Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in Balance of Unamortized Intangible Assets (goodwill)

For intangible assets related to business combinations, the following is a summary of the changes in the balance of unamortized intangible assets (goodwill) during the years ended December 31, 2014, 2013 and 2012:

(dollars in thousands)	For the Twelve Months Ended December 31,
	2014		2013		2012
Gross balance at beginning of year	$	4,205	$	4,205	$	3,905
Accumulated impairment balance beginning of year	—		—		—
Effect of Granite merger	—		—		300
Impairment	—		—		—
Accumulated balance at end of year	$	4,205	$	4,205	$	4,205

Changes in Original Carrying Amount of Amortized Intangible Assets

For intangible assets related to business combinations, the following is a summary of the gross carrying amount and accumulated amortization of amortized intangible assets and the carrying amount of unamortized intangible assets:

(dollars in thousands)	As of December 31,
	2014		2013
Core deposit premium related to whole bank acquisitions:
Carrying amount	$	13,102	$	13,102
Accumulated amortization	9,147		7,739
Net core deposit premium	$	3,955	$	5,363

Estimated Amortization Expense for Intangible Assets

The following table presents the estimated amortization expense for intangible assets related to business combinations for each of the five calendar years ending December 31, 2019 and the estimated amount amortizable thereafter. These estimates are subject to change in future periods to the extent management determines it is necessary to make adjustments to the carrying value or estimated useful lives of amortized intangible assets.

(dollars in thousands)	Estimated Amortization Expense
2015	$	1,385
2016	834
2017	613
2018	613
2019	510
Total	$	3,955