Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Accumulated Undistributed (Overdistributed) Earnings
Beginning balance (in shares) at Dec. 31, 2022		55,299,484
Beginning balance at Dec. 31, 2022	$ 883,634	$ 55	$ 1,044,547	$ (160,968)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(338,029)
Repurchases of common stock	(3,592)		(3,592)
Net investment income	29,858			29,858
Net realized losses on investments	(4,525)			(4,525)
Net unrealized gains (losses) on investments	(56,378)			(56,378)
Dividends declared and payable	(18,687)			(18,687)
Ending balance (in shares) at Mar. 31, 2023		54,961,455
Ending balance at Mar. 31, 2023	830,310	$ 55	1,040,955	(210,700)
Beginning balance (in shares) at Dec. 31, 2022		55,299,484
Beginning balance at Dec. 31, 2022	$ 883,634	$ 55	1,044,547	(160,968)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(666,657)
Repurchases of common stock	$ (6,818)
Net investment income	53,274
Net realized losses on investments	(23,453)
Net unrealized gains (losses) on investments	$ (32,972)
Ending balance (in shares) at Jun. 30, 2023	54,632,827	54,632,827
Ending balance at Jun. 30, 2023	$ 836,364	$ 55	1,037,729	(201,420)
Beginning balance (in shares) at Dec. 31, 2022		55,299,484
Beginning balance at Dec. 31, 2022	$ 883,634	$ 55	1,044,547	(160,968)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(1,114,848)
Repurchases of common stock	$ (11,518)
Net investment income	105,022
Net realized losses on investments	(31,927)
Net unrealized gains (losses) on investments	$ 22,219
Ending balance (in shares) at Dec. 31, 2023	54,184,636	54,184,636
Ending balance at Dec. 31, 2023	$ 879,563	$ 54	1,033,030	(153,521)
Beginning balance (in shares) at Mar. 31, 2023		54,961,455
Beginning balance at Mar. 31, 2023	830,310	$ 55	1,040,955	(210,700)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(328,628)
Repurchases of common stock	(3,226)		(3,226)
Net investment income	23,416			23,416
Net realized losses on investments	(18,928)			(18,928)
Net unrealized gains (losses) on investments	23,406			23,406
Dividends declared and payable	$ (18,614)			(18,614)
Ending balance (in shares) at Jun. 30, 2023	54,632,827	54,632,827
Ending balance at Jun. 30, 2023	$ 836,364	$ 55	1,037,729	(201,420)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(168,023)
Repurchases of common stock	(1,801)	$ (1)	(1,800)
Net investment income	29,990			29,990
Net realized losses on investments	(8,123)			(8,123)
Net unrealized gains (losses) on investments	25,606			25,606
Dividends declared and payable	(21,276)			(21,276)
Ending balance (in shares) at Sep. 30, 2023		54,464,804
Ending balance at Sep. 30, 2023	860,760	$ 54	1,035,929	(175,223)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(280,168)
Repurchases of common stock	(2,899)		(2,899)
Net investment income	21,758			21,758
Net realized losses on investments	(351)			(351)
Net unrealized gains (losses) on investments	29,585			29,585
Dividends declared and payable	$ (29,290)			(29,290)
Ending balance (in shares) at Dec. 31, 2023	54,184,636	54,184,636
Ending balance at Dec. 31, 2023	$ 879,563	$ 54	1,033,030	(153,521)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(1,114,848)	(424,031)
Repurchases of common stock	$ (4,670)		(4,670)
Net investment income	32,593			32,593
Net realized losses on investments	(9,736)			(9,736)
Net unrealized gains (losses) on investments	(16,412)			(16,412)
Dividends declared and payable	(18,279)			(18,279)
Ending balance (in shares) at Mar. 31, 2024		53,760,605
Ending balance at Mar. 31, 2024	$ 863,059	$ 54	1,028,360	(165,355)
Beginning balance (in shares) at Dec. 31, 2023	54,184,636	54,184,636
Beginning balance at Dec. 31, 2023	$ 879,563	$ 54	1,033,030	(153,521)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)	(659,013)
Repurchases of common stock	$ (7,341)
Net investment income	55,556
Net realized losses on investments	(30,013)
Net unrealized gains (losses) on investments	$ 3,280
Ending balance (in shares) at Jun. 30, 2024	53,525,623	53,525,623
Ending balance at Jun. 30, 2024	$ 860,806	$ 54	1,025,689	(164,937)
Beginning balance (in shares) at Mar. 31, 2024		53,760,605
Beginning balance at Mar. 31, 2024	863,059	$ 54	1,028,360	(165,355)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock (in shares)		(234,982)
Repurchases of common stock	(2,671)		(2,671)
Net investment income	22,963			22,963
Net realized losses on investments	(20,277)			(20,277)
Net unrealized gains (losses) on investments	19,692			19,692
Dividends declared and payable	$ (21,960)			(21,960)
Ending balance (in shares) at Jun. 30, 2024	53,525,623	53,525,623
Ending balance at Jun. 30, 2024	$ 860,806	$ 54	$ 1,025,689	$ (164,937)