Note 9 - Retirement Plans (Details) - Summary of Net Funded Status (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in projected benefit obligation:
Service cost	$ 5,165	$ 4,452	$ 3,447
Interest cost	3,553	3,315	2,943
Fair value of pension plan assets at beginning of year	46,662
Fair value of pension plan assets at end of year	58,063	46,662
Active Defined Benefit Pension Plan [Member]
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	83,236	67,033
Service cost	5,165	4,452
Interest cost	3,553	3,315
Actuarial (gains) losses	(7,158)	9,546
Fair value of pension plan assets at beginning of year	46,662	35,011
Actual return on plan assets	8,216	3,728
Company contributions	4,448	9,033
Benefits paid	(1,263)	(1,110)
Fair value of pension plan assets at end of year	58,063	46,662
Funded status of pension plan	(25,470)	(36,574)
Projected benefit obligation at end of year	83,533	83,236
Amounts recognized in our balance sheets consist of:
Accrued benefit cost	(10,337)	(6,336)
Accumulated other comprehensive income	(15,133)	(30,238)
Net liability recognized	$ (25,470)	$ (36,574)