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, shares at Dec. 31, 2017		1,886
Balance, beginning of year at Dec. 31, 2017	$ 177,921	$ 0	$ 161,891	$ 15,945	$ 85
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	11,123		11,123
Dividends paid	(1,509)		(1,509)
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 related to stock appreciation rights	150		150
Cumulative effect adjustment for adoption of new accounting standards	0		13,627	(13,627)
Net unrealized gain (loss) on investments	(1,512)			(1,512)
Net loss attributable to noncontrolling interests	(30)				(30)
Balance, end of year, shares at Jun. 30, 2018		1,887
Balance, end of year at Jun. 30, 2018	186,113	$ 0	185,252	806	55
Balance, beginning of year, shares at Mar. 31, 2018		1,887
Balance, beginning of year at Mar. 31, 2018	180,062	$ 0	178,971	1,009	82
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	6,947		6,947
Dividends paid	(754)		(754)
Shares of common stock repurchased and retired (in shares)		0
Shares of common stock repurchased and retired	0		0
Stock options and stock appreciation rights exercised (in shares)		0
Stock options and stock appreciation rights exercised	0		0
Share-based compensation expense related to stock appreciation rights	88		88
Cumulative effect adjustment for adoption of new accounting standards	0		0	0
Net unrealized gain (loss) on investments	(203)			(203)
Net loss attributable to noncontrolling interests	(27)				(27)
Balance, end of year, shares at Jun. 30, 2018		1,887
Balance, end of year at Jun. 30, 2018	186,113	$ 0	185,252	806	55
Balance, beginning of year, shares at Dec. 31, 2018		1,887
Balance, beginning of year at Dec. 31, 2018	175,639	$ 0	174,690	949	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	12,126		12,126
Dividends paid	(1,511)		(1,511)
Shares of common stock repurchased and retired (in shares)		0
Shares of common stock repurchased and retired	(11)		11
Stock options and stock appreciation rights exercised (in shares)		2
Stock options and stock appreciation rights exercised	0		0
Share-based compensation expense related to stock appreciation rights	147		147
Net unrealized gain (loss) on investments	1,905			1,905
Net loss attributable to noncontrolling interests	0
Balance, end of year, shares at Jun. 30, 2019		1,889
Balance, end of year at Jun. 30, 2019	188,295	$ 0	185,441	2,854	0
Balance, beginning of year, shares at Mar. 31, 2019		1,889
Balance, beginning of year at Mar. 31, 2019	182,729	$ 0	180,637	2,092	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to the Company	5,500		5,500
Dividends paid	(756)		(756)
Shares of common stock repurchased and retired (in shares)		0
Shares of common stock repurchased and retired	0		0
Stock options and stock appreciation rights exercised (in shares)		0
Stock options and stock appreciation rights exercised	1		1
Share-based compensation expense related to stock appreciation rights	59		59
Net unrealized gain (loss) on investments	762			762
Net loss attributable to noncontrolling interests	0
Balance, end of year, shares at Jun. 30, 2019		1,889
Balance, end of year at Jun. 30, 2019	$ 188,295	$ 0	$ 185,441	$ 2,854	$ 0