Schedule II - Condensed Financial Information of Registrant - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flow from operating activities [Abstract]
Net income (loss) (As adjusted)	$ (6,398)	$ 3,667	$ 2,449	$ 6,116	$ (282)	$ 5,342	$ 1,261	$ 38,856
Adjustments to reconcile net income to net cash provided by
Depreciation and amortization						1,166	869	624
Share-based compensation						2,846	4,420	4,527
Changes in operating assets and liabilities [Abstract]
Deferred income taxes, net of other comprehensive income						235	(4,716)	6,077
Income taxes receivable, net						4,361	(11,769)	(2,445)
Other, net						(15,158)	8,486	(1,024)
Cash flow from investing activities [Abstract]
Sales, maturities and redemptions of investments securities						38,038	81,812	12,760
Purchases of property and equipment						(976)	(2,147)	(1,736)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]
Proceeds from issuance of long-term debt						45,000	0	5,000
Non-controlling interest equity investment						0	0	18,743
Tax impact related to share-based compensation						0	589	1,564
Issuance of common stock for share-based awards						103	361	171
Purchases of Federated National Holding Company common stock						(10,616)	(11,317)	0
Dividends paid						(4,251)	(4,677)	(1,847)
Net increase in cash and cash equivalents						11,635	21,555	12,881
Cash and cash equivalents at beginning of period			74,593	74,593	74,593	74,593	53,038	40,157
Cash and cash equivalents at end of period						86,228	74,593	53,038
Parent Company [Member]
Cash flow from operating activities [Abstract]
Net income (loss) (As adjusted)						5,342	1,261	38,856
Adjustments to reconcile net income to net cash provided by
Equity in undistributed income of consolidated subsidiaries						(16,902)	(10,691)	(70,321)
Depreciation and amortization						88	73	64
Share-based compensation						2,846	4,420	4,527
Changes in operating assets and liabilities [Abstract]
Deferred income taxes, net of other comprehensive income						(2,057)	2,127	(153)
Income taxes receivable, net						6,411	2,978	24,352
Capital contribution payable						0	0	(18,501)
Due to subsidiaries						20,468	23,574	6,430
Other, net						1,450	3,786	2,057
Net cash provided by operating activities						17,646	27,528	(12,689)
Cash flow from investing activities [Abstract]
Capital contributions to consolidated subsidiaries, net						(25,000)	0	(32,743)
Sales, maturities and redemptions of investments securities						42,979	76,928	38,612
Purchases of investment securities						(26,828)	(83,724)	(21,354)
Purchases of property and equipment						(102)	(299)	(113)
Net cash used in investing activities						(8,951)	(7,095)	(15,598)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]
Proceeds from issuance of long-term debt						45,000	0	0
Non-controlling interest equity investment						0	0	18,743
Tax impact related to share-based compensation						0	589	1,564
Issuance of common stock for share-based awards						103	361	171
Purchases of Federated National Holding Company common stock						(10,616)	(11,317)	0
Dividends paid						(4,251)	(4,677)	(1,847)
Net cash (used in) provided by financing activities						30,236	(15,044)	18,631
Net increase in cash and cash equivalents						38,931	5,389	(9,656)
Cash and cash equivalents at beginning of period			$ 7,786	$ 7,786	$ 7,786	7,786	2,397	12,053
Cash and cash equivalents at end of period						$ 46,717	$ 7,786	$ 2,397