Employee Benefit Plans Amounts Recognized on Balance Sheet Table (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Prepaid benefit cost	$ 1,020	$ 1,060
Current liabilities	(410)	(390)
Noncurrent liabilities	(11,480)	(13,940)
Net liability recognized at December 31	(10,870)	(13,270)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Prepaid benefit cost	0	0
Current liabilities	(90)	(110)
Noncurrent liabilities	(880)	(930)
Net liability recognized at December 31	$ (970)	$ (1,040)