MORTGAGE SERVICING RIGHTS (Tables)

12 Months Ended

Dec. 31, 2016

MORTGAGE SERVICING RIGHTS [Abstract]

Data and Assumptions Used in Fair Value Calculation

	2016	2015	2014
	(Dollars in thousands)
Unpaid principal balance	$6,384,649	$6,011,236	$5,686,756
Weighted-average prepayment speed (CPR)	9.4	10.3	11.6
Discount rate (annual percentage)	9.8	9.8	9.8
Weighted-average coupon interest rate (percentage)	3.9	4.0	4.1
Weighted-average remaining maturity (months)	323.0	319.0	314.0
Weighted-average servicing fee (basis points)	26.7	26.6	26.5

Activity in Class of Mortgage Servicing Assets

		2016	2015
	(In thousands)
Fair value at beginning of year		$        57,268	$        51,296
Additions:
Origination of servicing assets		14,706	14,139
Changes in fair value:
Due to payoffs/paydowns		(8,231)	(6,999)
Due to change in valuation inputs or assumptions
used in the valuation model		1,526	(1,161)
Other changes in fair value		(6)	(7)
Fair value at end of year		$        65,263	$        57,268