Fair Value Disclosures - Additional Information (Detail)				3 Months Ended			12 Months Ended
	Jul. 01, 2014 USD ($)	Jan. 27, 2014 USD ($)	May. 01, 2013 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2014	Jun. 30, 2013 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2015 USD ($) loan borrowers
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent Consideration from New Acquisition							$ 1,525,000	$ 6,105,000	$ 454,000
Valuation adjustments for loans held for sale							0	0
Carrying value of impaired loans held for investment				$ 48,933,000			48,933,000
Valuation allowance of impaired loans held for investment				322,000			322,000	998,000
Mortgage Servicing Rights Carrying Amount Before Valuation Allowance				5,900,000			5,900,000	5,500,000
Mortgage Servicing Rights Valuation Allowance				0			0	0
Goodwill impairment							0	0	$ 0
Impairment of intangible assets							0
Sterner Insurance Associates Inc [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Potential cash payments from contingent consideration, minimum	$ 0
Potential cash payments from contingent consideration, maximum	$ 3,900,000
Potential cash payments from contingent consideration, period of measurement (in years)	2 years
Potential cash payments from contingent consideration, end date	Jun. 30, 2017
Contingent Consideration from New Acquisition							1,525,000	635,000
Girard Partners [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Potential cash payments from contingent consideration, minimum		$ 0
Potential cash payments from contingent consideration, maximum		$ 13,800,000
Potential cash payments from contingent consideration, period of measurement (in years)		4 years
Potential cash payments from contingent consideration, end date		Dec. 31, 2018
Contingent Consideration from New Acquisition							0	5,470,000
Reduction of other noninterest expense							550,000
John T Fretz Insurance Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Potential cash payments from contingent consideration, minimum			$ 0
Potential cash payments from contingent consideration, maximum			$ 360,000
Potential cash payments from contingent consideration, end date			Apr. 30, 2016
Contingent Consideration from New Acquisition							0	0
Remaining potential cash payments from contingent consideration, period of measurement (in years)			1 year
Javers Group [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Potential cash payments from contingent consideration, period of measurement (in years)					3 years
Potential cash payments from contingent consideration, end date					Jun. 30, 2015
Reduction of other noninterest expense						$ 959,000
Fair value of contingent consideration liability				0			0
Original potential cash payments from contingent consideration, minimum						0
Original potential cash payments from contingent consideration, maximum						$ 1,700,000
Real Estate-Construction [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nonaccrual Loans Held for Sale, Number of Loans | loan										2
Nonaccrual Loans Held for Sale, Number or Borrowers | borrowers										1
Amount of Nonaccrual Loans Transferred to Loans Held for Sale										$ 4,000,000
Amount of Held for Sale Nonaccrual Loans Sold				4,000,000
Carrying value of impaired loans held for investment				0			0	5,931,000
Valuation allowance of impaired loans held for investment				0			0	0
Held for Investment [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of impaired loans held for investment				$ 48,900,000			$ 48,900,000	$ 56,200,000