Earning Per Common Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Numerator for basic and diluted earnings per common share:
Net income	$ (41,152)	$ 6,408	$ 5,434	$ (1,858)	$ 78	$ 4,500	$ 3,216	$ (2,433)	$ (31,168)	$ 5,361	[1]
Denominator:
Weighted average shares outstanding (shares)									10,362,000	10,334,000
Denominator for basic earnings per common share (shares)									10,362,000	10,334,000
Effect of dilutive securities:
Other stock compensation plans (shares)									0	149,000
Dilutive potential common shares (shares)									0	149,000
Denominator for diluted earnings per common share - adjusted weighted average shares outstanding and assumed conversions (shares)									10,362,000	10,483,000
Basic (loss) earnings per common share (usd per share)	$ (3.97)	$ 0.62	$ 0.52	$ (0.18)	$ 0.01	$ 0.44	$ 0.31	$ (0.24)	$ (3.01)	$ 0.52
Diluted (loss) earnings per common share (usd per share)	$ (3.97)	$ 0.61	$ 0.52	$ (0.18)	$ 0.01	$ 0.43	$ 0.31	$ (0.24)	$ (3.01)	$ 0.51
Anti-dilutive share, shares									117,000

[1] The balances as of January 1, 2017 and the year ended December 31, 2017 amounts have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 6 to the Consolidated Financial Statements.