Restatement and Revision of Previously Issued Consolidated Financial Statements - Consolidated Statements of Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	$ 42,544	$ 49,189	$ 52,958	$ 56,818	$ 46,935	$ 39,753	$ 41,147	$ 42,026	$ 56,818	$ 42,026	$ 56,818	$ 42,026	$ 56,818	$ 42,026	$ 62,948
Net income (loss)	(7,304)	(2,200)	(618)	(3,385)	13,861	7,141	(1,121)	(2,183)	(4,003)	(3,304)	(6,203)	3,837	(13,507)	17,698	15,884
Issuance of common stock, net of conversions	(1)			1	(444)	246	198	324					0	324	0
Purchase of treasury stock	0	(3,626)	(2,334)										(5,960)	0
Stock compensation expense	367	801	822	807	792	399	1,472	955					2,797	3,618
Cash dividends	(1,217)	(1,215)	(1,242)	(1,177)	(1,166)	(1,165)	(1,165)	(1,162)					(4,851)	(4,658)	(38,000)
Other comprehensive loss	1,761	(654)	(643)	(192)	(3,349)	548	(961)	863					272	(2,899)	1,409
Reclassification adjustment to net income	116	249	246	86	189	13	183	324					697	709	947
Balance, end of period	$ 36,266	$ 42,544	$ 49,189	$ 52,958	$ 56,818	$ 46,935	$ 39,753	$ 41,147	49,189	39,753	42,544	46,935	$ 36,266	$ 56,818	$ 42,026
Common stock dividends (in dollars per share)	$ 0.9	$ 0.9	$ 0.9	$ 0.085	$ 0.085	$ 0.085	$ 0.085	$ 0.085					$ 0.355	$ 0.34	$ 0.085
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				$ 65,438				$ 46,408	65,438	46,408	65,438	46,408	$ 65,438	$ 46,408	$ 65,268
Net income (loss)	$ (1,214)	$ 397	$ (944)	(1,761)	$ 15,032	$ 8,044	$ (874)	(418)	(2,705)	(1,292)	(2,308)	6,752	(3,522)	21,784	17,905
Issuance of common stock, net of conversions													0	324	0
Purchase of treasury stock													(5,960)	0
Stock compensation expense													2,632	3,618
Cash dividends													(4,851)	(4,658)	(38,000)
Other comprehensive loss													719	(2,841)	1,450
Reclassification adjustment to net income													603	803	947
Balance, end of period	55,059				65,438								$ 55,059	$ 65,438	$ 46,408
Common stock dividends (in dollars per share)													$ 0.355	$ 0.34	$ 0.085
Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(8,620)				(4,382)	(8,620)	(4,382)	(8,620)	(4,382)	$ (8,620)	$ (4,382)	$ (2,320)
Net income (loss)	(6,090)	(2,597)	326	(1,624)	(1,171)	(903)	(247)	(1,765)	(1,298)	(2,012)	(3,895)	(2,915)	(9,985)	(4,086)	(2,021)
Stock compensation expense													165
Other comprehensive loss													(447)	(58)	(41)
Reclassification adjustment to net income				100									94	(94)
Balance, end of period	(18,793)				(8,620)								$ (18,793)	$ (8,620)	$ (4,382)
Common stock dividends (in dollars per share)													$ 0.355	$ 0.34	$ 0.085
Capital in Excess of Par Value (1)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	54,143	53,342	52,520	51,714	51,366	50,721	49,051	47,773	51,714	47,773	51,714	47,773	$ 51,714	$ 47,773	$ 75,031
Issuance of common stock, net of conversions	(1)			(1)	(444)	246	198	323					(2)	323	(136)
Stock compensation expense	367	801	822	807	792	399	1,472	955					2,797	3,618
Cash dividends	0	0	0	0											(27,122)
Balance, end of period	54,509	54,143	53,342	52,520	51,714	51,366	50,721	49,051	53,342	50,721	54,143	51,366	54,509	51,714	47,773
Capital in Excess of Par Value (1) | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				51,714				47,773	51,714	47,773	51,714	47,773	51,714	47,773	75,031
Issuance of common stock, net of conversions													(2)	323	(136)
Stock compensation expense													2,632	3,618
Cash dividends															(27,122)
Balance, end of period	54,344				51,714								54,344	51,714	47,773
Capital in Excess of Par Value (1) | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0				0	0	0	0	0	0	0	0
Stock compensation expense													165
Balance, end of period	165				0								165	0	0
Treasury Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	(5,960)	(2,334)	0	0				0	0	0	0	0	0	0	0
Purchase of treasury stock	0	(3,626)	(2,334)										(5,960)
Balance, end of period	(5,960)	(5,960)	(2,334)	0	0				(2,334)		(5,960)		(5,960)	0	0
Treasury Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0				0	0	0	0	0	0	0	0
Purchase of treasury stock													(5,960)
Balance, end of period	(5,960)				0								(5,960)	0	0
Treasury Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0				0	0	0	0	0	0	0	0
Balance, end of period	0				0								0	0	0
Retained Earnings (1)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	12,231	15,646	17,506	22,068	9,373	3,397	5,683	7,860	22,068	7,860	22,068	7,860	22,068	7,860	4,016
Net income (loss)	(7,304)	(2,200)	(618)	(3,385)	13,861	7,141	(1,121)	(2,183)					(13,507)	17,698	15,884
Cash dividends	(1,217)	(1,215)	(1,242)	(1,177)	(1,166)	(1,165)	(1,165)	(1,162)					(4,851)	(4,658)	(10,878)
Reclassification adjustment to net income														0
Balance, end of period	3,710	12,231	15,646	17,506	22,068	9,373	3,397	5,683	15,646	3,397	12,231	9,373	3,710	22,068	7,860
Retained Earnings (1) | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				30,897				12,603	30,897	12,603	30,897	12,603	30,897	12,603	6,738
Net income (loss)													(3,522)	21,784	17,905
Cash dividends													(4,851)	(4,658)	(10,878)
Reclassification adjustment to net income														0
Balance, end of period	22,524				30,897								22,524	30,897	12,603
Retained Earnings (1) | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(8,829)				(4,743)	(8,829)	(4,743)	(8,829)	(4,743)	(8,829)	(4,743)	(2,722)
Net income (loss)													(9,985)	(4,086)	(2,021)
Balance, end of period	(18,814)				(8,829)								(18,814)	(8,829)	(4,743)
Accumulated Other Comprehensive Income (Loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	(18,009)	(17,604)	(17,207)	(17,101)	(13,941)	(14,502)	(13,724)	(13,743)	(17,101)	(13,743)	(17,101)	(13,743)	(17,101)	(13,743)	(16,099)
Other comprehensive loss	1,761	(654)	(643)	(192)	(3,349)	548	(961)	863					272	(2,899)	1,409
Reclassification adjustment to net income	116	249	246	86	189	13	183	324					697	709	947
Balance, end of period	(16,132)	(18,009)	(17,604)	(17,207)	(17,101)	(13,941)	(14,502)	(13,724)	(17,604)	(14,502)	(18,009)	(13,941)	(16,132)	(17,101)	(13,743)
Accumulated Other Comprehensive Income (Loss) | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(17,310)				(14,104)	(17,310)	(14,104)	(17,310)	(14,104)	(17,310)	(14,104)	(16,501)
Other comprehensive loss													719	(2,841)	1,450
Reclassification adjustment to net income													603	803	947
Balance, end of period	(15,988)				(17,310)								(15,988)	(17,310)	(14,104)
Accumulated Other Comprehensive Income (Loss) | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				209				361	209	361	209	361	209	361	402
Other comprehensive loss													(447)	(58)	(41)
Reclassification adjustment to net income													94	(94)
Balance, end of period	(144)				209								(144)	209	361
Class A Common Stock | Common Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	95	95	95	93	92	92	92	88	93	88	93	88	93	88	0
Issuance of common stock, net of conversions	3			2	1			4					5	5	88
Balance, end of period	98	95	95	95	93	92	92	92	95	92	95	92	98	93	88
Class A Common Stock | Common Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				93				88	93	88	93	88	93	88	0
Issuance of common stock, net of conversions													5	5	88
Balance, end of period	98				93								98	93	88
Class A Common Stock | Common Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0				0	0	0	0	0	0	0	0
Balance, end of period	0				0								0	0	0
Class B Common Stock | Common Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	44	44	44	44	45	45	45	48	44	48	44	48	44	48	0
Issuance of common stock, net of conversions	(3)				(1)			(3)					(3)	(4)	48
Balance, end of period	41	$ 44	$ 44	44	44	$ 45	$ 45	45	44	45	44	45	41	44	48
Class B Common Stock | Common Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				44				48	44	48	44	48	44	48	0
Issuance of common stock, net of conversions													(3)	(4)	48
Balance, end of period	41				44								41	44	48
Class B Common Stock | Common Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				$ 0				$ 0	$ 0	$ 0	$ 0	$ 0	0	0	0
Balance, end of period	$ 0				$ 0								0	0	0
Common Class A and B
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends														(4,658)	(1,162)
Common Class A and B | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends															(1,162)
Common Class A and B | Retained Earnings (1)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends													$ (4,851)	$ (4,658)	(1,162)
Common Class A and B | Retained Earnings (1) | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends															$ (1,162)