Loans and Allowance for Loan Losses - Activity in Alll by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				$ 38,725				$ 37,656	$ 38,725	$ 37,656
Charge-offs									(1,560)	(2,644)
Recoveries									611	613
Net charge-offs									(949)	(2,031)
Provisions charged to operations	454	(12)	516	300	2,446	233	248	173	1,258	3,100	4,515
Balance at end of period	39,034				38,725				39,034	38,725	37,656
Non-residential real estate owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				5,104				5,300	5,104	5,300
Charge-offs									(3)	(96)
Recoveries									20	3
Net charge-offs									17	(93)
Provisions charged to operations									(294)	(103)
Balance at end of period	4,827				5,104				4,827	5,104
Non-residential real estate other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				9,865				8,648	9,865	8,648
Charge-offs									(19)	(195)
Recoveries									12	53
Net charge-offs									(7)	(142)
Provisions charged to operations									1,168	1,359
Balance at end of period	11,026				9,865				11,026	9,865
Residential real estate primary mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				2,781				2,734	2,781	2,734
Charge-offs									(162)	(222)
Recoveries									32	85
Net charge-offs									(130)	(137)
Provisions charged to operations									174	184
Balance at end of period	2,825				2,781				2,825	2,781
Residential real estate all other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				7,034				7,030	7,034	7,030
Charge-offs									(209)	(394)
Recoveries									33	49
Net charge-offs									(176)	(345)
Provisions charged to operations									(150)	349
Balance at end of period	6,708				7,034				6,708	7,034
Non-consumer non-real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				9,385				9,156	9,385	9,156
Charge-offs									(217)	(590)
Recoveries									175	171
Net charge-offs									(42)	(419)
Provisions charged to operations									(366)	648
Balance at end of period	8,977				9,385				8,977	9,385
Consumer non-real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				2,451				2,315	2,451	2,315
Charge-offs									(597)	(509)
Recoveries									225	194
Net charge-offs									(372)	(315)
Provisions charged to operations									477	451
Balance at end of period	2,556				2,451				2,556	2,451
Other loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				1,885				1,886	1,885	1,886
Charge-offs									(300)	(265)
Recoveries									75	34
Net charge-offs									(225)	(231)
Provisions charged to operations									331	230
Balance at end of period	1,991				1,885				1,991	1,885
Acquired loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				220				587	220	587
Charge-offs									(53)	(373)
Recoveries									39	24
Net charge-offs									(14)	(349)
Provisions charged to operations									(82)	(18)
Balance at end of period	$ 124				$ 220				$ 124	$ 220