Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other Long-Term Liabilities [Line Items]
Supplemental employees' retirement plan (SERP)	$ 156,427	$ 158,984
Total	44,916	51,427
Other Liabilities
Other Long-Term Liabilities [Line Items]
Supplemental employees' retirement plan (SERP)	6,998	9,654
Deferred compensation	15,238	16,244
Long-term incentive plan	8,346	7,973
Noncurrent income taxes payable	2,903	2,672
Environmental remediation liability	3,763	9,307
Other	$ 7,668	$ 5,577