Restatement of Previously Issued Financial Statements - Statements of Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	$ 53,396	$ 36,266	$ 52,958	$ 56,818	$ 36,266	$ 56,818
Net income (loss)	7,760	21,512	(618)	(3,385)	29,272	(4,003)
Issuance of common stock, net of conversions		0		1		1
Stock Repurchased During Period, Value			2,334			(2,334)
Share-based compensation expense	1,263	554	822	807		1,629
Cash dividends	(1,228)	(1,226)	(1,242)	(1,177)
Other comprehensive loss	656	(4,015)	(643)	(192)		(835)
Reclassification adjustment to net income	(295)	305	246	86		332
Balance, end of period	$ 61,552	$ 53,396	$ 49,189	$ 52,958	61,552	$ 49,189
Cash Dividends on Class A Common and Class B Common per share (in usd per share)	$ 0.085	$ 0.09	$ 0.09	$ 0.085		$ 0.085
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				$ 65,438		$ 65,438
Net income (loss)			$ (944)			(2,705)
Issuance of common stock, net of conversions						1
Stock Repurchased During Period, Value						(2,334)
Share-based compensation expense						1,629
Other comprehensive loss						(751)
Reclassification adjustment to net income						238
Balance, end of period			59,097			$ 59,097
Cash Dividends on Class A Common and Class B Common per share (in usd per share)						$ 0.085
Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(8,620)		$ (8,620)
Net income (loss)			326			(1,298)
Other comprehensive loss						(85)
Reclassification adjustment to net income						94
Balance, end of period			(9,909)			$ (9,909)
Cash Dividends on Class A Common and Class B Common per share (in usd per share)						$ 0.085
Capital in Excess of Par Value
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	$ 55,062	$ 54,509	52,520	51,714	54,509	$ 51,714
Issuance of common stock, net of conversions		(1)		(1)		(1)
Share-based compensation expense	1,263	554	822	807		1,629
Balance, end of period	56,325	55,062	53,342	52,520	56,325	53,342
Capital in Excess of Par Value | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				51,714		51,714
Issuance of common stock, net of conversions						(1)
Share-based compensation expense						1,629
Balance, end of period			53,342			53,342
Capital in Excess of Par Value | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0		0
Balance, end of period			0			0
Treasury Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	(5,960)	(5,960)	0	0	(5,960)	0
Stock Repurchased During Period, Value			2,334			(2,334)
Balance, end of period	(5,960)	(5,960)	(2,334)	0	(5,960)	(2,334)
Treasury Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Stock Repurchased During Period, Value						(2,334)
Balance, end of period			(2,334)			(2,334)
Treasury Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0		0
Balance, end of period			0			0
Retained Earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	23,996	3,710	17,506	22,068	3,710	22,068
Net income (loss)	7,760	21,512	(618)	(3,385)		(4,003)
Cash dividends	(1,228)	(1,226)	(1,242)	(1,177)
Balance, end of period	30,528	23,996	15,646	17,506	30,528	15,646
Retained Earnings | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				30,897		30,897
Net income (loss)						(2,705)
Balance, end of period			25,773			25,773
Retained Earnings | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(8,829)		(8,829)
Net income (loss)						(1,298)
Balance, end of period			(10,127)			(10,127)
Accumulated Other Comprehensive Income (Loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	(19,842)	(16,132)	(17,207)	(17,101)	(16,132)	(17,101)
Other comprehensive loss	656	(4,015)	(643)	(192)		(835)
Reclassification adjustment to net income	(295)	305	246	86		332
Balance, end of period	(19,481)	(19,842)	(17,604)	(17,207)	(19,481)	(17,604)
Accumulated Other Comprehensive Income (Loss) | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				(17,310)		(17,310)
Other comprehensive loss						(751)
Reclassification adjustment to net income						238
Balance, end of period			(17,823)			(17,823)
Accumulated Other Comprehensive Income (Loss) | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				209		209
Other comprehensive loss						(85)
Reclassification adjustment to net income						94
Balance, end of period			218			218
Class A Common Stock | Common Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	99	98	95	93	98	93
Issuance of common stock, net of conversions		1		2		2
Balance, end of period	99	99	95	95	99	95
Class A Common Stock | Common Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				93		93
Issuance of common stock, net of conversions						2
Balance, end of period			95			95
Class A Common Stock | Common Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				0		0
Balance, end of period			0			0
Class B Common Stock | Common Stock
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period	41	41	44	44	41	44
Balance, end of period	$ 41	$ 41	44	44	$ 41	44
Class B Common Stock | Common Stock | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				44		44
Balance, end of period			44			44
Class B Common Stock | Common Stock | Restatement Impacts
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Balance, beginning of period				$ 0		0
Balance, end of period			$ 0			0
Common Class A and B
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends						(2,419)
Common Class A and B | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends						(2,419)
Common Class A and B | Retained Earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends						(2,419)
Common Class A and B | Retained Earnings | As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cash dividends						$ (2,419)