Note 12 - Employee Benefit and Retirement Plans - Status of Defined Benefit Plans (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Amounts recognized in balance sheet
Amortization of net loss	$ (16,800,000)	$ (300,000)
US and UK Plans Combined [Member]
Benefit obligation at beginning of year	169,680,000	159,213,000	$ 169,696,000
Interest cost	5,417,000	6,013,000	6,077,000
Exchange rate changes	(1,013,000)	(1,697,000)	707,000
Benefits paid	(7,203,000)	(7,217,000)	(6,489,000)
Actuarial (gain) loss	17,309,000	13,368,000	(10,778,000)
Actual return on plan assets	2,163,000	6,589,000	2,545,000
Employer contributions	7,687,000	5,413,000	4,366,000
Benefits paid	(7,203,000)	(7,217,000)	(6,489,000)
Exchange rate changes	(845,000)	(1,445,000)	493,000
Funded status at end of year	(60,364,000)	(47,647,000)	(40,520,000)
Amounts recognized in balance sheet
Current liability	(373,000)	(324,000)	(67,000)
Noncurrent liability	(59,991,000)	(47,323,000)	(40,453,000)
Net amount recognized in balance sheet	(60,364,000)	(47,647,000)	(40,520,000)
Accumulated loss	(19,113,000)	(15,590,000)	(4,038,000)
Amounts not yet recognized as a component of net periodic benefit cost	(19,113,000)	(15,590,000)	(4,038,000)
Accumulated net periodic benefit cost in excess of contributions	(41,249,000)	(32,057,000)	(36,482,000)
Interest cost	5,417,000	6,013,000	6,077,000
Expected return on plan assets	(5,193,000)	(5,129,000)	(5,140,000)
Recognized actuarial loss	16,753,000	284,000	26,000
Net periodic benefit cost	16,977,000	1,168,000	963,000
Net loss	(53,000)	(38,000)	(28,000)
Projected benefit obligation	184,190,000	169,680,000	159,213,000
Accumulated benefit obligation	184,190,000	169,680,000	159,213,000
Fair value of assets	123,826,000	122,033,000	118,693,000
Benefit obligation at beginning of year	169,680,000	159,213,000	169,696,000
Benefits paid	(7,203,000)	(7,217,000)	(6,489,000)
Actuarial (gain) loss	17,309,000	13,368,000	(10,778,000)
Actual return on plan assets	2,163,000	6,589,000	2,545,000
Employer contributions	7,687,000	5,413,000	4,366,000
Benefits paid	(7,203,000)	(7,217,000)	(6,489,000)
Funded status at end of year	(60,364,000)	(47,647,000)	(40,520,000)
Exchange rate changes	(1,013,000)	(1,697,000)	707,000
Benefit obligation at end of year	184,190,000	169,680,000	159,213,000
Benefits paid	(7,203,000)	(7,217,000)	(6,489,000)
Exchange rate changes	(845,000)	(1,445,000)	493,000
US and UK Plans Combined [Member] | Change in Plan Assets [Member]
Fair value of plan assets at beginning of year	122,033,000	118,693,000	117,778,000
Amounts recognized in balance sheet
Fair value of plan assets at beginning of year	122,033,000	118,693,000	117,778,000
Fair value of plan assets at end of year	123,826,000	122,033,000	118,693,000
US Domestic Plan [Member]
Benefit obligation at beginning of year	126,380,000	116,277,000	124,138,000
Interest cost	4,417,000	4,854,000	4,804,000
Benefits paid	(5,682,000)	(5,565,000)	(4,786,000)
Actuarial (gain) loss	13,016,000	10,814,000	(7,879,000)
Actual return on plan assets	1,071,000	4,132,000	1,645,000
Employer contributions	6,753,000	4,443,000	3,353,000
Benefits paid	(5,682,000)	(5,565,000)	(4,786,000)
Funded status at end of year	(50,839,000)	(41,230,000)	(34,137,000)
Amounts recognized in balance sheet
Current liability	(373,000)	(324,000)	(67,000)
Noncurrent liability	(50,466,000)	(40,906,000)	(34,070,000)
Net amount recognized in balance sheet	(50,839,000)	(41,230,000)	(34,137,000)
Accumulated loss	(14,507,000)	(13,196,000)	(2,731,000)
Amounts not yet recognized as a component of net periodic benefit cost	(14,507,000)	(13,196,000)	(2,731,000)
Accumulated net periodic benefit cost in excess of contributions	(36,332,000)	(28,034,000)	(31,406,000)
Interest cost	4,417,000	4,854,000	4,804,000
Expected return on plan assets	(4,249,000)	(4,067,000)	(4,026,000)
Recognized actuarial loss	14,883,000	284,000	26,000
Net periodic benefit cost	15,051,000	1,071,000	804,000
Net loss	(38,000)	(38,000)	(28,000)
Projected benefit obligation	138,131,000	126,380,000	116,277,000
Fair value of assets	87,292,000	85,150,000	82,140,000
Benefit obligation at beginning of year	126,380,000	116,277,000	124,138,000
Service cost
Plan curtailment
Benefits paid	(5,682,000)	(5,565,000)	(4,786,000)
Actuarial (gain) loss	$ 13,016,000	$ 10,814,000	$ (7,879,000)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.73%	3.56%	4.27%
Actual return on plan assets	$ 1,071,000	$ 4,132,000	$ 1,645,000
Employer contributions	6,753,000	4,443,000	3,353,000
Benefits paid	(5,682,000)	(5,565,000)	(4,786,000)
Funded status at end of year	$ (50,839,000)	$ (41,230,000)	$ (34,137,000)
Discount rate	3.56%	4.27%	3.92%
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets	5.00%	5.00%	5.00%
Accumulated benefit obligation	$ 138,131,000	$ 126,380,000	$ 116,277,000
Benefit obligation at end of year	138,131,000	126,380,000	116,277,000
Benefits paid	(5,682,000)	(5,565,000)	(4,786,000)
US Domestic Plan [Member] | Change in Plan Assets [Member]
Fair value of plan assets at beginning of year	85,150,000	82,140,000	81,928,000
Amounts recognized in balance sheet
Fair value of plan assets at beginning of year	85,150,000	82,140,000	81,928,000
Fair value of plan assets at end of year	87,292,000	85,150,000	82,140,000
UK Plan [Member]
Benefit obligation at beginning of year	43,300,000	42,936,000	45,558,000
Interest cost	1,000,000	1,159,000	1,273,000
Exchange rate changes	(1,013,000)	(1,697,000)	707,000
Benefits paid	(1,521,000)	(1,652,000)	(1,703,000)
Actuarial (gain) loss	4,293,000	2,554,000	(2,899,000)
Actual return on plan assets	1,092,000	2,457,000	900,000
Employer contributions	934,000	970,000	1,013,000
Benefits paid	(1,521,000)	(1,652,000)	(1,703,000)
Exchange rate changes	(854,000)	(1,445,000)	493,000
Funded status at end of year	(9,525,000)	(6,417,000)	(6,383,000)
Amounts recognized in balance sheet
Noncurrent liability	(9,525,000)	(6,417,000)	(6,383,000)
Net amount recognized in balance sheet	(9,525,000)	(6,417,000)	(6,383,000)
Accumulated loss	(4,608,000)	(2,394,000)	(1,307,000)
Amounts not yet recognized as a component of net periodic benefit cost	(4,608,000)	(2,394,000)	(1,307,000)
Interest cost	1,000,000	1,159,000	1,273,000
Expected return on plan assets	(944,000)	(1,062,000)	(1,114,000)
Net periodic benefit cost	1,926,000	97,000	159,000
Projected benefit obligation	46,059,000	43,300,000	42,936,000
Fair value of assets	36,534,000	36,883,000	36,553,000
Benefit obligation at beginning of year	43,300,000	42,936,000	45,558,000
Benefits paid	(1,521,000)	(1,652,000)	(1,703,000)
Actuarial (gain) loss	$ 4,293,000	$ 2,554,000	$ (2,899,000)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	1.59%	2.39%	2.80%
Actual return on plan assets	$ 1,092,000	$ 2,457,000	$ 900,000
Employer contributions	934,000	970,000	1,013,000
Benefits paid	(1,521,000)	(1,652,000)	(1,703,000)
Funded status at end of year	$ (9,525,000)	$ (6,417,000)	$ (6,383,000)
Discount rate	2.39%	2.80%	2.73%
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets	2.62%	2.98%	3.01%
Accumulated benefit obligation	$ 46,059,000	$ 43,300,000	$ 42,936,000
Exchange rate changes	(1,013,000)	(1,697,000)	707,000
Benefit obligation at end of year	46,059,000	43,300,000	42,936,000
Benefits paid	(1,521,000)	(1,652,000)	(1,703,000)
Exchange rate changes	(854,000)	(1,445,000)	493,000
Accumulated net periodic benefit cost in excess of contributions	(4,917,000)	(4,023,000)	(5,076,000)
Amortization of net loss	1,870,000
UK Plan [Member] | Change in Plan Assets [Member]
Fair value of plan assets at beginning of year	36,883,000	36,553,000
Amounts recognized in balance sheet
Fair value of plan assets at beginning of year	36,883,000	36,553,000
Fair value of plan assets at end of year	36,534,000	36,883,000	36,553,000
UK Plan [Member] | Debt Security, Corporate, US [Member]
Fair value of plan assets at beginning of year	36,883,000	36,553,000	35,850,000
Amounts recognized in balance sheet
Fair value of plan assets at beginning of year	$ 36,883,000	36,553,000	35,850,000
Fair value of plan assets at end of year		$ 36,883,000	$ 36,553,000