Note 10 - Long-term Debt - Long-term Debt (Details) - USD ($)		Dec. 31, 2019	Dec. 31, 2018
Total debt		$ 21,261,997	$ 14,565,295
Less: current portion		(2,726,981)	(1,455,441)
Long-term debt		18,535,016	13,109,854
East West Bank [Member]
Total debt	[1]	$ 6,989,016	5,053,539
East West Bank [Member] | Minimum [Member]
Interest rate	[1]	3.94%
East West Bank [Member] | Maximum [Member]
Interest rate	[1]	4.25%
Capital Bank [Member]
Interest rate	[2]	3.85%
Total debt	[2]	$ 4,967,075	5,138,988
Bank of America [Member]
Total debt	[3]	$ 4,263,663	1,363,211
Bank of America [Member] | Minimum [Member]
Interest rate	[3]	3.90%
Bank of America [Member] | Maximum [Member]
Interest rate	[3]	5.51%
JP Morgan [Member]
Interest rate	[4]	3.07%
Total debt	[4]	$ 2,702,371
Bank of Montreal [Member]
Total debt	[5]	$ 508,564	2,256,724
Bank of Montreal [Member] | Minimum [Member]
Interest rate	[5]	5.87%
Bank of Montreal [Member] | Maximum [Member]
Interest rate	[5]	5.99%
Peoples United Bank [Member]
Total debt	[5]	$ 1,114,993
Peoples United Bank [Member] | Minimum [Member]
Interest rate	[5]	5.75%
Peoples United Bank [Member] | Maximum [Member]
Interest rate	[5]	7.53%
Other Finance Companies [Member]
Total debt	[5]	$ 716,315	$ 752,833
Other Finance Companies [Member] | Minimum [Member]
Interest rate	[5]	3.90%
Other Finance Companies [Member] | Maximum [Member]
Interest rate	[5]	6.14%

[1] Guaranteed by two shareholders of the Company, as well as five subsidiaries of the Company, Han Feng, TT, MFD, R&N Holding and R&N Lexington. Also secured by assets of Han Feng and R&N Lexington and R&N Holding, two real properties of R&N Holding, and a parcel of real property owned by R&N Lexington. Balloon payment of $2,293,751 is due in 2027 and another balloon payments of $3,007,239 is due in 2029.

[2] Guaranteed by two shareholders, as well as Han Feng, a subsidiary of the Company. Also secured by a real property owned by HG Realty. Balloon payment for this debt is $3,116,687.

[3] Guaranteed by two shareholders, as well as two subsidiaries of the Company, NSF and BB. Secured by real property, equipment and fixtures, inventories, receivables and all other personal property owned by NSF. Balloon payment for this long-term debt is $1,382,046.

[4] Secured by specific vehicles and equipment as defined in loan agreements.

[5] Secured by vehicles.