Goodwill and Other Intangible Assets

(a) Goodwill

The Company’s goodwill represents the excess of the purchase price over the fair value of net assets acquired in the recent Premier Merger on July 2, 2018 and Puget Sound Merger on January 16, 2018 and the historical acquisitions of Washington Banking Company on May 1, 2014; Valley Community Bancshares on July 15, 2013; Western Washington Bancorp in 2006 and North Pacific Bank in 1998.

The following table presents the change in goodwill for the periods indicated:



	Year Ended December 31,
	2018		2017		2016
	(In thousands)
Balance at the beginning of the period	$	119,029	$	119,029	$	119,029
Additions as a result of acquisitions⁽¹⁾	121,910		—		—
Balance at the end of the period	$	240,939	$	119,029	$	119,029


⁽¹⁾	See Note (2) Business Combinations

At December 31, 2018, the Company’s step-one analysis concluded that the reporting unit’s fair value of the reporting unit exceeded the carrying value, such that the Company's goodwill was not considered impaired. Similarly, no goodwill impairment charges were required, or recorded, for the years ended December 31, 2017 and 2016. Even though there was no goodwill impairment at December 31, 2018, changes in the economic environment, operations of the reporting unit or other adverse events could result in future impairment charges which could have a material impact on the Company’s operating results.

(b) Other Intangible Assets

The other intangible assets represent the core deposit intangible ("CDI") acquired in business combinations. The useful life of the CDI was estimated to be ten years related to the acquisitions of Premier Commercial Bancorp, Puget Sound Bancorp, Washington Banking Company, and Valley Community Bancshares and estimated to be five years related to the acquisition of Northwest Commercial Bank.

The following table presents the change in other intangible assets for the periods indicated:



	Year Ended December 31,
	2018			2017			2016
	(In thousands)
Balance at the beginning of the year	$	6,088		$	7,374		$	8,789
Additions as a result of acquisitions ⁽¹⁾	18,345			—			—
Amortization	(3,819		)	(1,286		)	(1,415		)
Balance at the end of the year	$	20,614		$	6,088		$	7,374


⁽¹⁾	See Note (2) Business Combinations

The estimated aggregate amortization expense related to these intangible assets for future years is as follows:



	Year Ending December 31,
	(In thousands)
2019	$	4,001
2020	3,525
2021	3,111
2022	2,750
2023	2,435
Thereafter	4,792
	$	20,614