Note 2 - Investments - Realized Gains and Losses Related to the Sale of Securities (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Gross gains	$ 163,220	$ 20,612	$ 216,011	$ 64,907
Gross losses	(3)	(26,537)	(398)	(289,785)
Realized gains (losses)	163,217	(5,925)	215,613	(224,878)
Gross gains	163,220	20,612	216,011	64,907
Gross losses	$ (3)	$ (26,537)	$ (398)	$ (289,785)

The gross gain realized from the sale, exchange, redemption, or retirement of securities, not separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

No definition available.

Name:	usac_GainOnSaleOfSecuritiesGross
Namespace Prefix:	usac_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration