$ 250	$ 1,000
BKF Capital \| Charleston, SC office
RELATED PARTY TRANSACTIONS
Revenue from related parties per month	$ 2,465
Qualstar
Due from Qualstar
Due from Qualstar, beginning balance				22,000		17,000	2,000	2,000
Billed to Qualstar by Interlink				81,000	1,000	145,000	7,000
Paid by Qualstar to Interlink				(93,000)	(1,000)	(152,000)	(9,000)
Due from Qualstar, end balance				10,000		10,000		17,000
Due to Qualstar
Due to Qualstar, beginning balance				1,000	1,000		1,000	$ 1,000
Billed to Interlink by Qualstar				4,000	3,000	8,000	5,000
Paid by Interlink to Qualstar				(4,000)	(3,000)	(7,000)	(5,000)
Due to Qualstar, end balance				$ 1,000	$ 1,000	$ 1,000	$ 1,000