Fair Value (Detail) - Carrying Value of Mortgage Servicing Rights - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance		$ 1,728	$ 1,893	$ 985
New mortgage servicing rights		342	315	1,060
Changes in valuation inputs and assumptions	[1]	(11)	(480)	63
Other changes in fair value	[1],[2]	(206)	0	(215)
Ending balance		1,853	1,728	1,893
Contractual servicing fees earned during the year	[1]	546	520	418
Total amount of loans being serviced for the benefit of others at the end of the year		$ 242,915	$ 220,372	$ 214,458

[1] Included in mortgage banking income in the Consolidated Statements of Income and relate to assets still held at the end of the year.

[2] Primarily represents changes in expected future cash flows over time due to payoffs and paydowns.