Stockholders' Equity (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) Vote $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Jan. 01, 2018 USD ($)	Jul. 28, 2004 shares
Changes in the components of stockholders' equity
Balance at the beginning of the period	$ 59,222,000
Net (loss) earnings	6,889,000	$ 8,426,000	$ 3,801,000
Dividends paid	2,930,000	2,944,000	1,840,000
Unrealized gain on equity investments, net of income taxes		22,000	8,000
Change in pension net actuarial loss and prior service cost, net of income taxes	155,000	(70,000)	$ (279,000)
Balance at the end of the period	$ 62,888,000	$ 59,222,000
Preferred stock, shares issued | shares	0	0
Accumulated other comprehensive loss, net of income taxes
Net actuarial loss and prior service cost not yet recognized in net periodic benefit cost, net of income tax benefit of $0,000,000 and $2,410,000, respectively	$ (3,358,000)	$ (3,513,000)
Accumulated unrealized gain on available-for-sale securities, net of income tax expense of $52,000		73,000
Accumulated other comprehensive loss	(3,358,000)	(3,440,000)
Income tax benefit on net actuarial loss and prior service cost not yet recognized in net periodic benefit cost	$ 2,350,000	2,410,000
Income tax expense on accumulated unrealized gain on available-for-sale securities		$ 52,000
Minimum percentage of common stock to be acquired for rights to detach and be traded separately from common stock	10.00%
Minimum percentage of common stock to be announced for tender or exchange for rights to detach and be traded separately from common stock	10.00%
Share Repurchase Authorization 2004
Changes in the components of stockholders' equity
Number of shares purchased and retired | shares	308,928	130,741	37,813
Average purchase price of shares purchased and retired (in dollars per share) | $ / shares	$ 2.08	$ 2.07	$ 2.22
Number of shares of common stock authorized to be repurchased | shares					2,000,000
Remaining number of shares authorized to be repurchased | shares	700,649
Restricted Stock
Changes in the components of stockholders' equity
Number of shares purchased and retired | shares	47,236	46,179	44,311
Average purchase price of shares purchased and retired (in dollars per share) | $ / shares	$ 2.00	$ 2.27	$ 2.33
Class A Common Stock
Changes in the components of stockholders' equity
Number of votes per share | Vote	10
Common Stock | Common Stock
Changes in the components of stockholders' equity
Balance at the beginning of the period		$ 1,828,000	$ 1,822,000
Issuance of restricted stock awards, net of forfeitures	$ 15,000	15,000	14,000
Repurchase and retirement of common stock	(35,000)	(18,000)	(8,000)
Balance at the end of the period	$ 1,805,000		1,828,000
Number of votes per share | Vote	1
Common Stock | Common Stock | Previously reported
Changes in the components of stockholders' equity
Balance at the beginning of the period	$ 1,825,000
Balance at the end of the period		1,825,000
Common Stock | Class A Common Stock
Changes in the components of stockholders' equity
Balance at the beginning of the period		1,851,000	1,851,000
Balance at the end of the period	1,851,000		1,851,000
Common Stock | Class A Common Stock | Previously reported
Changes in the components of stockholders' equity
Balance at the beginning of the period	1,851,000
Balance at the end of the period		1,851,000
Additional Paid-in Capital
Changes in the components of stockholders' equity
Balance at the beginning of the period		101,858,000	101,742,000
Issuance of restricted stock awards, net of forfeitures	(15,000)	(15,000)	(14,000)
Stock-based compensation	(302,000)	364,000	284,000
Repurchase and retirement of common stock	(715,000)	(363,000)	(181,000)
Excess tax benefit on restricted stock			27,000
Balance at the end of the period	101,416,000		101,858,000
Additional Paid-in Capital | Previously reported
Changes in the components of stockholders' equity
Balance at the beginning of the period	101,844,000
Balance at the end of the period		101,844,000
Accumulated Deficit
Changes in the components of stockholders' equity
Balance at the beginning of the period		(48,340,000)	(50,301,000)
Net (loss) earnings	6,889,000	8,426,000	3,801,000
Dividends paid	$ (2,930,000)	$ (2,944,000)	$ (1,840,000)
Dividends paid (in dollars per share) | $ / shares	$ 0.08	$ 0.08	$ 0.05
Balance at the end of the period	$ (38,826,000)		$ (48,340,000)
Accumulated Deficit | Previously reported
Changes in the components of stockholders' equity
Balance at the beginning of the period	(42,858,000)
Balance at the end of the period		$ (42,858,000)
Accumulated Deficit | ASU 2016-01 | Adjustment
Changes in the components of stockholders' equity
Adoption of ASU 2016-01 (see NOTE 2)	73,000			$ 73,000
Accumulated Other Comprehensive Loss
Changes in the components of stockholders' equity
Balance at the beginning of the period		(3,392,000)	(3,121,000)
Unrealized gain on equity investments, net of income taxes		22,000	8,000
Change in pension net actuarial loss and prior service cost, net of income taxes	155,000	(70,000)	(279,000)
Balance at the end of the period	(3,358,000)		(3,392,000)
Income tax expense (benefit) on unrealized gain (loss) on available-for-sale securities		15,000	(6,000)
Income tax benefit (expense) on change in net actuarial loss and prior service cost	(60,000)	(48,000)	$ 191,000
Accumulated Other Comprehensive Loss | Previously reported
Changes in the components of stockholders' equity
Balance at the beginning of the period	(3,440,000)
Balance at the end of the period		$ (3,440,000)
Accumulated Other Comprehensive Loss | ASU 2016-01 | Adjustment
Changes in the components of stockholders' equity
Adoption of ASU 2016-01 (see NOTE 2)	$ (73,000)			$ (73,000)