Loans Receivable and Allowance for Loan Losses - Changes in Accretable Discount Related to Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield balance, beginning of period	$ 17,606	$ 22,557	$ 32,174
Accretion to interest income	(2,299)	(3,201)	(6,213)
Reclassification from nonaccretable difference and disposals, net	(2,360)	(1,750)	(3,404)
Accretable yield balance, end of period	$ 12,947	$ 17,606	$ 22,557