Other Noncurrent Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other Noncurrent Liabilities [Abstract]
Pension liabilities	$ 49,820	$ 105,425
Postretirement benefits other than pensions	78,821	73,060
Interest rate swap agreement	4,718	4,251
Deferred compensation	2,087	2,234
Other	566	626
Total	$ 136,012	$ 185,596