Accumulated Other Comprehensive Loss - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes		$ 4,445		$ (2,455)		$ 4,646	$ 52,950
Income tax provision (benefit)		1,104		(1,505)		1,486	17,556
Net income (loss)		3,341		(950)		3,160	35,394
Reclassification out of Accumulated Other Comprehensive Income
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)		(56)	[1]	(85)	[1]	(292)	(255)	[1]
Defined Benefit Plan Items | Reclassification out of Accumulated Other Comprehensive Income
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior-service cost	[1],[2]	(89)		(136)		(266)	(408)
Income (loss) before income taxes	[1]	(89)		(136)		(266)	(408)
Income tax provision (benefit)	[1]	33		51		100	153
Net income (loss)	[1]	(56)		$ (85)		(166)	$ (255)
Gain on sale of investment | Reclassification out of Accumulated Other Comprehensive Income
Schedule of Reclassifciations Out of Accumulated Other Comprehensive Income [Line Items]
Recognition of gain on sale of investment	[1]	0				(200)
Income (loss) before income taxes	[1]	0				(200)
Income tax provision (benefit)	[1]	0				74
Net income (loss)	[1]	$ 0				$ (126)

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

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