Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interest [Member]
Balance, beginning of year at Dec. 31, 2016	$ 155,136	$ 0	$ 143,284	$ 11,761	$ 91
Balance, beginning of year, shares at Dec. 31, 2016		1,884
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	25,707		25,707
Dividends	(7,073)		(7,073)
Shares of common stock repurchased and retired (in shares)		(1)
Shares of common stock repurchased and retired	(246)		(246)
Stock options and stock appreciation rights exercised (in shares)		3
Stock options and stock appreciation rights exercised	0		0
Share-based compensation expense	219		219
Amortization related to postretirement health benefits	6			6
Accumulated postretirement benefit obligation adjustment	46			46
Net unrealized gain (loss) on investments	4,132			4,132
Net income (loss) attributable to noncontrolling interest	(6)				(6)
Balance, end of year at Dec. 31, 2017	177,921	$ 0	161,891	15,945	85
Balance, end of year, shares at Dec. 31, 2017		1,886
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	21,892		21,892
Dividends	(23,017)		(23,017)
Shares of common stock repurchased and retired (in shares)		0
Shares of common stock repurchased and retired	(29)		(29)
Stock options and stock appreciation rights exercised (in shares)		1
Stock options and stock appreciation rights exercised	(1)		(1)
Share-based compensation expense	327		327
Cumulative-effect adjustment for adoption of new accounting standards	0		13,627	(13,627)
Accumulated postretirement benefit obligation adjustment	37			37
Net unrealized gain (loss) on investments	(1,406)			(1,406)
Subsidiary return of capital	(52)				(52)
Net income (loss) attributable to noncontrolling interest	(33)				(33)
Balance, end of year at Dec. 31, 2018	175,639	$ 0	174,690	949	0
Balance, end of year, shares at Dec. 31, 2018		1,887
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	31,458		31,458
Dividends	(18,131)		(18,131)
Shares of common stock repurchased and retired (in shares)		0
Shares of common stock repurchased and retired	(19)		(19)
Stock options and stock appreciation rights exercised (in shares)		2
Stock options and stock appreciation rights exercised	0		0
Share-based compensation expense	264		264
Accumulated postretirement benefit obligation adjustment	0
Net unrealized gain (loss) on investments	2,151			2,151
Net income (loss) attributable to noncontrolling interest	0
Balance, end of year at Dec. 31, 2019	$ 191,362	$ 0	$ 188,262	$ 3,100	$ 0
Balance, end of year, shares at Dec. 31, 2019		1,889