Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)
Balance, beginning of year at Dec. 31, 2021			$ 25	$ 203,375	$ 621,384	$ 54,337
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation				3,655
Net income (loss)		$ 15,031			15,031
Dividends on common stock ($0.64, $0.64, and $0.63 per share)					(15,860)
Change in net unrealized investment gain (loss)	[1]					(138,138)
Change in liability for underfunded employee benefit plans	[2]					(3,695)
Foreign currency translation adjustment		0
Balance, end of year at Dec. 31, 2022		740,114	$ 25	207,030	620,555	(87,496)
Balance, beginning of year (in shares) at Dec. 31, 2021			25,082,104
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation (in shares)			128,437
Balance, ending of year (in shares) at Dec. 31, 2022			25,210,541
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation				2,956
Net income (loss)		(29,700)			(29,700)
Dividends on common stock ($0.64, $0.64, and $0.63 per share)					(16,164)
Change in net unrealized investment gain (loss)	[1]					21,402
Change in liability for underfunded employee benefit plans	[2]					15,137
Foreign currency translation adjustment		0
Balance, end of year at Dec. 31, 2023		$ 733,745	$ 25	209,986	574,691	(50,957)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation (in shares)			59,301
Balance, ending of year (in shares) at Dec. 31, 2023		25,269,842	25,269,842
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation				5,865
Net income (loss)		$ 61,957			61,957
Dividends on common stock ($0.64, $0.64, and $0.63 per share)					(16,212)
Change in net unrealized investment gain (loss)	[1]					(5,274)
Change in liability for underfunded employee benefit plans	[2]					1,650
Foreign currency translation adjustment		(200)				(200)
Balance, end of year at Dec. 31, 2024		$ 781,531	$ 25	$ 215,851	$ 620,436	$ (54,781)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock based compensation (in shares)			108,449
Balance, ending of year (in shares) at Dec. 31, 2024		25,378,291	25,378,291

[1] The change in net unrealized gain (loss) is net of reclassification adjustments and income taxes.

[2] The change in liability for underfunded employee benefit plans is net of income taxes.