Note 5. Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 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
	Three Months Ended June 30,						Six Months Ended June 30,
(Dollars in thousands)	2014			2013			2014			2013
Interest cost on benefit obligation	$	18,767		$	17,422		$	37,638		$	35,011
Expected return on plan assets	(23,309		)	(23,005		)	(46,636		)	(45,662		)
Amortization of actuarial loss	2,375			4,486			4,850			9,136
Amortization of prior-service costs	405			417			809			835
Net periodic benefit income	$	(1,762	)	$	(680	)	$	(3,339	)	$	(680	)

Non 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]

	Non-Qualified Pension Plans
	Three Months Ended June 30,				Six Months Ended June 30,
(Dollars in thousands)	2014		2013		2014		2013
Interest cost on benefit obligation	$	864	$	803	$	1,726	$	1,607
Amortization of actuarial loss	219		280		438		559
Amortization of prior-service costs	1		2		2		3
Net periodic benefit expense	$	1,084	$	1,085	$	2,166	$	2,169

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 June 30,						Six Months Ended June 30,
(Dollars in thousands)	2014			2013			2014			2013
Service cost	$	271		$	313		$	542		$	742
Interest cost on benefit obligation	671			848			1,343			1,739
Amortization of actuarial gain	(656		)	—			(1,313		)	—
Amortization of prior-service credit	(716		)	(263		)	(1,432		)	(526		)
Net periodic benefit expense (income)	$	(430	)	$	898		$	(860	)	$	1,955