OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2018

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
Additions	—			1,612			1,612
Amortization	(2,006		)	(1,859		)	(3,865		)
Balance as of December 31, 2018	$	—		$	15,596		$	15,596

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 as of December 31, 2018 and 2017 are presented below:



	December 31, 2018							December 31, 2017
	Gross Carrying Value		Accumulated Amortization			Net Carrying Value		Gross Carrying Value		Accumulated Amortization			Net Carrying Value
	(Dollars in thousands)
Core deposit premium	$	44,642	$	(44,642	)	$	—	$	44,642	$	(42,636	)	$	2,006
Mortgage servicing rights	66,013		(50,417		)	15,596		64,401		(48,558		)	15,843
Total	$	110,655	$	(95,059	)	$	15,596	$	109,043	$	(91,194	)	$	17,849

Schedule of estimated amortization expense

Based on our mortgage servicing rights held as of December 31, 2018, estimated amortization expense for the next five succeeding fiscal years and all years thereafter are as follows (dollars in thousands):



Year Ending December 31:
2019	$	1,615
2020	1,315
2021	1,100
2022	931
2023	781
Thereafter	9,854
Total	$	15,596

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,
	2018			2017
	(Dollars in thousands)
Fair market value, beginning of period	$	17,161		$	18,087
Fair market value, end of period	17,696			17,161
Weighted average discount rate	9.5		%	9.5		%
Weighted average prepayment speed assumption	14.5		%	16.0		%