Condensed Financial Information of HCI Group, Inc. - Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 1,856	$ 27,580	$ 26,576
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	13,754	8,133	6,460
Net realized investment (gains) losses	(6,472)	(1,000)	254
Net unrealized investment gains	(1,363)	(679)	(7,950)
Net amortization of premiums (accretion of discount) on investments in fixed-maturity securities	169	(100)	50
Depreciation and amortization	5,549	8,747	8,942
Net (income) loss from limited partnership interests	(4,947)	1,595	(1,176)
Distributions received from limited partnership interests	3,604	1,215	4,176
Other-than-temporary impairment losses	0	0	289
Credit losses on investments	0	(611)	0
Debt conversion expense	1,754	0	0
Loss on repurchases of convertible senior notes	0	150	0
Equity in income of subsidiaries	(417)	57	83
Deferred income taxes	1,142	8,123	1,871
Changes in operating assets and liabilities:
Income taxes	470	(3,514)	(69)
Other assets	4,487	(4,578)	(7,837)
Accrued expenses and other liabilities	1,642	20,303	4,218
Net cash provided by operating activities	96,503	77,311	54,047
Cash flows from investing activities:
Investments in limited partnership interests	(3,756)	(4,241)	(1,174)
Purchase of fixed-maturity securities	(18,303)	(34,951)	(82,662)
Purchase of equity securities	(102,801)	(68,223)	(24,637)
Purchase of short-term and other investments	(1,307)	(200)	(1,178)
Purchase of property and equipment	(3,318)	(6,437)	(2,887)
Proceeds from sales of fixed-maturity securities	23,055	81,433	7,947
Proceeds from calls, repayments and maturities of fixed-maturity securities	23,430	84,459	59,343
Proceeds from sales of equity securities	112,310	47,312	37,669
Distributions from limited partnership interests	4,657	2,086	2,121
Return of capital from subsidiary	623		0
Net cash provided by (used in) investing activities	36,852	143,215	50,459
Cash flows from financing activities:
Repurchases of common stock	(1,314)	(1,547)	(1,203)
Repurchases of common stock under share repurchase plan	0	(5,161)	(18,851)
Repurchases of convertible senior notes	0	(4,459)
Debt issuance costs	(152)	(165)	(459)
Cash dividends	(14,065)	(12,694)	(13,012)
Cash dividends received under share repurchase forward contract	306	306	306
Net (repayment) borrowing under revolving credit facility	(8,750)	14,000	9,750
Proceeds from exercise of stock options	0	63	63
Debt conversion expense paid	(1,895)
Net cash used in financing activities	64,301	(16,705)	(114,724)
Net increase (decrease) in cash, cash equivalents and restricted cash	197,602	203,823	(10,240)
Cash and cash equivalents at beginning of year	433,741
Cash and cash equivalents at end of year	631,343	433,741
HCI Group [Member]
Cash flows from operating activities:
Net income (loss)	1,856	27,580	26,576
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	5,874	4,488	3,638
Net realized investment (gains) losses	(3,344)	(330)	541
Net unrealized investment gains	(92)	(229)	(1,385)
Net amortization of premiums (accretion of discount) on investments in fixed-maturity securities	3	(42)	66
Depreciation and amortization	1,490	4,686	5,194
Net (income) loss from limited partnership interests	(2,608)	1,781	(701)
Distributions received from limited partnership interests	1,477	844	1,661
Credit losses on investments		(20)
Debt conversion expense	1,754
Loss on repurchases of convertible senior notes		150
Equity in income of subsidiaries	(9,274)	(41,440)	(38,740)
Deferred income taxes	232	(935)	(916)
Changes in operating assets and liabilities:
Income taxes	5,067	(9,791)	4,462
Other assets	2,679	(629)	(3,042)
Accrued expenses and other liabilities	(5,620)	1,096	1,750
Due to related parties	5,360	17,438	(16,754)
Net cash provided by operating activities	4,854	4,687	(17,650)
Cash flows from investing activities:
Investments in limited partnership interests	(2,616)	(3,376)	(1,602)
Investment in note receivable – related party	(40,000)	(22,000)
Purchase of fixed-maturity securities	(1,685)	(7)	(234)
Purchase of equity securities	(76,786)	(35,855)	(8,733)
Purchase of short-term and other investments	(1,307)	(200)	(187)
Purchase of property and equipment	(365)	(742)	(176)
Proceeds from sales of fixed-maturity securities	134	447	477
Proceeds from calls, repayments and maturities of fixed-maturity securities	145	27	35,361
Proceeds from sales of equity securities	78,555	30,688	9,906
Proceeds from sales, redemptions and maturities of short-term and other investments	3,618	537	25,733
Collection of note receivable – related party	23,280
Distributions from limited partnership interests	2,567	1,614	948
Dividends received from subsidiary	41,900	52,500	44,000
Return of capital from subsidiary		9	6,000
Investment in subsidiaries	(10,000)	(22,629)	(5,000)
Net cash provided by (used in) investing activities	17,440	1,013	106,493
Cash flows from financing activities:
Repurchases of common stock	(1,314)	(1,547)	(1,203)
Repurchases of common stock under share repurchase plan		(5,161)	(18,851)
Repurchases of convertible senior notes		(4,459)
Debt issuance costs	(152)		(459)
Cash dividends	(14,065)	(12,694)	(13,012)
Cash dividends received under share repurchase forward contract	306	306	306
Net (repayment) borrowing under revolving credit facility	(8,750)	14,000	9,750
Proceeds from exercise of stock options		63	63
Debt conversion expense paid	(1,895)
Repayment of long-term debt	(2)	(2)	(89,991)
Net cash used in financing activities	(25,872)	(9,494)	(113,397)
Net increase (decrease) in cash, cash equivalents and restricted cash	(3,578)	(3,794)	(24,554)
Cash and cash equivalents at beginning of year	13,944	17,738	42,292
Cash and cash equivalents at end of year	$ 10,366	$ 13,944	$ 17,738