Accumulated Other Comprehensive Loss - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes		$ (2,292)	$ (5,570)
Income tax provision (benefit)		(310)	(2,535)
Net income (loss)		(1,982)	$ (3,035)
Reclassification out of Accumulated Other Comprehensive Income
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	[1]	(168)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of prior-service cost
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior-service cost	[2],[3]	(228)
Income (loss) before income taxes		(228)
Income tax provision (benefit)		60
Net income (loss)		$ (168)

[1] Amounts in parentheses indicate credits to profit/loss

[2] All amounts are net of tax. Amounts in parentheses indicate debits

[3] This accumulated other comprehensive loss component is included in the computation of net periodic benefit cost (see Note 6).