Mortgage Servicing Rights - Changes in Mortgage Servicing Rights (Detail) (Mortgage Servicing Rights [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Mortgage Servicing Rights [Member]
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Beginning of period	$ 5,378	$ 5,227	$ 5,519	$ 4,152
Servicing rights capitalized	365	544	724	2,183
Amortization of servicing rights	(561)	(287)	(1,068)	(1,099)
Changes in valuation allowance	243	0	250	248
End of period	5,425	5,484	5,425	5,484
Mortgage loans serviced for others	$ 779,701	$ 736,017	$ 779,701	$ 736,017