Business Segments (Reconciliation of Operating Profit (Loss) from Segments to Consolidated) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information
Interest expense	$ (1,958)	$ (2,108)
Interest income	71	56
Other income (expense)	608	(5)
Equity in loss of nonconsolidated investments	(3)	(200)
Loss before income taxes	(1,497)	(1,991)
Operating Segments
Segment Reporting Information
Profit for reportable segments	3,951	1,809
Segment Reconciling Items
Segment Reporting Information
Interest expense	(1,958)	(2,108)
Interest income	71	56
Other income (expense)	608	(5)
LIFO (expense) income	(164)	11
Equity in loss of nonconsolidated investments	(3)	(200)
Unallocated corporate assets
Segment Reporting Information
Unallocated corporate expense and other unallocated charges	$ (4,002)	$ (1,554)