ntangible Assets

The carrying amount of the Company’s goodwill as of March 31, 2016 and December 31, 2015 was $105.4 million. There was no impairment of goodwill during the three months ended March 31, 2016 and 2015.

Core deposit intangible assets are amortized over their estimated lives, which range from seven to ten years. Amortization expense related to core deposit intangible assets totaled $212 thousand and $267 thousand for the three months ended March 31, 2016 and 2015, respectively. The following table provides information regarding the core deposit intangibles at March 31, 2016:



		As of March 31, 2016
	Amortization period	Gross Carrying Amount		Accumulated Amortization
		(In thousands)
Core deposit—Center Financial Corporation acquisition	7 years	$	4,100	$	(3,365	)
Core deposit—PIB acquisition	7 years	603		(401		)
Core deposit—Foster acquisition	10 years	2,763		(1,093		)
Total		$	7,466	$	(4,859	)

Servicing assets are recognized when SBA loans are sold with servicing retained with the income statement effect recorded in net gains on sales of SBA loans. Servicing assets are initially recorded at fair value based on the present value of the contractually specified servicing fee, net of servicing costs, over the estimated life of the loan, using a discount rate based on the related note rate. The Company’s servicing costs approximates the industry average servicing costs of 40 basis points. All classes of servicing assets are subsequently measured using the amortization method which requires servicing rights to be amortized into noninterest income in proportion to, and over the period of, the estimated future net servicing income of the underlying loans.

Management periodically evaluates servicing assets for impairment based upon the fair value of the rights as compared to the carrying amount. Impairment is determined by stratifying rights into groupings based on loan type. Impairment is recognized through a valuation allowance for an individual grouping, to the extent that fair value is less than the carrying amount.

The changes in servicing assets for the three months ended March 31, 2016 were as follows:



	Three Months Ended March 31,
	2016			2015
	(In thousands)
Balance at beginning of period	$	12,000		$	10,341
Additions through originations of servicing assets	777			1,045
Amortization	(921		)	(857		)
Balance at end of period	$	11,856		$	10,529

The Company utilizes the discounted cash flow method to calculate the initial excess servicing assets. The inputs used in determining the fair value of the servicing assets at March 31, 2016 and December 31, 2015 are presented below.



	March 31, 2016	December 31, 2015
	Range	Range
Weighted-average discount rate	5.57% ~ 6.12%	5.59% ~ 6.01%
Constant prepayment rate	7.20% ~ 11.90%	7.30% ~11.90%