Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2013

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Periodic Benefit Costs of Pension and Post-Retirement Healthcare

Components of the net periodic benefit cost related to the Company's qualified pension plans and post-retirement healthcare plans for the three months ended March 31, 2013 and 2012 are presented below (in thousands).

	Three Months Ended March 31, 2013					Three Months Ended March 31, 2012
	Qualified Pension			Post- retirement Healthcare		Qualified Pension			Post- retirement Healthcare
Service cost	$	4,638		$	7,482	$	4,096		$	6,784
Interest cost	3,697			6,493		3,662			6,182
Expected return on plan assets	(3,170		)	—		(3,279		)	(8		)
Amortization of actuarial loss	1,156			2,235		517			1,682
Plan settlement	—			—		356			—
Net periodic benefit cost	$	6,321		$	16,210	$	5,352		$	14,640