Goodwill and Other Intangible Assets - Summary of Core Deposit Intangibles (Detail) - Core Deposit Intangibles [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Core deposit intangibles, Beginning balance	$ 8,074
Core deposit intangibles, Reductions/Amortization	0
Core deposit intangibles, Additions	2,046
Core deposit intangibles, Ending balance	10,120
Accumulated amortization, Beginning balance	(2,180)
Accumulated amortization, Reductions/Amortization	(1,377)
Accumulated amortization, Additions	0
Accumulated amortization, Ending balance	(3,577)
Core deposit intangibles, net, Beginning balance	5,894
Core deposit intangibles, net, Reductions/Amortization	(1,377)
Core deposit intangibles, net, Additions	2,046
Core deposit intangibles, net, Ending balance	$ 6,563