OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of changes in other intangible assets

The following table presents changes in our core deposit premium and mortgage servicing rights for the periods presented:



	Core Deposit Premium			Mortgage Servicing Rights			Total
	(Dollars in thousands)
Balance as of December 31, 2015	$	7,355		$	17,797		$	25,152
Additions	—			3,048			3,048
Amortization	(2,675		)	(5,066		)	(7,741		)
Balance as of December 31, 2016	$	4,680		$	15,779		$	20,459
Additions	—			2,352			2,352
Amortization	(2,674		)	(2,288		)	(4,962		)
Balance as of December 31, 2017	$	2,006		$	15,843		$	17,849

Schedule of gross carrying value and accumulated amortization related to intangible assets

The gross carrying value, accumulated amortization and net carrying value related to our core deposit premium and mortgage servicing rights are presented below:



	December 31, 2017							December 31, 2016
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
	(Dollars in thousands)
Core deposit premium	$	44,642	$	(42,636	)	$	2,006	$	44,642	$	(39,962	)	$	4,680
Mortgage servicing rights	64,401		(48,558		)	15,843		62,049		(46,270		)	15,779
Total	$	109,043	$	(91,194	)	$	17,849	$	106,691	$	(86,232	)	$	20,459

Schedule of estimated amortization expense

Based on our core deposit premium and mortgage servicing rights held as of December 31, 2017, estimated amortization expense for the next five succeeding fiscal years and all years thereafter are as follows:



	Estimated Amortization Expense
	Core Deposit Premium		Mortgage Servicing Rights		Total
	(Dollars in thousands)
2018	$	2,006	$	2,171	$	4,177
2019	—		1,705		1,705
2020	—		1,407		1,407
2021	—		1,183		1,183
2022	—		990		990
Thereafter	—		8,387		8,387
Total	$	2,006	$	15,843	$	17,849

Schedule of fair market value and key assumptions used in determining the fair market value of our mortgage servicing rights

The following table presents the fair market value and key assumptions used in determining the fair market value of our mortgage servicing rights:



	Year Ended December 31,
	2017			2016
	(Dollars in thousands)
Fair market value, beginning of period	$	18,087		$	18,345
Fair market value, end of period	17,161			18,087
Weighted average discount rate	9.5		%	9.5		%
Weighted average prepayment speed assumption	16.0		%	14.3		%