Note 8. Employee Benefit Plans (Detail) - Net Periodic Pension Cost (Income) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Benefits [Member]
Service cost	$ 3,877	$ 2,203	$ 2,269
Interest cost	4,114	3,724	3,661
Expected return on plan assets	(5,481)	(5,041)	(4,673)
Amortization of prior service cost	403	602	602
Amortization of net gain (loss) from earlier periods	880	867	1,232
Net periodic pension cost	3,793	2,355	3,091
Other Benefits [Member]
Service cost	54	46	15
Interest cost	77	73	55
Amortization of prior service cost	45	53	(3)
Amortization of net gain (loss) from earlier periods	(43)	(46)	(43)
Net periodic pension cost	$ 133	$ 126	$ 24