Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2012

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs

The components of net periodic benefit cost are as follows:

	Pension Benefits
	Three Months Ended June 30,						Six Months Ended June 30,
	2012			2011			2012			2011
Components of Net Periodic Pension Cost
Service Cost	$	1,799		$	1,531		$	3,598		$	3,062
Interest Cost	2,965			2,860			5,930			5,720
Expected return on assets	(3,034		)	(3,328		)	(6,068		)	(6,656		)
Amortization of unrecognized prior service costs	97			98			194			196
Cumulative net loss	2,593			1,780			5,186			3,560
Net periodic pension cost	$	4,420		$	2,941		$	8,840		$	5,882

	Postretirement Benefits
	Three Months Ended June 30,					Six Months Ended June 30,
	2012			2011		2012			2011
Components of Net Periodic Postretirement Cost
Service Cost	$	19		$	14	$	38		$	28
Interest Cost	174			221		348			442
Amortization of unrecognized prior service costs	(117		)	—		(234		)	—
Cumulative net loss	72			28		144			56
Net periodic postretirement cost	$	148		$	263	$	296		$	526