GOODWILL AND OTHER INTANGIBLES AND MORTGAGE SERVICING RIGHTS

A summary of goodwill and other intangibles was as follows.



(in thousands)	December 31, 2018		December 31, 2017
Goodwill	$	107,366	$	107,366
Core deposit intangibles	12,562		16,477
Customer list intangibles	4,379		4,563
Other intangibles	16,941		21,040
Goodwill and other intangibles, net	$	124,307	$	128,406

Goodwill: Goodwill was $107.4 million at both December 31, 2018 and December 31, 2017. During 2017, goodwill increased due to the First Menasha acquisition. See Note 1 for the Company’s accounting policy for goodwill and see Note 2 for additional information on the Company’s acquisitions.

Other intangibles: Other intangible assets, consisting of core deposit intangibles and customer list intangibles, are amortized over their estimated finite lives. During 2018, customer list intangibles increased due to the purchase of a brokerage book of business, while during 2017, core deposit intangibles increased due to the First Menasha acquisition and customer list intangibles increased due to a modification to the contingent earn-out payment on the financial advisor business acquired in 2016, fixing the previously variable earn-out payment on a portion of the purchase price. See Note 1 for the Company’s accounting policy for other intangibles and see Note 2 for additional information on the Company’s acquisitions.



(in thousands)	December 31, 2018			December 31, 2017
Core deposit intangibles:
Gross carrying amount	$	29,015		$	29,015
Accumulated amortization	(16,453		)	(12,538		)
Net book value	$	12,562		$	16,477
Additions during the period	$	—		$	3,670
Amortization during the period	$	3,915		$	4,294
Customer list intangibles:
Gross carrying amount	$	5,523		5,233
Accumulated amortization	(1,144		)	(670		)
Net book value	$	4,379		$	4,563
Additions during the period	$	290		$	870
Amortization during the period	$	474		$	401

Mortgage servicing rights: A summary of the changes in the MSR asset was as follows.



(in thousands)	December 31, 2018			December 31, 2017
MSR asset:
MSR asset at beginning of year	$	3,187		$	1,922
Capitalized MSR	1,203			876
MSR asset acquired	—			874
Amortization during the period	(641		)	(485		)
MSR asset at end of year	$	3,749		$	3,187
Fair value of MSR asset at end of period	$	6,347		$	4,097
Residential mortgage loans serviced for others	$	603,446		$	518,419
Net book value of MSR asset to loans serviced for others	0.62		%	0.61		%

The Company periodically evaluates its mortgage servicing rights asset for impairment. No valuation allowance or impairment charge was recorded for 2018 or 2017. See Note 1 for the Company’s accounting policy for MSRs, see Note 2 for additional information on the Company’s acquisitions, and see Note 18 for additional information on the fair value of the MSR asset.

The following table shows the estimated future amortization expense for amortizing intangible assets and the MSR asset. The projections are based on existing asset balances, the current interest rate environment and prepayment speeds as of December 31, 2018. The actual amortization expense the Company recognizes in any given period may be significantly different depending upon acquisition or sale activities, changes in interest rates, prepayment speeds, market conditions, regulatory requirements and events or circumstances that indicate the carrying amount of an asset may not be recoverable.



(in thousands)	Core deposit intangibles		Customer list intangibles		MSR asset
Years Ending December 31,
2019	$	3,337	$	507	$	697
2020	2,657		507		680
2021	2,167		507		531
2022	1,735		507		531
2023	1,273		483		419
Thereafter	1,393		1,868		891
Total	$	12,562	$	4,379	$	3,749