INCOME TAXES - Income Tax Reconciliation (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Statutory federal income tax rate applied to pre-tax income	21.00%	35.00%	21.00%	35.00%
State income taxes	1.30%	0.70%	1.30%	0.60%
Investment income not subject to tax	(3.40%)	(3.00%)	(3.30%)	(3.10%)
Uncertain tax positions	0.00%	0.40%	0.00%	0.50%
Change in State Tax Rate	(1.50%)	0.00%	(0.80%)	0.00%
Other	0.10%	(0.10%)	0.20%	(0.10%)
Effective tax rate (as a percent)	17.50%	33.00%	18.40%	32.90%