Inventories (Income Statement, Comprehensive Income, and Cashflows Impact) (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
Consolidated Statement of Operations
Total cost of sale		$ 135,791	$ 139,827	$ 100,262		$ 103,575	$ 116,932	$ 97,461	$ 509,810	$ 431,116
(Loss) income before income taxes		6,426	6,162	(1,333)		4,566	3,691	(2,002)	(26,711)	10,051
Tax (benefit) provisions (benefit)		18	728	525		66	475	431	4,457	4,690
Net (loss) income	$ (41,152)	$ 6,408	$ 5,434	$ (1,858)	$ 78	$ 4,500	$ 3,216	$ (2,433)	$ (31,168)	$ 5,361	[1]
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
Consolidated Statements of Comprehensive Income
Other comprehensive income (loss)									$ (4,424)	$ 7,522
Comprehensive income									(35,592)	12,883
Consolidated Statements of Cashflows
Deferred income taxes									(1,598)	(1,222)
Inventories									(23,403)	(14,657)
Other current liabilities									4,046	(588)
Previously Reported
Consolidated Statement of Operations
Total cost of sale		$ 137,492	$ 140,376	$ 100,426		$ 105,127	$ 117,124	$ 97,450		433,125
(Loss) income before income taxes		4,725	5,613	(1,497)		3,014	3,499	(1,991)		8,042
Tax (benefit) provisions (benefit)		(246)	673	525		(208)	475	431		3,929
Net (loss) income		$ 4,971	$ 4,940	$ (2,022)	$ 289	$ 3,222	$ 3,024	$ (2,422)		$ 4,113
Basic (loss) earnings per common share (usd per share)		$ 0.48	$ 0.48	$ (0.20)	$ 0.03	$ 0.31	$ 0.29	$ (0.23)		$ 0.40
Diluted (loss) earnings per common share (usd per share)		$ 0.47	$ 0.47	$ (0.20)	$ 0.03	$ 0.31	$ 0.29	$ (0.23)		$ 0.39
Consolidated Statements of Comprehensive Income
Other comprehensive income (loss)										$ 7,522
Comprehensive income										11,635
Consolidated Statements of Cashflows
Deferred income taxes										(1,983)
Inventories										(12,648)
Other current liabilities										(588)
Adjustments
Consolidated Statement of Operations
Total cost of sale		$ (1,701)	$ (549)	$ (164)		$ (1,552)	$ (192)	$ 11		(2,009)
(Loss) income before income taxes		1,701	549	164		1,552	192	(11)		2,009
Tax (benefit) provisions (benefit)		264	55	0		274	0	0		761
Net (loss) income		$ 1,437	$ 494	$ 164		$ 1,278	$ 192	$ (11)		$ 1,248
Basic (loss) earnings per common share (usd per share)		$ 0.14	$ 0.04	$ 0.02		$ 0.13	$ 0.02	$ (0.01)		$ 0.12
Diluted (loss) earnings per common share (usd per share)		$ 0.14	$ 0.05	$ 0.02		$ 0.12	$ 0.02	$ (0.01)		$ 0.12
Consolidated Statements of Comprehensive Income
Other comprehensive income (loss)										$ 0
Comprehensive income										1,248
Consolidated Statements of Cashflows
Deferred income taxes										761
Inventories										(2,009)
Other current liabilities										$ 0
Effects of change
Consolidated Statement of Operations
Total cost of sale									(6,634)
(Loss) income before income taxes									6,634
Tax (benefit) provisions (benefit)									3,920
Net (loss) income									$ 2,714
Basic (loss) earnings per common share (usd per share)									$ 0.26
Diluted (loss) earnings per common share (usd per share)									$ 0.26
Consolidated Statements of Comprehensive Income
Other comprehensive income (loss)									$ 0
Comprehensive income									2,714
Consolidated Statements of Cashflows
Deferred income taxes									2,830
Inventories									(6,634)
Other current liabilities									1,090
Pro forma
Consolidated Statement of Operations
Total cost of sale									516,444
(Loss) income before income taxes									(33,345)
Tax (benefit) provisions (benefit)									537
Net (loss) income									$ (33,882)
Basic (loss) earnings per common share (usd per share)									$ (3.27)
Diluted (loss) earnings per common share (usd per share)									$ (3.27)
Consolidated Statements of Comprehensive Income
Other comprehensive income (loss)									$ (4,424)
Comprehensive income									(38,306)
Consolidated Statements of Cashflows
Deferred income taxes									(4,428)
Inventories									(16,769)
Other current liabilities									$ 2,956

[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.