Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2014	$ 205,148	$ 10,426	$ 127,526	$ 135,949	$ (68,753)	$ 0
Stock-based compensation	1,103		1,103
Comprehensive (loss) income:
Net (loss) income	1,373			1,373
Other comprehensive (loss) income	11,154				11,154
Comprehensive income (loss)	12,527
Issuance of common stock including excess tax benefits of $0,$0,$0 for 2015, 2016 and 2017	225	14	211
Cash dividends ($0.72, $0.36 and $0.09 per share for 2015, 2016 and 2017)	(7,580)			(7,580)
Ending Balance at Dec. 31, 2015	211,423	10,440	128,840	129,742	(57,599)	0
Noncontrolling interest associated with Åkersacquisition (Note 2)	2,019					2,019
Stock-based compensation	1,482		1,482
Comprehensive (loss) income:
Net (loss) income	(79,809)			(79,820)		11
Other comprehensive (loss) income	(3,400)				(3,286)	(114)
Comprehensive income (loss)	(83,209)					(103)
Issuance of common stock including excess tax benefits of $0,$0,$0 for 2015, 2016 and 2017	22,598	1,831	20,767
Cash dividends ($0.72, $0.36 and $0.09 per share for 2015, 2016 and 2017)	(4,479)			(4,479)
Ending Balance at Dec. 31, 2016	149,834	12,271	151,089	45,443	(60,885)	1,916
Stock-based compensation	1,555		1,555
Comprehensive (loss) income:
Net (loss) income	(11,302)			(12,089)		787
Other comprehensive (loss) income	22,330				22,213	117
Comprehensive income (loss)	11,028					904
Stranded tax effect (Note 15)	0			6,088	(6,088)
Issuance of common stock including excess tax benefits of $0,$0,$0 for 2015, 2016 and 2017	438	90	348
Cash dividends ($0.72, $0.36 and $0.09 per share for 2015, 2016 and 2017)	(1,094)			(1,094)
Ending Balance at Dec. 31, 2017	$ 161,761	$ 12,361	$ 152,992	$ 38,348	$ (44,760)	$ 2,820