Goodwill and Core Deposit Intangibles

Management analyzes its goodwill for impairment on an annual basis and between annual tests in certain circumstances, such as upon material adverse changes in legal, business, regulatory and economic factors. An impairment loss is recorded to the extent that the carrying amount of goodwill exceeds its implied fair value. The Company performed an impairment assessment as of July 1, 2018 and 2017 and concluded that there was no impairment to goodwill.

Goodwill



	As of March 31,
	2019			2018
Net carrying value at beginning of three month period	$	546.7		$	444.7
Measurement period adjustment to previously recorded goodwill	(0.4		)	0.9
Net carrying value at end of period	$	546.3		$	445.6

Core deposit intangibles (“CDI”)



	As of March 31,
	2019			2018
Gross CDI, beginning of period	$	89.7		$	74.0
Accumulated amortization	(35.1		)	(26.7		)
Net CDI, end of period	$	54.6		$	47.3

The Company recorded $2.3 million and $1.8 million of CDI amortization expense for the three months ended March 31, 2019 and 2018.

CDI are evaluated for impairment if events and circumstances indicate a possible impairment and are amortized using an accelerated method based on the estimated weighted average useful lives of the related deposits, which is generally ten years.

The following table provides the estimated future CDI amortization expense:



Years Ending December 31,
2019 remaining	$	6.6
2020	8.1
2021	7.5
2022	6.9
2023	6.3
Thereafter	19.2
Total	$	54.6