Intangible Assets - Summary of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 19,076
Accumulated Amortization	(7,527)
Net Carrying Amount	11,549	10,273	11,595
Core deposit intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	12,681
Accumulated Amortization	(4,938)
Net Carrying Amount	7,743
Customer relationship intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,699
Accumulated Amortization	(2,428)
Net Carrying Amount	3,271
Mortgage servicing intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	696
Accumulated Amortization	(161)
Net Carrying Amount	$ 535