Note 9 - Accrued Retirement Benefits (Details) - Accrued Retirement Benefits (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Accrued retirement benefits	$ 7,284	$ 21,310
Less current portion	(391)	(443)
Non-current portion of accrued retirement benefits	6,893	20,867
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued retirement benefits	2,540	16,941
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued retirement benefits	4,468	3,972
Deferred Compensation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued retirement benefits	$ 276	$ 397