VARIABLE INTEREST ENTITY (Carrying Amount of VIE Consolidated Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Investments
Debt securities - available-for-sale, at fair value:	$ 443,458	$ 428,641
Equity securities, at fair value	20,824	17,758
Total investments	468,834	451,525
Cash and cash equivalents	100,589	64,423
Reinsurance recoverable	301,922	211,424
Prepaid reinsurance premiums	69,858	108,577
Premiums receivable, net	22,684	29,791
Deferred acquisition costs, net	40,232	39,436
Other assets	27,441	14,975
Total assets	1,035,587	925,371
Liabilities
Loss and loss adjustment expense reserves	374,124	296,230	$ 236,214	$ 230,515
Unearned premiums	275,860	281,992
Reinsurance payable	31,399	63,599
Debt, net of deferred financing costs	98,401	44,404
Other liabilities	33,320	19,302
Total liabilities	$ 817,671	$ 710,112