Condensed Financial Information of HCI Group, Inc. - Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income (loss)	$ 79,034	$ (58,511)	$ 1,856
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock-based compensation expense	9,348	15,107	13,754
Net realized investment losses (gains)	1,996	1,187	(6,472)
Net unrealized investment (gains) losses	(3,215)	7,153	(1,363)
Net (accretion of discount) amortization of premiums on investments in fixed-maturity securities	(4,497)	(961)	169
Depreciation and amortization	8,184	8,010	5,549
Net income from limited partnership investments	(661)	(3,963)	(4,947)
Distributions from limited partnership interests	1,148	3,001	3,604
Debt conversion expense	0	0	1,754
Equity in (income) loss of subsidiaries	0	(495)	(417)
Total deferred taxes	(1,102)	(9,881)	1,142
Changes in operating assets and liabilities:
Income taxes	10,509	1,277	470
Other assets	(19,893)	(15,581)	4,487
Accrued expenses and other liabilities	14,264	(8,397)	1,642
Net cash (used in) provided by operating activities	230,658	(12)	96,503
Cash flows from investing activities:
Investments in limited partnership interests	(1,483)	(1,967)	(3,756)
Purchase of fixed-maturity securities	(332,152)	(614,843)	(18,303)
Purchase of equity securities	(20,501)	(22,887)	(102,801)
Purchase of short-term and other investments	(81)	(42)	(1,307)
Purchase of intangible assets	(1,786)	(3,800)	0
Purchase of property and equipment	(6,502)	(6,341)	(3,318)
Proceeds from sales of fixed-maturity securities	22,326	11,716	23,055
Proceeds from calls, repayments and maturities of fixed-maturity securities	328,719	151,415	23,430
Proceeds from sales of equity securities	12,202	31,605	112,310
Proceeds from sales, redemptions and maturities of short-term and other investments	53	570	3,629
Distributions received from limited partnership interests	3,115	5,360	4,657
Net cash (used in) provided by investing activities	4,269	(434,537)	36,852
Cash flows from financing activities:
Net proceeds from issuance of common stock	84,572	0	0
Repurchases of common stock	(784)	(71,242)	(1,314)
Repurchases of common stock under share repurchase plan	0	(17,070)	0
Debt issuance costs	(378)	(6,041)	(152)
Cash dividends paid	(13,719)	(15,233)	(14,065)
Cash dividends received under share repurchase forward contract	0	76	306
Net (repayment) borrowing under revolving credit facility	0	(15,000)	(8,750)
Debt conversion expense paid	0	0	(1,895)
Net cash provided by (used in) financing activities	67,117	41,067	64,301
Net increase (decrease) in cash and cash equivalents	302,002	(393,580)	197,602
Cash and cash equivalents at beginning of year	237,763
Cash and cash equivalents at end of year	539,765	237,763
HCI Group [Member]
Cash flows from operating activities:
Net income (loss)	64,488	(58,511)	1,856
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Stock-based compensation expense	4,323	6,430	5,874
Net realized investment losses (gains)	554	1,154	(3,344)
Net unrealized investment (gains) losses	(1,060)	1,609	(92)
Net (accretion of discount) amortization of premiums on investments in fixed-maturity securities	(41)	(110)	3
Depreciation and amortization	1,633	1,403	1,490
Net income from limited partnership investments	(737)	(3,345)	(2,608)
Distributions from limited partnership interests	833	2,123	1,477
Debt conversion expense	0	0	1,754
Equity in (income) loss of subsidiaries	(70,832)	47,331	(9,274)
Total deferred taxes	649	(895)	232
Changes in operating assets and liabilities:
Income taxes	(1,247)	11,708	5,067
Other assets	383	(2,805)	2,679
Accrued expenses and other liabilities	1,165	4,078	(5,620)
Due to related parties	8,340	38,696	5,360
Net cash (used in) provided by operating activities	8,451	48,866	4,854
Cash flows from investing activities:
Investments in limited partnership interests	(1,192)	(1,261)	(2,616)
Investment in note receivable - related party	(25,000)	(15,000)	(40,000)
Purchase of fixed-maturity securities	(26,585)	(52,576)	(1,685)
Purchase of equity securities	(4,904)	(11,406)	(76,786)
Purchase of short-term and other investments	(81)	(42)	(1,307)
Purchase of intangible assets	0	(3,800)	0
Purchase of property and equipment	(478)	(581)	(365)
Proceeds from sales of fixed-maturity securities	33	86	134
Proceeds from calls, repayments and maturities of fixed-maturity securities	26,626	54,178	145
Proceeds from sales of equity securities	4,660	10,975	78,555
Proceeds from sales, redemptions and maturities of short-term and other investments	53	570	3,618
Collection of note receivable - related party	0	0	23,280
Distributions received from limited partnership interests	3,025	4,759	2,567
Dividends received from subsidiary	40,500	51,500	41,900
Investment in subsidiaries	(22,000)	(41,868)	(10,000)
Net cash (used in) provided by investing activities	(5,343)	(4,466)	17,440
Cash flows from financing activities:
Net proceeds from issuance of common stock	84,572	0	0
Repurchases of common stock	(784)	(71,242)	(1,314)
Repurchases of common stock under share repurchase plan	0	(17,070)	0
Debt issuance costs	(170)	(6,041)	(152)
Cash dividends paid	(13,719)	(15,233)	(14,065)
Cash dividends received under share repurchase forward contract	0	76	306
Net (repayment) borrowing under revolving credit facility	(0)	(15,000)	(8,750)
Debt conversion expense paid	0	0	(1,895)
Proceeds from issuance of long-term debt	0	172,500	0
Repayment of long-term debt	0	(1)	(2)
Net cash provided by (used in) financing activities	69,899	47,989	(25,872)
Net increase (decrease) in cash and cash equivalents	73,007	92,389	(3,578)
Cash and cash equivalents at beginning of year	102,755	10,366	13,944
Cash and cash equivalents at end of year	$ 175,762	$ 102,755	$ 10,366