Note 9 - Retirement Plans (Detail) - Summary of net funded status (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in projected benefit obligation:
Service cost	$ 4,452	$ 3,447	$ 3,199
Interest cost	3,315	2,943	2,658
Fair value of pension plan assets at beginning of year	35,011
Fair value of pension plan assets at end of year	46,662	35,011
Active Defined Benefit Pension Plan [Member]
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	67,033	50,055
Service cost	4,452	3,447
Interest cost	3,315	2,943
Actuarial losses	9,546	11,521
Fair value of pension plan assets at beginning of year	35,011	33,039
Actual return on plan assets	3,728	275
Company contributions	9,033	2,630
Benefits paid	(1,110)	(933)
Fair value of pension plan assets at end of year	46,662	35,011
Funded status of pension plan	(36,574)	(32,022)
Projected benefit obligation at end of year	83,236	67,033
Amounts recognized in our balance sheets consist of:
Accrued benefit cost	(6,336)	(7,684)
Accumulated other comprehensive income	(30,238)	(24,338)
Net liability recognized	$ (36,574)	$ (32,022)