Esop Plan - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
ESOP shares | shares	600,000
ESOP common stock, per share | $ / shares	$ 13.14
ESOP borrowed	$ 7,900,000
Accrued ESOP contribution liability	$ 630,000
Two Thousand Fifteen Employee Stock Ownership Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
ESOP shares committed to release | shares	37,063