Employee Benefit Plan Obligations (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Prior service cost	$ (543)
Net actuarial loss	3,105
Pension Benefits [Member]
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Net actuarial loss	1,799
Postretirement Benefits [Member]
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Prior service cost	(543)
Net actuarial loss	$ 1,306