S&T Bancorp (STBA) 10-Q 31 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 29, 2013
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Entity Registrant Name	S&T BANCORP INC
Entity Central Index Key	719220
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		29,738,305

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS
Cash and due from banks, including interest-bearing deposits of $160,420 and $257,116 at September 30, 2013 and December 31, 2012, respectively	$234,928	$337,711
Securities available-for-sale, at fair value	488,162	452,266
Loans held for sale	3,695	22,499
Portfolio loans, net of unearned income	3,511,335	3,346,622
Allowance for loan losses	-47,983	-46,484
Portfolio loans, net	3,463,352	3,300,138
Bank owned life insurance	60,001	58,619
Premises and equipment, net	37,792	38,676
Federal Home Loan Bank and other restricted stock, at cost	15,049	15,315
Goodwill	175,820	175,733
Other intangible assets, net	4,128	5,350
Other assets	105,201	120,395
Total Assets	4,588,128	4,526,702
LIABILITIES
Noninterest-bearing demand	974,262	960,980
Interest-bearing demand	324,291	316,760
Money market	308,445	361,233
Savings	1,039,115	965,571
Certificates of deposit	1,048,090	1,033,884
Total Deposits	3,694,203	3,638,428
Securities sold under repurchase agreements	33,290	62,582
Short-term borrowings	175,000	75,000
Long-term borrowings	22,390	34,101
Junior subordinated debt securities	45,619	90,619
Other liabilities	62,198	88,550
Total Liabilities	4,032,700	3,989,280
SHAREHOLDERS' EQUITY
Common stock ($2.50 par value) Authorized-50,000,000 shares Issued-31,197,365 shares at September 30, 2013 and December 31, 2012 Outstanding-29,738,305 shares at September 30, 2013 and 29,732,209 shares at December 31, 2012	77,993	77,993
Additional paid-in capital	77,835	77,458
Retained earnings	461,044	436,039
Accumulated other comprehensive income (loss)	-21,168	-13,582
Treasury stock (1,459,060 shares at September 30, 2013 and 1,465,156 shares at December 31, 2012, at cost)	-40,276	-40,486
Total Shareholders' Equity	555,428	537,422
Total Liabilities and Shareholders' Equity	$4,588,128	$4,526,702

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]
Cash and due from banks, interest-bearing amounts	$160,420	$257,116
Common stock, par value	$2.50	$2.50
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	31,197,365	31,197,365
Common stock, shares outstanding	29,738,305	29,732,209
Treasury stock, shares	1,459,060	1,465,156

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
INTEREST INCOME
Loans, including fees	$35,733	$36,121	$106,543	$109,054
Investment securities:
Taxable	1,889	1,829	5,631	5,660
Tax-exempt	865	788	2,513	2,319
Dividends	94	82	290	297
Total Interest Income	38,581	38,820	114,977	117,330
INTEREST EXPENSE
Deposits	2,717	3,958	8,870	13,184
Borrowings and junior subordinated debt securities	590	1,067	2,568	3,211
Total Interest Expense	3,307	5,025	11,438	16,395
NET INTEREST INCOME	35,274	33,795	103,539	100,935
Provision for loan losses	3,419	2,305	6,749	18,600
Net Interest Income After Provision for Loan Losses	31,855	31,490	96,790	82,335
NONINTEREST INCOME
Securities gains, net	3	2,170	5	3,016
Service charges on deposit accounts	2,801	2,567	7,744	7,407
Debit and credit card fees	2,764	2,966	8,365	8,472
Wealth management fees	2,747	2,397	8,143	7,393
Insurance fees	1,738	1,731	5,156	4,941
Mortgage banking	265	797	1,658	2,174
Gain on sale of merchant card servicing business			3,093
Other	2,224	2,118	6,051	6,944
Total Noninterest Income	12,542	14,746	40,215	40,347
NONINTEREST EXPENSE
Salaries and employee benefits	14,910	14,819	45,701	45,933
Data processing	2,137	2,012	6,938	7,448
Net occupancy	1,910	1,978	6,037	5,594
Furniture and equipment	1,084	1,414	3,623	3,861
Other taxes	1,039	982	2,953	2,533
Professional services and legal	996	1,440	3,141	4,548
FDIC insurance	629	838	2,112	2,164
Marketing	607	759	2,088	2,156
Other	4,631	6,776	15,352	18,909
Total Noninterest Expense	27,943	31,018	87,945	93,146
Income Before Taxes	16,454	15,218	49,060	29,536
Provision for income taxes	4,207	2,623	10,380	4,861
Net Income	12,247	12,595	38,680	24,675
Earnings per share-basic	$0.41	$0.43	$1.30	$0.85
Earnings per share-diluted	$0.41	$0.43	$1.30	$0.85
Dividends declared per share	$0.15	$0.15	$0.45	$0.45
Comprehensive Income	$12,874	$14,514	$31,094	$27,313

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Shareholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
In Thousands
Balance at Dec. 31, 2011	$490,526	$74,285	$52,637	$421,468	($14,108)	($43,756)
Net income	24,675			24,675
Other comprehensive income (loss), net of tax	2,638				2,638
Cash dividends declared	-12,897			-12,897
Common stock issued in acquisition	27,610	3,708	23,902
Treasury stock issued for restricted awards	999			-2,310		3,309
Recognition of restricted stock compensation expense	721		721
Tax expense from stock-based compensation	-30		-30
Balance at Sep. 30, 2012	534,242	77,993	77,230	430,936	-11,470	-40,447
Balance at Dec. 31, 2012	537,422	77,993	77,458	436,039	-13,582	-40,486
Net income	38,680			38,680
Other comprehensive income (loss), net of tax	-7,586				-7,586
Cash dividends declared	-13,379			-13,379
Treasury stock issued for restricted awards	-86			-296		210
Recognition of restricted stock compensation expense	424		424
Tax expense from stock-based compensation	-47		-47
Balance at Sep. 30, 2013	$555,428	$77,993	$77,835	$461,044	($21,168)	($40,276)

Consolidated_Statements_of_Cha1

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash dividends declared, per share	$0.45	$0.45
Common stock issued in acquisition, shares		1,483,327
Treasury stock issued for restricted awards, net of forfeitures	22,189	122,879
Forfeitures of restricted stock, shares	16,093	3,863
Common Stock [Member]
Common stock issued in acquisition, shares		1,483,327
Additional Paid-in Capital [Member]
Common stock issued in acquisition, shares		1,483,327
Retained Earnings [Member]
Cash dividends declared, per share	$0.45	$0.45
Treasury stock issued for restricted awards, net of forfeitures	22,189	122,879
Forfeitures of restricted stock, shares	16,093	3,863
Treasury Stock [Member]
Treasury stock issued for restricted awards, net of forfeitures	22,189	122,879
Forfeitures of restricted stock, shares	16,093	3,863

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
OPERATING ACTIVITIES
Net income	$38,680	$24,675
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	6,749	18,600
Provision for unfunded loan commitments	143	1,956
Depreciation and amortization	4,320	5,306
Net amortization of discounts and premiums	2,757	1,591
Stock-based compensation expense	508	683
Securities gains, net	-5	-3,016
Net gain on sale of merchant card servicing business	-3,093
Tax expense from stock-based compensation	47	30
Mortgage loans originated for sale	-55,702	-62,920
Proceeds from the sale of loans	77,540	63,661
Gain on the sale of loans, net	-776	-1,079
Net (increase) decrease in interest receivable	-21	51
Net decrease in interest payable	-2,230	-1,251
Net decrease in other assets	21,543	10,677
Net (decrease) increase in other liabilities	-22,543	19,537
Net Cash Provided by Operating Activities	67,917	78,501
INVESTING ACTIVITIES
Purchases of securities available-for-sale	-102,419	-118,857
Proceeds from maturities, prepayments and calls of securities available-for-sale	50,177	79,122
Proceeds from sales of securities available-for-sale	94	66,575
Net proceeds from the redemption of Federal Home Loan Bank stock	265	3,557
Net (increase) decrease in loans	-177,433	55,119
Purchases of premises and equipment	-2,599	-1,779
Proceeds from the sale of premises and equipment	625	142
Net cash acquired from bank acquisitions		18,639
Proceeds from the sale of merchant card servicing business	4,750
Net Cash (Used in) Provided by Investing Activities	-226,540	102,518
FINANCING ACTIVITIES
Net increase in core deposits	41,570	119,088
Net increase (decrease) in certificates of deposit	13,785	-172,541
Net (decrease) increase in securities sold under repurchase agreements	-29,292	15,121
Net increase (decrease) in short-term borrowings	100,000	-50,000
Proceeds from long-term borrowings		4,311
Repayments of long-term borrowings	-11,711	-8,520
Repayment of junior subordinated debt	-45,000
Purchase of treasury shares	-86	-48
Sale of treasury shares		1,047
Cash dividends paid to common shareholders	-13,379	-12,897
Tax expense from stock-based compensation	-47	-30
Net Cash Provided by (Used in) Financing Activities	55,840	-104,469
Net (decrease) increase in cash and cash equivalents	-102,783	76,550
Cash and cash equivalents at beginning of period	337,711	270,526
Cash and Cash Equivalents at End of Period	234,928	347,076
Supplemental Disclosures
Interest paid	13,668	17,575
Income taxes paid, net of refunds	8,130	1,394
Net assets (liabilities) from acquisitions, excluding cash and cash equivalents		-683
Transfers to other real estate owned and other repossessed assets	$493	$864

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Basis of Presentation	NOTE 1. BASIS OF PRESENTATION
	Principles of Consolidation
	The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or S&T, and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting.
	Basis of Presentation
	The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles, or GAAP, in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our annual report on Form 10-K for the year ended December 31, 2012, filed with the Securities and Exchange Commission, or SEC, on February 25, 2013. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly our financial position and the results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period.
	Reclassification
	Certain amounts in the prior periods’ financial statements and footnotes have been reclassified to conform to the current period’s presentation. The reclassifications had no significant effect on our results of operations or financial condition.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
	Recently Adopted Accounting Standards Updates
	Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2013-02, Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income. ASU 2013-02 requires reporting the effect of significant reclassifications out of accumulated other comprehensive income by component on the respective line items in the income statement parenthetically or in the notes to the financial statements if the amounts being reclassified are required under GAAP to be reclassified in their entirety to net income. This ASU is effective for public companies prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2012 and early adoption is permitted. We have elected the option of reporting in the notes to the financial statements. The adoption of ASU 2013-02 impacted only our disclosures and did not have an impact on our results of operations or financial position.
	Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities
	In January 2013, the FASB issued ASU No. 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities in order to clarify the scope of ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, issued in December 2011. ASU 2011-11 required entities to disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an agreement similar to a master netting arrangement. This ASU was issued to allow investors to better compare financial statements prepared under GAAP with financial statements prepared under International Financial Reporting Standards, or IFRS. ASU 2013-01 clarified that ASU 2011-11 applies to derivatives, sale and repurchase agreements and reverse sale of repurchase agreements, and securities borrowing and securities lending arrangements, but does not apply to standard commercial contracts that permit either party to net in the event of default under the applicable contract or to broker-dealer unsettled regular-way trades. Both ASUs are effective for public companies retrospectively for fiscal years, and interim periods within those years, beginning on or after January 1, 2013. The adoption of ASU 2013-01 and ASU 2011-11 impacted only our disclosures and did not have an impact on our results of operations or financial position.
	Recently Issued Accounting Standards Updates not yet Adopted
	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date
	In February 2013, the FASB issued ASU No. 2013-04, Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. The ASU requires the measurement of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of the amount the reporting entity agreed to pay on the basis of its arrangement with its co-obligors as well as any additional amount that the entity expects to pay on behalf of its co-obligors. The new standard is effective retrospectively for fiscal years and interim periods within those years, beginning after December 15, 2013, and early adoption is permitted. The adoption of this ASU is not expected to have a material impact on our results of operations or financial position.
	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Tax Credit Carry forward Exists
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Tax Credit Carry forward Exists. The ASU requires that entities should present an unrecognized tax benefit as a reduction of the deferred tax asset for a net operating loss, or NOL, or similar tax loss or tax credit carry forward rather than as a liability when the uncertain tax position would reduce the NOL or other carry forward under the tax law. No new disclosures will be necessary. The new standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013, and should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted. The adoption of this ASU is expected to impact the presentation of our statement of financial position, but is not expected to have any impact on our results of operations.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 2. EARNINGS PER SHARE
	The following table reconciles the numerators and denominators of basic earnings per share with that of diluted earnings per share for the periods presented:
		Three Months Ended September 30,				Nine Months Ended September 30,
	(dollars in thousands, except shares and per share data)	2013		2012		2013		2012
	Numerator for Earnings per Share—Basic:
	Net income	$	12,247	$	12,595	$	38,680	$	24,675
	Less: Income allocated to participating shares		33		50		114		107
	Net Income Allocated to Shareholders	$	12,214	$	12,545	$	38,566	$	24,568
	Numerator for Earnings per Share—Diluted:
	Net income	$	12,247	$	12,595	$	38,680	$	24,675
	Net Income Available to Shareholders	$	12,247	$	12,595	$	38,680	$	24,675
	Denominators:
	Weighted Average Shares Outstanding—Basic		29,658,065		29,244,588		29,644,646		28,740,582
	Add: Dilutive potential shares		27,535		32,644		35,132		33,614
	Denominator for Treasury Stock Method—Diluted		29,685,600		29,277,232		29,679,778		28,774,196
	Weighted Average Shares Outstanding—Basic		29,658,065		29,244,588		29,644,646		28,740,582
	Add: Average participating shares outstanding		80,240		116,402		87,725		125,240
	Denominator for Two-Class Method—Diluted		29,738,305		29,360,990		29,732,371		28,865,822
	Earnings per share—basic	$	0.41	$	0.43	$	1.3	$	0.85
	Earnings per share—diluted	$	0.41	$	0.43	$	1.3	$	0.85
	Warrants considered anti-dilutive excluded from dilutive potential shares		517,012		517,012		517,012		517,012
	Stock options considered anti-dilutive excluded from dilutive potential shares		612,768		748,964		632,481		751,492
	Restricted stock considered anti-dilutive excluded from dilutive potential shares		52,705		48,717		52,593		56,585

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 3. FAIR VALUE MEASUREMENTS
	We use fair value measurements when recording and disclosing certain financial assets and liabilities. Securities available-for-sale, trading assets and derivatives are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record other assets at fair value on a nonrecurring basis, such as loans held for sale, impaired loans, other real estate owned, or OREO, mortgage servicing rights, or MSRs, and certain other assets.
	Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants at the measurement date. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets or liabilities; it is not a forced transaction. In determining fair value, we use various valuation approaches, including market, income and cost approaches. The fair value standard establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing an asset or liability, which is developed, based on market data we have obtained from independent sources. Unobservable inputs reflect our estimate of assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances.
	The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows:
	Level 1: valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets.
	Level 2: valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data.
	Level 3: valuation is derived from other valuation methodologies, including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value.
	A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our policy is to recognize transfers between any of the fair value hierarchy levels at the end of the reporting period in which the transfer occurred.
	The following are descriptions of the valuation methodologies that we use for financial instruments recorded at fair value on either a recurring or nonrecurring basis.
	Recurring Basis
	Securities Available-for-Sale
	Securities available-for-sale include both debt and equity securities. We obtain fair values for debt securities from a third-party pricing service which utilizes several sources for valuing fixed-income securities. We validate prices received from our pricing service through comparison to a secondary pricing service and broker quotes. We review the methodologies of the pricing service which provides us with a sufficient understanding of the valuation models, assumptions, inputs and pricing to reasonably measure the fair value of our securities. The market evaluation sources for debt securities include observable inputs rather than significant unobservable inputs and are classified as Level 2. The service provider utilizes pricing models that vary by asset class and include available trade, bid and other market information. Generally, the methodologies include broker quotes, proprietary models, vast descriptive terms and conditions databases, as well as extensive quality control programs.
	Marketable equity securities that have an active, quotable market are classified as Level 1. Marketable equity securities that are quotable, but are thinly traded or inactive, are classified as Level 2 and securities that are not readily traded and do not have a quotable market are classified as Level 3.
	Trading Assets
	We use quoted market prices to determine the fair value of our trading assets. Our trading assets are held in a Rabbi Trust under a deferred compensation plan and are invested in readily quoted mutual funds. Accordingly, these assets are classified as Level 1.
	Derivative Financial Instruments
	We use derivative instruments including interest rate swaps for commercial loans with our customers and we sell mortgage loans in the secondary market and enter into interest rate lock commitments. We calculate the fair value for derivatives using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Each valuation considers the contractual terms of the derivative, including the period to maturity and uses observable market based inputs, such as interest rate curves and implied volatilities. Accordingly, derivatives are classified as Level 2. We incorporate credit valuation adjustments into the valuation models to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk in calculating fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements and collateral postings.
	Nonrecurring Basis
	Loans Held for Sale
	Loans held for sale consist of 1-4 family residential loans originated for sale in the secondary market and, from time to time, certain loans transferred from the loan portfolio to loans held for sale, all of which are carried at the lower of cost or fair value. The fair value of 1-4 family residential loans is based on the principal or most advantageous market currently offered for similar loans using observable market data. The fair value of the loans transferred from the loan portfolio is based on the amounts offered for these loans in currently pending sales transactions. Loans held for sale carried at fair value are classified as Level 3.
	Impaired Loans
	Impaired loans are carried at the lower of carrying value or fair value. Fair value is determined as the recorded investment balance less any specific reserve. We establish a specific reserve based on the following three impairment methods: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate, 2) the loan’s observable market price or 3) the fair value of the collateral less estimated selling costs when the loan is collateral dependent and we expect to liquidate the collateral. However, if repayment is expected to come from the operation of the collateral, rather than liquidation, then we do not consider estimated selling costs in determining the fair value of the collateral. Collateral values are generally based upon appraisals by approved, independent state certified appraisers. Appraisals may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or our knowledge of the borrower and the borrower’s business. Impaired loans carried at fair value are classified as Level 3.
	OREO and Other Repossessed Assets
	OREO and other repossessed assets obtained in partial or total satisfaction of a loan are recorded at the lower of recorded investment in the loan or fair value less cost to sell. Subsequent to foreclosure, these assets are carried at the lower of the amount recorded at acquisition date or fair value less cost to sell. Accordingly, it may be necessary to record nonrecurring fair value adjustments. Fair value, when recorded, is generally based upon appraisals by approved, independent state certified appraisers. Like impaired loans, appraisals on OREO may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or other information available to us. OREO and other repossessed assets are classified as Level 3.
	Mortgage Servicing Rights
	The fair value of MSRs is determined by calculating the present value of estimated future net servicing cash flows, considering expected mortgage loan prepayment rates, discount rates, servicing costs and other economic factors, which are determined based on current market conditions. The expected rate of mortgage loan prepayments is the most significant factor driving the value of MSRs. MSRs are considered impaired if the carrying value exceeds fair value. The valuation model includes significant unobservable inputs; therefore, MSRs are classified as Level 3 within the fair value hierarchy.
	Other Assets
	We measure certain other assets at fair value on a nonrecurring basis. Fair value is based on the application of lower of cost or fair value accounting, or write-downs of individual assets. Valuation methodologies used to measure fair value are consistent with overall principles of fair value accounting and consistent with those described above.
	Financial Instruments
	In addition to financial instruments recorded at fair value in our financial statements, fair value accounting guidance requires disclosure of the fair value of all of an entity’s assets and liabilities that are considered financial instruments. The majority of our assets and liabilities are considered financial instruments. Many of these instruments lack an available trading market as characterized by a willing buyer and willing seller engaged in an exchange transaction. Also, it is our general practice and intent to hold our financial instruments to maturity and to not engage in trading or sales activities with respect to such financial instruments. For fair value disclosure purposes, we substantially utilize the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, we use present value methods to determine the fair value of our financial instruments.
	Cash and Cash Equivalents and Other Short-Term Assets
	The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks, including interest-bearing deposits, approximate fair value.
	Loans
	The fair value of variable rate performing loans is based on carrying values adjusted for credit risk. The fair value of fixed rate performing loans is estimated using a discounted cash flow analyses that utilizes interest rates currently being offered for similar loans and adjusted for credit risk. The fair value of nonperforming loans is based on their carrying values less any specific reserve. The carrying amount of accrued interest approximates fair value.
	Bank Owned Life Insurance
	Fair value approximates net cash surrender value.
	Deposits
	The fair values disclosed for deposits without defined maturities (e.g., noninterest and interest-bearing demand, money market and savings accounts) are by definition equal to the amounts payable on demand. The carrying amounts for variable rate, fixed-term time deposits approximate their fair values. Estimated fair values for fixed rate and other time deposits are based on discounted cash flow analysis using interest rates currently offered for time deposits with similar terms. The carrying amount of accrued interest approximates fair value.
	Short-Term Borrowings
	The carrying amounts of securities sold under repurchase agreements, federal funds purchased and other short-term borrowings approximate their fair values.
	Long-Term Borrowings
	The fair values disclosed for fixed rate long-term borrowings are determined by discounting their contractual cash flows using current interest rates for long-term borrowings of similar remaining maturities. The carrying amounts of variable rate long-term borrowings approximate their fair values.
	Junior Subordinated Debt Securities
	The variable rate junior subordinated debt securities reprice quarterly; therefore, the fair values are based on the carrying values.
	Loan Commitments and Standby Letters of Credit
	Off-balance sheet financial instruments consist of commitments to extend credit and letters of credit. Except for interest rate lock commitments, estimates of the fair value of these off-balance sheet items are not made because of the short-term nature of these arrangements and the credit standing of the counterparties.
	Other
	Estimates of fair value are not made for items that are not defined as financial instruments, including such items as our core deposit intangibles and the value of our trust operations.
	The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at September 30, 2013 and December 31, 2012. There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented.
		September 30, 2013
	(dollars in thousands)	Level 1		Level 2			Level 3			Total
	ASSETS
	Securities available-for-sale:
	Obligations of U.S. government corporations and agencies	$	—	$	237,398		$	—		$	237,398
	Collateralized mortgage obligations of U.S. government corporations and agencies		—		44,877			—			44,877
	Residential mortgage-backed securities of U.S. government corporations and agencies		—		51,250			—			51,250
	Commercial mortgage-backed securities of U.S. government corporations and agencies		—		30,680			—			30,680
	Obligations of states and political subdivisions		—		114,817			—			114,817
	Marketable equity securities		183		8,957			—			9,140
	Total securities available-for-sale		183		487,979			—			488,162
	Trading securities held in a Rabbi Trust		2,545		—			—			2,545
	Total securities		2,728		487,979			—			490,707
	Derivative financial assets:
	Interest rate swaps		—		16,084			—			16,084
Interest rate lock commitments		—		206			—			206
Total Assets	$	2,728	$	504,269		$	—		$	506,997
LIABILITIES
Derivative financial liabilities:
Interest rate swaps	$	—	$	16,025		$	—		$	16,025
Forward sale contracts		—		162			—			162
Total Liabilities	$	—	$	16,187		$	—		$	16,187
	December 31, 2012
(dollars in thousands)	Level 1		Level 2			Level 3			Total
ASSETS
Securities available-for-sale:
Obligations of U.S. government corporations and agencies	$	—	$	212,066		$	—		$	212,066
Collateralized mortgage obligations of U.S. government corporations and agencies		—		57,896			—			57,896
Residential mortgage-backed securities of U.S. government corporations and agencies		—		50,623			—			50,623
Commercial mortgage-backed securities of U.S. government corporations and agencies		—		10,158			—			10,158
Obligations of states and political subdivisions		—		112,767			—			112,767
Marketable equity securities		140		8,316			300			8,756
Total securities available-for-sale		140		451,826			300			452,266
Trading securities held in a Rabbi Trust		2,223		—			—			2,223
Total securities		2,363		451,826			300			454,489
Derivative financial assets:
Interest rate swaps		—		23,748			—			23,748
Interest rate lock commitments		—		467			—			467
Total Assets	$	2,363	$	476,041		$	300		$	478,704
LIABILITIES
Derivative financial liabilities:
Interest rate swaps	$	—	$	23,522		$	—		$	23,522
Forward sale contracts		—		48			—			48
Total Liabilities	$	—	$	23,570		$	—		$	23,570
We classify financial instruments as Level 3 when valuation models are used because significant inputs are not observable in the market. The following table presents the changes in assets measured at fair value on a recurring basis for which we have utilized Level 3 inputs to determine the fair value:
	Three Months Ended September 30,					Nine Months Ended September 30,
(dollars in thousands)	2013		2012			2013			2012
Balance at beginning of period	$	—	$	556		$	300		$	462
Total gains included in other comprehensive income(1)		—		19			44			50
Net purchases, sales, issuances and settlements		—		(300	)		—			(237	)
Transfers out of Level 3		—		—			(344	)		—
Balance at end of period	$	—	$	275		$	—		$	275
(1) Changes in estimated fair value of available-for-sale investments are recorded in accumulated other comprehensive income/loss, while realized gains and losses from sales are recorded in security gains (losses), net in the Consolidated Statements of Comprehensive Income.
In the second quarter of 2013, $0.3 million was transferred out of Level 3 into Level 2 as a result of a security becoming listed on a national exchange. There were no Level 3 liabilities measured at fair value on a recurring basis for any of the periods presented.
We may be required to measure certain assets and liabilities on a nonrecurring basis. The following table presents our assets that are measured at estimated fair value on a nonrecurring basis by the fair value hierarchy level at September 30, 2013 and December 31, 2012. There were no liabilities measured at estimated fair value on a nonrecurring basis during these periods. Loans held for sale are recorded at the lower of cost or fair value. We had no loans held for sale that were recorded at fair value at September 30, 2013 and December 31, 2012.
	September 30, 2013											December 31, 2012
(dollars in thousands)	Level 1		Level 2			Level 3			Total			Level 1		Level 2		Level 3		Total
ASSETS
Impaired loans	$	—	$	—		$	23,482		$	23,482		$	—	$	—	$	44,059	$	44,059
Other real estate owned		—		—			221			221			—		—		585		585
Mortgage servicing rights		—		—			2,960			2,960			—		—		2,106		2,106
Total Assets	$	—	$	—		$	26,663		$	26,663		$	—	$	—	$	46,750	$	46,750
The carrying values and fair values of our financial instruments at September 30, 2013 and December 31, 2012 are presented in the following tables:
			Fair Value Measurements at September 30, 2013
(dollars in thousands)	Carrying		Total			Level 1			Level 2			Level 3
	Value(1)
ASSETS
Cash and due from banks, including interest-bearing deposits	$	234,928	$	234,928		$	234,928		$	—		$	—
Securities available-for-sale		488,162		488,162			183			487,979			—
Loans held for sale		3,695		3,829			—			—			3,829
Portfolio loans, net of unearned income		3,511,335		3,479,150			—			—			3,479,150
Bank owned life insurance		60,001		60,001			—			60,001			—
FHLB and other restricted stock		15,049		15,049			—			—			15,049
Trading securities held in a Rabbi Trust		2,545		2,545			2,545			—			—
Mortgage servicing rights		2,820		2,960			—			—			2,960
Interest rate swaps		16,084		16,084			—			16,084			—
Interest rate lock commitments		206		206			—			206			—
LIABILITIES
Deposits	$	3,694,203	$	3,696,214		$	—		$	—		$	3,696,214
Securities sold under repurchase agreements		33,290		33,290			—			—			33,290
Short-term borrowings		175,000		175,000			—			—			175,000
Long-term borrowings		22,390		23,718			—			—			23,718
Junior subordinated debt securities		45,619		45,619			—			—			45,619
Interest rate swaps		16,025		16,025			—			16,025			—
Forward sale contracts		162		162			—			162			—
(1) As reported in the Consolidated Balance Sheets
			Fair Value Measurements at December 31, 2012
(dollars in thousands)	Carrying		Total			Level 1			Level 2			Level 3
	Value(1)
ASSETS
Cash and due from banks, including interest-bearing deposits	$	337,711	$	337,711		$	337,711		$	—		$	—
Securities available-for-sale		452,266		452,266			140			451,826			300
Loans held for sale		22,499		22,601			—			—			22,601
Portfolio loans, net of unearned income		3,346,622		3,347,602			—			—			3,347,602
Bank owned life insurance		58,619		58,619			—			58,619			—
FHLB and other restricted stock		15,315		15,315			—			—			15,315
Trading securities held in a Rabbi Trust		2,223		2,223			2,223			—			—
Mortgage servicing rights		2,106		2,106			—			—			2,106
Interest rate swaps		23,748		23,748			—			23,748			—
Interest rate lock commitments		467		467			—			467			—
LIABILITIES
Deposits	$	3,638,428	$	3,643,683		$	—		$	—		$	3,643,683
Securities sold under repurchase agreements		62,582		62,582			—			—			62,582
Short-term borrowings		75,000		75,000			—			—			75,000
Long-term borrowings		34,101		36,235			—			—			36,235
Junior subordinated debt securities		90,619		90,619			—			—			90,619
Interest rate swaps		23,522		23,522			—			23,522			—
Forward sale contracts		48		48			—			48			—
(1) As reported in the Consolidated Balance Sheets

Securities_AvailableforSale

Securities Available-for-Sale	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]
Securities Available-for-Sale
	NOTE 4. SECURITIES AVAILABLE-FOR-SALE
	The following table indicates the composition of the securities available-for-sale portfolio as of the dates presented:
		September 30, 2013										December 31, 2012
	(dollars in thousands)	Amortized		Gross			Gross			Fair		Amortized		Gross			Gross		Fair
		Cost		Unrealized			Unrealized			Value		Cost		Unrealized			Unrealized		Value
				Gains			Losses							Gains			Losses
	Obligations of U.S. government corporations and agencies	$	236,739	$	2,614		$	(1,955	)	$	237,398	$	207,229	$	4,890		$	-53	$	212,066
	Collateralized mortgage obligations of U.S. government corporations and agencies		44,474		607			(204	)		44,877		56,085		1,811			—		57,896
	Residential mortgage-backed securities of U.S. government corporations and agencies		50,021		1,759			(530	)		51,250		47,279		3,344			—		50,623
	Commercial mortgage-backed securities of U.S. government corporations and agencies		31,524		—			(844	)		30,680		10,129		29			—		10,158
	Obligations of states and political subdivisions		115,362		1,705			(2,250	)		114,817		107,911		4,908			-52		112,767
	Debt Securities		478,120		6,685			(5,783	)		479,022		428,633		14,982			-105		443,510
	Marketable equity securities		7,580		1,560			—			9,140		7,672		1,095			-11		8,756
	Total	$	485,700	$	8,245		$	(5,783	)	$	488,162	$	436,305	$	16,077		$	-116	$	452,266
	Realized gains and losses on the sale of securities are determined using the specific-identification method. The following table shows the composition of gross and net realized gains and losses for the periods presented:
		Three Months Ended September 30,					Nine Months Ended September 30,
	(dollars in thousands)	2013		2012			2013			2012
	Gross realized gains	$	3	$	2,170		$	5		$	3,027
	Gross realized losses		—		—			—			11
	Net Realized Gains	$	3	$	2,170		$	5		$	3,016
	The following tables indicate the fair value and the age of gross unrealized losses by investment category as of the dates presented:
		September 30, 2013
		Less Than 12 Months					12 Months or More					Total
	(dollars in thousands)	Fair Value		Unrealized			Fair Value			Unrealized		Fair Value		Unrealized
				Losses						Losses				Losses
	Obligations of U.S. government corporations and agencies	$	115,358	$	(1,955	)	$	—		$	—	$	115,358	$	(1,955	)
	Collateralized mortgage obligations of U.S. government corporations and agencies		19,414		(204	)		—			—		19,414		(204	)
	Residential mortgage-backed securities of U.S. government corporations and agencies		23,386		(530	)		—			—		23,386		(530	)
	Commercial mortgage-backed securities of U.S. government corporations and agencies		30,680		(844	)		—			—		30,680		(844	)
	Obligations of states and political subdivisions		55,690		(2,250	)		—			—		55,690		(2,250	)
	Debt Securities		244,528		(5,783	)		—			—		244,528		(5,783	)
	Marketable equity securities		—		—			—			—		—		—
	Total Temporarily Impaired Securities	$	244,528	$	(5,783	)	$	—		$	—	$	244,528	$	(5,783	)
		December 31, 2012
		Less Than 12 Months					12 Months or More					Total
	(dollars in thousands)	Fair Value		Unrealized			Fair Value			Unrealized		Fair Value		Unrealized
				Losses						Losses				Losses
	Obligations of U.S. government corporations and agencies	$	11,370	$	(53	)	$	—		$	—	$	11,370	$	(53	)
	Collateralized mortgage obligations of U.S. government corporations and agencies		—		—			—			—		—		—
	Residential mortgage-backed securities of U.S. government corporations and agencies		—		—			—			—		—		—
	Commercial mortgage-backed securities of U.S. government corporations and agencies		—		—			—			—		—		—
	Obligations of states and political subdivisions		11,285		(52	)		—			—		11,285		(52	)
	Debt Securities		22,655		(105	)		—			—		22,655		(105	)
	Marketable equity securities		228		(11	)		—			—		228		(11	)
	Total Temporarily Impaired Securities	$	22,883	$	(116	)	$	—		$	—	$	22,883	$	(116	)
	We do not believe any individual unrealized loss as of September 30, 2013 represents an other than temporary impairment, or OTTI. As of September 30, 2013, the unrealized losses on thirty-seven debt securities were attributable to changes in interest rates and not related to the credit quality of these securities. All debt securities are determined to be investment grade and are paying principal and interest according to the contractual terms of the security. There were no unrealized losses on marketable equity securities as of September 30, 2013. We do not intend to sell and it is not likely that we will be required to sell any of the securities, referenced in the table above, in an unrealized loss position before recovery of their amortized cost.
	Net unrealized gains of $1.6 million and $10.4 million were included in accumulated other comprehensive loss, net of tax, at September 30, 2013 and December 31, 2012. Gross unrealized gains of $5.4 million and $10.5 million, net of tax, were netted against gross unrealized losses of $3.8 million and $0.1 million, for these same periods. There were no unrealized losses reclassified into earnings to record OTTI during the period ended September 30, 2013 and minimal losses were reclassified into earnings to record OTTI during the period ended September 30, 2012.
	The amortized cost and fair value of securities available-for-sale at September 30, 2013, by contractual maturity, are included in the table below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
		September 30, 2013
	(dollars in thousands)	Amortized		Fair Value
		Cost
	Obligations of U.S. government corporations and agencies, and obligations of states and political subdivisions
	Due in one year or less	$	34,297	$	34,537
	Due after one year through five years		154,121		156,195
	Due after five years through ten years		77,405		76,221
	Due after ten years		86,278		85,262
			352,101		352,215
	Collateralized mortgage obligations of U.S. government corporations and agencies		44,474		44,877
	Residential mortgage-backed securities of U.S. government corporations and agencies		50,021		51,250
	Commercial Mortgage-backed securities of U.S. government corporations and agencies		31,524		30,680
	Debt Securities		478,120		479,022
	Marketable equity securities		7,580		9,140
	Total	$	485,700	$	488,162
At September 30, 2013 and December 31, 2012, securities with carrying values of $314.3 million and $307.5 million were pledged for various regulatory and legal requirements.

Loans_and_Loans_Held_for_Sale

Loans and Loans Held for Sale	9 Months Ended
	Sep. 30, 2013
Receivables [Abstract]
Loans and Loans Held for Sale	NOTE 5. LOANS AND LOANS HELD FOR SALE
	Loans are presented net of unearned income of $1.0 million and $0.2 million at September 30, 2013 and December 31, 2012. The following table indicates the composition of the loans as of the dates presented:
	(dollars in thousands)	September 30, 2013				December 31, 2012
	Commercial
	Commercial real estate	$	1,567,814			$	1,452,133
	Commercial and industrial		827,699				791,396
	Commercial construction		152,206				168,143
	Total Commercial Loans		2,547,719				2,411,672
	Consumer
	Residential mortgage		477,141				427,303
	Home equity		413,097				431,335
	Installment and other consumer		69,043				73,875
	Consumer construction		4,335				2,437
	Total Consumer Loans		963,616				934,950
	Total Portfolio Loans		3,511,335				3,346,622
	Loans held for sale		3,695				22,499
	Total Loans	$	3,515,030			$	3,369,121
	We attempt to limit our exposure to credit risk by diversifying our loan portfolio and actively managing concentrations. When concentrations exist in certain segments, we mitigate this risk by monitoring the relevant economic indicators and internal risk rating trends and through stress testing of the loans in these segments. Total commercial loans represented 73 percent of total portfolio loans at September 30, 2013 and 72 percent of total portfolio loans at December 31, 2012. Within our commercial portfolio, the commercial real estate, or CRE, and commercial construction portfolios combined comprise 68 percent of total commercial loans and 49 percent of total portfolio loans at September 30, 2013 and 67 percent of total commercial loans and 48 percent of total portfolio loans at December 31, 2012. Further segmentation of the CRE and commercial construction portfolios by industry and collateral type reveal no concentration in excess of nine percent of total loans at either September 30, 2013 or December 31, 2012. The majority of both commercial and consumer loans are made to businesses and individuals in Western Pennsylvania resulting in a geographic concentration. The conditions of the local and regional economies are monitored closely through publicly available data as well as information supplied by our customers. Management believes underwriting guidelines, active monitoring of economic conditions and ongoing review by credit administration mitigates the concentration risk present in the loan portfolio. Only the CRE and commercial construction portfolios combined have any significant out-of-state exposure with 22 percent of the combined portfolio and 11 percent of total loans being out-of-state loans at September 30, 2013 and 19 percent of the combined portfolio and 9 percent of total loans being out-of-state loans at December 31, 2012. Our CRE and commercial construction portfolios combined out-of-state exposure, excluding the contiguous states of Ohio, West Virginia, New York and Maryland, was 8.2 percent of the combined portfolio and 4.0 percent of total loans at September 30, 2013 and 8.4 percent of the combined portfolio and 4.1 percent of total loans at December 31, 2012. Management has the knowledge and experience in these markets which are identified as in market lending opportunities for our organization.
	Troubled Debt Restructurings, or TDRs, are loans where we, for economic or legal reasons related to a borrower’s financial difficulties, grant a concession to the borrower that we would not otherwise grant. We strive to identify borrowers in financial difficulty early and work with them to modify the terms before their loan reaches nonaccrual status. These modified terms generally include extensions of maturity dates at a stated interest rate lower than the current market rate for a new loan with similar risk characteristics, reductions in contractual interest rates or principal deferment. While unusual, there may be instances of principal forgiveness. These modifications are generally for longer term periods that would not be considered insignificant. Additionally, we classify loans where the debt obligation has been discharged through a Chapter 7 Bankruptcy and not reaffirmed as TDRs.
	We individually evaluate all substandard commercial loans that experienced a forbearance or change in terms agreement, as well as all substandard consumer and residential mortgage loans that entered into an agreement to modify their existing loan to determine if they should be designated as TDRs. All TDRs are considered to be impaired loans and will be reported as impaired loans for the remaining life of the loan, unless the restructuring agreement specifies an interest rate equal to or greater than the rate that would be accepted at the time of the restructuring for a new loan with comparable risk and it is fully expected that the remaining principal and interest will be collected according to the restructured agreement. Further, all impaired loans are reported as nonaccrual loans unless the loan is a TDR that has met the requirements to be returned to accruing status. TDRs can be returned to accruing status if the ultimate collectability of all contractual amounts due, according to the restructured agreement, is not in doubt and there is a period of a minimum of six months of satisfactory payment performance by the borrower either immediately before or after the restructuring.
	The following table summarizes the restructured loans as of the dates presented:
		September 30, 2013								December 31, 2012
	(dollars in thousands)	Accruing		Nonaccruing				Total		Accruing			Nonaccruing		Total
		TDRs		TDRs				TDRs		TDRs			TDRs		TDRs
	Commercial real estate	$	15,619	$	7,150			$	22,769	$	14,220		$	9,584	$	23,804
	Commercial and industrial		7,595		1,926				9,521		8,270			939		9,209
	Commercial construction		5,574		9,652				15,226		11,734			5,324		17,058
	Residential mortgage		2,689		1,054				3,743		3,078			2,752		5,830
	Home equity		3,999		612				4,611		4,195			341		4,536
	Installment and other consumer		148		—				148		24			—		24
	Total	$	35,624	$	20,394			$	56,018	$	41,521		$	18,940	$	60,461
	We returned three TDRs to accruing status during the three months ended September 30, 2013 totaling $1.7 million and four TDRs totaling $1.9 million to accruing status during the nine months ended September 30, 2013. We did not return any TDRs to accruing status during the three months or nine months ended September 30, 2012.
	The following tables present the restructured loans for the three and nine month periods ended September 30, 2013 and September 30, 2012:
		Three Months Ended September 30, 2013
	(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
		Loans		Outstanding				Outstanding		in Recorded
				Recorded				Recorded		Investment
				Investment(1)				Investment(1)
	Commercial real estate
	Interest rate reduction and maturity date extension		2	$	664			$	644	$	(20	)
	Commercial and industrial
	Principal deferral		1		278				278		—
	Residential mortgage
	Interest rate reduction		1		54				54		—
	Home equity
	Chapter 7 bankruptcy(2)		8		772				767		(5	)
	Installment and other consumer
	Chapter 7 bankruptcy(2)		3		17				15		(2	)
	Total by Concession Type
	Principal deferral		1		278				278		—
	Interest rate reduction		1		54				54		—
	Interest rate reduction and maturity date extension		2		664				644		(20	)
	Chapter 7 bankruptcy(2)		11		789				782		(7	)
	Total		15	$	1,785			$	1,758	$	(27	)
	(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
	(2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.
		Nine Months Ended September 30, 2013
	(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
		Loans		Outstanding				Outstanding		in Recorded
				Recorded				Recorded		Investment
				Investment(1)				Investment(1)
	Commercial real estate
	Principal deferral		3	$	1,541			$	1,288	$	(253	)
	Interest rate reduction and maturity date extension		2		664				644		(20	)
Principal forgiveness(2)		1		4,339				4,339		—
Chapter 7 bankruptcy(3)		7		258				255		(3	)
Commercial and industrial
Principal deferral		2		670				665		(5	)
Maturity date extension		1		751				751		—
Chapter 7 bankruptcy(3)		1		3				3		—
Residential mortgage
Principal deferral		2		153				153		—
Interest rate reduction		1		54				54		—
Chapter 7 bankruptcy(3)		8		353				344		(9	)
Home equity
Principal deferral		1		174				45		(129	)
Chapter 7 bankruptcy(3)		31		1,420				1,407		(13	)
Installment and other consumer
Chapter 7 bankruptcy(3)		9		90				88		(2	)
Total by Concession Type
Principal Deferral		8		2,538				2,151		(387	)
Interest rate reduction		1		54				54		—
Interest rate reduction and maturity date extension		2		664				644		(20	)
Principal forgiveness(2)		1		4,339				4,339		—
Maturity date extension		1		751				751		—
Chapter 7 bankruptcy(3)		56		2,124				2,097		(27	)
Total		69	$	10,470			$	10,036	$	(434	)
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
(2) This loan had debt forgiveness of $0.1 million to the customer; however, the loan was previously charged off to a balance below the actual contractual balance.
(3) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.
	Three Months Ended September 30, 2012
(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
	Loans		Outstanding				Outstanding		in Recorded
			Recorded				Recorded		Investment
			Investment(1)				Investment(1)
Commercial construction
Maturity date extension		7	$	2,905			$	2,257	$	(648	)
Residential mortgage
Maturity date extension		1		35				35		—
Interest rate reduction		1		32				32		—
Total by Concession Type
Maturity date extension		8		2,940				2,292		(648	)
Interest rate reduction		1		32				32		—
Total		9	$	2,972			$	2,324	$	(648	)
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
	Nine Months Ended September 30, 2012
(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
	Loans		Outstanding				Outstanding		in Recorded
			Recorded				Recorded		Investment
			Investment(1)				Investment(1)
Commercial real estate
Maturity date extension		1	$	160			$	157	$	(3	)
Interest rate reduction		1		575				565		(10	)
Commercial and industrial
Maturity date extension		2		2,576				2,430		(146	)
Commercial construction
Maturity date extension		7		2,905				2,257		(648	)
Residential mortgage
Maturity date extension		1		475				460		(15	)
Interest rate reduction		2		67				67		—
Total by Concession Type
Maturity date extension		11		6,116				5,304		(812	)
Interest rate reduction		3		642				632		(10	)
Total		14	$	6,758			$	5,936	$	(822	)
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
For the three months ended September 30, 2013, we modified three loans that were not considered to be TDRs, including two commercial and industrial, or C&I, loans totaling $0.8 million and a $0.9 million residential mortgage loan. For the nine months ended September 30, 2013, we modified eight loans that were not considered to be TDRs, including five C&I loans totaling $6.1 million, two commercial construction loans totaling $0.6 million and a $0.9 million residential mortgage loan. Modifications primarily represented insignificant delays in the timing of payments, concessions where we were adequately compensated through principal pay downs, fees or additional collateral or we concluded that no concession was granted. As of September 30, 2013 we have no commitments to lend additional funds on any TDRs.
Defaulted TDRs are defined as loans having a payment default of 90 days or more after the restructuring takes place. The following table is a summary of TDRs which defaulted during the three and nine month periods ended September 30, 2013 and 2012 that had been restructured within the last twelve months prior to defaulting:
	Defaulted TDRs
	For the						For the					For the				For the
	Three Months Ended						Three Months Ended					Nine Months Ended				Nine Months Ended
	September 30, 2013						September 30, 2012					September 30, 2013				September 30, 2012
(dollars in thousands)	Number of		Recorded				Number of		Recorded			Number of		Recorded		Number of		Recorded
	Defaults		Investment				Defaults		Investment			Defaults		Investment		Defaults		Investment
Commercial real estate		1	$	75				1	$	270			1	$	75		2	$	329
Commercial and Industrial		1		435				—		—			1		435		—		—
Commercial construction		—		—				—		—			—		—		3		2,659
Residential real estate		4		450				—		—			7		514		3		2,359
Home equity		1		42				—		—			5		193		—		—
Total		7	$	1,002				1	$	270			14	$	1,217		8	$	5,347
The following table is a summary of nonperforming assets as of the dates presented:
(dollars in thousands)	September 30, 2013		December 31, 2012
Nonperforming Assets
Nonaccrual loans	$	16,005	$	36,018
Nonaccrual TDRs		20,394		18,940
Total nonaccrual loans		36,399		54,958
OREO		460		911
Total Nonperforming Assets	$	36,859	$	55,869
OREO consists of 8 properties and is included in other assets in the Consolidated Balance Sheets. It is our policy to obtain OREO appraisals on an annual basis.

Allowance_for_Loan_Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2013
Receivables [Abstract]
Allowance for Loan Losses	NOTE 6. ALLOWANCE FOR LOAN LOSSES
	We maintain an allowance for loan losses, or ALL, at a level determined to be adequate to absorb estimated probable credit losses inherent in the loan portfolio as of the balance sheet date. We develop and document a systematic ALL methodology based on the following portfolio segments: 1) CRE, 2) C&I, 3) Commercial Construction, 4) Consumer Real Estate and 5) Other Consumer.
	The following are key risks within each portfolio segment:
	CRE—Loans secured by commercial purpose real estate, including both owner occupied properties and investment properties for various purposes such as hotels, strip malls and apartments. Operations of the individual projects as well as global cash flows of the debtors are the primary sources of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type as well as the business prospects of the lessee, if the project is not owner occupied.
	C&I—Loans made to operating companies or manufacturers for the purpose of production, operating capacity, accounts receivable, inventory or equipment financing. Cash flow from the operations of the company is the primary source of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the industry of the company. Collateral for these types of loans often do not have sufficient value in a distressed or liquidation scenario to satisfy the outstanding debt.
	Commercial Construction—Loans made to finance construction of buildings or other structures, as well as to finance the acquisition and development of raw land for various purposes. While the risk of these loans is generally confined to the construction period, if there are problems, the project may not be complete, and as such, may not provide sufficient cash flow on its own to service the debt or have sufficient value in a liquidation to cover the outstanding principal. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the type of project and the experience and resources of the developer.
	Consumer Real Estate—Loans secured by first and second liens such as home equity loans, home equity lines of credit and 1-4 family residences, including purchase money mortgages. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The state of the local housing market can also have a significant impact on this segment because low demand and/or declining home values can limit the ability of borrowers to sell a property and satisfy the debt.
	Other Consumer—Loans made to individuals that may be secured by assets other than 1-4 family residences, as well as unsecured loans. This segment includes auto loans, unsecured loans and lines and credit cards. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The value of the collateral, if there is any, is less likely to be a source of repayment due to less certain collateral values.
	We further assess risk within each portfolio segment by pooling loans with similar risk characteristics. For the commercial loan classes, the most important indicator of risk is the internally assigned risk rating, including pass, special mention and substandard. Consumer loans are pooled by type of collateral and first or second lien positions for consumer real estate loans. Historical loss rates are applied to these loan pools to determine the reserve for loans collectively evaluated for impairment. Management continuously monitors various credit quality indicators for both the commercial and consumer loan portfolios, including delinquency, nonperforming status and changes in risk ratings on a monthly basis.
	We continuously monitor our ALL methodology to ensure that it is responsive to the current economic environment. Over the past year, the economic conditions within our markets have stabilized, and we have experienced significant improvement in our credit quality, including lower net charge-offs, lower delinquency, lower non-performing loans and lower special mention and substandard loans compared to December 31, 2012. Accordingly, the assumptions used within the ALL were reevaluated in the third quarter of 2013 to be responsive to the improved economic environment and the changes in our credit quality.
	The ALL methodology for groups of loans collectively evaluated for impairment is comprised of both a quantitative and qualitative analysis. A key assumption in the quantitative component of the reserve is the loss emergence period, or LEP. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is confirmed. In general, the LEP will be shorter in an economic slowdown or recession and longer during times of economic stability or growth, as customers are better able to delay loss confirmation after a potential loss event has occurred. Due to the recent improvement in economic conditions, we completed an internal study utilizing our loan charge-off history to recalibrate the LEPs of the commercial portfolio segments. Consistent with the improved economic conditions, the LEPs have lengthened, and as a result, we lengthened our LEP assumption for each of the commercial portfolio segments. We believe that the consumer portfolio segment LEPs have also lengthened as they are influenced by the same improvement in economic conditions that impacted the commercial portfolio segments. We therefore also lengthened the LEP assumption for the consumer portfolio segments in the third quarter of 2013.
	The changes made to the ALL assumptions were applied prospectively and did not result in a material change to the total ALL at September 30, 2013. Lengthening the LEP does increase the historical loss rates and therefore the quantitative component of the ALL. We believe this makes the quantitative component of the ALL more reflective of inherent losses that exist within the loan portfolio, which resulted in a decrease in the qualitative component of the ALL. The changes to the LEPs also improved our insight into the inherent risk of the individual commercial portfolio segments. As the economic conditions have improved, our data indicates that the CRE segment has less inherent loss and that the C&I segment contains greater inherent loss. The ALL at September 30, 2013 reflects these changes within the CRE and C&I portfolio segments.
	The following tables present the age analysis of past due loans segregated by class of loans as of September 30, 2013 and December 31, 2012:
		September 30, 2013
	(dollars in thousands)	Current			30-59 Days			60-89 Days			Nonaccrual			Total Past			Total Loans
					Past Due			Past Due						Due
	Commercial real estate	$	1,549,998		$	1,095		$	242		$	16,479		$	17,816		$	1,567,814
	Commercial and industrial		820,425			3,100			277			3,897			7,274			827,699
	Commercial construction		140,551			1,971			—			9,684			11,655			152,206
	Residential mortgage		471,639			715			1,766			3,021			5,502			477,141
	Home equity		407,072			2,291			443			3,291			6,025			413,097
	Installment and other consumer		68,740			221			55			27			303			69,043
	Consumer construction		4,335			—			—			—			—			4,335
	Totals	$	3,462,760		$	9,393		$	2,783		$	36,399		$	48,575		$	3,511,335
		December 31, 2012
	(dollars in thousands)	Current			30-59 Days			60-89 Days			Nonaccrual			Total Past			Total Loans
					Past Due			Past Due						Due
	Commercial real estate	$	1,418,934		$	2,230		$	413		$	30,556		$	33,199		$	1,452,133
	Commercial and industrial		780,315			4,409			237			6,435			11,081			791,396
	Commercial construction		150,823			10,542			—			6,778			17,320			168,143
	Residential mortgage		416,364			1,713			1,948			7,278			10,939			427,303
	Home equity		424,485			2,332			865			3,653			6,850			431,335
	Installment and other consumer		73,334			406			95			40			541			73,875
	Consumer construction		2,219			—			—			218			218			2,437
	Totals	$	3,266,474		$	21,632		$	3,558		$	54,958		$	80,148		$	3,346,622
	We continually monitor the commercial loan portfolio through an internal risk rating system. Loan risk ratings are assigned based upon the creditworthiness of the borrower and are reviewed on an ongoing basis according to our internal policies. Loans within the pass rating generally have a lower risk of loss than loans risk rated as special mention and substandard.
	Our risk ratings are consistent with regulatory guidance and are as follows:
	Pass—The loan is currently performing and is of high quality.
	Special Mention—A special mention loan has potential weaknesses that warrant management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects or in the strength of our credit position at some future date. Economic and market conditions, beyond the borrower’s control, may in the future necessitate this classification.
	Substandard—A substandard loan is not adequately protected by the net worth and/or paying capacity of the borrower or by the collateral pledged, if any. Substandard loans have a well-defined weakness, or weaknesses that jeopardize the liquidation of the debt. These loans are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected.
	The following tables summarize the recorded investment in commercial loan classes by internally assigned risk ratings as of the dates presented:
		September 30, 2013
	(dollars in thousands)	Commercial			% of			Commercial			% of			Commercial			% of			Total		% of
		Real Estate			Total			and Industrial			Total			Construction			Total					Total
	Pass	$	1,458,589			93	%	$	771,597			93.2	%	$	119,120			78.3	%	$	2,349,306		92.2	%
	Special mention		51,849			3.3	%		34,238			4.1	%		16,755			11	%		102,842		4	%
	Substandard		57,376			3.7	%		21,864			2.7	%		16,331			10.7	%		95,571		3.8	%
	Total	$	1,567,814			100	%	$	827,699			100	%	$	152,206			100	%	$	2,547,719		100	%
		December 31, 2012
	(dollars in thousands)	Commercial			% of			Commercial			% of			Commercial			% of			Total		% of
		Real Estate			Total			and Industrial			Total			Construction			Total					Total
	Pass	$	1,265,810			87.2	%	$	718,070			90.7	%	$	118,841			70.7	%	$	2,102,721		87.2	%
	Special mention		96,156			6.6	%		42,016			5.3	%		30,748			18.3	%		168,920		7	%
	Substandard		90,167			6.2	%		31,310			4	%		18,554			11	%		140,031		5.8	%
	Total	$	1,452,133			100	%	$	791,396			100	%	$	168,143			100	%	$	2,411,672		100	%
	We monitor the delinquent status of the consumer portfolio on a monthly basis. Loans are considered nonperforming when interest and principal are 90 days or more past due or management has determined that a material deterioration in the borrower’s financial condition exists. The risk of loss is generally highest for nonperforming loans.
	The following tables indicate the recorded investment in consumer loan classes by performing and nonperforming status as of the dates presented:
		September 30, 2013
	(dollars in thousands)	Residential			% of			Home			% of			Installment			% of			Consumer		% of			Total		% of
		Mortgage			Total			Equity			Total			and other			Total			Construction		Total					Total
														consumer
	Performing	$	474,120			99.4	%	$	409,806			99.2	%	$	69,016			99.9	%	$	4,335		100	%	$	957,277		99.3	%
	Nonperforming		3,021			0.6	%		3,291			0.8	%		27			0.1	%		—		—			6,339		0.7	%
	Total	$	477,141			100	%	$	413,097			100	%	$	69,043			100	%	$	4,335		100	%	$	963,616		100	%
	December 31, 2012
(dollars in thousands)	Residential			% of			Home			% of			Installment			% of			Consumer		% of			Total		% of
	Mortgage			Total			Equity			Total			and other			Total			Construction		Total					Total
													consumer
Performing	$	420,025			98.3	%	$	427,682			99.2	%	$	73,835			99.9	%	$	2,219		91.1	%	$	923,761		98.8	%
Nonperforming		7,278			1.7	%		3,653			0.8	%		40			0.1	%		218		8.9	%		11,189		1.2	%
Total	$	427,303			100	%	$	431,335			100	%	$	73,875			100	%	$	2,437		100	%	$	934,950		100	%
We individually evaluate all substandard and nonaccrual commercial loans greater than $0.5 million for impairment. Loans are considered to be impaired when based upon current information and events it is probable that we will be unable to collect all principal and interest payments due according to the original contractual terms of the loan agreement. All TDRs are considered to be impaired loans and will be reported as an impaired loan for the remaining life of the loan, unless the restructuring agreement specifies an interest rate equal to or greater than the rate that would be accepted at the time of the restructuring for a new loan with comparable risk and it is expected that the remaining principal and interest will be fully collected according to the restructured agreement. For all TDRs, regardless of size, as well as all other impaired loans, we conduct further analysis to determine the probable loss and assign a specific reserve to the loan if deemed appropriate.
The following table presents investments in loans considered to be impaired and related information on those impaired loans as of September 30, 2013 and December 31, 2012:
	September 30, 2013									December 31, 2012
(dollars in thousands)	Recorded			Unpaid			Related						Unpaid			Related
	Investment			Principal			Allowance			Recorded			Principal			Allowance
				Balance						Investment			Balance
With a related allowance recorded:
Commercial real estate	$	1,014		$	2,291		$	64		$	6,138		$	6,864		$	1,226
Commercial and industrial		—			—			—			1,864			2,790			1,002
Commercial construction		5,929			5,929			3,139			799			896			3
Consumer real estate		98			98			56			—			—			—
Other consumer		34			34			19			—			—			—
Total with a Related Allowance Recorded		7,075			8,352			3,278			8,801			10,550			2,231
Without a related allowance recorded:
Commercial real estate		27,309			38,351			—			33,856			45,953			—
Commercial and industrial		10,128			12,406			—			11,419			12,227			—
Commercial construction		9,329			17,873			—			17,713			27,486			—
Consumer real estate		8,256			9,267			—			10,827			12,025			—
Other consumer		114			119			—			25			25			—
Total without a Related Allowance Recorded		55,136			78,016			—			73,840			97,716			—
Total:
Commercial real estate		28,323			40,642			64			39,994			52,817			1,226
Commercial and industrial		10,128			12,406			—			13,283			15,017			1,002
Commercial construction		15,258			23,802			3,139			18,512			28,382			3
Consumer real estate		8,354			9,365			56			10,827			12,025			—
Other consumer		148			153			19			25			25			—
Total	$	62,211		$	86,368		$	3,278		$	82,641		$	108,266		$	2,231
As of September 30, 2013, CRE loans of $28.3 million comprised 46 percent of the total impaired loans of $62.2 million. These impaired loans are collateralized primarily by commercial real estate properties such as retail or strip malls, office buildings and various other types of commercial purpose properties. These loans are generally considered collateral dependent and charge-offs are recorded when a confirmed loss exists. Approximately $13.5 million of charge-offs have been recorded relating to these CRE loans over the life of these loans. It is our policy to order appraisals on an annual basis on impaired loans or sooner if facts and circumstances warrant. As of September 30, 2013, an estimated fair value less cost to sell of approximately $41.6 million existed for CRE impaired loans. We have current appraisals on all but $0.3 million of the $28.3 million of impaired CRE loans.
The following tables summarize investments in loans considered to be impaired and related information on those impaired loans for the periods presented:
	For the Three Months Ended
	September 30, 2013						September 30, 2012
(dollars in thousands)	Average			Interest			Average			Interest
	Recorded			Income			Recorded			Income
	Investment			Recognized			Investment			Recognized
With a related allowance recorded:
Commercial real estate	$	1,014		$	—		$	6,430		$	15
Commercial and industrial		—			—			784			(9	)
Commercial construction		5,929			49			4,236			19
Consumer real estate		100			2			—			—
Other consumer		35			1			—			—
Total with a Related Allowance Recorded		7,078			52			11,450			25
Without a related allowance recorded:
Commercial real estate		27,489			271			38,962			268
Commercial and industrial		10,995			68			13,238			101
Commercial construction		9,768			46			23,349			113
Consumer real estate		8,349			114			5,729			9
Other consumer		119			1			—			—
Total without a Related Allowance Recorded		56,720			500			81,278			491
Total:
Commercial real estate		28,503			271			45,392			283
Commercial and industrial		10,995			68			14,022			92
Commercial construction		15,697			95			27,585			132
Consumer real estate		8,449			116			5,729			9
Other consumer		154			2			—			—
Total	$	63,798		$	552		$	92,728		$	516
	For the Nine Months Ended
	September 30, 2013						September 30, 2012
(dollars in thousands)	Average			Interest			Average			Interest
	Recorded			Income			Recorded			Income
	Investment			Recognized			Investment			Recognized
With a related allowance recorded:
Commercial real estate	$	2,526		$	5		$	5,629		$	209
Commercial and industrial		—			—			1,813			—
Commercial construction		1,976			49			5,661			49
Consumer real estate		62			—			—			—
Other consumer		21			3			—			—
Total with a Related Allowance Recorded		4,585			57			13,103			258
Without a related allowance recorded:
Commercial real estate		29,951			330			43,332			915
Commercial and industrial		11,964			203			11,725			265
Commercial construction		14,492			271			22,926			450
Consumer real estate		8,912			693			6,489			70
Other consumer		110			4			—			—
Total without a Related Allowance Recorded		65,429			1,501			84,472			1,700
Total:
Commercial real estate		32,477			335			48,961			1,124
Commercial and industrial		11,964			203			13,538			265
Commercial construction		16,468			320			28,587			499
Consumer real estate		8,974			693			6,489			70
Other consumer		131			7			—			—
Total	$	70,014		$	1,558		$	97,575		$	1,958
The following tables detail activity in the ALL for the periods presented:
	Three Months Ended September 30, 2013
(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
	Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
Balance at beginning of period	$	23,484		$	9,123		$	5,812		$	6,655		$	1,031		$	46,105
Charge-offs		(840	)		(759	)		(480	)		(585	)		(327	)		(2,991	)
Recoveries		617			167			481			122			63			1,450
Net (Charge-offs)/ Recoveries		(223	)		(592	)		1			(463	)		(264	)		(1,541	)
Provision for loan losses		(5,572	)		6,268			2,186			185			352			3,419
Balance at End of Period	$	17,689		$	14,799		$	7,999		$	6,377		$	1,119		$	47,983
	Three Months Ended September 30, 2012
(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
	Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
Balance at beginning of period	$	24,696		$	11,874		$	5,938		$	3,401		$	780		$	46,689
Charge-offs		(2,344	)		(520	)		(970	)		(268	)		(278	)		(4,380	)
Recoveries		570			609			395			18			73			1,665
Net (Charge-offs)/ Recoveries		(1,774	)		89			(575	)		(250	)		(205	)		(2,715	)
Provision for loan losses		1,283			(3,216	)		3,162			752			324			2,305
Balance at End of Period	$	24,205		$	8,747		$	8,525		$	3,903		$	899		$	46,279
	Nine Months Ended September 30, 2013
(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
	Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
Balance at beginning of period	$	25,246		$	7,759		$	7,500		$	5,058		$	921		$	46,484
Charge-offs		(3,649	)		(2,682	)		(923	)		(1,822	)		(978	)		(10,054	)
Recoveries		2,939			457			536			630			242			4,804
Net (Charge-offs)/ Recoveries		(710	)		(2,225	)		(387	)		(1,192	)		(736	)		(5,250	)
Provision for loan losses		(6,847	)		9,265			886			2,511			934			6,749
Balance at End of Period	$	17,689		$	14,799		$	7,999		$	6,377		$	1,119		$	47,983
	Nine Months Ended September 30, 2012
(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
	Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
Balance at beginning of period	$	29,804		$	11,274		$	3,703		$	3,166		$	894		$	48,841
Charge-offs		(7,918	)		(4,488	)		(9,261	)		(1,228	)		(756	)		(23,651	)
Recoveries		748			857			494			127			263			2,489
Net (Charge-offs)/ Recoveries		(7,170	)		(3,631	)		(8,767	)		(1,101	)		(493	)		(21,162	)
Provision for loan losses		1,571			1,104			13,589			1,838			498			18,600
Balance at End of Period	$	24,205		$	8,747		$	8,525		$	3,903		$	899		$	46,279
The following tables present the ALL and recorded investments in loans by category as of September 30, 2013 and December 31, 2012:
	September 30, 2013
	Allowance for Loan Losses									Portfolio Loans
(dollars in thousands)	Individually			Collectively			Total			Individually			Collectively			Total
	Evaluated for			Evaluated for						Evaluated for			Evaluated for
	Impairment			Impairment						Impairment			Impairment
Commercial real estate	$	64		$	17,625		$	17,689		$	28,323		$	1,539,491		$	1,567,814
Commercial and industrial		—			14,799			14,799			10,128			817,571			827,699
Commercial construction		3,139			4,860			7,999			15,258			136,948			152,206
Consumer real estate		56			6,321			6,377			8,354			886,219			894,573
Other consumer		19			1,100			1,119			148			68,895			69,043
Total	$	3,278		$	44,705		$	47,983		$	62,211		$	3,449,124		$	3,511,335
	December 31, 2012
	Allowance for Loan Losses									Portfolio Loans
(dollars in thousands)	Individually			Collectively			Total			Individually			Collectively			Total
	Evaluated for			Evaluated for						Evaluated for			Evaluated for
	Impairment			Impairment						Impairment			Impairment
Commercial real estate	$	1,226		$	24,020		$	25,246		$	39,994		$	1,412,139		$	1,452,133
Commercial and industrial		1,002			6,757			7,759			13,283			778,113			791,396
Commercial construction		3			7,497			7,500			18,512			149,631			168,143
Consumer real estate		—			5,058			5,058			10,827			850,248			861,075
Other consumer		—			921			921			25			73,850			73,875
Total	$	2,231		$	44,253		$	46,484		$	82,641		$	3,263,981		$	3,346,622

Derivative_Instruments_and_Hed

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	NOTE 7. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES
	Interest Rate Swaps
	Interest rate swaps are contracts in which a series of interest rate flows (fixed and variable) are exchanged over a prescribed period. The notional amounts on which the interest payments are based are not exchanged. In some cases, we utilize interest rate swaps for commercial loans. These derivative positions relate to transactions in which we enter into an interest rate swap with a customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on a same notional amount at a fixed rate. At the same time, we agree to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate loan while we receive a variable yield. These agreements could have floors or caps on the contracted interest rates.
	Pursuant to our agreements with various financial institutions, we may receive collateral or may be required to post collateral based upon mark-to-market positions. Beyond unsecured threshold levels, collateral in the form of cash or securities may be made available to counterparties of swap transactions. Based upon our current positions and related future collateral requirements relating to them, we believe any effect on its cash flow or liquidity position to be immaterial.
	Derivatives contain an element of credit risk, the possibility that we will incur a loss because a counterparty, which may be a financial institution or a customer, fails to meet its contractual obligations. All derivative contracts with financial institutions may be executed only with counterparties approved by our Asset and Liability Committee, or ALCO, and derivatives with customers may only be executed with customers within collateral coverage and credit exposure limits. Interest rate swaps are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the fair value of the derivatives are recorded in current, earnings and included in other noninterest income in the Consolidated Statements of Comprehensive Income.
	Interest Rate Lock Commitments and Forward Sale Contracts
	In the normal course of business, we sell originated mortgage loans into the secondary mortgage loan market. We offer interest rate lock commitments to potential borrowers. Whenever a customer requests these products, a mortgage originator quotes a secondary market rate guaranteed for that day by the investor. The commitments are generally for 60 days and guarantee a specified interest rate for a loan if underwriting standards are met, but the commitment does not obligate the potential borrower to close on the loan. Accordingly, some commitments expire prior to becoming loans. However, if the borrower accepts the guaranteed rate, we can encounter pricing risk if interest rates increase significantly before the loan can be closed and sold. We may utilize forward sale contracts in order to mitigate this pricing risk. The rate lock is executed between the mortgagee and us, and generally these rate locks are bundled. A forward sale contract is then executed between us and the investor. Both the interest rate lock commitment bundle and the corresponding forward sale contract are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the fair value of the derivatives during the commitment period are recorded in current earnings and included in mortgage banking in the Consolidated Statements of Comprehensive Income.
	The following table indicates the amounts representing the value of derivative assets and derivative liabilities as of the dates presented:
		Derivatives						Derivatives
		(included in Other Assets)						(included in Other Liabilities)
	(dollars in thousands)	September 30, 2013			December 31, 2012			September 30, 2013			December 31, 2012
	Derivatives not Designated as Hedging Instruments
	Interest Rate Swap Contracts—Commercial Loans
	Fair value	$	16,084		$	23,748		$	16,025		$	23,522
	Notional amount		257,678			227,532			257,678			227,532
	Collateral posted		—			—			12,978			19,595
	Interest Rate Lock Commitments—Mortgage Loans
	Fair value		206			467			—			—
	Notional amount		4,670			14,287			—			—
	Forward Sale Contracts—Mortgage Loans
	Fair value		—			—			162			48
	Notional amount		—			—			7,425			14,100
	Presenting offsetting derivatives that are subject to legally enforceable netting arrangements with the same party is permitted. For example, we may have a derivative asset as well as a derivative liability with the same counterparty to a swap transaction and are permitted to offset the asset position and the liability position resulting in a net presentation.
	The following table indicates the gross amounts of derivative assets and derivative liabilities, the amounts offset, and the carrying values in the Consolidated Balance Sheets as of the dates presented:
		Derivatives						Derivatives
		(included in Other Assets)						(included in Other Liabilities)
	(dollars in thousands)	September 30, 2013			December 31, 2012			September 30, 2013			December 31, 2012
	Derivatives not Designated as Hedging Instruments
	Gross amounts recognized	$	16,445		$	24,262		$	16,386		$	24,036
	Gross amounts offset		(361	)		(514	)		(361	)		(514	)
	Net amounts presented in the Consolidated Balance Sheets		16,084			23,748			16,025			23,522
	Gross amounts not offset(1)		—			—			(12,978	)		(19,595	)
	Net Amount	$	16,084		$	23,748		$	3,047		$	3,927
	(1) Amounts represent posted collateral.
	The following table indicates the gain or loss recognized in income on derivatives for the periods presented:
		Three Months Ended September 30,						Nine Months Ended September 30,
	(dollars in thousands)	2013			2012			2013			2012
	Derivatives not Designated as Hedging Instruments
	Interest rate swap contracts—commercial loans	$	(10	)	$	(19	)	$	(166	)	$	164
	Interest rate lock commitments—mortgage loans		231			257			(261	)		629
	Forward sale contracts—mortgage loans		(519	)		(101	)		(114	)		(212	)
	Total Derivative (Loss) Gain	$	(298	)	$	137		$	(541	)	$	581

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Borrowings	NOTE 8. BORROWINGS
	Short-term borrowings are for terms under one year and were comprised of retail repurchase agreements, or REPOs, and Federal Home Loan Bank, or FHLB, advances. We define repurchase agreements with our local retail customers as retail REPOs. Securities pledged as collateral under these REPO financing arrangements cannot be sold or repledged by the secured party and are therefore accounted for as a secured borrowing. FHLB advances are for various terms secured by a blanket lien on residential mortgages and other loans secured by real estate.
	Long-term borrowings are for original terms greater than one year and are comprised of FHLB advances and junior subordinated debt securities. Long-term FHLB advances have the same collateral requirements as their short-term equivalents.
	We had total long-term borrowings outstanding of $19.1 million at a fixed rate and $48.7 million at a variable rate at September 30, 2013, excluding a capital lease of $0.2 million which is classified as long-term borrowings.
	Information pertaining to borrowings is summarized in the table below as of the dates presented:
		September 30, 2013					December 31, 2012
	(dollars in thousands)	Balance		Weighted			Balance		Weighted
				Average Rate					Average Rate
	Short-term borrowings
	Securities sold under repurchase agreements	$	33,290		0.01	%	$	62,582		0.2	%
	Short-term borrowings		175,000		0.28	%		75,000		0.19	%
	Total short-term borrowings		208,290		0.24	%		137,582		0.19	%
	Long-term borrowings
	Junior subordinated debt securities		45,619		2.71	%		90,619		3.01	%
	Other long-term borrowings		22,390		3.01	%		34,101		3.17	%
	Total long-term borrowings		68,009		2.81	%		124,720		3.05	%
	Total Borrowings	$	276,299		0.87	%	$	262,302		1.55	%
	We had total borrowings at September 30, 2013 and December 31, 2012 at the FHLB of Pittsburgh of $197.2 million and $108.9 million. This consisted of $22.2 in long-term borrowings and $175.0 in short-term borrowings at September 30, 2013. At September 30, 2013, we had a maximum borrowing capacity of $1.5 billion with a remaining borrowing availability of $1.3 billion with the FHLB of Pittsburgh.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 9. COMMITMENTS AND CONTINGENCIES
	Commitments
	In the normal course of business, we offer off-balance sheet credit arrangements to enable our customers to meet their financing objectives. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the financial statements. Our exposure to credit loss, in the event a customer does not satisfy the terms of their agreement, equals the contractual amount of the obligation less the value of any collateral. We apply the same credit policies in making commitments and standby letters of credit that are used for the underwriting of loans to customers. Commitments generally have fixed expiration dates, annual renewals or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon; the total commitment amounts do not necessarily represent future cash requirements. Our allowance for unfunded commitments totaled $3.1 million at September 30, 2013 and $3.0 million at December 31, 2012. The increase in the allowance for unfunded commitments is due to an increase in lending commitments. The allowance for unfunded commitments is included in other liabilities in the Consolidated Balance Sheets.
	Estimates of the fair value of these off-balance sheet items were not made because of the short-term nature of these arrangements and the credit standing of the counterparties.
	The following table sets forth the commitments and letters of credit as of the dates presented:
	(dollars in thousands)	September 30, 2013		December 31, 2012
	Commitments to extend credit	$	1,042,572	$	874,137
	Standby letters of credit		80,653		95,399
	Total	$	1,123,225	$	969,536
	Litigation
	In the normal course of business, we are subject to various legal and administrative proceedings and claims. While any type of litigation contains a level of uncertainty, we believe that the outcome of such proceedings or claims will not have a material adverse effect on our consolidated financial position.

Other_Comprehensive_Income

Other Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]
Other Comprehensive Income	NOTE 10. OTHER COMPREHENSIVE INCOME
	The following tables show the tax effects of the components of other comprehensive income for the periods presented:
		Three Months Ended September 30, 2013									Three Months Ended September 30, 2012
	(dollars in thousands)	Pre-Tax			Tax			Net of Tax			Pre-Tax			Tax			Net of Tax
		Amount			(Expense)			Amount			Amount			(Expense)			Amount
					Benefit									Benefit
	Change in unrealized gains/losses on securities available-for-sale	$	335		$	(117	)	$	218		$	4,373		$	(1,530	)	$	2,843
	Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income(1)		(3	)		1			(2	)		(2,170	)		760			(1,410	)
	Adjustment to funded status of employee benefit plans		631			(220	)		411			750			(264	)		486
	Other Comprehensive Income (Loss)	$	963		$	(336	)	$	627		$	2,953		$	(1,034	)	$	1,919
	(1) Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.
		Nine Months Ended September 30, 2013									Nine Months Ended September 30, 2012
	(dollars in thousands)	Pre-Tax			Tax			Net of Tax			Pre-Tax			Tax			Net of Tax
		Amount			(Expense)			Amount			Amount			(Expense)			Amount
					Benefit									Benefit
	Change in unrealized gains/losses on securities available-for-sale	$	(13,494	)	$	4,723		$	(8,771	)	$	5,188		$	(1,815	)	$	3,373
	Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income(1)		(5	)		2			(3	)		(3,016	)		1,056			(1,960	)
	Adjustment to funded status of employee benefit plans		1,827			(639	)		1,188			1,887			(662	)		1,225
	Other Comprehensive Income (Loss)	$	(11,672	)	$	4,086		$	(7,586	)	$	4,059		$	(1,421	)	$	2,638
	(1) Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.

Employee_Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2013
Compensation And Retirement Disclosure [Abstract]
Employee Benefits	NOTE 11. EMPLOYEE BENEFITS
	We maintain a defined benefit pension plan, or Plan, covering substantially all employees hired prior to January 1, 2008. The benefits are based on years of service and the employee’s compensation for the highest five consecutive years in the last ten years. Contributions are intended to provide for benefits attributed to employee service to date and for those benefits expected to be earned in the future. At this time, we are not required to make a cash contribution to the Plan in 2013. We contributed $3.1 million to the Plan in December 2012. The expected long-term rate of return on plan assets is 8.00 percent. For the current year there are no changes to the Plan.
	The following table summarizes the components of net periodic pension cost and other changes in plan assets and benefit obligation recognized in other comprehensive gain/loss for the periods presented:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(dollars in thousands)	2013			2012			2013			2012
	Components of Net Periodic Pension Cost
	Service cost—benefits earned during the period	$	659		$	636		$	2,075		$	2,090
	Interest cost on projected benefit obligation		997			1,117			2,989			3,269
	Expected return on plan assets		(1,526	)		(1,364	)		(4,656	)		(4,172	)
	Amortization of prior service cost (credit)		(34	)		(34	)		(102	)		(99	)
	Recognized net actuarial loss		642			711			1,818			1,852
	Net Periodic Pension Expense	$	738		$	1,066		$	2,124		$	2,940

Segments

Segments	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segments	NOTE 12. SEGMENTS
	We manage three reportable operating segments including Community Banking, Insurance and Wealth Management.
		•		Our Community Banking segment offers services which include accepting time and demand deposit accounts, originating commercial and consumer loans and providing letters of credit and credit card services.
		•		Our Insurance segment includes a full-service insurance agency offering commercial property and casualty insurance, group life and health coverage, employee benefit solutions and personal insurance lines.
		•		Our Wealth Management segment offers discount brokerage services, services as executor and trustee under wills and deeds, guardian and custodian of employee benefits and other trust and brokerage services, as well as a registered investment advisor that manages private investment accounts for individuals and institutions.
	The following table represents total assets by reportable operating segment as of the dates presented:
	(dollars in thousands)		September 30, 2013		December 31, 2012
	Community Banking		$	4,579,528	$	4,518,799
	Insurance			7,358		6,697
	Wealth Management			1,242		1,206
	Total Assets		$	4,588,128	$	4,526,702
	The following tables provide financial information for our three segments for the three and nine month periods ended September 30, 2013 and 2012. The financial results of the business segments include allocations for shared services based on an internal analysis that supports line of business performance measurement. Shared services include expenses such as employee benefits, occupancy expense, computer support and corporate overhead. Even with these allocations, the financial results are not necessarily indicative of the business segments’ financial condition and results of operations if they existed as independent entities.
	The information provided under the caption “Eliminations” represents operations not considered to be reportable segments and/or general operating expenses and eliminations and adjustments, which are necessary for purposes of reconciling to the Consolidated Financial Statements.
			Three Months Ended September 30, 2013
	(dollars in thousands)		Community		Insurance		Wealth		Eliminations			Consolidated
			Banking				Management
	Interest income		$	38,540	$	—	$	137	$	(96	)	$	38,581
	Interest expense			3,949		—		—		(642	)		3,307
	Net interest income (expense)			34,591		—		137		546			35,274
	Provision for loan losses			3,419		—		—		—			3,419
	Noninterest income			8,321		1,459		2,744		18			12,542
	Noninterest expense			22,252		1,357		2,379		741			26,729
	Depreciation expense			816		12		7		—			835
	Amortization of intangible assets			355		13		11		—			379
	Provision (benefit) for income taxes			4,179		27		178		(177	)		4,207
	Net Income		$	11,891	$	50	$	306	$	—		$	12,247
			Three Months Ended September 30, 2012
	(dollars in thousands)		Community		Insurance		Wealth		Eliminations			Consolidated
			Banking				Management
	Interest income		$	38,715	$	—	$	119	$	(14	)	$	38,820
	Interest expense			5,340		—		—		(315	)		5,025
	Net interest income (expense)			33,375		—		119		301			33,795
	Provision for loan losses			2,305		—		—		—			2,305
	Noninterest income			10,731		1,481		2,394		140			14,746
	Noninterest expense			24,586		1,398		2,401		1,228			29,613
	Depreciation expense			968		12		8		—			988
	Amortization of intangible assets			391		13		13		—			417
	Provision (benefit) for income taxes			3,333		21		56		(787	)		2,623
	Net Income		$	12,523	$	37	$	35	$	—		$	12,595
			Nine Months Ended September 30, 2013
	(dollars in thousands)		Community		Insurance		Wealth		Eliminations			Consolidated
			Banking				Management
	Interest income		$	114,733	$	1	$	411	$	(168	)	$	114,977
	Interest expense			13,403		—		—		(1,965	)		11,438
	Net interest income (expense)			101,330		1		411		1,797			103,539
	Provision for loan losses			6,749		—		—		—			6,749
	Noninterest income			27,144		4,406		8,130		535			40,215
	Noninterest expense			68,680		3,910		7,257		4,208			84,055
	Depreciation expense			2,609		35		23		—			2,667
	Amortization of intangible assets			1,148		38		37		—			1,223
	Provision (benefit) for income taxes			11,617		148		491		(1,876	)		10,380
	Net Income		$	37,671	$	276	$	733	$	—		$	38,680
			Nine Months Ended September 30, 2012
	(dollars in thousands)		Community		Insurance		Wealth		Eliminations			Consolidated
			Banking				Management
	Interest income		$	116,968	$	1	$	325	$	36		$	117,330
	Interest expense			17,244		—		—		(849	)		16,395
	Net interest income (expense)			99,724		1		325		885			100,935
	Provision for loan losses			18,600		—		—		—			18,600
	Noninterest income			28,230		4,196		7,375		546			40,347
	Noninterest expense			73,850		4,119		7,037		3,917			88,923
	Depreciation expense			2,887		37		23		—			2,947
	Amortization of intangible assets			1,193		39		44		—			1,276
	Provision (benefit) for income taxes			7,057		1		289		(2,486	)		4,861
Net Income		$	24,367	$	1	$	307	$	—		$	24,675

Sale_of_Merchant_Card_Servicin

Sale of Merchant Card Servicing Business	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]
Sale of Merchant Card Servicing Business	NOTE 13. SALE OF MERCHANT CARD SERVICING BUSINESS
	We sold our merchant card servicing business for $4.8 million during the first quarter of 2013. Consequently, we terminated an agreement with our existing merchant processor and incurred deconversion and termination fees of $1.7 million. As a result of this transaction, we recognized a gain of $3.1 million in the first quarter of 2013. In conjunction with the sale of the merchant card servicing business, we entered into a marketing and sales alliance agreement with the purchaser for an initial term of ten years. The agreement provides that we will actively market and refer our customers to the purchaser and in return will receive a share of the future revenue. Future revenue is dependent on the number of referrals, number of new merchant accounts and volume of activity.

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation
	The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or S&T, and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting.
Basis of Presentation	Basis of Presentation
	The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles, or GAAP, in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our annual report on Form 10-K for the year ended December 31, 2012, filed with the Securities and Exchange Commission, or SEC, on February 25, 2013. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly our financial position and the results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period.
Reclassification	Reclassification
	Certain amounts in the prior periods’ financial statements and footnotes have been reclassified to conform to the current period’s presentation. The reclassifications had no significant effect on our results of operations or financial condition.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income	Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2013-02, Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income. ASU 2013-02 requires reporting the effect of significant reclassifications out of accumulated other comprehensive income by component on the respective line items in the income statement parenthetically or in the notes to the financial statements if the amounts being reclassified are required under GAAP to be reclassified in their entirety to net income. This ASU is effective for public companies prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2012 and early adoption is permitted. We have elected the option of reporting in the notes to the financial statements. The adoption of ASU 2013-02 impacted only our disclosures and did not have an impact on our results of operations or financial position.
Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities	Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities
	In January 2013, the FASB issued ASU No. 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities in order to clarify the scope of ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, issued in December 2011. ASU 2011-11 required entities to disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an agreement similar to a master netting arrangement. This ASU was issued to allow investors to better compare financial statements prepared under GAAP with financial statements prepared under International Financial Reporting Standards, or IFRS. ASU 2013-01 clarified that ASU 2011-11 applies to derivatives, sale and repurchase agreements and reverse sale of repurchase agreements, and securities borrowing and securities lending arrangements, but does not apply to standard commercial contracts that permit either party to net in the event of default under the applicable contract or to broker-dealer unsettled regular-way trades. Both ASUs are effective for public companies retrospectively for fiscal years, and interim periods within those years, beginning on or after January 1, 2013. The adoption of ASU 2013-01 and ASU 2011-11 impacted only our disclosures and did not have an impact on our results of operations or financial position.
Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date	Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date
	In February 2013, the FASB issued ASU No. 2013-04, Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. The ASU requires the measurement of obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date as the sum of the amount the reporting entity agreed to pay on the basis of its arrangement with its co-obligors as well as any additional amount that the entity expects to pay on behalf of its co-obligors. The new standard is effective retrospectively for fiscal years and interim periods within those years, beginning after December 15, 2013, and early adoption is permitted. The adoption of this ASU is not expected to have a material impact on our results of operations or financial position.
Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Tax Credit Carry Forward Exists	Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Tax Credit Carry forward Exists
	In July 2013, the FASB issued ASU No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Tax Credit Carry forward Exists. The ASU requires that entities should present an unrecognized tax benefit as a reduction of the deferred tax asset for a net operating loss, or NOL, or similar tax loss or tax credit carry forward rather than as a liability when the uncertain tax position would reduce the NOL or other carry forward under the tax law. No new disclosures will be necessary. The new standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013, and should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted. The adoption of this ASU is expected to impact the presentation of our statement of financial position, but is not expected to have any impact on our results of operations.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share	The following table reconciles the numerators and denominators of basic earnings per share with that of diluted earnings per share for the periods presented:
		Three Months Ended September 30,				Nine Months Ended September 30,
	(dollars in thousands, except shares and per share data)	2013		2012		2013		2012
	Numerator for Earnings per Share—Basic:
	Net income	$	12,247	$	12,595	$	38,680	$	24,675
	Less: Income allocated to participating shares		33		50		114		107
	Net Income Allocated to Shareholders	$	12,214	$	12,545	$	38,566	$	24,568
	Numerator for Earnings per Share—Diluted:
	Net income	$	12,247	$	12,595	$	38,680	$	24,675
	Net Income Available to Shareholders	$	12,247	$	12,595	$	38,680	$	24,675
	Denominators:
	Weighted Average Shares Outstanding—Basic		29,658,065		29,244,588		29,644,646		28,740,582
	Add: Dilutive potential shares		27,535		32,644		35,132		33,614
	Denominator for Treasury Stock Method—Diluted		29,685,600		29,277,232		29,679,778		28,774,196
	Weighted Average Shares Outstanding—Basic		29,658,065		29,244,588		29,644,646		28,740,582
	Add: Average participating shares outstanding		80,240		116,402		87,725		125,240
	Denominator for Two-Class Method—Diluted		29,738,305		29,360,990		29,732,371		28,865,822
	Earnings per share—basic	$	0.41	$	0.43	$	1.3	$	0.85
	Earnings per share—diluted	$	0.41	$	0.43	$	1.3	$	0.85
	Warrants considered anti-dilutive excluded from dilutive potential shares		517,012		517,012		517,012		517,012
	Stock options considered anti-dilutive excluded from dilutive potential shares		612,768		748,964		632,481		751,492
	Restricted stock considered anti-dilutive excluded from dilutive potential shares		52,705		48,717		52,593		56,585

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at September 30, 2013 and December 31, 2012. There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented.
		September 30, 2013
	(dollars in thousands)	Level 1		Level 2			Level 3			Total
	ASSETS
	Securities available-for-sale:
	Obligations of U.S. government corporations and agencies	$	—	$	237,398		$	—		$	237,398
	Collateralized mortgage obligations of U.S. government corporations and agencies		—		44,877			—			44,877
	Residential mortgage-backed securities of U.S. government corporations and agencies		—		51,250			—			51,250
	Commercial mortgage-backed securities of U.S. government corporations and agencies		—		30,680			—			30,680
	Obligations of states and political subdivisions		—		114,817			—			114,817
	Marketable equity securities		183		8,957			—			9,140
	Total securities available-for-sale		183		487,979			—			488,162
	Trading securities held in a Rabbi Trust		2,545		—			—			2,545
	Total securities		2,728		487,979			—			490,707
	Derivative financial assets:
	Interest rate swaps		—		16,084			—			16,084
	Interest rate lock commitments		—		206			—			206
	Total Assets	$	2,728	$	504,269		$	—		$	506,997
	LIABILITIES
	Derivative financial liabilities:
	Interest rate swaps	$	—	$	16,025		$	—		$	16,025
	Forward sale contracts		—		162			—			162
	Total Liabilities	$	—	$	16,187		$	—		$	16,187
		December 31, 2012
	(dollars in thousands)	Level 1		Level 2			Level 3			Total
	ASSETS
	Securities available-for-sale:
	Obligations of U.S. government corporations and agencies	$	—	$	212,066		$	—		$	212,066
	Collateralized mortgage obligations of U.S. government corporations and agencies		—		57,896			—			57,896
	Residential mortgage-backed securities of U.S. government corporations and agencies		—		50,623			—			50,623
	Commercial mortgage-backed securities of U.S. government corporations and agencies		—		10,158			—			10,158
	Obligations of states and political subdivisions		—		112,767			—			112,767
	Marketable equity securities		140		8,316			300			8,756
	Total securities available-for-sale		140		451,826			300			452,266
	Trading securities held in a Rabbi Trust		2,223		—			—			2,223
	Total securities		2,363		451,826			300			454,489
	Derivative financial assets:
	Interest rate swaps		—		23,748			—			23,748
	Interest rate lock commitments		—		467			—			467
	Total Assets	$	2,363	$	476,041		$	300		$	478,704
	LIABILITIES
	Derivative financial liabilities:
	Interest rate swaps	$	—	$	23,522		$	—		$	23,522
	Forward sale contracts		—		48			—			48
	Total Liabilities	$	—	$	23,570		$	—		$	23,570
Changes in Assets Classified as Level 3 in Fair Value Hierarchy	The following table presents the changes in assets measured at fair value on a recurring basis for which we have utilized Level 3 inputs to determine the fair value:
		Three Months Ended September 30,					Nine Months Ended September 30,
	(dollars in thousands)	2013		2012			2013			2012
	Balance at beginning of period	$	—	$	556		$	300		$	462
	Total gains included in other comprehensive income(1)		—		19			44			50
	Net purchases, sales, issuances and settlements		—		(300	)		—			(237	)
	Transfers out of Level 3		—		—			(344	)		—
	Balance at end of period	$	—	$	275		$	—		$	275
	(1) Changes in estimated fair value of available-for-sale investments are recorded in accumulated other comprehensive income/loss, while realized gains and losses from sales are recorded in security gains (losses), net in the Consolidated Statements of Comprehensive Income.
Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy	We had no loans held for sale that were recorded at fair value at September 30, 2013 and December 31, 2012.
		September 30, 2013											December 31, 2012
	(dollars in thousands)	Level 1		Level 2			Level 3			Total			Level 1		Level 2		Level 3		Total
	ASSETS
	Impaired loans	$	—	$	—		$	23,482		$	23,482		$	—	$	—	$	44,059	$	44,059
	Other real estate owned		—		—			221			221			—		—		585		585
	Mortgage servicing rights		—		—			2,960			2,960			—		—		2,106		2,106
	Total Assets	$	—	$	—		$	26,663		$	26,663		$	—	$	—	$	46,750	$	46,750
Carrying Values and Fair Values of Financial Instruments	The carrying values and fair values of our financial instruments at September 30, 2013 and December 31, 2012 are presented in the following tables:
				Fair Value Measurements at September 30, 2013
	(dollars in thousands)	Carrying		Total			Level 1			Level 2			Level 3
		Value(1)
	ASSETS
	Cash and due from banks, including interest-bearing deposits	$	234,928	$	234,928		$	234,928		$	—		$	—
	Securities available-for-sale		488,162		488,162			183			487,979			—
	Loans held for sale		3,695		3,829			—			—			3,829
	Portfolio loans, net of unearned income		3,511,335		3,479,150			—			—			3,479,150
	Bank owned life insurance		60,001		60,001			—			60,001			—
	FHLB and other restricted stock		15,049		15,049			—			—			15,049
	Trading securities held in a Rabbi Trust		2,545		2,545			2,545			—			—
	Mortgage servicing rights		2,820		2,960			—			—			2,960
	Interest rate swaps		16,084		16,084			—			16,084			—
	Interest rate lock commitments		206		206			—			206			—
	LIABILITIES
	Deposits	$	3,694,203	$	3,696,214		$	—		$	—		$	3,696,214
	Securities sold under repurchase agreements		33,290		33,290			—			—			33,290
	Short-term borrowings		175,000		175,000			—			—			175,000
	Long-term borrowings		22,390		23,718			—			—			23,718
	Junior subordinated debt securities		45,619		45,619			—			—			45,619
	Interest rate swaps		16,025		16,025			—			16,025			—
	Forward sale contracts		162		162			—			162			—
	(1) As reported in the Consolidated Balance Sheets
				Fair Value Measurements at December 31, 2012
	(dollars in thousands)	Carrying		Total			Level 1			Level 2			Level 3
		Value(1)
	ASSETS
	Cash and due from banks, including interest-bearing deposits	$	337,711	$	337,711		$	337,711		$	—		$	—
	Securities available-for-sale		452,266		452,266			140			451,826			300
	Loans held for sale		22,499		22,601			—			—			22,601
	Portfolio loans, net of unearned income		3,346,622		3,347,602			—			—			3,347,602
	Bank owned life insurance		58,619		58,619			—			58,619			—
	FHLB and other restricted stock		15,315		15,315			—			—			15,315
	Trading securities held in a Rabbi Trust		2,223		2,223			2,223			—			—
	Mortgage servicing rights		2,106		2,106			—			—			2,106
	Interest rate swaps		23,748		23,748			—			23,748			—
	Interest rate lock commitments		467		467			—			467			—
	LIABILITIES
	Deposits	$	3,638,428	$	3,643,683		$	—		$	—		$	3,643,683
	Securities sold under repurchase agreements		62,582		62,582			—			—			62,582
	Short-term borrowings		75,000		75,000			—			—			75,000
	Long-term borrowings		34,101		36,235			—			—			36,235
	Junior subordinated debt securities		90,619		90,619			—			—			90,619
	Interest rate swaps		23,522		23,522			—			23,522			—
	Forward sale contracts		48		48			—			48			—
	(1) As reported in the Consolidated Balance Sheets

Securities_AvailableforSale_Ta

Securities Available-for-Sale (Tables)	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]
Composition of Securities Available-for-Sale	The following table indicates the composition of the securities available-for-sale portfolio as of the dates presented:
		September 30, 2013										December 31, 2012
	(dollars in thousands)	Amortized		Gross			Gross			Fair		Amortized		Gross			Gross		Fair
		Cost		Unrealized			Unrealized			Value		Cost		Unrealized			Unrealized		Value
				Gains			Losses							Gains			Losses
	Obligations of U.S. government corporations and agencies	$	236,739	$	2,614		$	(1,955	)	$	237,398	$	207,229	$	4,890		$	-53	$	212,066
	Collateralized mortgage obligations of U.S. government corporations and agencies		44,474		607			(204	)		44,877		56,085		1,811			—		57,896
	Residential mortgage-backed securities of U.S. government corporations and agencies		50,021		1,759			(530	)		51,250		47,279		3,344			—		50,623
	Commercial mortgage-backed securities of U.S. government corporations and agencies		31,524		—			(844	)		30,680		10,129		29			—		10,158
	Obligations of states and political subdivisions		115,362		1,705			(2,250	)		114,817		107,911		4,908			-52		112,767
	Debt Securities		478,120		6,685			(5,783	)		479,022		428,633		14,982			-105		443,510
	Marketable equity securities		7,580		1,560			—			9,140		7,672		1,095			-11		8,756
	Total	$	485,700	$	8,245		$	(5,783	)	$	488,162	$	436,305	$	16,077		$	-116	$	452,266
Schedule of Gross and Net Realized Gains and Losses on Sale of Securities	The following table shows the composition of gross and net realized gains and losses for the periods presented:
		Three Months Ended September 30,					Nine Months Ended September 30,
	(dollars in thousands)	2013		2012			2013			2012
	Gross realized gains	$	3	$	2,170		$	5		$	3,027
	Gross realized losses		—		—			—			11
	Net Realized Gains	$	3	$	2,170		$	5		$	3,016
Fair Value and Age of Gross Unrealized Losses by Investment Category	The following tables indicate the fair value and the age of gross unrealized losses by investment category as of the dates presented:
		September 30, 2013
		Less Than 12 Months					12 Months or More					Total
	(dollars in thousands)	Fair Value		Unrealized			Fair Value			Unrealized		Fair Value		Unrealized
				Losses						Losses				Losses
	Obligations of U.S. government corporations and agencies	$	115,358	$	(1,955	)	$	—		$	—	$	115,358	$	(1,955	)
	Collateralized mortgage obligations of U.S. government corporations and agencies		19,414		(204	)		—			—		19,414		(204	)
	Residential mortgage-backed securities of U.S. government corporations and agencies		23,386		(530	)		—			—		23,386		(530	)
	Commercial mortgage-backed securities of U.S. government corporations and agencies		30,680		(844	)		—			—		30,680		(844	)
	Obligations of states and political subdivisions		55,690		(2,250	)		—			—		55,690		(2,250	)
	Debt Securities		244,528		(5,783	)		—			—		244,528		(5,783	)
	Marketable equity securities		—		—			—			—		—		—
	Total Temporarily Impaired Securities	$	244,528	$	(5,783	)	$	—		$	—	$	244,528	$	(5,783	)
		December 31, 2012
		Less Than 12 Months					12 Months or More					Total
	(dollars in thousands)	Fair Value		Unrealized			Fair Value			Unrealized		Fair Value		Unrealized
				Losses						Losses				Losses
	Obligations of U.S. government corporations and agencies	$	11,370	$	(53	)	$	—		$	—	$	11,370	$	(53	)
	Collateralized mortgage obligations of U.S. government corporations and agencies		—		—			—			—		—		—
	Residential mortgage-backed securities of U.S. government corporations and agencies		—		—			—			—		—		—
	Commercial mortgage-backed securities of U.S. government corporations and agencies		—		—			—			—		—		—
	Obligations of states and political subdivisions		11,285		(52	)		—			—		11,285		(52	)
	Debt Securities		22,655		(105	)		—			—		22,655		(105	)
	Marketable equity securities		228		(11	)		—			—		228		(11	)
	Total Temporarily Impaired Securities	$	22,883	$	(116	)	$	—		$	—	$	22,883	$	(116	)
Amortized Cost and Fair Value of Available-for-Sale Securities	The amortized cost and fair value of securities available-for-sale at September 30, 2013, by contractual maturity, are included in the table below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
		September 30, 2013
	(dollars in thousands)	Amortized		Fair Value
		Cost
	Obligations of U.S. government corporations and agencies, and obligations of states and political subdivisions
	Due in one year or less	$	34,297	$	34,537
	Due after one year through five years		154,121		156,195
	Due after five years through ten years		77,405		76,221
	Due after ten years		86,278		85,262
			352,101		352,215
	Collateralized mortgage obligations of U.S. government corporations and agencies		44,474		44,877
	Residential mortgage-backed securities of U.S. government corporations and agencies		50,021		51,250
	Commercial Mortgage-backed securities of U.S. government corporations and agencies		31,524		30,680
	Debt Securities		478,120		479,022
	Marketable equity securities		7,580		9,140
	Total	$	485,700	$	488,162

Loans_and_Loans_Held_for_Sale_

Loans and Loans Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2013
Receivables [Abstract]
Composition of Loans	The following table indicates the composition of the loans as of the dates presented:
	(dollars in thousands)	September 30, 2013				December 31, 2012
	Commercial
	Commercial real estate	$	1,567,814			$	1,452,133
	Commercial and industrial		827,699				791,396
	Commercial construction		152,206				168,143
	Total Commercial Loans		2,547,719				2,411,672
	Consumer
	Residential mortgage		477,141				427,303
	Home equity		413,097				431,335
	Installment and other consumer		69,043				73,875
	Consumer construction		4,335				2,437
	Total Consumer Loans		963,616				934,950
	Total Portfolio Loans		3,511,335				3,346,622
	Loans held for sale		3,695				22,499
	Total Loans	$	3,515,030			$	3,369,121
Restructured Loans for Periods Presented	The following table summarizes the restructured loans as of the dates presented:
		September 30, 2013								December 31, 2012
	(dollars in thousands)	Accruing		Nonaccruing				Total		Accruing			Nonaccruing		Total
		TDRs		TDRs				TDRs		TDRs			TDRs		TDRs
	Commercial real estate	$	15,619	$	7,150			$	22,769	$	14,220		$	9,584	$	23,804
	Commercial and industrial		7,595		1,926				9,521		8,270			939		9,209
	Commercial construction		5,574		9,652				15,226		11,734			5,324		17,058
	Residential mortgage		2,689		1,054				3,743		3,078			2,752		5,830
	Home equity		3,999		612				4,611		4,195			341		4,536
	Installment and other consumer		148		—				148		24			—		24
	Total	$	35,624	$	20,394			$	56,018	$	41,521		$	18,940	$	60,461
Restructured Loans for Periods Stated	The following tables present the restructured loans for the three and nine month periods ended September 30, 2013 and September 30, 2012:
		Three Months Ended September 30, 2013
	(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
		Loans		Outstanding				Outstanding		in Recorded
				Recorded				Recorded		Investment
				Investment(1)				Investment(1)
	Commercial real estate
	Interest rate reduction and maturity date extension		2	$	664			$	644	$	(20	)
	Commercial and industrial
	Principal deferral		1		278				278		—
	Residential mortgage
	Interest rate reduction		1		54				54		—
	Home equity
	Chapter 7 bankruptcy(2)		8		772				767		(5	)
	Installment and other consumer
	Chapter 7 bankruptcy(2)		3		17				15		(2	)
	Total by Concession Type
	Principal deferral		1		278				278		—
	Interest rate reduction		1		54				54		—
	Interest rate reduction and maturity date extension		2		664				644		(20	)
	Chapter 7 bankruptcy(2)		11		789				782		(7	)
	Total		15	$	1,785			$	1,758	$	(27	)
	(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
	(2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.
		Nine Months Ended September 30, 2013
	(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
		Loans		Outstanding				Outstanding		in Recorded
				Recorded				Recorded		Investment
				Investment(1)				Investment(1)
	Commercial real estate
	Principal deferral		3	$	1,541			$	1,288	$	(253	)
	Interest rate reduction and maturity date extension		2		664				644		(20	)
	Principal forgiveness(2)		1		4,339				4,339		—
	Chapter 7 bankruptcy(3)		7		258				255		(3	)
	Commercial and industrial
	Principal deferral		2		670				665		(5	)
	Maturity date extension		1		751				751		—
	Chapter 7 bankruptcy(3)		1		3				3		—
	Residential mortgage
	Principal deferral		2		153				153		—
	Interest rate reduction		1		54				54		—
	Chapter 7 bankruptcy(3)		8		353				344		(9	)
	Home equity
	Principal deferral		1		174				45		(129	)
	Chapter 7 bankruptcy(3)		31		1,420				1,407		(13	)
	Installment and other consumer
	Chapter 7 bankruptcy(3)		9		90				88		(2	)
	Total by Concession Type
	Principal Deferral		8		2,538				2,151		(387	)
	Interest rate reduction		1		54				54		—
	Interest rate reduction and maturity date extension		2		664				644		(20	)
	Principal forgiveness(2)		1		4,339				4,339		—
	Maturity date extension		1		751				751		—
	Chapter 7 bankruptcy(3)		56		2,124				2,097		(27	)
	Total		69	$	10,470			$	10,036	$	(434	)
	(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
	(2) This loan had debt forgiveness of $0.1 million to the customer; however, the loan was previously charged off to a balance below the actual contractual balance.
	(3) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.
		Three Months Ended September 30, 2012
	(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
		Loans		Outstanding				Outstanding		in Recorded
				Recorded				Recorded		Investment
				Investment(1)				Investment(1)
	Commercial construction
Maturity date extension		7	$	2,905			$	2,257	$	(648	)
Residential mortgage
Maturity date extension		1		35				35		—
Interest rate reduction		1		32				32		—
Total by Concession Type
Maturity date extension		8		2,940				2,292		(648	)
Interest rate reduction		1		32				32		—
Total		9	$	2,972			$	2,324	$	(648	)
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
	Nine Months Ended September 30, 2012
(dollars in thousands)	Number of		Pre-Modification				Post-Modification		Total Difference
	Loans		Outstanding				Outstanding		in Recorded
			Recorded				Recorded		Investment
			Investment(1)				Investment(1)
Commercial real estate
Maturity date extension		1	$	160			$	157	$	(3	)
Interest rate reduction		1		575				565		(10	)
Commercial and industrial
Maturity date extension		2		2,576				2,430		(146	)
Commercial construction
Maturity date extension		7		2,905				2,257		(648	)
Residential mortgage
Maturity date extension		1		475				460		(15	)
Interest rate reduction		2		67				67		—
Total by Concession Type
Maturity date extension		11		6,116				5,304		(812	)
Interest rate reduction		3		642				632		(10	)
Total		14	$	6,758			$	5,936	$	(822	)
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
Summary of Nonperforming Assets of Defaulted TDRs	The following table is a summary of TDRs which defaulted during the three and nine month periods ended September 30, 2013 and 2012 that had been restructured within the last twelve months prior to defaulting:
		Defaulted TDRs
		For the						For the					For the				For the
		Three Months Ended						Three Months Ended					Nine Months Ended				Nine Months Ended
		September 30, 2013						September 30, 2012					September 30, 2013				September 30, 2012
	(dollars in thousands)	Number of		Recorded				Number of		Recorded			Number of		Recorded		Number of		Recorded
		Defaults		Investment				Defaults		Investment			Defaults		Investment		Defaults		Investment
	Commercial real estate		1	$	75				1	$	270			1	$	75		2	$	329
	Commercial and Industrial		1		435				—		—			1		435		—		—
	Commercial construction		—		—				—		—			—		—		3		2,659
	Residential real estate		4		450				—		—			7		514		3		2,359
	Home equity		1		42				—		—			5		193		—		—
	Total		7	$	1,002				1	$	270			14	$	1,217		8	$	5,347
Summary of Nonperforming Assets	The following table is a summary of nonperforming assets as of the dates presented:
	(dollars in thousands)	September 30, 2013		December 31, 2012
	Nonperforming Assets
	Nonaccrual loans	$	16,005	$	36,018
	Nonaccrual TDRs		20,394		18,940
	Total nonaccrual loans		36,399		54,958
	OREO		460		911
	Total Nonperforming Assets	$	36,859	$	55,869

Allowance_for_Loan_Losses_Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2013
Receivables [Abstract]
Age Analysis of Past Due Loans Segregated by Class of Loans	The following tables present the age analysis of past due loans segregated by class of loans as of September 30, 2013 and December 31, 2012:
		September 30, 2013
	(dollars in thousands)	Current			30-59 Days			60-89 Days			Nonaccrual			Total Past			Total Loans
					Past Due			Past Due						Due
	Commercial real estate	$	1,549,998		$	1,095		$	242		$	16,479		$	17,816		$	1,567,814
	Commercial and industrial		820,425			3,100			277			3,897			7,274			827,699
	Commercial construction		140,551			1,971			—			9,684			11,655			152,206
	Residential mortgage		471,639			715			1,766			3,021			5,502			477,141
	Home equity		407,072			2,291			443			3,291			6,025			413,097
	Installment and other consumer		68,740			221			55			27			303			69,043
	Consumer construction		4,335			—			—			—			—			4,335
	Totals	$	3,462,760		$	9,393		$	2,783		$	36,399		$	48,575		$	3,511,335
		December 31, 2012
	(dollars in thousands)	Current			30-59 Days			60-89 Days			Nonaccrual			Total Past			Total Loans
					Past Due			Past Due						Due
	Commercial real estate	$	1,418,934		$	2,230		$	413		$	30,556		$	33,199		$	1,452,133
	Commercial and industrial		780,315			4,409			237			6,435			11,081			791,396
	Commercial construction		150,823			10,542			—			6,778			17,320			168,143
	Residential mortgage		416,364			1,713			1,948			7,278			10,939			427,303
	Home equity		424,485			2,332			865			3,653			6,850			431,335
	Installment and other consumer		73,334			406			95			40			541			73,875
	Consumer construction		2,219			—			—			218			218			2,437
	Totals	$	3,266,474		$	21,632		$	3,558		$	54,958		$	80,148		$	3,346,622
Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings	The following tables summarize the recorded investment in commercial loan classes by internally assigned risk ratings as of the dates presented:
		September 30, 2013
	(dollars in thousands)	Commercial			% of			Commercial			% of			Commercial			% of			Total		% of
		Real Estate			Total			and Industrial			Total			Construction			Total					Total
	Pass	$	1,458,589			93	%	$	771,597			93.2	%	$	119,120			78.3	%	$	2,349,306		92.2	%
	Special mention		51,849			3.3	%		34,238			4.1	%		16,755			11	%		102,842		4	%
	Substandard		57,376			3.7	%		21,864			2.7	%		16,331			10.7	%		95,571		3.8	%
	Total	$	1,567,814			100	%	$	827,699			100	%	$	152,206			100	%	$	2,547,719		100	%
		December 31, 2012
	(dollars in thousands)	Commercial			% of			Commercial			% of			Commercial			% of			Total		% of
		Real Estate			Total			and Industrial			Total			Construction			Total					Total
	Pass	$	1,265,810			87.2	%	$	718,070			90.7	%	$	118,841			70.7	%	$	2,102,721		87.2	%
	Special mention		96,156			6.6	%		42,016			5.3	%		30,748			18.3	%		168,920		7	%
	Substandard		90,167			6.2	%		31,310			4	%		18,554			11	%		140,031		5.8	%
	Total	$	1,452,133			100	%	$	791,396			100	%	$	168,143			100	%	$	2,411,672		100	%
Recorded Investment in Consumer Loan Classes by Performing and Nonperforming Status	The following tables indicate the recorded investment in consumer loan classes by performing and nonperforming status as of the dates presented:
		September 30, 2013
	(dollars in thousands)	Residential			% of			Home			% of			Installment			% of			Consumer		% of			Total		% of
		Mortgage			Total			Equity			Total			and other			Total			Construction		Total					Total
														consumer
	Performing	$	474,120			99.4	%	$	409,806			99.2	%	$	69,016			99.9	%	$	4,335		100	%	$	957,277		99.3	%
	Nonperforming		3,021			0.6	%		3,291			0.8	%		27			0.1	%		—		—			6,339		0.7	%
	Total	$	477,141			100	%	$	413,097			100	%	$	69,043			100	%	$	4,335		100	%	$	963,616		100	%
		December 31, 2012
	(dollars in thousands)	Residential			% of			Home			% of			Installment			% of			Consumer		% of			Total		% of
		Mortgage			Total			Equity			Total			and other			Total			Construction		Total					Total
														consumer
	Performing	$	420,025			98.3	%	$	427,682			99.2	%	$	73,835			99.9	%	$	2,219		91.1	%	$	923,761		98.8	%
	Nonperforming		7,278			1.7	%		3,653			0.8	%		40			0.1	%		218		8.9	%		11,189		1.2	%
	Total	$	427,303			100	%	$	431,335			100	%	$	73,875			100	%	$	2,437		100	%	$	934,950		100	%
Investments in Loans Considered to be Impaired and Related Information on Impaired Loans	The following table presents investments in loans considered to be impaired and related information on those impaired loans as of September 30, 2013 and December 31, 2012:
		September 30, 2013									December 31, 2012
	(dollars in thousands)	Recorded			Unpaid			Related						Unpaid			Related
		Investment			Principal			Allowance			Recorded			Principal			Allowance
					Balance						Investment			Balance
	With a related allowance recorded:
	Commercial real estate	$	1,014		$	2,291		$	64		$	6,138		$	6,864		$	1,226
	Commercial and industrial		—			—			—			1,864			2,790			1,002
	Commercial construction		5,929			5,929			3,139			799			896			3
	Consumer real estate		98			98			56			—			—			—
	Other consumer		34			34			19			—			—			—
	Total with a Related Allowance Recorded		7,075			8,352			3,278			8,801			10,550			2,231
	Without a related allowance recorded:
	Commercial real estate		27,309			38,351			—			33,856			45,953			—
	Commercial and industrial		10,128			12,406			—			11,419			12,227			—
	Commercial construction		9,329			17,873			—			17,713			27,486			—
	Consumer real estate		8,256			9,267			—			10,827			12,025			—
	Other consumer		114			119			—			25			25			—
	Total without a Related Allowance Recorded		55,136			78,016			—			73,840			97,716			—
	Total:
	Commercial real estate		28,323			40,642			64			39,994			52,817			1,226
	Commercial and industrial		10,128			12,406			—			13,283			15,017			1,002
	Commercial construction		15,258			23,802			3,139			18,512			28,382			3
	Consumer real estate		8,354			9,365			56			10,827			12,025			—
	Other consumer		148			153			19			25			25			—
	Total	$	62,211		$	86,368		$	3,278		$	82,641		$	108,266		$	2,231
	The following tables summarize investments in loans considered to be impaired and related information on those impaired loans for the periods presented:
		For the Three Months Ended
		September 30, 2013						September 30, 2012
	(dollars in thousands)	Average			Interest			Average			Interest
		Recorded			Income			Recorded			Income
		Investment			Recognized			Investment			Recognized
	With a related allowance recorded:
	Commercial real estate	$	1,014		$	—		$	6,430		$	15
	Commercial and industrial		—			—			784			(9	)
	Commercial construction		5,929			49			4,236			19
	Consumer real estate		100			2			—			—
	Other consumer		35			1			—			—
	Total with a Related Allowance Recorded		7,078			52			11,450			25
	Without a related allowance recorded:
	Commercial real estate		27,489			271			38,962			268
	Commercial and industrial		10,995			68			13,238			101
	Commercial construction		9,768			46			23,349			113
	Consumer real estate		8,349			114			5,729			9
	Other consumer		119			1			—			—
	Total without a Related Allowance Recorded		56,720			500			81,278			491
	Total:
	Commercial real estate		28,503			271			45,392			283
	Commercial and industrial		10,995			68			14,022			92
	Commercial construction		15,697			95			27,585			132
	Consumer real estate		8,449			116			5,729			9
	Other consumer		154			2			—			—
	Total	$	63,798		$	552		$	92,728		$	516
		For the Nine Months Ended
		September 30, 2013						September 30, 2012
	(dollars in thousands)	Average			Interest			Average			Interest
		Recorded			Income			Recorded			Income
		Investment			Recognized			Investment			Recognized
	With a related allowance recorded:
	Commercial real estate	$	2,526		$	5		$	5,629		$	209
	Commercial and industrial		—			—			1,813			—
	Commercial construction		1,976			49			5,661			49
	Consumer real estate		62			—			—			—
	Other consumer		21			3			—			—
Total with a Related Allowance Recorded		4,585			57			13,103			258
Without a related allowance recorded:
Commercial real estate		29,951			330			43,332			915
Commercial and industrial		11,964			203			11,725			265
Commercial construction		14,492			271			22,926			450
Consumer real estate		8,912			693			6,489			70
Other consumer		110			4			—			—
Total without a Related Allowance Recorded		65,429			1,501			84,472			1,700
Total:
Commercial real estate		32,477			335			48,961			1,124
Commercial and industrial		11,964			203			13,538			265
Commercial construction		16,468			320			28,587			499
Consumer real estate		8,974			693			6,489			70
Other consumer		131			7			—			—
Total	$	70,014		$	1,558		$	97,575		$	1,958
Summary of Allowance for Loan Losses	The following tables detail activity in the ALL for the periods presented:
		Three Months Ended September 30, 2013
	(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
		Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
	Balance at beginning of period	$	23,484		$	9,123		$	5,812		$	6,655		$	1,031		$	46,105
	Charge-offs		(840	)		(759	)		(480	)		(585	)		(327	)		(2,991	)
	Recoveries		617			167			481			122			63			1,450
	Net (Charge-offs)/ Recoveries		(223	)		(592	)		1			(463	)		(264	)		(1,541	)
	Provision for loan losses		(5,572	)		6,268			2,186			185			352			3,419
	Balance at End of Period	$	17,689		$	14,799		$	7,999		$	6,377		$	1,119		$	47,983
		Three Months Ended September 30, 2012
	(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
		Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
	Balance at beginning of period	$	24,696		$	11,874		$	5,938		$	3,401		$	780		$	46,689
	Charge-offs		(2,344	)		(520	)		(970	)		(268	)		(278	)		(4,380	)
	Recoveries		570			609			395			18			73			1,665
	Net (Charge-offs)/ Recoveries		(1,774	)		89			(575	)		(250	)		(205	)		(2,715	)
	Provision for loan losses		1,283			(3,216	)		3,162			752			324			2,305
	Balance at End of Period	$	24,205		$	8,747		$	8,525		$	3,903		$	899		$	46,279
		Nine Months Ended September 30, 2013
	(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
		Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
	Balance at beginning of period	$	25,246		$	7,759		$	7,500		$	5,058		$	921		$	46,484
	Charge-offs		(3,649	)		(2,682	)		(923	)		(1,822	)		(978	)		(10,054	)
	Recoveries		2,939			457			536			630			242			4,804
	Net (Charge-offs)/ Recoveries		(710	)		(2,225	)		(387	)		(1,192	)		(736	)		(5,250	)
	Provision for loan losses		(6,847	)		9,265			886			2,511			934			6,749
	Balance at End of Period	$	17,689		$	14,799		$	7,999		$	6,377		$	1,119		$	47,983
		Nine Months Ended September 30, 2012
	(dollars in thousands)	Commercial			Commercial and			Commercial			Consumer			Other			Total
		Real Estate			Industrial			Construction			Real Estate			Consumer			Loans
	Balance at beginning of period	$	29,804		$	11,274		$	3,703		$	3,166		$	894		$	48,841
	Charge-offs		(7,918	)		(4,488	)		(9,261	)		(1,228	)		(756	)		(23,651	)
	Recoveries		748			857			494			127			263			2,489
	Net (Charge-offs)/ Recoveries		(7,170	)		(3,631	)		(8,767	)		(1,101	)		(493	)		(21,162	)
	Provision for loan losses		1,571			1,104			13,589			1,838			498			18,600
	Balance at End of Period	$	24,205		$	8,747		$	8,525		$	3,903		$	899		$	46,279
Summary of Allowance for Loan Losses and Recorded Investments	The following tables present the ALL and recorded investments in loans by category as of September 30, 2013 and December 31, 2012:
		September 30, 2013
		Allowance for Loan Losses									Portfolio Loans
	(dollars in thousands)	Individually			Collectively			Total			Individually			Collectively			Total
		Evaluated for			Evaluated for						Evaluated for			Evaluated for
		Impairment			Impairment						Impairment			Impairment
	Commercial real estate	$	64		$	17,625		$	17,689		$	28,323		$	1,539,491		$	1,567,814
	Commercial and industrial		—			14,799			14,799			10,128			817,571			827,699
	Commercial construction		3,139			4,860			7,999			15,258			136,948			152,206
	Consumer real estate		56			6,321			6,377			8,354			886,219			894,573
	Other consumer		19			1,100			1,119			148			68,895			69,043
	Total	$	3,278		$	44,705		$	47,983		$	62,211		$	3,449,124		$	3,511,335
		December 31, 2012
		Allowance for Loan Losses									Portfolio Loans
	(dollars in thousands)	Individually			Collectively			Total			Individually			Collectively			Total
		Evaluated for			Evaluated for						Evaluated for			Evaluated for
		Impairment			Impairment						Impairment			Impairment
	Commercial real estate	$	1,226		$	24,020		$	25,246		$	39,994		$	1,412,139		$	1,452,133
	Commercial and industrial		1,002			6,757			7,759			13,283			778,113			791,396
	Commercial construction		3			7,497			7,500			18,512			149,631			168,143
	Consumer real estate		—			5,058			5,058			10,827			850,248			861,075
	Other consumer		—			921			921			25			73,850			73,875
	Total	$	2,231		$	44,253		$	46,484		$	82,641		$	3,263,981		$	3,346,622

Derivative_Instruments_and_Hed1

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Value of Derivative Assets and Derivative Liabilities	The following table indicates the amounts representing the value of derivative assets and derivative liabilities as of the dates presented:
		Derivatives						Derivatives
		(included in Other Assets)						(included in Other Liabilities)
	(dollars in thousands)	September 30, 2013			December 31, 2012			September 30, 2013			December 31, 2012
	Derivatives not Designated as Hedging Instruments
	Interest Rate Swap Contracts—Commercial Loans
	Fair value	$	16,084		$	23,748		$	16,025		$	23,522
	Notional amount		257,678			227,532			257,678			227,532
	Collateral posted		—			—			12,978			19,595
	Interest Rate Lock Commitments—Mortgage Loans
	Fair value		206			467			—			—
	Notional amount		4,670			14,287			—			—
	Forward Sale Contracts—Mortgage Loans
	Fair value		—			—			162			48
	Notional amount		—			—			7,425			14,100
Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities	The following table indicates the gross amounts of derivative assets and derivative liabilities, the amounts offset, and the carrying values in the Consolidated Balance Sheets as of the dates presented:
		Derivatives						Derivatives
		(included in Other Assets)						(included in Other Liabilities)
	(dollars in thousands)	September 30, 2013			December 31, 2012			September 30, 2013			December 31, 2012
	Derivatives not Designated as Hedging Instruments
	Gross amounts recognized	$	16,445		$	24,262		$	16,386		$	24,036
	Gross amounts offset		(361	)		(514	)		(361	)		(514	)
	Net amounts presented in the Consolidated Balance Sheets		16,084			23,748			16,025			23,522
	Gross amounts not offset(1)		—			—			(12,978	)		(19,595	)
	Net Amount	$	16,084		$	23,748		$	3,047		$	3,927
	(1) Amounts represent posted collateral.
Amount of Gain or Loss Recognized in Income on Derivatives	The following table indicates the gain or loss recognized in income on derivatives for the periods presented:
		Three Months Ended September 30,						Nine Months Ended September 30,
	(dollars in thousands)	2013			2012			2013			2012
	Derivatives not Designated as Hedging Instruments
	Interest rate swap contracts—commercial loans	$	(10	)	$	(19	)	$	(166	)	$	164
	Interest rate lock commitments—mortgage loans		231			257			(261	)		629
	Forward sale contracts—mortgage loans		(519	)		(101	)		(114	)		(212	)
	Total Derivative (Loss) Gain	$	(298	)	$	137		$	(541	)	$	581

Borrowings_Tables

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]
Summary of Information Pertaining to Borrowings	Information pertaining to borrowings is summarized in the table below as of the dates presented:
		September 30, 2013					December 31, 2012
	(dollars in thousands)	Balance		Weighted			Balance		Weighted
				Average Rate					Average Rate
	Short-term borrowings
	Securities sold under repurchase agreements	$	33,290		0.01	%	$	62,582		0.2	%
	Short-term borrowings		175,000		0.28	%		75,000		0.19	%
	Total short-term borrowings		208,290		0.24	%		137,582		0.19	%
	Long-term borrowings
	Junior subordinated debt securities		45,619		2.71	%		90,619		3.01	%
	Other long-term borrowings		22,390		3.01	%		34,101		3.17	%
	Total long-term borrowings		68,009		2.81	%		124,720		3.05	%
	Total Borrowings	$	276,299		0.87	%	$	262,302		1.55	%

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]
Commitments and Letters of Credit	The following table sets forth the commitments and letters of credit as of the dates presented:
	(dollars in thousands)	September 30, 2013		December 31, 2012
	Commitments to extend credit	$	1,042,572	$	874,137
	Standby letters of credit		80,653		95,399
	Total	$	1,123,225	$	969,536

Other_Comprehensive_Income_Tab

Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]
Other Comprehensive Income	The following tables show the tax effects of the components of other comprehensive income for the periods presented:
		Three Months Ended September 30, 2013									Three Months Ended September 30, 2012
	(dollars in thousands)	Pre-Tax			Tax			Net of Tax			Pre-Tax			Tax			Net of Tax
		Amount			(Expense)			Amount			Amount			(Expense)			Amount
					Benefit									Benefit
	Change in unrealized gains/losses on securities available-for-sale	$	335		$	(117	)	$	218		$	4,373		$	(1,530	)	$	2,843
	Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income(1)		(3	)		1			(2	)		(2,170	)		760			(1,410	)
	Adjustment to funded status of employee benefit plans		631			(220	)		411			750			(264	)		486
	Other Comprehensive Income (Loss)	$	963		$	(336	)	$	627		$	2,953		$	(1,034	)	$	1,919
	(1) Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.
		Nine Months Ended September 30, 2013									Nine Months Ended September 30, 2012
	(dollars in thousands)	Pre-Tax			Tax			Net of Tax			Pre-Tax			Tax			Net of Tax
		Amount			(Expense)			Amount			Amount			(Expense)			Amount
					Benefit									Benefit
	Change in unrealized gains/losses on securities available-for-sale	$	(13,494	)	$	4,723		$	(8,771	)	$	5,188		$	(1,815	)	$	3,373
	Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income(1)		(5	)		2			(3	)		(3,016	)		1,056			(1,960	)
	Adjustment to funded status of employee benefit plans		1,827			(639	)		1,188			1,887			(662	)		1,225
	Other Comprehensive Income (Loss)	$	(11,672	)	$	4,086		$	(7,586	)	$	4,059		$	(1,421	)	$	2,638
	(1) Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.

Employee_Benefits_Tables

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2013
Compensation And Retirement Disclosure [Abstract]
Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit	The following table summarizes the components of net periodic pension cost and other changes in plan assets and benefit obligation recognized in other comprehensive gain/loss for the periods presented:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
	(dollars in thousands)	2013			2012			2013			2012
	Components of Net Periodic Pension Cost
	Service cost—benefits earned during the period	$	659		$	636		$	2,075		$	2,090
	Interest cost on projected benefit obligation		997			1,117			2,989			3,269
	Expected return on plan assets		(1,526	)		(1,364	)		(4,656	)		(4,172	)
	Amortization of prior service cost (credit)		(34	)		(34	)		(102	)		(99	)
	Recognized net actuarial loss		642			711			1,818			1,852
	Net Periodic Pension Expense	$	738		$	1,066		$	2,124		$	2,940

Segments_Tables

Segments (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Total Assets by Reportable Operating Segment	The following table represents total assets by reportable operating segment as of the dates presented:
	(dollars in thousands)	September 30, 2013		December 31, 2012
	Community Banking	$	4,579,528	$	4,518,799
	Insurance		7,358		6,697
	Wealth Management		1,242		1,206
	Total Assets	$	4,588,128	$	4,526,702
Financial Information of Segments	The information provided under the caption “Eliminations” represents operations not considered to be reportable segments and/or general operating expenses and eliminations and adjustments, which are necessary for purposes of reconciling to the Consolidated Financial Statements.
		Three Months Ended September 30, 2013
	(dollars in thousands)	Community		Insurance		Wealth		Eliminations			Consolidated
		Banking				Management
	Interest income	$	38,540	$	—	$	137	$	(96	)	$	38,581
	Interest expense		3,949		—		—		(642	)		3,307
	Net interest income (expense)		34,591		—		137		546			35,274
	Provision for loan losses		3,419		—		—		—			3,419
	Noninterest income		8,321		1,459		2,744		18			12,542
	Noninterest expense		22,252		1,357		2,379		741			26,729
	Depreciation expense		816		12		7		—			835
	Amortization of intangible assets		355		13		11		—			379
	Provision (benefit) for income taxes		4,179		27		178		(177	)		4,207
	Net Income	$	11,891	$	50	$	306	$	—		$	12,247
		Three Months Ended September 30, 2012
	(dollars in thousands)	Community		Insurance		Wealth		Eliminations			Consolidated
		Banking				Management
	Interest income	$	38,715	$	—	$	119	$	(14	)	$	38,820
	Interest expense		5,340		—		—		(315	)		5,025
	Net interest income (expense)		33,375		—		119		301			33,795
	Provision for loan losses		2,305		—		—		—			2,305
	Noninterest income		10,731		1,481		2,394		140			14,746
	Noninterest expense		24,586		1,398		2,401		1,228			29,613
	Depreciation expense		968		12		8		—			988
	Amortization of intangible assets		391		13		13		—			417
	Provision (benefit) for income taxes		3,333		21		56		(787	)		2,623
	Net Income	$	12,523	$	37	$	35	$	—		$	12,595
		Nine Months Ended September 30, 2013
	(dollars in thousands)	Community		Insurance		Wealth		Eliminations			Consolidated
		Banking				Management
	Interest income	$	114,733	$	1	$	411	$	(168	)	$	114,977
	Interest expense		13,403		—		—		(1,965	)		11,438
	Net interest income (expense)		101,330		1		411		1,797			103,539
	Provision for loan losses		6,749		—		—		—			6,749
	Noninterest income		27,144		4,406		8,130		535			40,215
	Noninterest expense		68,680		3,910		7,257		4,208			84,055
	Depreciation expense		2,609		35		23		—			2,667
	Amortization of intangible assets		1,148		38		37		—			1,223
	Provision (benefit) for income taxes		11,617		148		491		(1,876	)		10,380
	Net Income	$	37,671	$	276	$	733	$	—		$	38,680
		Nine Months Ended September 30, 2012
	(dollars in thousands)	Community		Insurance		Wealth		Eliminations			Consolidated
		Banking				Management
	Interest income	$	116,968	$	1	$	325	$	36		$	117,330
	Interest expense		17,244		—		—		(849	)		16,395
	Net interest income (expense)		99,724		1		325		885			100,935
	Provision for loan losses		18,600		—		—		—			18,600
	Noninterest income		28,230		4,196		7,375		546			40,347
	Noninterest expense		73,850		4,119		7,037		3,917			88,923
	Depreciation expense		2,887		37		23		—			2,947
	Amortization of intangible assets		1,193		39		44		—			1,276
	Provision (benefit) for income taxes		7,057		1		289		(2,486	)		4,861
	Net Income	$	24,367	$	1	$	307	$	—		$	24,675

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail)	Sep. 30, 2013
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of outstanding common stock of investees accounted for using equity method of accounting	20.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of outstanding common stock of investees accounted for using equity method of accounting	50.00%

Earnings_Per_Share_Reconciles_

Earnings Per Share - Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator for Earnings per Share-Basic:
Net income	$12,247	$12,595	$38,680	$24,675
Less: Income allocated to participating shares	33	50	114	107
Net Income Allocated to Shareholders	12,214	12,545	38,566	24,568
Numerator for Earnings per Share-Diluted:
Net income	12,247	12,595	38,680	24,675
Net Income Available to Shareholders	$12,247	$12,595	$38,680	$24,675
Denominators:
Weighted Average Shares Outstanding-Basic	29,658,065	29,244,588	29,644,646	28,740,582
Add: Dilutive potential shares	27,535	32,644	35,132	33,614
Denominator for Treasury Stock Method-Diluted	29,685,600	29,277,232	29,679,778	28,774,196
Weighted Average Shares Outstanding-Basic	29,658,065	29,244,588	29,644,646	28,740,582
Add: Average participating shares outstanding	80,240	116,402	87,725	125,240
Denominator for Two-Class Method-Diluted	29,738,305	29,360,990	29,732,371	28,865,822
Earnings per share-basic	$0.41	$0.43	$1.30	$0.85
Earnings per share-diluted	$0.41	$0.43	$1.30	$0.85
Warrants [Member]
Denominators:
Anti-dilutive excluded from dilutive potential shares	517,012	517,012	517,012	517,012
Stock Options [Member]
Denominators:
Anti-dilutive excluded from dilutive potential shares	612,768	748,964	632,481	751,492
Restricted Stock [Member]
Denominators:
Anti-dilutive excluded from dilutive potential shares	52,705	48,717	52,593	56,585

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012
	Loans		Loans	Loans	Level 3 [Member]	Level 3 [Member]
Loans Receivable [Line Items]
Fair value of asset transfer from Level 1 to Level 2 on recurring basis	$0		$0
Fair value of asset transfer from Level 2 to Level 1 on recurring basis	0		0
Fair value of liabilities transfer from Level 1 to Level 2 on recurring basis	0		0
Fair value of liabilities transfer from Level 2 to Level 1 recurring basis	0		0
Transfers out of Level 3		300,000	-344,000
Liabilities measured at fair value on a recurring basis					0	0
Number of loans, held for sale	0		0	0
Liabilities measured at estimated fair value on nonrecurring basis	$0		$0	$0

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

In Thousands, unless otherwise specified

Obligations of U.S. Government Corporations and Agencies [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Obligations of States and Political Subdivisions [Member]

Obligations of States and Political Subdivisions [Member]

Marketable Equity Securities [Member]

Marketable Equity Securities [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Level 1 [Member]

Level 1 [Member]

Level 1 [Member]

Level 1 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 2 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Level 3 [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Obligations of States and Political Subdivisions [Member]

Obligations of States and Political Subdivisions [Member]

Marketable Equity Securities [Member]

Marketable Equity Securities [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Lock Commitments [Member]

Interest Rate Lock Commitments [Member]

Forward Sale Contracts [Member]

Forward Sale Contracts [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Fair Value Measurements, Recurring [Member]

Marketable Equity Securities [Member]

Marketable Equity Securities [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Obligations of States and Political Subdivisions [Member]

Obligations of States and Political Subdivisions [Member]

Marketable Equity Securities [Member]

Marketable Equity Securities [Member]

Interest Rate Swaps [Member]

Interest Rate Swaps [Member]

Interest Rate Lock Commitments [Member]

Interest Rate Lock Commitments [Member]

Forward Sale Contracts [Member]

Forward Sale Contracts [Member]

Obligations of U.S. Government Corporations and Agencies [Member]

Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]

Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]

Obligations of States and Political Subdivisions [Member]

Marketable Equity Securities [Member]

Marketable Equity Securities [Member]

Interest Rate Swaps [Member]

Interest Rate Lock Commitments [Member]

Forward Sale Contracts [Member]

ASSETS

Total securities available-for-sale

$488,162

$452,266

$237,398

$212,066

$44,877

$57,896

$51,250

$50,623

$30,680

$10,158

$114,817

$112,767

$9,140

$8,756

$488,162

$452,266

$237,398

$212,066

$44,877

$57,896

$51,250

$50,623

$30,680

$10,158

$114,817

$112,767

$9,140

$8,756

$183

$140

$183

$140

$487,979

$451,826

$237,398

$212,066

$44,877

$57,896

$51,250

$50,623

$30,680

$10,158

$114,817

$112,767

$8,957

$8,316

$300

$300

Trading securities held in a Rabbi Trust

2,545

2,223

2,545

2,223

Total securities

490,707

454,489

2,728

2,363

487,979

451,826

300

Derivative financial assets

16,084

23,748

206

467

16,084

23,748

206

467

Total Assets

506,997

478,704

2,728

2,363

504,269

476,041

300

LIABILITIES

Derivative financial liabilities

16,025

23,522

162

48

16,025

23,522

162

48

Total Liabilities

$16,187

$23,570

$16,187

$23,570

$0

$0

Fair_Value_Measurements_Change

Fair Value Measurements - Changes in Assets Classified as Level 3 in Fair Value Hierarchy (Detail) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Disclosures [Abstract]
Balance at beginning of period			$556	$300	$462
Total gains included in other comprehensive income			19	44	50
Net purchases, sales, issuances and settlements			-300		-237
Transfers out of Level 3		300		-344
Balance at end of period			$275		$275

Fair_Value_Measurements_Assets1

Fair Value Measurements - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Detail) (Fair Value, Measurements, Nonrecurring [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS
Impaired loans	$23,482	$44,059
Other real estate owned	221	585
Mortgage servicing rights	2,960	2,106
Total Assets	26,663	46,750
Level 1 [Member]
ASSETS
Impaired loans
Other real estate owned
Mortgage servicing rights
Total Assets
Level 2 [Member]
ASSETS
Impaired loans
Other real estate owned
Mortgage servicing rights
Total Assets
Level 3 [Member]
ASSETS
Impaired loans	23,482	44,059
Other real estate owned	221	585
Mortgage servicing rights	2,960	2,106
Total Assets	$26,663	$46,750

Fair_Value_Measurements_Carryi

Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS
Securities available-for-sale	$488,162	$452,266
FHLB and other restricted stock	15,049	15,315
LIABILITIES
Junior subordinated debt securities	45,619	90,619
Carrying Value [Member]
ASSETS
Cash and due from banks, including interest-bearing deposits	234,928	337,711
Securities available-for-sale	488,162	452,266
Loans held for sale	3,695	22,499
Portfolio loans, net of unearned income	3,511,335	3,346,622
Bank owned life insurance	60,001	58,619
FHLB and other restricted stock	15,049	15,315
Trading securities held in a Rabbi Trust	2,545	2,223
Mortgage servicing rights	2,820	2,106
LIABILITIES
Deposits	3,694,203	3,638,428
Securities sold under repurchase agreements	33,290	62,582
Short-term borrowings	175,000	75,000
Long-term borrowings	22,390	34,101
Junior subordinated debt securities	45,619	90,619
Carrying Value [Member] | Interest Rate Swaps [Member]
ASSETS
Derivative financial assets	16,084	23,748
LIABILITIES
Derivative financial liabilities	16,025	23,522
Carrying Value [Member] | Interest Rate Lock Commitments [Member]
ASSETS
Derivative financial assets	206	467
Carrying Value [Member] | Forward Sale Contracts [Member]
LIABILITIES
Derivative financial liabilities	162	48
Fair Value Measurements [Member]
ASSETS
Cash and due from banks, including interest-bearing deposits	234,928	337,711
Securities available-for-sale	488,162	452,266
Loans held for sale	3,829	22,601
Portfolio loans, net of unearned income	3,479,150	3,347,602
Bank owned life insurance	60,001	58,619
FHLB and other restricted stock	15,049	15,315
Trading securities held in a Rabbi Trust	2,545	2,223
Mortgage servicing rights	2,960	2,106
LIABILITIES
Deposits	3,696,214	3,643,683
Securities sold under repurchase agreements	33,290	62,582
Short-term borrowings	175,000	75,000
Long-term borrowings	23,718	36,235
Junior subordinated debt securities	45,619	90,619
Fair Value Measurements [Member] | Level 1 [Member]
ASSETS
Cash and due from banks, including interest-bearing deposits	234,928	337,711
Securities available-for-sale	183	140
Trading securities held in a Rabbi Trust	2,545	2,223
Mortgage servicing rights
Fair Value Measurements [Member] | Level 2 [Member]
ASSETS
Securities available-for-sale	487,979	451,826
Bank owned life insurance	60,001	58,619
Mortgage servicing rights
Fair Value Measurements [Member] | Level 3 [Member]
ASSETS
Securities available-for-sale		300
Loans held for sale	3,829	22,601
Portfolio loans, net of unearned income	3,479,150	3,347,602
FHLB and other restricted stock	15,049	15,315
Mortgage servicing rights	2,960	2,106
LIABILITIES
Deposits	3,696,214	3,643,683
Securities sold under repurchase agreements	33,290	62,582
Short-term borrowings	175,000	75,000
Long-term borrowings	23,718	36,235
Junior subordinated debt securities	45,619	90,619
Fair Value Measurements [Member] | Interest Rate Swaps [Member]
ASSETS
Derivative financial assets	16,084	23,748
LIABILITIES
Derivative financial liabilities	16,025	23,522
Fair Value Measurements [Member] | Interest Rate Swaps [Member] | Level 2 [Member]
ASSETS
Derivative financial assets	16,084	23,748
LIABILITIES
Derivative financial liabilities	16,025	23,522
Fair Value Measurements [Member] | Interest Rate Lock Commitments [Member]
ASSETS
Derivative financial assets	206	467
Fair Value Measurements [Member] | Interest Rate Lock Commitments [Member] | Level 2 [Member]
ASSETS
Derivative financial assets	206	467
Fair Value Measurements [Member] | Forward Sale Contracts [Member]
LIABILITIES
Derivative financial liabilities	162	48
Fair Value Measurements [Member] | Forward Sale Contracts [Member] | Level 2 [Member]
LIABILITIES
Derivative financial liabilities	$162	$48

Securities_AvailableforSale_Co

Securities Available-for-Sale - Composition of Securities Available-for-Sale (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$485,700	$436,305
Gross Unrealized Gains	8,245	16,077
Gross Unrealized Losses	-5,783	-116
Fair Value	488,162	452,266
Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	236,739	207,229
Gross Unrealized Gains	2,614	4,890
Gross Unrealized Losses	-1,955	-53
Fair Value	237,398	212,066
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	44,474	56,085
Gross Unrealized Gains	607	1,811
Gross Unrealized Losses	-204
Fair Value	44,877	57,896
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50,021	47,279
Gross Unrealized Gains	1,759	3,344
Gross Unrealized Losses	-530
Fair Value	51,250	50,623
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	31,524	10,129
Gross Unrealized Gains		29
Gross Unrealized Losses	-844
Fair Value	30,680	10,158
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	115,362	107,911
Gross Unrealized Gains	1,705	4,908
Gross Unrealized Losses	-2,250	-52
Fair Value	114,817	112,767
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	478,120	428,633
Gross Unrealized Gains	6,685	14,982
Gross Unrealized Losses	-5,783	-105
Fair Value	479,022	443,510
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,580	7,672
Gross Unrealized Gains	1,560	1,095
Gross Unrealized Losses		-11
Fair Value	$9,140	$8,756

Securities_AvailableforSale_Sc

Securities Available-for-Sale - Schedule of Gross and Net Realized Gains and Losses on Sale of Securities (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments Debt And Equity Securities [Abstract]
Gross realized gains	$3	$2,170	$5	$3,027
Gross realized losses				11
Net Realized Gains	$3	$2,170	$5	$3,016

Securities_AvailableforSale_Fa

Securities Available-for-Sale - Fair Value and Age of Gross Unrealized Losses by Investment Category (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	$244,528	$22,883
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-5,783	-116
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	244,528	22,883
Available-for-sale Securities, Unrealized Losses, Total	-5,783	-116
Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	115,358	11,370
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-1,955	-53
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	115,358	11,370
Available-for-sale Securities, Unrealized Losses, Total	-1,955	-53
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	19,414
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-204
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	19,414
Available-for-sale Securities, Unrealized Losses, Total	-204
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	23,386
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-530
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	23,386
Available-for-sale Securities, Unrealized Losses, Total	-530
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	30,680
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-844
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	30,680
Available-for-sale Securities, Unrealized Losses, Total	-844
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	55,690	11,285
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-2,250	-52
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	55,690	11,285
Available-for-sale Securities, Unrealized Losses, Total	-2,250	-52
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value	244,528	22,655
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	-5,783	-105
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total	244,528	22,655
Available-for-sale Securities, Unrealized Losses, Total	-5,783	-105
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Less Than 12 Months, Fair Value		228
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses		-11
Available-for-sale Securities, 12 Months or More, Fair Value
Available-for-sale Securities, 12 Months or More, Unrealized Losses
Available-for-sale Securities, Fair Value, Total		228
Available-for-sale Securities, Unrealized Losses, Total	$0	($11)

Securities_AvailableforSale_Ad

Securities Available-for-Sale - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
	Securities
Schedule of Available-for-sale Securities [Line Items]
Number of debt securities on which unrealized losses were primarily attributable to changes in interest	37
Total temporarily impaired securities	$5,783,000	$116,000
Net unrealized gains included in accumulated other comprehensive loss, net of tax	1,600,000	10,400,000
Gross unrealized gains, net of taxes	5,400,000	10,500,000
Gross unrealized losses, net of taxes	3,800,000	100,000
Unrealized losses reclassified out of accumulated other comprehensive income into earnings	0
Carrying values of securities	314,300,000	307,500,000
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total temporarily impaired securities	$0	$11,000

Securities_AvailableforSale_Am

Securities Available-for-Sale - Amortized Cost and Fair Value of Available-for-Sale Securities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$485,700	$436,305
Fair Value	488,162	452,266
Obligations of U.S. Government Corporations and Agencies, and Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	34,297
Due after one year through five years, Amortized Cost	154,121
Due after five years through ten years, Amortized Cost	77,405
Due after ten years, Amortized Cost	86,278
Available-for-sale Securities, Debt Maturities, Amortized Cost	352,101
Due in one year or less, Fair Value	34,537
Due after one year through five years, Fair Value	156,195
Due after five years through ten years, Fair Value	76,221
Due after ten years, Fair Value	85,262
Fair Value, Debt securities	352,215
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	44,474	56,085
Fair Value	44,877	57,896
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50,021	47,279
Fair Value	51,250	50,623
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	31,524	10,129
Fair Value	30,680	10,158
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	478,120	428,633
Fair Value	479,022	443,510
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,580	7,672
Fair Value	$9,140	$8,756

Loans_and_Loans_Held_for_Sale_1

Loans and Loans Held for Sale - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
	SecurityLoan	TDRs	Property	TDRs
	TDRs		TDRs
			SecurityLoan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income on loans	$1		$1		$0.20
Percentage of commercial loans in total portfolio loans	73.00%		73.00%		72.00%
Maximum concentration of commercial real estate and commercial construction portfolio in loans	9.00%		9.00%		9.00%
Financial receivable trouble debt restructuring reclassified to accruing trouble debt restructuring status	1.7		1.9
Number of TDRs returned back to accruing status	3	0	4	0
Number of loan modified	3		8
Commitment to lend additional funds on TDRs	0		0
Minimum period of loan payment defaults following restructure for TDRs to be in default			90 days
Other real estate owned properties			8
Commercial Real Estate and Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Combined percentage of commercial real estate and commercial construction in total commercial loans	68.00%		68.00%		67.00%
Combined percentage of commercial real estate and commercial construction in total portfolio loans	49.00%		49.00%		48.00%
Out-of-state exposure of combined portfolio	22.00%		22.00%		19.00%
Percentage of total loans out-of-state	11.00%		11.00%		9.00%
Out-of-state exposure of combined portfolio excluding contiguous states	8.20%		8.20%		8.40%
Percentage of total loans out-of-state excluding contiguous states	4.00%		4.00%		4.10%
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan modified	2		5
Loans modified not considered to be troubled debt restructuring	0.8		6.1
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan modified	1		1
Loans modified not considered to be troubled debt restructuring	0.9		0.9
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan modified			2
Loans modified not considered to be troubled debt restructuring			$0.60

Loans_and_Loans_Held_for_Sale_2

Loans and Loans Held for Sale - Composition of Loans (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Composition of the loans
Commercial Loans	$2,547,719	$2,411,672
Consumer Loans	963,616	934,950
Total Portfolio Loans	3,511,335	3,346,622
Loans held for sale	3,695	22,499
Total Loans	3,515,030	3,369,121
Commercial Real Estate [Member]
Composition of the loans
Commercial Loans	1,567,814	1,452,133
Total Portfolio Loans	1,567,814	1,452,133
Commercial and Industrial [Member]
Composition of the loans
Commercial Loans	827,699	791,396
Total Portfolio Loans	827,699	791,396
Commercial Construction [Member]
Composition of the loans
Commercial Loans	152,206	168,143
Total Portfolio Loans	152,206	168,143
Residential Mortgage [Member]
Composition of the loans
Consumer Loans	477,141	427,303
Total Portfolio Loans	477,141	427,303
Home Equity [Member]
Composition of the loans
Consumer Loans	413,097	431,335
Total Portfolio Loans	413,097	431,335
Installment and Other Consumer [Member]
Composition of the loans
Consumer Loans	69,043	73,875
Total Portfolio Loans	69,043	73,875
Consumer Construction [Member]
Composition of the loans
Consumer Loans	4,335	2,437
Total Portfolio Loans	$4,335	$2,437

Loans_and_Loans_Held_for_Sale_3

Loans and Loans Held for Sale - Restructured Loans for Periods Presented (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Accruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Nonaccruing TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Total TDRs [Member]

Commercial Real Estate [Member]

Commercial Real Estate [Member]

Commercial and Industrial [Member]

Commercial and Industrial [Member]

Commercial Construction [Member]

Commercial Construction [Member]

Residential Mortgage [Member]

Residential Mortgage [Member]

Home Equity [Member]

Home Equity [Member]

Installment and Other Consumer [Member]

Installment and Other Consumer [Member]

Commercial Real Estate [Member]

Commercial Real Estate [Member]

Commercial and Industrial [Member]

Commercial and Industrial [Member]

Commercial Construction [Member]

Commercial Construction [Member]

Residential Mortgage [Member]

Residential Mortgage [Member]

Home Equity [Member]

Home Equity [Member]

Commercial Real Estate [Member]

Commercial Real Estate [Member]

Commercial and Industrial [Member]

Commercial and Industrial [Member]

Commercial Construction [Member]

Commercial Construction [Member]

Residential Mortgage [Member]

Residential Mortgage [Member]

Home Equity [Member]

Home Equity [Member]

Installment and Other Consumer [Member]

Installment and Other Consumer [Member]

Financing Receivable, Modifications [Line Items]

Restructured loans

$1,758

$2,324

$10,036

$5,936

$35,624

$41,521

$15,619

$14,220

$7,595

$8,270

$5,574

$11,734

$2,689

$3,078

$3,999

$4,195

$148

$24

$20,394

$18,940

$7,150

$9,584

$1,926

$939

$9,652

$5,324

$1,054

$2,752

$612

$341

$56,018

$60,461

$22,769

$23,804

$9,521

$9,209

$15,226

$17,058

$3,743

$5,830

$4,611

$4,536

$148

$24

Loans_and_Loans_Held_for_Sale_4

Loans and Loans Held for Sale - Restructured Loans for Periods Stated (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	Loans	Loans	Loans	Loans
Financing Receivable, Modifications [Line Items]
Number of Loans	15	9	69	14
Pre-Modification Outstanding Recorded Investment	$1,785	$2,972	$10,470	$6,758
Post-Modification Outstanding Recorded Investment	1,758	2,324	10,036	5,936
Total Difference in Recorded Investment	-27	-648	-434	-822
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1		8
Pre-Modification Outstanding Recorded Investment	278		2,538
Post-Modification Outstanding Recorded Investment	278		2,151
Total Difference in Recorded Investment			-387
Interest Rate Reduction and Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2		2
Pre-Modification Outstanding Recorded Investment	664		664
Post-Modification Outstanding Recorded Investment	644		644
Total Difference in Recorded Investment	-20		-20
Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1
Pre-Modification Outstanding Recorded Investment			4,339
Post-Modification Outstanding Recorded Investment			4,339
Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	11		56
Pre-Modification Outstanding Recorded Investment	789		2,124
Post-Modification Outstanding Recorded Investment	782		2,097
Total Difference in Recorded Investment	-7		-27
Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans		8	1	11
Pre-Modification Outstanding Recorded Investment		2,940	751	6,116
Post-Modification Outstanding Recorded Investment		2,292	751	5,304
Total Difference in Recorded Investment		-648		-812
Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	1	1	3
Pre-Modification Outstanding Recorded Investment	54	32	54	642
Post-Modification Outstanding Recorded Investment	54	32	54	632
Total Difference in Recorded Investment				-10
Commercial Real Estate [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			3
Pre-Modification Outstanding Recorded Investment			1,541
Post-Modification Outstanding Recorded Investment			1,288
Total Difference in Recorded Investment			-253
Commercial Real Estate [Member] | Interest Rate Reduction and Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2		2
Pre-Modification Outstanding Recorded Investment	664		664
Post-Modification Outstanding Recorded Investment	644		644
Total Difference in Recorded Investment	-20		-20
Commercial Real Estate [Member] | Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1
Pre-Modification Outstanding Recorded Investment			4,339
Post-Modification Outstanding Recorded Investment			4,339
Commercial Real Estate [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			7
Pre-Modification Outstanding Recorded Investment			258
Post-Modification Outstanding Recorded Investment			255
Total Difference in Recorded Investment			-3
Commercial Real Estate [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans				1
Pre-Modification Outstanding Recorded Investment				160
Post-Modification Outstanding Recorded Investment				157
Total Difference in Recorded Investment				-3
Commercial Real Estate [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans				1
Pre-Modification Outstanding Recorded Investment				575
Post-Modification Outstanding Recorded Investment				565
Total Difference in Recorded Investment				-10
Commercial and Industrial [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1		2
Pre-Modification Outstanding Recorded Investment	278		670
Post-Modification Outstanding Recorded Investment	278		665
Total Difference in Recorded Investment			-5
Commercial and Industrial [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1
Pre-Modification Outstanding Recorded Investment			3
Post-Modification Outstanding Recorded Investment			3
Commercial and Industrial [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1	2
Pre-Modification Outstanding Recorded Investment			751	2,576
Post-Modification Outstanding Recorded Investment			751	2,430
Total Difference in Recorded Investment				-146
Residential Mortgage [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			2
Pre-Modification Outstanding Recorded Investment			153
Post-Modification Outstanding Recorded Investment			153
Residential Mortgage [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			8
Pre-Modification Outstanding Recorded Investment			353
Post-Modification Outstanding Recorded Investment			344
Total Difference in Recorded Investment			-9
Residential Mortgage [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans		1		1
Pre-Modification Outstanding Recorded Investment		35		475
Post-Modification Outstanding Recorded Investment		35		460
Total Difference in Recorded Investment				-15
Residential Mortgage [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	1	1	2
Pre-Modification Outstanding Recorded Investment	54	32	54	67
Post-Modification Outstanding Recorded Investment	54	32	54	67
Home Equity [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1
Pre-Modification Outstanding Recorded Investment			174
Post-Modification Outstanding Recorded Investment			45
Total Difference in Recorded Investment			-129
Home Equity [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	8		31
Pre-Modification Outstanding Recorded Investment	772		1,420
Post-Modification Outstanding Recorded Investment	767		1,407
Total Difference in Recorded Investment	-5		-13
Installment and Other Consumer [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3		9
Pre-Modification Outstanding Recorded Investment	17		90
Post-Modification Outstanding Recorded Investment	15		88
Total Difference in Recorded Investment	-2		-2
Commercial Construction [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans		7		7
Pre-Modification Outstanding Recorded Investment		2,905		2,905
Post-Modification Outstanding Recorded Investment		2,257		2,257
Total Difference in Recorded Investment		($648)		($648)

Loans_and_Loans_Held_for_Sale_5

Loans and Loans Held for Sale - Restructured Loans for Periods Stated (Parenthetical) (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Receivables [Abstract]
Debt forgiveness to customers	$0.10

Loans_and_Loans_Held_for_Sale_6

Loans and Loans Held for Sale - Summary of Nonperforming Assets of Defaulted TDRs (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	Contract	Contract	Contract	Contract
Financing Receivable, Modifications [Line Items]
Number of Defaults	7	1	14	8
Recorded Investment	$1,002	$270	$1,217	$5,347
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	1	1	1	2
Recorded Investment	75	270	75	329
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	1		1
Recorded Investment	435		435
Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults				3
Recorded Investment				2,659
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	4		7	3
Recorded Investment	450		514	2,359
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults	1		5
Recorded Investment	$42		$193

Loans_and_Loans_Held_for_Sale_7

Loans and Loans Held for Sale - Summary of Nonperforming Assets (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Nonperforming Assets
Nonaccrual loans	$36,399	$54,958
Nonaccrual TDRs	20,394	18,940
Total nonaccrual loans	36,399	54,958
OREO	460	911
Total Nonperforming Assets	$36,859	$55,869

Allowance_for_Loan_Losses_Age_

Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	$3,462,760	$3,266,474
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	9,393	21,632
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	2,783	3,558
Total nonaccrual loans	36,399	54,958
Financing Receivable, Recorded Investment, Past Due, Total	48,575	80,148
Total Portfolio Loans	3,511,335	3,346,622
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	1,549,998	1,418,934
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	1,095	2,230
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	242	413
Total nonaccrual loans	16,479	30,556
Financing Receivable, Recorded Investment, Past Due, Total	17,816	33,199
Total Portfolio Loans	1,567,814	1,452,133
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	820,425	780,315
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	3,100	4,409
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	277	237
Total nonaccrual loans	3,897	6,435
Financing Receivable, Recorded Investment, Past Due, Total	7,274	11,081
Total Portfolio Loans	827,699	791,396
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	140,551	150,823
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	1,971	10,542
Total nonaccrual loans	9,684	6,778
Financing Receivable, Recorded Investment, Past Due, Total	11,655	17,320
Total Portfolio Loans	152,206	168,143
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	471,639	416,364
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	715	1,713
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	1,766	1,948
Total nonaccrual loans	3,021	7,278
Financing Receivable, Recorded Investment, Past Due, Total	5,502	10,939
Total Portfolio Loans	477,141	427,303
Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	407,072	424,485
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	2,291	2,332
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	443	865
Total nonaccrual loans	3,291	3,653
Financing Receivable, Recorded Investment, Past Due, Total	6,025	6,850
Total Portfolio Loans	413,097	431,335
Installment and Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	68,740	73,334
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	221	406
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	55	95
Total nonaccrual loans	27	40
Financing Receivable, Recorded Investment, Past Due, Total	303	541
Total Portfolio Loans	69,043	73,875
Consumer Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Current	4,335	2,219
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due
Total nonaccrual loans		218
Financing Receivable, Recorded Investment, Past Due, Total		218
Total Portfolio Loans	$4,335	$2,437

Allowance_for_Loan_Losses_Reco

Allowance for Loan Losses - Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	$2,547,719	$2,411,672
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	2,349,306	2,102,721
Total percentage of recorded investment in commercial loan	92.20%	87.20%
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	102,842	168,920
Total percentage of recorded investment in commercial loan	4.00%	7.00%
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	95,571	140,031
Total percentage of recorded investment in commercial loan	3.80%	5.80%
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	1,567,814	1,452,133
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	1,458,589	1,265,810
Total percentage of recorded investment in commercial loan	93.00%	87.20%
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	51,849	96,156
Total percentage of recorded investment in commercial loan	3.30%	6.60%
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	57,376	90,167
Total percentage of recorded investment in commercial loan	3.70%	6.20%
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	827,699	791,396
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	771,597	718,070
Total percentage of recorded investment in commercial loan	93.20%	90.70%
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	34,238	42,016
Total percentage of recorded investment in commercial loan	4.10%	5.30%
Commercial and Industrial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	21,864	31,310
Total percentage of recorded investment in commercial loan	2.70%	4.00%
Commercial Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	152,206	168,143
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Commercial Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	119,120	118,841
Total percentage of recorded investment in commercial loan	78.30%	70.70%
Commercial Construction [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	16,755	30,748
Total percentage of recorded investment in commercial loan	11.00%	18.30%
Commercial Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total recorded investment in commercial loan	$16,331	$18,554
Total percentage of recorded investment in commercial loan	10.70%	11.00%

Allowance_for_Loan_Losses_Addi

Allowance for Loan Losses - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Evaluation for impairment of substandard and nonaccrual commercial loans	$500,000
Commercial real estate impaired loans fair value	41,600,000
Total amount of all impaired loans	62,211,000	82,641,000
Commercial real estate impaired loans current appraisals	28,300,000
Commercial real estate impaired loans needing current appraisals	300,000
Minimum [Member]
Financing Receivable, Impaired [Line Items]
Loans considered nonperforming (in days)	90 days
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Commercial real estate impaired loans fair value	28,300,000
Percentage of total impaired loans comprised	46.00%
Total amount of all impaired loans	28,323,000	39,994,000
Charge offs on loans	$13,500,000

Allowance_for_Loan_Losses_Reco1

Allowance for Loan Losses - Recorded Investment in Consumer Loan Classes by Performing and Nonperforming Status (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	$963,616	$934,950
% of Total	100.00%	100.00%
Accruing/Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	957,277	923,761
% of Total	99.30%	98.80%
Nonaccruing/Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	6,339	11,189
% of Total	0.70%	1.20%
Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	477,141	427,303
% of Total	100.00%	100.00%
Residential Mortgage [Member] | Accruing/Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	474,120	420,025
% of Total	99.40%	98.30%
Residential Mortgage [Member] | Nonaccruing/Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	3,021	7,278
% of Total	0.60%	1.70%
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	413,097	431,335
% of Total	100.00%	100.00%
Home Equity [Member] | Accruing/Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	409,806	427,682
% of Total	99.20%	99.20%
Home Equity [Member] | Nonaccruing/Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	3,291	3,653
% of Total	0.80%	0.80%
Installment and Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	69,043	73,875
% of Total	100.00%	100.00%
Installment and Other Consumer [Member] | Accruing/Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	69,016	73,835
% of Total	99.90%	99.90%
Installment and Other Consumer [Member] | Nonaccruing/Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	27	40
% of Total	0.10%	0.10%
Consumer Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	4,335	2,437
% of Total	100.00%	100.00%
Consumer Construction [Member] | Accruing/Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan	4,335	2,219
% of Total	100.00%	91.10%
Consumer Construction [Member] | Nonaccruing/Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded investment in consumer loan		$218
% of Total		8.90%

Allowance_for_Loan_Losses_Inve

Allowance for Loan Losses - Investments in Loans Considered to be Impaired and Related Information on Impaired Loans (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment	$7,075		$7,075		$8,801
With a related allowance recorded, Unpaid Principal Balance	8,352		8,352		10,550
With a related allowance recorded, Related Allowance	3,278		3,278		2,231
Without a related allowance recorded, Recorded Investment	55,136		55,136		73,840
Without a related allowance, Unpaid Principal Balance	78,016		78,016		97,716
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	62,211		62,211		82,641
Impaired Financing Receivable, Unpaid Principal Balance, Total	86,368		86,368		108,266
Impaired Financing Receivable, Related Allowance	3,278		3,278		2,231
With a related allowance recorded, Average Recorded Investment	7,078	11,450	4,585	13,103
With a related allowance recorded, Interest Income Recognized	52	25	57	258
Without a related allowance recorded, Average Recorded Investment	56,720	81,278	65,429	84,472
Without a related allowance recorded, Interest Income Recognized	500	491	1,501	1,700
Impaired Financing Receivable, Average Recorded Investment, Total	63,798	92,728	70,014	97,575
Impaired Financing Receivable, Interest Income Recognized, Total	552	516	1,558	1,958
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment	1,014		1,014		6,138
With a related allowance recorded, Unpaid Principal Balance	2,291		2,291		6,864
With a related allowance recorded, Related Allowance	64		64		1,226
Without a related allowance recorded, Recorded Investment	27,309		27,309		33,856
Without a related allowance, Unpaid Principal Balance	38,351		38,351		45,953
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	28,323		28,323		39,994
Impaired Financing Receivable, Unpaid Principal Balance, Total	40,642		40,642		52,817
Impaired Financing Receivable, Related Allowance	64		64		1,226
With a related allowance recorded, Average Recorded Investment	1,014	6,430	2,526	5,629
With a related allowance recorded, Interest Income Recognized		15	5	209
Without a related allowance recorded, Average Recorded Investment	27,489	38,962	29,951	43,332
Without a related allowance recorded, Interest Income Recognized	271	268	330	915
Impaired Financing Receivable, Average Recorded Investment, Total	28,503	45,392	32,477	48,961
Impaired Financing Receivable, Interest Income Recognized, Total	271	283	335	1,124
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment					1,864
With a related allowance recorded, Unpaid Principal Balance					2,790
With a related allowance recorded, Related Allowance					1,002
Without a related allowance recorded, Recorded Investment	10,128		10,128		11,419
Without a related allowance, Unpaid Principal Balance	12,406		12,406		12,227
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	10,128		10,128		13,283
Impaired Financing Receivable, Unpaid Principal Balance, Total	12,406		12,406		15,017
Impaired Financing Receivable, Related Allowance					1,002
With a related allowance recorded, Average Recorded Investment		784		1,813
With a related allowance recorded, Interest Income Recognized		-9
Without a related allowance recorded, Average Recorded Investment	10,995	13,238	11,964	11,725
Without a related allowance recorded, Interest Income Recognized	68	101	203	265
Impaired Financing Receivable, Average Recorded Investment, Total	10,995	14,022	11,964	13,538
Impaired Financing Receivable, Interest Income Recognized, Total	68	92	203	265
Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment	5,929		5,929		799
With a related allowance recorded, Unpaid Principal Balance	5,929		5,929		896
With a related allowance recorded, Related Allowance	3,139		3,139		3
Without a related allowance recorded, Recorded Investment	9,329		9,329		17,713
Without a related allowance, Unpaid Principal Balance	17,873		17,873		27,486
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	15,258		15,258		18,512
Impaired Financing Receivable, Unpaid Principal Balance, Total	23,802		23,802		28,382
Impaired Financing Receivable, Related Allowance	3,139		3,139		3
With a related allowance recorded, Average Recorded Investment	5,929	4,236	1,976	5,661
With a related allowance recorded, Interest Income Recognized	49	19	49	49
Without a related allowance recorded, Average Recorded Investment	9,768	23,349	14,492	22,926
Without a related allowance recorded, Interest Income Recognized	46	113	271	450
Impaired Financing Receivable, Average Recorded Investment, Total	15,697	27,585	16,468	28,587
Impaired Financing Receivable, Interest Income Recognized, Total	95	132	320	499
Consumer Real Estate [Member]
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment	98		98
With a related allowance recorded, Unpaid Principal Balance	98		98
With a related allowance recorded, Related Allowance	56		56
Without a related allowance recorded, Recorded Investment	8,256		8,256		10,827
Without a related allowance, Unpaid Principal Balance	9,267		9,267		12,025
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	8,354		8,354		10,827
Impaired Financing Receivable, Unpaid Principal Balance, Total	9,365		9,365		12,025
Impaired Financing Receivable, Related Allowance	56		56
With a related allowance recorded, Average Recorded Investment	100		62
With a related allowance recorded, Interest Income Recognized	2
Without a related allowance recorded, Average Recorded Investment	8,349	5,729	8,912	6,489
Without a related allowance recorded, Interest Income Recognized	114	9	693	70
Impaired Financing Receivable, Average Recorded Investment, Total	8,449	5,729	8,974	6,489
Impaired Financing Receivable, Interest Income Recognized, Total	116	9	693	70
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
With a related allowance recorded, Recorded Investment	34		34
With a related allowance recorded, Unpaid Principal Balance	34		34
With a related allowance recorded, Related Allowance	19		19
Without a related allowance recorded, Recorded Investment	114		114		25
Without a related allowance, Unpaid Principal Balance	119		119		25
Without a related allowance recorded, Related Allowance
Impaired Financing Receivable, Recorded Investment, Total	148		148		25
Impaired Financing Receivable, Unpaid Principal Balance, Total	153		153		25
Impaired Financing Receivable, Related Allowance	19		19
With a related allowance recorded, Average Recorded Investment	35		21
With a related allowance recorded, Interest Income Recognized	1		3
Without a related allowance recorded, Average Recorded Investment	119		110
Without a related allowance recorded, Interest Income Recognized	1		4
Impaired Financing Receivable, Average Recorded Investment, Total	154		131
Impaired Financing Receivable, Interest Income Recognized, Total	$2		$7

Allowance_for_Loan_Losses_Summ

Allowance for Loan Losses - Summary of Allowance for Loan Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$46,105	$46,689	$46,484	$48,841
Charge-offs	-2,991	-4,380	-10,054	-23,651
Recoveries	1,450	1,665	4,804	2,489
Net (Charge-offs)/ Recoveries	-1,541	-2,715	-5,250	-21,162
Provision for loan losses	3,419	2,305	6,749	18,600
Balance at End of Period	47,983	46,279	47,983	46,279
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	23,484	24,696	25,246	29,804
Charge-offs	-840	-2,344	-3,649	-7,918
Recoveries	617	570	2,939	748
Net (Charge-offs)/ Recoveries	-223	-1,774	-710	-7,170
Provision for loan losses	-5,572	1,283	-6,847	1,571
Balance at End of Period	17,689	24,205	17,689	24,205
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	9,123	11,874	7,759	11,274
Charge-offs	-759	-520	-2,682	-4,488
Recoveries	167	609	457	857
Net (Charge-offs)/ Recoveries	-592	89	-2,225	-3,631
Provision for loan losses	6,268	-3,216	9,265	1,104
Balance at End of Period	14,799	8,747	14,799	8,747
Commercial Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	5,812	5,938	7,500	3,703
Charge-offs	-480	-970	-923	-9,261
Recoveries	481	395	536	494
Net (Charge-offs)/ Recoveries	1	-575	-387	-8,767
Provision for loan losses	2,186	3,162	886	13,589
Balance at End of Period	7,999	8,525	7,999	8,525
Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	6,655	3,401	5,058	3,166
Charge-offs	-585	-268	-1,822	-1,228
Recoveries	122	18	630	127
Net (Charge-offs)/ Recoveries	-463	-250	-1,192	-1,101
Provision for loan losses	185	752	2,511	1,838
Balance at End of Period	6,377	3,903	6,377	3,903
Other Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	1,031	780	921	894
Charge-offs	-327	-278	-978	-756
Recoveries	63	73	242	263
Net (Charge-offs)/ Recoveries	-264	-205	-736	-493
Provision for loan losses	352	324	934	498
Balance at End of Period	$1,119	$899	$1,119	$899

Allowance_for_Loan_Losses_Summ1

Allowance for Loan Losses - Summary of Allowance for Loan Losses and Recorded Investments (Detail) (USD $)	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$3,278		$2,231
Allowance for Loan Losses, Collectively Evaluated for Impairment	44,705		44,253
Total Allowance for Loan Losses	47,983	46,105	46,484	46,279	46,689	48,841
Portfolio Loans, Individually Evaluated for Impairment	62,211		82,641
Portfolio Loans, Collectively Evaluated for Impairment	3,449,124		3,263,981
Total Portfolio Loans	3,511,335		3,346,622
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	64		1,226
Allowance for Loan Losses, Collectively Evaluated for Impairment	17,625		24,020
Total Allowance for Loan Losses	17,689	23,484	25,246	24,205	24,696	29,804
Portfolio Loans, Individually Evaluated for Impairment	28,323		39,994
Portfolio Loans, Collectively Evaluated for Impairment	1,539,491		1,412,139
Total Portfolio Loans	1,567,814		1,452,133
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment			1,002
Allowance for Loan Losses, Collectively Evaluated for Impairment	14,799		6,757
Total Allowance for Loan Losses	14,799	9,123	7,759	8,747	11,874	11,274
Portfolio Loans, Individually Evaluated for Impairment	10,128		13,283
Portfolio Loans, Collectively Evaluated for Impairment	817,571		778,113
Total Portfolio Loans	827,699		791,396
Commercial Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	3,139		3
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,860		7,497
Total Allowance for Loan Losses	7,999	5,812	7,500	8,525	5,938	3,703
Portfolio Loans, Individually Evaluated for Impairment	15,258		18,512
Portfolio Loans, Collectively Evaluated for Impairment	136,948		149,631
Total Portfolio Loans	152,206		168,143
Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	56
Allowance for Loan Losses, Collectively Evaluated for Impairment	6,321		5,058
Total Allowance for Loan Losses	6,377	6,655	5,058	3,903	3,401	3,166
Portfolio Loans, Individually Evaluated for Impairment	8,354		10,827
Portfolio Loans, Collectively Evaluated for Impairment	886,219		850,248
Total Portfolio Loans	894,573		861,075
Other Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	19
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,100		921
Total Allowance for Loan Losses	1,119	1,031	921	899	780	894
Portfolio Loans, Individually Evaluated for Impairment	148		25
Portfolio Loans, Collectively Evaluated for Impairment	68,895		73,850
Total Portfolio Loans	$69,043		$73,875

Derivative_Instruments_and_Hed2

Derivative Instruments and Hedging Activities - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
Offsetting [Abstract]
Period for commitments	60 days

Derivative_Instruments_and_Hed3

Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Detail) (Not Designated as Hedging Instruments [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	$16,084	$23,748
Fair value, Derivatives (included in Other Liabilities)	16,025	23,522
Other Assets [Member] | Interest Rate Swap Contracts-Commercial Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	16,084	23,748
Notional amount, Derivatives (included in Other Assets)	257,678	227,532
Collateral posted, Derivatives (included in Other Assets)
Other Assets [Member] | Interest Rate Lock Commitments - Mortgage Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	206	467
Notional amount, Derivatives (included in Other Assets)	4,670	14,287
Other Assets [Member] | Forward Sale Contracts-Mortgage Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)
Notional amount, Derivatives (included in Other Assets)
Other Liabilities [Member] | Interest Rate Swap Contracts-Commercial Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	16,025	23,522
Notional amount, Derivatives (included in Other Liabilities)	257,678	227,532
Collateral posted, Derivatives (included in Other Liabilities)	12,978	19,595
Other Liabilities [Member] | Interest Rate Lock Commitments - Mortgage Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)
Notional amount, Derivatives (included in Other Liabilities)
Other Liabilities [Member] | Forward Sale Contracts-Mortgage Loans [Member]
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	162	48
Notional amount, Derivatives (included in Other Liabilities)	$7,425	$14,100

Derivative_Instruments_and_Hed4

Derivative Instruments and Hedging Activities - Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities (Detail) (Not Designated as Hedging Instruments [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Not Designated as Hedging Instruments [Member]
Derivatives not Designated as Hedging Instruments
Gross amounts recognized	$16,445	$24,262
Gross amounts offset	-361	-514
Net amounts presented in the Consolidated Balance Sheets	16,084	23,748
Gross amounts not offset
Net Amount	16,084	23,748
Gross amounts recognized	16,386	24,036
Gross amounts offset	-361	-514
Net amounts presented in the Consolidated Balance Sheets	16,025	23,522
Gross amounts not offset	-12,978	-19,595
Net Amount	$3,047	$3,927

Derivative_Instruments_and_Hed5

Derivative Instruments and Hedging Activities - Amount of Gain or Loss Recognized in Income on Derivatives (Detail) (Not Designated as Hedging Instruments [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative (Loss) Gain	($298)	$137	($541)	$581
Interest Rate Swap Contracts-Commercial Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative (Loss) Gain	-10	-19	-166	164
Interest Rate Lock Commitments - Mortgage Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative (Loss) Gain	231	257	-261	629
Forward Sale Contracts-Mortgage Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivative (Loss) Gain	($519)	($101)	($114)	($212)

Borrowings_Additional_Informat

Borrowings - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Long Term And Short Term Debt [Line Items]
Total long-term debt outstanding at a fixed rate	$19,100,000
Total long-term debt outstanding at a variable rate	48,700,000
Capital lease	200,000
Total borrowings	197,200,000	108,900,000
Long-term borrowings	22,200,000
Short-term borrowings	175,000,000
Federal Home Loan Bank Advances [Member]
Long Term And Short Term Debt [Line Items]
Maximum borrowing capacity	1,500,000,000
Remaining borrowing capacity	$1,300,000,000

Borrowings_Summary_of_Informat

Borrowings - Summary of Information Pertaining to Borrowings (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Long Term And Short Term Debt [Line Items]
Short-term borrowings	$208,290	$137,582
Long-term borrowings	68,009	124,720
Total Borrowings	276,299	262,302
Short-term borrowings, Weighted Average Rate	0.24%	0.19%
Long-term borrowings, Weighted Average Rate	2.81%	3.05%
Total Borrowings, Weighted Average Rate	0.87%	1.55%
Securities Sold under Repurchase Agreements [Member]
Long Term And Short Term Debt [Line Items]
Short-term borrowings	33,290	62,582
Short-term borrowings, Weighted Average Rate	0.01%	0.20%
Short-Term Borrowings [Member]
Long Term And Short Term Debt [Line Items]
Short-term borrowings	175,000	75,000
Short-term borrowings, Weighted Average Rate	0.28%	0.19%
Junior Subordinated Debt Securities [Member]
Long Term And Short Term Debt [Line Items]
Long-term borrowings	45,619	90,619
Long-term borrowings, Weighted Average Rate	2.71%	3.01%
Other Long-Term Borrowings [Member]
Long Term And Short Term Debt [Line Items]
Long-term borrowings	$22,390	$34,101
Long-term borrowings, Weighted Average Rate	3.01%	3.17%

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]
Allowance for unfunded commitments	$3.10	$3

Commitments_and_Contingencies_2

Commitments and Contingencies - Commitments and Letters of Credit (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Commitment And Contingencies [Line Items]
Commitments and letters of credit	$1,123,225	$969,536
Commitments to Extend Credit [Member]
Commitment And Contingencies [Line Items]
Commitments and letters of credit	1,042,572	874,137
Standby Letters of Credit [Member]
Commitment And Contingencies [Line Items]
Commitments and letters of credit	$80,653	$95,399

Other_Comprehensive_Income_Oth

Other Comprehensive Income - Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pre-Tax Amount
Change in unrealized gains/losses on securities available-for-sale	$335	$4,373	($13,494)	$5,188
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	-3	-2,170	-5	-3,016
Adjustment to funded status of employee benefit plans	631	750	1,827	1,887
Other Comprehensive Income (Loss)	963	2,953	-11,672	4,059
Tax (Expense) Benefit
Change in unrealized gains/losses on securities available-for-sale	-117	-1,530	4,723	-1,815
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	1	760	2	1,056
Adjustment to funded status of employee benefit plans	-220	-264	-639	-662
Other Comprehensive Income (Loss)	-336	-1,034	4,086	-1,421
Net of Tax Amount
Change in unrealized gains/losses on securities available-for-sale	218	2,843	-8,771	3,373
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	-2	-1,410	-3	-1,960
Adjustment to funded status of employee benefit plans	411	486	1,188	1,225
Other Comprehensive Income (Loss)	$627	$1,919	($7,586)	$2,638

Employee_Benefits_Additional_I

Employee Benefits - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Compensation And Retirement Disclosure [Abstract]
Number of consecutive years of employee's compensation	5 years
Number of total years of employee's compensation	10 years
Contribution by employer		$3.10
Expected long-term rate of return on plan assets	8.00%

Employee_Benefits_Components_o

Employee Benefits - Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Components of Net Periodic Pension Cost
Service cost-benefits earned during the period	$659	$636	$2,075	$2,090
Interest cost on projected benefit obligation	997	1,117	2,989	3,269
Expected return on plan assets	-1,526	-1,364	-4,656	-4,172
Amortization of prior service cost (credit)	-34	-34	-102	-99
Recognized net actuarial loss	642	711	1,818	1,852
Net Periodic Pension Expense	$738	$1,066	$2,124	$2,940

Segments_Additional_Informatio

Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Segment
Segment Reporting [Abstract]
Number of reportable segment	3

Segments_Total_Assets_by_Repor

Segments - Total Assets by Reportable Operating Segment (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$4,588,128	$4,526,702
Community Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	4,579,528	4,518,799
Insurance [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	7,358	6,697
Wealth Management [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$1,242	$1,206

Segments_Financial_Information

Segments - Financial Information of Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	$38,581	$38,820	$114,977	$117,330
Interest expense	3,307	5,025	11,438	16,395
Net interest income (expense)	35,274	33,795	103,539	100,935
Provision for loan losses	3,419	2,305	6,749	18,600
Noninterest income	12,542	14,746	40,215	40,347
Noninterest expense	26,729	29,613	84,055	88,923
Depreciation expense	835	988	2,667	2,947
Amortization of intangible assets	379	417	1,223	1,276
Provision (benefit) for income taxes	4,207	2,623	10,380	4,861
Net Income	12,247	12,595	38,680	24,675
Operating Segments [Member] | Community Banking [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	38,540	38,715	114,733	116,968
Interest expense	3,949	5,340	13,403	17,244
Net interest income (expense)	34,591	33,375	101,330	99,724
Provision for loan losses	3,419	2,305	6,749	18,600
Noninterest income	8,321	10,731	27,144	28,230
Noninterest expense	22,252	24,586	68,680	73,850
Depreciation expense	816	968	2,609	2,887
Amortization of intangible assets	355	391	1,148	1,193
Provision (benefit) for income taxes	4,179	3,333	11,617	7,057
Net Income	11,891	12,523	37,671	24,367
Operating Segments [Member] | Insurance [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income			1	1
Net interest income (expense)			1	1
Noninterest income	1,459	1,481	4,406	4,196
Noninterest expense	1,357	1,398	3,910	4,119
Depreciation expense	12	12	35	37
Amortization of intangible assets	13	13	38	39
Provision (benefit) for income taxes	27	21	148	1
Net Income	50	37	276	1
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	137	119	411	325
Net interest income (expense)	137	119	411	325
Noninterest income	2,744	2,394	8,130	7,375
Noninterest expense	2,379	2,401	7,257	7,037
Depreciation expense	7	8	23	23
Amortization of intangible assets	11	13	37	44
Provision (benefit) for income taxes	178	56	491	289
Net Income	306	35	733	307
Eliminations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	-96	-14	-168	36
Interest expense	-642	-315	-1,965	-849
Net interest income (expense)	546	301	1,797	885
Noninterest income	18	140	535	546
Noninterest expense	741	1,228	4,208	3,917
Provision (benefit) for income taxes	($177)	($787)	($1,876)	($2,486)

Sale_of_Merchant_Card_Servicin1

Sale of Merchant Card Servicing Business - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Mar. 31, 2013	Sep. 30, 2013
Business Acquisition [Line Items]
Proceeds from sale of business		4,750,000
Gain on sale of business		3,093,000
Merchant Card Servicing Business [Member]
Business Acquisition [Line Items]
Proceeds from sale of business	4,800,000
Termination fee	1,700,000
Gain on sale of business	$3,100,000
Initial term of agreement		10 years