Carrying Amount, Estimated Fair Value and Fair Value Hierarchy Level (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011
Financial assets:
Cash and cash equivalents	$ 96,161		$ 175,686		$ 37,085	$ 69,140
Investment securities, available for sale	319,917		316,614
Investment securities, trading	2,357		1,447
Net portfolio loans and leases	1,484,988		1,384,031
Mortgage servicing rights	4,744		4,491
Other assets	10,506		10,912
Financial liabilities:
Deposits	1,550,656		1,634,682
Short-term borrowings	75,588		9,403		19,029
Long-term FHLB advances and other borrowings	191,645		161,315
Other liabilities	22,481		25,688
Carrying Amount
Financial assets:
Investment securities, available for sale	319,917	[1]	316,614	[1]
Total financial assets	1,932,080		1,907,416
Financial liabilities:
Total financial liabilities	1,841,212		1,832,321
Carrying Amount | Level 1
Financial assets:
Cash and cash equivalents	96,161	[1]	175,686	[1]
Carrying Amount | Level 2
Financial assets:
Investment securities, trading	2,357	[1]	1,447	[1]
Loans held for sale	1,284	[1]	3,412	[1]
Financial liabilities:
Deposits	1,550,656	[1]	1,634,682	[1]
Short-term borrowings	75,588	[1]	9,403	[1]
Long-term FHLB advances and other borrowings	191,645	[1]	161,315	[1]
Other liabilities	23,323	[1]	26,921	[1]
Carrying Amount | Level 3
Financial assets:
Net portfolio loans and leases	1,484,988	[1]	1,384,031	[1]
Mortgage servicing rights	4,744	[1]	4,491	[1]
Other assets	22,629	[1]	21,735	[1]
Estimated Fair Value
Financial assets:
Investment securities, available for sale	319,917	[1]	316,614	[1]
Total financial assets	1,921,814		1,936,221
Financial liabilities:
Total financial liabilities	1,840,784		1,835,971
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	96,161	[1]	175,686	[1]
Estimated Fair Value | Level 2
Financial assets:
Investment securities, trading	2,357	[1]	1,447	[1]
Loans held for sale	1,284	[1]	3,482	[1]
Financial liabilities:
Deposits	1,550,683	[1]	1,635,374	[1]
Short-term borrowings	75,588	[1]	9,403	[1]
Long-term FHLB advances and other borrowings	191,190	[1]	164,273	[1]
Other liabilities	23,323	[1]	26,921	[1]
Estimated Fair Value | Level 3
Financial assets:
Net portfolio loans and leases	1,473,844	[1]	1,412,619	[1]
Mortgage servicing rights	5,622	[1]	4,638	[1]
Other assets	$ 22,629	[1]	$ 21,735	[1]

[1] see Note 17 for a description of fair value hierarchy levels