DERIVATIVES (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Summary of Derivative Financial Instruments and Balances

The following table details the location and amounts recognized in the Consolidated Balance Sheets for client derivatives:

		December 31, 2017							December 31, 2016
				Estimated fair value							Estimated fair value
(Dollars in thousands)	Balance Sheet Location	Notional amount		Gain		Loss			Notional amount		Gain		Loss
Client derivatives
Matched interest rate swaps with borrower	Accrued interest and other assets and other liabilities	$	837,040	$	7,153	$	(5,529	)	$	677,028	$	8,401	$	(4,158	)
Matched interest rate swaps with counterparty	Accrued interest and other liabilities	837,040		5,529		(7,158		)	677,028		4,158		(8,429		)
Total		$	1,674,080	$	12,682	$	(12,687	)	$	1,354,056	$	12,559	$	(12,587	)

Disclosure by Type of Financial Instrument [Table Text Block]

The following table discloses the gross and net amounts of assets and liabilities recognized in the Consolidated Balance Sheets:

	December 31, 2017						December 31, 2016
(Dollars in thousands)	Gross amounts of recognized liabilities		Gross amounts offset in the Consolidated Balance Sheets		Net amounts of assets presented in the Consolidated Balance Sheets		Gross amounts of recognized liabilities		Gross amounts offset in the Consolidated Balance Sheets			Net amounts of assets presented in the Consolidated Balance Sheets
Client derivatives
Matched interest rate swaps	$	12,687	$	2,279	$	14,966	$	12,587	$	(462	)	$	12,125

Derivative Financial Instruments, Average Remaining Maturity and the Weighted-Average Interest Rates being Paid and Received

The following table details the derivative financial instruments, the average remaining maturities and the weighted-average interest rates being paid and received by First Financial at December 31, 2017:

							Weighted-Average Rate
(Dollars in thousands)	Notional amount		Average maturity (years)	Fair value			Receive		Pay
Client derivatives
Receive fixed, matched interest rate swaps with borrower	$	837,040	5.9	$	1,624		4.37	%	3.66	%
Pay fixed, matched interest rate swaps with counterparty	837,040		5.9	(1,629		)	3.66	%	4.37	%
Total client derivatives	$	1,674,080	5.9	$	(5	)	4.01	%	4.01	%