Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2013

Defined Benefit Pension Plans [Member]

Defined Benefit Plan Disclosure [Line Items]

Components Of Net Periodic Benefit Expense (Income)

	Qualified Pension Plans						Non-Qualified Pension Plans
	Three Months Ended March 31,						Three Months Ended March 31,
(Dollars in thousands)	2013			2012			2013		2012
Interest cost on benefit obligation	$	17,589		$	17,502		$	804	$	856
Expected return on plan assets	(22,657		)	(21,111		)	—		—
Amortization of actuarial loss	4,650			4,827			279		281
Amortization of prior-service costs	418			3			1		—
Net periodic benefit expense	$	—		$	1,221		$	1,084	$	1,137

Postretirement Medical Plan [Member]

Defined Benefit Plan Disclosure [Line Items]

Components Of Net Periodic Benefit Expense (Income)

	Three Months Ended March 31,
(Dollars in thousands)	2013			2012
Service cost	$	429		$	423
Interest cost on benefit obligation	891			1,021
Amortization of prior-service credit	(263		)	(302		)
Net periodic benefit expense	$	1,057		$	1,142