MORTGAGE SERVICING RIGHTS

Our portfolio of residential mortgage loans serviced for third parties was $2.59 billion and $2.49 billion as of June 30, 2017 and December 31, 2016, respectively. These loans were originated by BancShares and sold to third parties on a non-recourse basis with servicing rights retained. These retained servicing rights are recorded as a servicing asset and reported in other intangible assets on the Consolidated Balance Sheets. The mortgage servicing rights are initially recorded at fair value and then carried at the lower of amortized cost or fair market value.

The activity of the servicing asset for the three and six months ended June 30, 2017 and 2016 is presented in the following table:



	Three months ended June 30						Six months ended June 30
(Dollars in thousands)	2017			2016			2017			2016
Beginning balance	$	20,771		$	17,186		$	20,415		$	19,351
Servicing rights originated	1,123			1,351			2,825			2,328
Amortization	(1,370		)	(1,333		)	(2,720		)	(2,601		)
Valuation allowance (provision) reversal	—			(380		)	4			(2,254		)
Ending balance	$	20,524		$	16,824		$	20,524		$	16,824

The following table presents the activity in the servicing asset valuation allowance for the three and six months ended June 30, 2017 and 2016:



	Three months ended June 30				Six months ended June 30
(Dollars in thousands)	2017		2016		2017			2016
Beginning balance	$	—	$	1,969	$	4		$	95
Valuation allowance provision (reversal)	—		380		(4		)	2,254
Ending balance	$	—	$	2,349	$	—		$	2,349

Contractually specified mortgage servicing fees, late fees, and ancillary fees earned for the three months ended June 30, 2017 and 2016 were $1.9 million and $1.5 million, respectively, and reported in mortgage income in the Consolidated Statements of Income. For the six months ended June 30, 2017 and 2016, contractually specified mortgage servicing fees, late fees and ancillary fees earned were $3.6 million and $2.9 million, respectively.

The amortization expense related to mortgage servicing rights, included as a reduction of mortgage income in the Consolidated Statements of Income, was $1.4 million and $1.3 million for the three months ended June 30, 2017 and 2016, respectively. For the six months ended June 30, 2017 and 2016, amortization expense related to mortgage servicing rights was $2.7 million and $2.6 million, respectively. Mortgage income included an impairment for the three months ended June 30, 2016 of $380 thousand. For the six months ended June 30, 2017 and 2016, mortgage income included an impairment reversal of $4 thousand and an impairment of $2.3 million, respectively.

Valuation of mortgage servicing rights is performed using a pooling methodology. Similar loans are pooled together and evaluated on a discounted earnings basis to determine the present value of future earnings. Key economic assumptions used to value mortgage servicing rights as of June 30, 2017 and December 31, 2016 were as follows:



	June 30, 2017			December 31, 2016
Discount rate - conventional fixed loans	9.30		%	9.45		%
Discount rate - all loans excluding conventional fixed loans	10.30		%	10.45		%
Weighted average constant prepayment rate	10.41		%	10.42		%
Weighted average cost to service a loan	$	64.01		$	62.75