Intangible Assets - Summary of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 19,569
Accumulated Amortization	(7,995)
Net Carrying Amount	11,574	10,273	11,100
Core deposit intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	13,198
Accumulated Amortization	(5,305)
Net Carrying Amount	7,893
Customer relationship intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,699
Accumulated Amortization	(2,518)
Net Carrying Amount	3,181
Mortgage servicing intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	672
Accumulated Amortization	(172)
Net Carrying Amount	$ 500