Note 12 - Employee Benefit and Retirement Plans - Status of Defined Benefit Plans (Details) - USD ($)		12 Months Ended
	Dec. 31, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jan. 01, 2017	Jun. 30, 2016
Benefit obligation at beginning of year		$ 169,696,000	$ 175,233,000	$ 166,189,000
Service cost			1,405,000	2,757,000
Interest cost		6,077,000	6,246,000	7,032,000
Plan curtailment	$ (4,200,000)		(4,170,000)
Exchange rate changes		707,000	(909,000)	(7,825,000)
Benefits paid		(6,489,000)	(6,902,000)	(6,590,000)
Actuarial (gain) loss		(10,778,000)	(1,207,000)	13,670,000
Benefit obligation at end of year		159,213,000	169,696,000	175,233,000
Fair value of plan assets at beginning of year		117,778,000	115,015,000	122,787,000
Actual return on plan assets		2,545,000	5,302,000	226,000
Employer contributions		4,366,000	5,000,000	4,482,000
Benefits paid		(6,489,000)	(6,902,000)	(6,590,000)
Exchange rate changes		493,000	(637,000)	(5,890,000)
Fair value of plan assets at end of year		118,693,000	117,778,000	115,015,000
Funded status at end of year					$ (40,520,000)	$ (51,918,000)		$ (60,218,000)
Current liability					(67,000)	(63,000)		(45,000)
Noncurrent liability					(40,453,000)	(51,855,000)		(60,173,000)
Net amount recognized in balance sheet					(40,520,000)	(51,918,000)		(60,218,000)
Prior service cost
Accumulated loss					(4,038,000)	(12,131,000)		(17,849,000)
Amounts not yet recognized as a component of net periodic benefit cost					(4,038,000)	(12,131,000)		(17,849,000)
Accumulated net periodic benefit cost in excess of contributions					(36,482,000)	(39,787,000)		(42,369,000)
Expected return on plan assets		(5,140,000)	(5,173,000)	(6,268,000)
Recognized actuarial loss		26,000	107,000	17,878,000
Net periodic benefit cost		963,000	2,585,000	21,399,000
Prior service cost
Net loss					(28,000)	(26,000)		(114,000)
Projected benefit obligation					159,213,000	169,696,000		175,233,000
Accumulated benefit obligation					159,213,000	169,696,000		168,119,000
Fair value of assets					118,693,000	117,778,000		115,015,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.77%						4.31%
Fair value of plan assets at end of year		117,778,000	117,778,000	115,015,000	118,693,000	117,778,000		115,015,000
Benefits paid		(6,489,000)	(6,902,000)	(6,590,000)
UNITED STATES
Benefit obligation at beginning of year		124,138,000	130,863,000	116,398,000
Service cost			1,405,000	2,757,000
Interest cost		4,804,000	4,994,000	5,248,000
Plan curtailment			(4,170,000)
Benefits paid		(4,786,000)	(5,106,000)	(4,593,000)
Actuarial (gain) loss		(7,879,000)	(3,848,000)	11,053,000
Benefit obligation at end of year		116,277,000	124,138,000	130,863,000
Fair value of plan assets at beginning of year		81,928,000	81,910,000	84,853,000
Actual return on plan assets		1,645,000	1,079,000	(1,730,000)
Employer contributions		3,353,000	4,045,000	3,380,000
Benefits paid		(4,786,000)	(5,106,000)	(4,593,000)
Fair value of plan assets at end of year		82,140,000	81,928,000	81,910,000
Funded status at end of year					(34,137,000)	(42,210,000)		(48,953,000)
Current liability					(67,000)	(63,000)		(45,000)
Noncurrent liability					(34,070,000)	(42,147,000)		(48,908,000)
Net amount recognized in balance sheet					(34,137,000)	(42,210,000)		(48,953,000)
Prior service cost
Accumulated loss					(2,731,000)	(8,254,000)		(13,412,000)
Amounts not yet recognized as a component of net periodic benefit cost					(2,731,000)	(8,254,000)		(13,412,000)
Accumulated net periodic benefit cost in excess of contributions					(31,406,000)	(33,956,000)		(35,541,000)
Expected return on plan assets		(4,026,000)	(4,046,000)	(4,589,000)
Recognized actuarial loss		26,000	107,000	15,779,000
Net periodic benefit cost		804,000	2,460,000	19,195,000
Prior service cost
Net loss					(28,000)	(26,000)		(114,000)
Projected benefit obligation					116,277,000	124,138,000		130,863,000
Fair value of assets					$ 82,140,000	$ 81,928,000		$ 81,910,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate					4.27%	3.92%		3.77%
Fair value of plan assets at end of year		$ 81,928,000	$ 81,928,000	$ 81,910,000	$ 82,140,000	$ 81,928,000		$ 81,910,000
Discount rate		3.92%	3.77%	4.49%
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets		5.00%	5.00%	5.50%
Accumulated benefit obligation					116,277,000	124,138,000		123,749,000
Benefits paid		$ (4,786,000)	$ (5,106,000)	$ (4,593,000)
UNITED KINGDOM
Benefit obligation at beginning of year		45,558,000	44,370,000	49,791,000
Service cost
Interest cost		1,273,000	1,252,000	1,784,000
Exchange rate changes		707,000	(909,000)	(7,825,000)
Benefits paid		(1,703,000)	(1,796,000)	(1,997,000)
Actuarial (gain) loss		(2,899,000)	2,641,000	2,617,000
Benefit obligation at end of year		42,936,000	45,558,000	44,370,000
Fair value of plan assets at beginning of year		35,850,000	33,105,000	37,934,000
Actual return on plan assets		900,000	4,223,000	1,956,000
Employer contributions		1,013,000	954,000	1,102,000
Benefits paid		(1,703,000)	(1,796,000)	(1,997,000)
Exchange rate changes		493,000	(636,000)	(5,890,000)
Fair value of plan assets at end of year		36,553,000	35,850,000	33,105,000
Funded status at end of year					(6,383,000)	(9,708,000)		(11,265,000)
Noncurrent liability					(6,383,000)	(9,708,000)		(11,265,000)
Net amount recognized in balance sheet					(6,383,000)	(9,708,000)		(11,265,000)
Accumulated loss					(1,307,000)	(3,877,000)		(4,437,000)
Amounts not yet recognized as a component of net periodic benefit cost					(1,307,000)	(3,877,000)		(4,437,000)
Expected return on plan assets		(1,114,000)	(1,127,000)	(1,679,000)
Net periodic benefit cost		159,000	125,000	2,204,000
Projected benefit obligation					42,936,000	45,558,000		44,370,000
Fair value of assets					$ 36,553,000	$ 35,850,000		$ 33,105,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate					2.80%	2.73%		3.00%
Fair value of plan assets at end of year		$ 35,850,000	$ 35,850,000	$ 33,105,000	$ 36,553,000	$ 35,850,000		$ 33,105,000
Discount rate		2.73%	3.00%	3.90%
Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Expected Long Term Return on Assets		3.01%	3.59%	4.77%
Accumulated benefit obligation					42,936,000	45,558,000		44,370,000
Benefits paid		$ (1,703,000)	$ (1,796,000)	$ (1,997,000)
Prior service cost
Accumulated net periodic benefit cost in excess of contributions					$ (5,076,000)	$ (5,831,000)		$ (6,828,000)
Amortization of net loss				$ 2,099,000