Transfers of Financial Assets (Loans sold) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net gain on sale	$ 3,351	$ 3,753	$ 5,617	$ 7,013
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale	66,718	85,411	173,338	170,572
Loans sold with servicing rights retained	60,167	78,645	159,667	158,005
Net gain on sale	2,126	1,820	2,377	3,425
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	641	808	1,409	1,439
Fair value option adjustment	$ 584	$ 1,125	$ 1,831	$ 2,149