Note 14 - Stock-based Compensation and Purchase Plans (Tables)

12 Months Ended

Jun. 30, 2019

Notes Tables

Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]

	Restricted Stock Awards
	Number			Aggregate
	of			Intrinsic
	Shares			Value
Outstanding, June 30, 2018		120,010		$	12,258,515
Granted		70,085
Exercised / vested		(43,959	)	$	(885,810	)
Canceled		(18,094	)
Outstanding, June 30, 2019		128,042		$	9,365,632

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	2019			2018			2017
Risk-free interest rates		2.63	%		1.55	%		0.71	%
Expected life of option grants (in years)		3			3			3
Expected volatility of underlying stock		25.1	%		25.6	%		25.7	%
Expected quarterly dividends (per share)	$	0.18		$	0.16		$	0.14

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Annual Component								Performance Stock Units
				Weighted
	Number			Average		Aggregate			Number			Aggregate
	of			Exercise		Intrinsic			of			Intrinsic
	Shares			Price		Value			Shares			Value
Non-vested, June 30, 2018		31,760		$	62.71	$	442,850			58,028		$	5,013,531
Granted		13,625		$	76.65					28,803
Vested		(8,677	)	$	58.35	$	440,358			(6,639	)	$	508,614
Forfeited		(1,758	)	$	65.84					(11,140	)
Non-vested, June 30, 2019		34,950		$	69.07	$	(496,674	)		69,052		$	6,529,012