VARIABLE INTEREST ENTITY (Carrying Amount of VIE Consolidated Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Investments
Debt securities - available-for-sale, at fair value:	$ 429,457	$ 423,238
Equity securities, at fair value	16,515	15,434
Total investments (including $0 and $26,284 related to the VIE, respectively)	451,270	444,021
Cash and cash equivalents (including $0 and $14,211 related to the VIE, respectively)	55,591	86,228	$ 80,495	$ 74,593
Reinsurance recoverable	146,091	124,601
Prepaid reinsurance premiums	87,201	135,492
Premiums receivable, net of allowance of $72 and $70, respectively (including $0 and $1,184 related to the VIE, respectively)	45,667	46,393
Deferred acquisition costs	39,401	40,893
Other assets (including $0 and $2,322 related to the VIE, respectively)	10,130	13,403
TOTAL ASSETS	848,215	904,873
LIABILITIES
LIABILITIES:	236,214	230,515	$ 154,337	$ 158,110
Loss and loss adjustment expense reserves	282,397	294,423
Unearned premiums	38,489	71,944
Debt, net of deferred financing costs	44,328	49,251
Deferred Revenue	32,783	25,059
Deferred income taxes, net	640,135	677,414
Monarch Delaware - Variable Interest Entity
Investments
Debt securities - available-for-sale, at fair value:		25,111
Equity securities, at fair value		1,173
Total investments (including $0 and $26,284 related to the VIE, respectively)	0	26,284
Cash and cash equivalents (including $0 and $14,211 related to the VIE, respectively)	0	14,211
Reinsurance recoverable		3,323
Prepaid reinsurance premiums		2,481
Premiums receivable, net of allowance of $72 and $70, respectively (including $0 and $1,184 related to the VIE, respectively)	0	1,184
Deferred acquisition costs		1,722
Other assets (including $0 and $2,322 related to the VIE, respectively)	$ 0	2,322
TOTAL ASSETS		51,527
LIABILITIES
LIABILITIES:		6,356
Loss and loss adjustment expense reserves		8,752
Unearned premiums		1,802
Debt, net of deferred financing costs		4,930
Deferred Revenue		1,825
Deferred income taxes, net		$ 23,665