Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Total	Common Stock	Additional paid-in capital	Retaining Earnings	Accumulated other comprehensive income
Balance, beginning (in shares) at Dec. 31, 2021			25,082,104
Beginning balance at Dec. 31, 2021		$ 879,121	$ 25	$ 203,375	$ 621,384	$ 54,337
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		28,349			28,349
Stock based compensation (in shares)			37,140
Stock based compensation		631		631
Dividends on common stock		(3,767)			(3,767)
Change in net unrealized investment appreciation (depreciation)	[1]	(65,793)				(65,793)
Change in liability for underfunded employee benefit plans	[2]	(2,916)				(2,916)
Balance, ending (in shares) at Mar. 31, 2022			25,119,244
Ending balance at Mar. 31, 2022		835,625	$ 25	204,006	645,966	(14,372)
Balance, beginning (in shares) at Dec. 31, 2021			25,082,104
Beginning balance at Dec. 31, 2021		879,121	$ 25	203,375	621,384	54,337
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(5,089)
Balance, ending (in shares) at Sep. 30, 2022			25,191,414
Ending balance at Sep. 30, 2022		700,795	$ 25	206,811	604,469	(110,510)
Balance, beginning (in shares) at Mar. 31, 2022			25,119,244
Beginning balance at Mar. 31, 2022		835,625	$ 25	204,006	645,966	(14,372)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(10,457)			(10,457)
Stock based compensation (in shares)			67,404
Stock based compensation		2,159		2,159
Dividends on common stock		(4,028)			(4,028)
Change in net unrealized investment appreciation (depreciation)	[1]	(39,480)				(39,480)
Change in liability for underfunded employee benefit plans	[2]	(2,916)				(2,916)
Balance, ending (in shares) at Jun. 30, 2022			25,186,648
Ending balance at Jun. 30, 2022		780,903	$ 25	206,165	631,481	(56,768)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(22,981)			(22,981)
Stock based compensation (in shares)			4,766
Stock based compensation		646		646
Dividends on common stock		(4,031)			(4,031)
Change in net unrealized investment appreciation (depreciation)	[1]	(50,826)				(50,826)
Change in liability for underfunded employee benefit plans	[2]	(2,916)				(2,916)
Balance, ending (in shares) at Sep. 30, 2022			25,191,414
Ending balance at Sep. 30, 2022		$ 700,795	$ 25	206,811	604,469	(110,510)
Balance, beginning (in shares) at Dec. 31, 2022		25,210,541	25,210,541
Beginning balance at Dec. 31, 2022		$ 740,114	$ 25	207,030	620,555	(87,496)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		694			694
Stock based compensation (in shares)			21,012
Stock based compensation		980		980
Dividends on common stock		(4,037)			(4,037)
Change in net unrealized investment appreciation (depreciation)	[3]	14,650				14,650
Change in liability for underfunded employee benefit plans	[4]	(607)				(607)
Balance, ending (in shares) at Mar. 31, 2023			25,231,553
Ending balance at Mar. 31, 2023		$ 751,795	$ 25	208,010	617,213	(73,453)
Balance, beginning (in shares) at Dec. 31, 2022		25,210,541	25,210,541
Beginning balance at Dec. 31, 2022		$ 740,114	$ 25	207,030	620,555	(87,496)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		$ (49,308)
Balance, ending (in shares) at Sep. 30, 2023		25,263,742	25,263,742
Ending balance at Sep. 30, 2023		$ 644,937	$ 25	209,931	559,126	(124,145)
Balance, beginning (in shares) at Mar. 31, 2023			25,231,553
Beginning balance at Mar. 31, 2023		751,795	$ 25	208,010	617,213	(73,453)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(56,382)			(56,382)
Stock based compensation (in shares)			31,396
Stock based compensation		977		977
Dividends on common stock		(4,042)			(4,042)
Change in net unrealized investment appreciation (depreciation)	[3]	(15,376)				(15,376)
Change in liability for underfunded employee benefit plans	[4]	(606)				(606)
Balance, ending (in shares) at Jun. 30, 2023			25,262,949
Ending balance at Jun. 30, 2023		676,365	$ 25	208,987	556,788	(89,435)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		6,380			6,380
Stock based compensation (in shares)			793
Stock based compensation		944		944
Dividends on common stock		(4,042)			(4,042)
Change in net unrealized investment appreciation (depreciation)	[3]	(34,103)				(34,103)
Change in liability for underfunded employee benefit plans	[4]	$ (607)				(607)
Balance, ending (in shares) at Sep. 30, 2023		25,263,742	25,263,742
Ending balance at Sep. 30, 2023		$ 644,937	$ 25	$ 209,931	$ 559,126	$ (124,145)

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

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

[3] The change in net unrealized appreciation (depreciation) is net of reclassification adjustments and income taxes.

[4] The change in liability for underfunded employee benefit plans is net of reclassification adjustments and income taxes.