Condensed Financial Information of HCI Group, Inc. - Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements Captions [Line Items]
Net unrealized investment gains (losses)													$ 1,363	$ 679	$ 7,950
Net other-than-temporary impairment losses													0	0	(289)
Credit losses on investments													0	(611)	0
Other income													6,447	1,854	1,882
Loss on repurchases of convertible senior notes													0	(150)	0
Interest expense	$ (657)	$ (1,664)	$ (2,000)	$ (2,079)	$ (2,888)	$ (2,856)	$ (3,020)	$ (2,970)	$ (2,927)	$ (2,907)	$ (2,884)	$ (4,337)	(6,400)	(11,734)	(13,055)
Debt conversion expense													(1,754)	0	0
Income tax benefit													(3,991)	(9,348)	(9,517)
Equity in income of subsidiaries													417	(57)	(83)
Net income after noncontrolling interests													1,856	27,580	26,576
HCI Group [Member]
Condensed Financial Statements Captions [Line Items]
Net investment income (loss)													3,115	(676)	2,295
Net realized investment gains (losses)													3,344	330	(541)
Net unrealized investment gains (losses)													92	229	1,385
Credit losses on investments														(20)
Other income													222
Loss on repurchases of convertible senior notes														(150)
Interest expense													(5,467)	(10,710)	(12,042)
Debt conversion expense													(1,754)
Operating expenses													(9,056)	(6,887)	(6,353)
Loss before income tax benefit and equity in income of subsidiaries													(9,504)	(17,884)	(15,256)
Income tax benefit													2,086	4,024	3,092
Net loss before equity in income of subsidiaries													(7,418)	(13,860)	(12,164)
Equity in income of subsidiaries													9,274	41,440	38,740
Net income after noncontrolling interests													$ 1,856	$ 27,580	$ 26,576