Retirement and Postretirement Benefits Other than Pension Plans (Tables)

6 Months Ended

Jun. 30, 2012

Pension Plans, Defined Benefit [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic pension and postretirement benefit expense

	Three months ended						Six months ended
	June 30,						June 30,
	2012			2011			2012			2011
Interest cost	$	1,087		$	1,209		$	2,174		$	2,417
Expected return on plan assets		(1,173	)		(1,334	)		(2,346	)		(2,667	)
Amortization of net actuarial loss		1,170			619			2,340			1,238
Total net periodic pension expense	$	1,084		$	494		$	2,168		$	988

Other Postretirement Benefit Plans, Defined Benefit [Member]

Defined Benefit Plan Disclosure [Line Items]

Net periodic pension and postretirement benefit expense

	Three months ended						Six months ended
	June 30,						June 30,
	2012			2011			2012			2011
Service cost	$	15		$	15		$	29		$	29
Interest cost		253			257			507			515
Amortization of net actuarial loss		176			—			352			—
Amortization of prior service credit		(109	)		—			(217	)		—
Amortization of curtailment gain		(22	)		(61	)		(44	)		(122	)
Total net postretirement benefit expense	$	313		$	211		$	627		$	422