Note 13 - Employee Retirement Plans - Net Periodic Benefit Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Service cost	$ 85,000	$ 90,000	$ 82,000
Interest cost	124,000	144,000	160,000
Expected return on plan assets	(165,000)	(178,000)	(174,000)
Amortization of prior service cost (credit)	6,000	6,000	6,000
Recognition of actuarial loss	(229,000)	95,000
Total net periodic benefit expense	117,000	227,000	103,000
Settlement charge	1,000
Total expense	118,000	227,000	103,000
Curtailment effects			(3,000)
Settlements	(2,000)	(1,000)	(2,000)
Current year actuarial loss	84,000	191,000	212,000
Recognition of actuarial (loss)	(64,000)	(165,000)	(29,000)
Current year prior service cost			25,000
Amortization of prior service (cost) credit	(6,000)	(6,000)	(6,000)
Total recognized in other comprehensive (income) loss	12,000	19,000	197,000
Total recognized in net periodic benefit cost and other comprehensive (income) loss	130,000	246,000	300,000
Recognition of Actuarial Gain [Member]
Recognition of actuarial loss	67,000	165,000	29,000
United States Pension Plan of US Entity [Member]
Service cost	61,000	64,000	55,000
Interest cost	111,000	126,000	137,000
Expected return on plan assets	(153,000)	(166,000)	(159,000)
Amortization of prior service cost (credit)	6,000	7,000	7,000
Recognition of actuarial loss	(145,000)	87,000
Total net periodic benefit expense	80,000	193,000	44,000
Settlement charge	1,000
Total expense	81,000	193,000	44,000
Curtailment effects
Settlements	(2,000)
Current year actuarial loss	63,000	189,000	198,000
Recognition of actuarial (loss)	(55,000)	(162,000)	(4,000)
Current year prior service cost			25,000
Amortization of prior service (cost) credit	(6,000)	(7,000)	(7,000)
Total recognized in other comprehensive (income) loss	0	20,000	212,000
Total recognized in net periodic benefit cost and other comprehensive (income) loss	81,000	213,000	256,000
United States Pension Plan of US Entity [Member] | Recognition of Actuarial Gain [Member]
Recognition of actuarial loss	55,000	162,000	4,000
Foreign Pension Plan [Member]
Service cost	24,000	26,000	27,000
Interest cost	13,000	18,000	23,000
Expected return on plan assets	(12,000)	(12,000)	(15,000)
Amortization of prior service cost (credit)		(1,000)	(1,000)
Recognition of actuarial loss	(84,000)	8,000
Total net periodic benefit expense	37,000	34,000	59,000
Total expense	37,000	34,000	59,000
Curtailment effects			(3,000)
Settlements		(1,000)	(2,000)
Current year actuarial loss	21,000	2,000	14,000
Recognition of actuarial (loss)	(9,000)	(3,000)	(25,000)
Current year prior service cost
Amortization of prior service (cost) credit		1,000	1,000
Total recognized in other comprehensive (income) loss	12,000	(1,000)	(15,000)
Total recognized in net periodic benefit cost and other comprehensive (income) loss	49,000	33,000	44,000
Foreign Pension Plan [Member] | Recognition of Actuarial Gain [Member]
Recognition of actuarial loss	$ 12,000	$ 3,000	$ 25,000