Other Long-Term Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other Long-Term Liabilities [Line Items]
Supplemental employees' retirement plan (SERP)	$ 148,703	$ 135,829
Total	49,410	56,885
Other Liabilties [Member]
Other Long-Term Liabilities [Line Items]
Supplemental employees' retirement plan (SERP)	10,035	11,546
Deferred compensation	12,665	11,556
Long-term incentive plan	6,084	5,089
Noncurrent income taxes payable	3,886	4,313
Environmental remediation liability	9,903	9,941
Other	6,837	14,440
Total	$ 49,410	$ 56,885