Pension and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2013

Pension and Other Postretirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

	Pension Benefits						Postretirement Benefits
	Three Months Ended June 30,						Three Months Ended June 30,
Components of Net Periodic Benefit Cost	2013			2012			2013			2012
Service cost	$	5,534		$	5,532		$	647		$	518
Interest cost	5,982			6,123			711			828
Expected return on plan assets	(5,979		)	(5,910		)	—			—
Amortization of:
Net actuarial loss	6,860			5,408			422			435
Prior service cost (gain)	338			340			(540		)	(565		)
Net periodic benefit cost	$	12,735		$	11,493		$	1,240		$	1,216
	Pension Benefits						Postretirement Benefits
	Six Months Ended June 30,						Six Months Ended June 30,
Components of Net Periodic Benefit Cost	2013			2012			2013			2012
Service cost	$	12,059		$	11,107		$	1,322		$	1,168
Interest cost	11,957			12,448			1,436			1,678
Expected return on plan assets	(11,954		)	(11,835		)	—			—
Amortization of:
Net actuarial loss	13,185			10,558			897			860
Prior service cost (gain)	688			690			(1,090		)	(1,090		)
Net periodic benefit cost	$	25,935		$	22,968		$	2,565		$	2,616