Note 12 - Minimum Regulatory Capital Requirement (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]

	Actual					Minimum Capital Requirement (1)					Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions
	Amount		Ratio			Amount		Ratio			Amount		Ratio
December 31, 201 7
Total capital (to risk weighted assets)
NBI consolidated	$	198,468		24.542	%	$	74,804		9.250	%		N/A		N/A
NBB		195,903		24.316	%		74,523		9.250	%	$	80,566		10.000	%
Tier 1 capital (to risk weighted assets)
NBI consolidated	$	190,543		23.562	%	$	58,630		7.250	%		N/A		N/A
NBB		187,978		23.332	%		58,410		7.250	%	$	64,452		8.000	%
Common Equity Tier 1 capital (to risk weighted assets)
NBI consolidated	$	190,543		23.562	%	$	46,500		5.750	%		N/A		N/A
NBB		187,978		23.332	%		46,325		5.750	%	$	52,368		6.500	%
Tier 1 capital (to average assets)
NBI consolidated	$	190,543		15.424	%	$	49,413		4.000	%		N/A		N/A
NBB		187,978		15.254	%		49,293		4.000	%	$	61,616		5.000	%

	Actual					Minimum Capital Requirement					Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions
	Amount		Ratio			Amount		Ratio			Amount		Ratio
December 31, 201 6
Total capital (to risk weighted assets)
NBI consolidated	$	191,006		26.575	%	$	57,499		8.625	%		N/A		N/A
NBB		188,095		26.296	%		57,224		8.625	%	$	71,529		10.000	%
Tier 1 capital (to risk weighted assets)
NBI consolidated	$	182,706		25.420	%	$	43,124		6.625	%		N/A		N/A
NBB		179,795		25.136	%		42,918		6.625	%	$	57,224		8.000	%
Common Equity Tier 1 capital (to risk weighted assets)
NBI consolidated	$	182,706		25.420	%	$	32,343		5.125	%		N/A		N/A
NBB		179,795		25.136	%		32,188		5.125	%	$	46,494		6.500	%
Tier 1 capital (to average assets)
NBI consolidated	$	182,706		15.121	%	$	48,333		4.000	%		N/A		N/A
NBB		179,795		14.964	%		48,060		4.000	%	$	60,075		5.000	%