Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2013

Employee Benefit Plans

Schedule of net periodic cost (benefit)

	Three months ended June 30,
	Defined Benefit Pension Plan						Post-Retirement Medical Plan						Supplemental Executive Retirement Plan
	2013			2012			2013			2012			2013		2012
Components of net periodic cost (benefit):
Service cost	$	1,260		$	1,136		$	233		$	225		$	250	$	562
Interest cost	5,171			5,258			123			150			637		724
Expected return on plan assets	(6,029		)	(5,462		)	—			—			—		—
Amortization of transition obligation	—			—			—			—			—		—
Amortization of unrecognized prior service cost (benefit)	13			13			(413		)	(413		)	233		233
Amortization of loss (gain) from earlier periods	3,895			2,524			(104		)	(94		)	325		147
Net periodic cost (benefit)	$	4,310		$	3,469		$	(161	)	$	(132	)	$	1,445	$	1,666

	Six months ended June 30,
	Defined Benefit Pension Plan						Post-Retirement Medical Plan						Supplemental Executive Retirement Plan
	2013			2012			2013			2012			2013		2012
Components of net periodic cost (benefit):
Service cost	$	2,519		$	2,175		$	465		$	408		$	501	$	492
Interest cost	10,344			10,472			246			284			1,274		1,448
Expected return on plan assets	(12,058		)	(10,889		)	—			—			—		—
Amortization of transition obligation	—			—			—			(825		)	—		—
Amortization of unrecognized prior service cost (benefit)	26			26			(825		)	—			466		466
Amortization of loss (gain) from earlier periods	7,789			4,370			(207		)	(227		)	650		294
Net periodic cost (benefit)	$	8,620		$	6,154		$	(321	)	$	(360	)	$	2,891	$	2,700

Schedule of contributions to the Defined Benefit Pension Plan and payments made to the Post-Retirement Medical Plan and the Supplemental Executive Retirement Plan

	Three months ended June 30,
	2013		2012
Contributions to the Defined Benefit Pension Plan	$	2,025	$	10,056
Payments to the Post-Retirement Medical Plan	129		63
Payments to the Supplemental Executive Retirement Plan	930		698

	Six months ended June 30,
	2013		2012
Contributions to the Defined Benefit Pension Plan	$	2,025	$	13,300
Payments to the Post-Retirement Medical Plan	282		237
Payments to the Supplemental Executive Retirement Plan	1,860		1,396