Benefit Plans Benefit Plans - Summary of Benefit Plan (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Pension Benefits [Member]
Change in benefit obligation
Benefit obligation at beginning of year	$ 636,210		$ 552,760
Service cost	11,446		10,854		9,994
Interest cost	31,831		31,491		30,723
Actuarial loss	96,016		63,079
Plan participant contributions	0		0
Medicare retiree drug subsidy reimbursements	0		0
Benefits paid	(23,909)		(21,932)
Settlements	(77,910)		0
Other	27		(42)
Benefit obligation at end of year	673,711		636,210		552,760
Change in plan assets
Fair value of plan assets at beginning of year	485,489		450,632
Actual return on plan assets	58,560		33,471
Employer contributions	15,711		23,318
Plan participant contributions	0		0
Benefits paid	(23,909)		(21,932)
Settlements	(62,754)		0
Fair value of plan assets at end of year	473,097		485,489		450,632
Funded status	(200,614)		(150,721)
Amounts recognized in balance sheets
Current liabilities	2,931		2,846
Noncurrent liabilities	197,683	[1]	147,875	[1]
Unrecognized net actuarial loss	(238,144)	[2]	(213,712)	[2]
Unrecognized prior service cost (benefit)	(1,679)	[2]	(1,935)
Net amount recognized	(39,209)		(64,926)
Change in accumulated other comprehensive income
Balance at beginning of year	(215,647)		(155,050)
Prior service cost (credit) recognized during the year	258		259
Net actuarial losses recognized during the year	16,777		9,497
Net actuarial (losses) gains occuring during the year	(63,118)		(70,353)
Settlements	21,907		0
Balance at end of year	(239,823)		(215,647)		(155,050)
Other Benefits [Member]
Change in benefit obligation
Benefit obligation at beginning of year	17,022		16,885
Service cost	0		0		0
Interest cost	814		930		993
Actuarial loss	(414)		1,277
Plan participant contributions	79		114
Medicare retiree drug subsidy reimbursements	166		177
Benefits paid	(1,940)		(2,361)
Settlements	0		0
Other	0		0
Benefit obligation at end of year	15,727		17,022		16,885
Change in plan assets
Fair value of plan assets at beginning of year	0		0
Actual return on plan assets	0		0
Employer contributions	1,861		2,247
Plan participant contributions	79		114
Benefits paid	(1,940)		(2,361)
Settlements	0		0
Fair value of plan assets at end of year	0		0		0
Funded status	(15,727)		(17,022)
Amounts recognized in balance sheets
Current liabilities	1,574		1,693
Noncurrent liabilities	14,153	[1]	15,329	[1]
Unrecognized net actuarial loss	(4,982)	[2]	(5,884)	[2]
Unrecognized prior service cost (benefit)	933		1,450
Net amount recognized	11,678		12,588
Change in accumulated other comprehensive income
Balance at beginning of year	(4,434)		(3,029)
Prior service cost (credit) recognized during the year	(517)		(517)
Net actuarial losses recognized during the year	488		389
Net actuarial (losses) gains occuring during the year	414		(1,277)
Settlements	0		0
Balance at end of year	$ (4,049)		$ (4,434)		$ (3,029)

[1] Included in the consolidated balance sheets in pensions and other benefits and other postretirement benefits are international plans.

[2] Represents amounts in accumulated other comprehensive loss that have not yet been recognized as components of net periodic benefit cost.