Employee Benefits Plans (Details) - Amount recognized in the consolidated balance sheet - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Compensation Plan [Member]
Employee Benefits Plans (Details) - Amount recognized in the consolidated balance sheet [Line Items]
Current liabilities	$ (450)	$ (448)
Noncurrent liabilities	(4,219)	(4,301)
Total	(4,669)	(4,749)
Supplemental Employee Retirement Plan [Member]
Employee Benefits Plans (Details) - Amount recognized in the consolidated balance sheet [Line Items]
Current liabilities	(155)	(155)
Noncurrent liabilities	(1,724)	(1,797)
Total	(1,879)	(1,952)
Other Postretirement Benefit Plan [Member]
Employee Benefits Plans (Details) - Amount recognized in the consolidated balance sheet [Line Items]
Current liabilities	(88)	(92)
Noncurrent liabilities	(622)	(735)
Total	$ (710)	$ (827)