Loans and Loans Held for Sale - Summary of Nonperforming Assets of Defaulted TDRs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Contract	Dec. 31, 2013 Contract
Financing Receivable, Modifications [Line Items]
Number of Defaults	3	17
Recorded Investment	$ 64	$ 1,313
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	0	1
Recorded Investment	0	75
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	0	2
Recorded Investment	0	438
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	1	8
Recorded Investment	20	607
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	2	6
Recorded Investment	$ 44	$ 193