Note 5. Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2014

Qualified Pension Plans [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

	Qualified Pension Plans						Non-Qualified Pension Plans
	Three Months Ended March 31,						Three Months Ended March 31,
(Dollars in thousands)	2014			2013			2014		2013
Interest cost on benefit obligation	$	18,871		$	17,589		$	862	$	804
Expected return on plan assets	(23,327		)	(22,657		)	—		—
Amortization of actuarial loss	2,475			4,650			219		279
Amortization of prior-service costs	404			418			1		1
Net periodic benefit expense (income)	$	(1,577	)	$	—		$	1,082	$	1,084

Postretirement Medical Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

	Three Months Ended March 31,
(Dollars in thousands)	2014			2013
Service cost	$	271		$	429
Interest cost on benefit obligation	672			891
Amortization of actuarial gain	(657		)	—
Amortization of prior-service credit	(716		)	(263		)
Net periodic benefit expense (income)	$	(430	)	$	1,057