Segment Information - Summary of Segment Information Reconciled to Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended												12 Months Ended
	Aug. 16, 2016	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 15, 2016
Revenue:
Net premiums earned		$ 52,758	$ 54,177	$ 52,965	$ 53,522	$ 55,771	$ 43,964	$ 61,847	$ 63,036	$ 63,352	$ 63,300	$ 58,528	$ 58,447	$ 213,422	$ 224,618	$ 243,627
Net investment income (loss)														16,581	11,439	9,087
Net realized investment (losses) gains														6,183	4,346	2,601
Net unrealized investment (losses) gains														(10,202)	92
Net other-than-temporary impairment losses														(80)	(1,467)	(2,482)
Policy fee income														3,389	3,622	3,914
Gain on repurchases of convertible senior notes																153
Gain on bargain purchase	$ 2,071															2,071
Gain on remeasurement of previously held interest																4,005	$ 4,005
Other														1,999	1,756	1,470
Total revenue		52,997	61,743	58,813	57,739	61,623	47,490	67,580	67,713	72,371	69,808	61,520	60,747	231,292	244,406	264,446
Expenses:
Losses and loss adjustment expenses		42,101	25,769	21,803	19,655	23,204	89,231	27,665	25,529	45,406	25,909	26,272	27,080	109,328	165,629	124,667
Amortization of deferred policy acquisition costs														35,204	35,663	37,868
Interest expense		4,569	4,552	4,505	4,470	4,439	4,408	4,378	3,542	2,967	2,672	2,611	2,829	18,096	16,767	11,079
Loss on repurchases of senior notes															743
Depreciation and amortization														1,369	1,238	1,272
Other														40,393	39,990	42,704
Total operating expenses		64,342	49,820	47,293	42,935	44,676	113,508	53,275	48,571	66,470	49,779	50,291	51,050	204,390	260,030	217,590
Income (loss) before income taxes		$ (11,345)	$ 11,923	$ 11,520	$ 14,804	$ 16,947	$ (66,018)	$ 14,305	$ 19,142	$ 5,901	$ 20,029	$ 11,229	$ 9,697	26,902	(15,624)	46,856
Operating Segments [Member] | Insurance Operations [Member]
Revenue:
Net premiums earned														213,422	224,618	243,627
Net investment income (loss)														10,862	9,898	8,440
Net realized investment (losses) gains														4,639	3,978	2,450
Net unrealized investment (losses) gains														(8,688)
Net other-than-temporary impairment losses														0	(1,258)	(2,467)
Policy fee income														3,389	3,622	3,914
Other														583	693	684
Total revenue														224,207	241,551	256,648
Expenses:
Losses and loss adjustment expenses														109,328	165,629	124,667
Amortization of deferred policy acquisition costs														35,204	35,663	37,868
Interest expense														1
Depreciation and amortization														125	128	158
Other														25,797	27,547	31,351
Total operating expenses														170,455	228,967	194,044
Income (loss) before income taxes														53,752	12,584	62,604
Total revenue from non-affiliates														224,207	241,551	256,648
Operating Segments [Member] | Real Estate Operations [Member]
Revenue:
Net investment income (loss)														1	6	18
Gain on bargain purchase																2,071
Gain on remeasurement of previously held interest																4,005
Other														9,324	7,046	4,505
Total revenue														9,325	7,052	10,599
Expenses:
Interest expense														1,568	1,250	561
Depreciation and amortization														2,373	2,121	814
Other														4,254	4,022	2,921
Total operating expenses														8,195	7,393	4,296
Income (loss) before income taxes														1,130	(341)	6,303
Total revenue from non-affiliates														7,718	5,525	9,072
Operating Segments [Member] | Corporate and Other [Member]
Revenue:
Net investment income (loss)														5,554	2,974	1,162
Net realized investment (losses) gains														1,544	368	151
Net unrealized investment (losses) gains														(1,514)	92
Net other-than-temporary impairment losses														(80)	(209)	(15)
Gain on repurchases of convertible senior notes																153
Other														4,999	4,417	4,104
Total revenue														10,503	7,642	5,555
Expenses:
Interest expense														17,008	15,704	10,518
Loss on repurchases of senior notes															743
Depreciation and amortization														1,011	939	908
Other														20,464	18,123	16,180
Total operating expenses														38,483	35,509	27,606
Income (loss) before income taxes														(27,980)	(27,867)	(22,051)
Total revenue from non-affiliates														9,331	6,958	5,470
Intersegment Eliminations [Member]
Revenue:
Net investment income (loss)														164	(1,439)	(533)
Other														(12,907)	(10,400)	(7,823)
Total revenue														(12,743)	(11,839)	(8,356)
Expenses:
Interest expense														(481)	(187)
Depreciation and amortization														(2,140)	(1,950)	(608)
Other														(10,122)	(9,702)	(7,748)
Total operating expenses														$ (12,743)	$ (11,839)	$ (8,356)