FAIR VALUE MEASURES - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) from change in fair value of mortgages loans held for sale	$ 4.4	$ 4.2
Net gains (losses) from change in fair value of derivative financial instruments	$ 2.1	$ (2.1)
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	7 years
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	10 years
US Premium Financing Holding Company | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	3 years
US Premium Financing Holding Company | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	15 years