United Bankshares (UBSI) 10-Q 10 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'UBSI	'
Entity Registrant Name	'UNITED BANKSHARES INC/WV	'
Entity Central Index Key	'0000729986	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	69,204,424

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets	'	'
Cash and due from banks	$186,774	$134,808
Interest-bearing deposits with other banks	403,775	281,090
Federal funds sold	721	719
Total cash and cash equivalents	591,270	416,617
Securities available for sale at estimated fair value (amortized cost-$1,171,947 at September 30, 2014 and $813,049 at December 31, 2013)	1,162,559	775,284
Securities held to maturity (estimated fair value-$38,381 at September 30, 2014 and $38,293 at December 31, 2013)	39,969	40,965
Other investment securities	104,714	73,093
Loans held for sale	5,773	4,236
Loans	9,030,483	6,713,599
Less: Unearned income	-14,580	-9,016
Loans net of unearned income	9,015,903	6,704,583
Less: Allowance for loan losses	-75,721	-74,198
Net loans	8,940,182	6,630,385
Bank premises and equipment	78,007	69,897
Goodwill	712,065	375,547
Accrued interest receivable	32,740	26,666
Other assets	417,784	322,634
TOTAL ASSETS	12,085,063	8,735,324
Deposits:	'	'
Noninterest-bearing	2,538,310	1,874,520
Interest-bearing	6,214,947	4,747,051
Total deposits	8,753,257	6,621,571
Borrowings:	'	'
Federal funds purchased	30,120	27,685
Securities sold under agreements to repurchase	396,818	188,069
Federal Home Loan Bank borrowings	930,679	592,069
Other long-term borrowings	249,863	198,628
Reserve for lending-related commitments	1,477	2,143
Accrued expenses and other liabilities	69,176	63,427
TOTAL LIABILITIES	10,431,390	7,693,592
Shareholders' Equity	'	'
Preferred stock, $1.00 par value; Authorized-50,000,000 shares, none issued	0	0
Common stock, $2.50 par value; Authorized-100,000,000 shares; issued-69,224,451 and 50,867,630 at September 30, 2014 and December 31, 2013, respectively, including 27,459 and 437,363 shares in treasury at September 30, 2014 and December 31, 2013, respectively	173,061	127,169
Surplus	740,003	237,674
Retained earnings	765,219	734,945
Accumulated other comprehensive loss	-23,670	-43,047
Treasury stock, at cost	-940	-15,009
TOTAL SHAREHOLDERS' EQUITY	1,653,673	1,041,732
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$12,085,063	$8,735,324

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Securities available for sale, amortized cost	$1,171,947	$813,049
Securities held to maturity	$38,381	$38,293
Preferred stock, par value	$1	$1
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$2.50	$2.50
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	69,224,451	50,867,630
Common stock, shares in treasury	27,459	437,363

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest income	'	'	'	'
Interest and fees on loans	$97,874	$71,264	$281,663	$213,909
Interest on federal funds sold and other short-term investments	241	157	656	446
Interest and dividends on securities:	'	'	'	'
Taxable	7,873	4,585	21,869	11,973
Tax-exempt	869	699	2,632	2,187
Total interest income	106,857	76,705	306,820	228,515
Interest expense	'	'	'	'
Interest on deposits	7,077	6,569	20,493	20,403
Interest on short-term borrowings	234	276	911	694
Interest on long-term borrowings	3,628	2,230	10,264	6,763
Total interest expense	10,939	9,075	31,668	27,860
Net interest income	95,918	67,630	275,152	200,655
Provision for loan losses	4,748	4,777	15,628	14,924
Net interest income after provision for loan losses	91,170	62,853	259,524	185,731
Other income	'	'	'	'
Fees from trust and brokerage services	4,474	4,006	13,708	12,206
Fees from deposit services	11,134	10,341	31,595	30,173
Bankcard fees and merchant discounts	1,101	1,003	2,974	2,699
Other service charges, commissions, and fees	512	599	1,541	1,786
Income from bank-owned life insurance	1,325	1,138	4,021	4,712
Income from mortgage banking	774	605	1,471	2,309
Net gain on the sale of bank premises	0	0	8,976	0
Other income	404	542	1,328	2,279
Total other-than-temporary impairment losses	-561	0	485	285
Portion of loss recognized in other comprehensive income	-4,153	0	-6,259	-1,256
Net other-than-temporary impairment losses	-4,714	0	-5,774	-971
Net gains on sales/calls of investment securities	1,309	101	2,134	589
Net investment securities (losses) gains	-3,405	101	-3,640	-382
Total other income	16,319	18,335	61,974	55,782
Other expense	'	'	'	'
Employee compensation	22,173	17,269	68,726	50,830
Employee benefits	4,753	5,842	15,567	17,510
Net occupancy expense	6,400	4,931	19,349	14,943
Other real estate owned (OREO) expense	1,818	1,535	4,968	5,135
Equipment expense	2,376	1,960	6,518	5,370
Data processing expense	3,785	2,880	10,611	8,424
Bankcard processing expense	350	331	1,022	988
FDIC insurance expense	1,981	1,539	5,559	4,662
Other expense	14,211	12,298	43,930	37,519
Total other expense	57,847	48,585	176,250	145,381
Income before income taxes	49,642	32,603	145,248	96,132
Income taxes	16,382	10,433	48,617	30,164
Net income	$33,260	$22,170	$96,631	$65,968
Earnings per common share:	'	'	'	'
Basic	$0.48	$0.44	$1.45	$1.31
Diluted	$0.48	$0.44	$1.44	$1.31
Dividends per common share	$0.32	$0.31	$0.96	$0.93
Average outstanding shares:	'	'	'	'
Basic	69,044,876	50,378,613	66,836,396	50,336,741
Diluted	69,269,309	50,472,959	67,069,352	50,402,455

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$33,260	$22,170	$96,631	$65,968
Change in net unrealized gain (loss) on available-for-sale (AFS) securities, net of tax	1,635	2,977	18,445	1,210
Accretion of the net unrealized loss on the transfer of AFS securities to held-to-maturity (HTM) securities, net of tax	2	2	4	4
Change in pension plan assets, net of tax	309	740	928	2,223
Comprehensive income, net of tax	$35,206	$25,889	$116,008	$69,405

Consolidated_Statement_of_Chan

Consolidated Statement of Changes in Shareholders' Equity (USD $)	Total	Common Stock [Member]	Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
In Thousands, except Share data, unless otherwise specified
Beginning Balance at Dec. 31, 2013	$1,041,732	$127,169	$237,674	$734,945	($43,047)	($15,009)
Beginning Balance, shares at Dec. 31, 2013	'	50,867,630	'	'	'	'
Comprehensive income:	'	'	'	'	'	'
Net income	96,631	0	0	96,631	0	0
Other comprehensive income, net of tax:	19,377	0	0	0	19,377	0
Comprehensive income, net of tax	116,008	'	'	'	'	'
Stock based compensation expense	1,593	0	1,593	0	0	0
Acquisition of Virginia Commerce Bancorp, Inc. (18,330,347 shares)	552,262	45,826	506,436	0	0	0
Acquisition of Virginia Commerce Bancorp, Inc., shares	'	18,330,347	'	'	'	'
Distribution of treasury stock for deferred compensation plan (3,637 shares)	81	0	0	0	0	81
Purchase of treasury stock (726 shares)	-25	0	0	0	0	-25
Cash dividends ($0.96 per share)	-66,357	0	0	-66,357	0	0
Grant of restricted stock (66,949 shares)	0	0	-2,305	0	0	2,305
Forfeiture of restricted stock (2,338 shares)	0	0	81	0	0	-81
Common stock options exercised (368,856 shares)	8,379	66	-3,476	0	0	11,789
Common stock options exercised, shares	368,856	26,474	'	'	'	342,382
Ending Balance at Sep. 30, 2014	$1,653,673	$173,061	$740,003	$765,219	($23,670)	($940)
Ending Balance, shares at Sep. 30, 2014	'	69,224,451	'	'	'	'

Consolidated_Statement_of_Chan1

Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (USD $)	9 Months Ended
	Sep. 30, 2014
Cash dividends per share	$0.96
Common stock options exercised, shares	368,856
Common Stock [Member]	'
Acquisition of Virginia Commerce Bancorp, Inc., shares	18,330,347
Grant of restricted stock, shares	66,949
Forfeiture of restricted stock, shares	2,338
Common stock options exercised, shares	26,474
Treasury Stock [Member]	'
Distribution of treasury stock for deferred compensation plan, shares	3,637
Purchase of treasury stock, shares	726
Common stock options exercised, shares	342,382

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]	'	'
NET CASH PROVIDED BY OPERATING ACTIVITIES	$99,495	$106,745
INVESTING ACTIVITIES	'	'
Proceeds from maturities and calls of securities held to maturity	897	1,227
Proceeds from sales of securities available for sale	92,413	7,061
Proceeds from maturities and calls of securities available for sale	408,079	580,791
Purchases of securities available for sale	-403,277	-709,876
Purchases of bank premises and equipment	-6,300	-3,110
Proceeds from sales of bank premises and equipment	11,428	201
Redemption of bank-owned life insurance policies	8,930	1,953
Purchases of other investment securities	-59,123	-31,491
Proceeds from sales and redemptions of other investment securities	42,282	22,332
Acquisition of Virginia Commerce Bancorp, Inc., net of cash paid	97,298	0
Net change in loans	-308,225	-98,333
NET CASH USED IN INVESTING ACTIVITIES	-115,598	-229,245
FINANCING ACTIVITIES	'	'
Cash dividends paid	-60,354	-46,808
Excess tax benefits from stock-based compensation arrangements	482	122
Acquisition of treasury stock	-2	-92
Proceeds from exercise of stock options	7,172	1,601
Repayment of long-term Federal Home Loan Bank borrowings	-421,390	-26,402
Proceeds from issuance of long-term Federal Home Loan Bank borrowings	775,000	275,000
Distribution of treasury stock for deferred compensation plan	81	77
Changes in:	'	'
Deposits	110,112	-147,182
Federal funds purchased, securities sold under agreements to repurchase and other short-term borrowings	-220,345	-23,854
NET CASH PROVIDED BY FINANCING ACTIVITIES	190,756	32,462
Increase (Decrease) in cash and cash equivalents	174,653	-90,038
Cash and cash equivalents at beginning of year	416,617	432,077
Cash and cash equivalents at end of period	$591,270	$342,039

General

General	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
General	'
	1. GENERAL
	The accompanying unaudited consolidated interim financial statements of United Bankshares, Inc. and Subsidiaries (“United” or “the Company”) have been prepared in accordance with accounting principles for interim financial information generally accepted in the United States and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, the financial statements do not contain all of the information and footnotes required by accounting principles generally accepted in the United States. In preparing the consolidated financial statements, management is required to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. The financial statements presented as of September 30, 2014 and 2013 and for the three-month and nine-month periods then ended have not been audited. The consolidated balance sheet as of December 31, 2013 has been extracted from the audited financial statements included in United’s 2013 Annual Report to Shareholders. The accounting and reporting policies followed in the presentation of these financial statements are consistent with those applied in the preparation of the 2013 Annual Report of United on Form 10-K. To conform to the 2013 presentation, certain reclassifications have been made to prior period amounts, which had no impact on net income, comprehensive income or stockholders’ equity. In the opinion of management, all adjustments necessary for a fair presentation of financial position and results of operations for the interim periods have been made. Such adjustments are of a normal and recurring nature.
	The accompanying consolidated interim financial statements include the accounts of United and its wholly owned subsidiaries. United considers all of its principal business activities to be bank related. All significant intercompany accounts and transactions have been eliminated in the consolidated financial statements. Dollars are in thousands, except per share or unless otherwise noted.
	New Accounting Standards
	In August 2014, the FASB issued ASU 2014-14, “Receivables-Troubled Debt Restructurings by Creditors (Subtopic 310-40), Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure.” ASU 2014-14 was issued to clarify the classification and measurement of certain foreclosed residential and nonresidential mortgage loans that are either fully or partially guaranteed under government programs. Specifically, creditors should reclassify loans that are within the scope of ASU 2014-14 to “other receivables” upon foreclosure, rather than reclassifying them to other real estate owned (OREO). ASU 2014-14 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In June 2014, the FASB issued ASU 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period.” ASU 2014-12 amends the guidance in FASB ASC 718, “Compensation-Stock Compensation”, to bring consistency to the accounting for share-based payment awards that require a specific performance target to be achieved in order for employees to become eligible to vest in the awards. The amendments affect all entities that grant their employees share-based payments in which the terms of the award provide that a performance target that affects vesting could be achieved after the requisite service period. ASU 2014-12 is effective for United on January 1, 2016, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In June 2014, the FASB issued ASU 2014-11, “Transfers and Servicing (Topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures.” ASU 2014-11 modifies accounting for repurchase-to-maturity transactions and repurchase financing arrangements, as well as modifies required disclosures. Under ASU 2014-11, repurchase-to-maturity transactions, repurchase agreements executed as repurchase financings, and other typical repurchase agreements are accounted for as secured borrowings. ASU 2014-11 also eliminates off-balance-sheet accounting for transfers of financial assets with contemporaneous repurchase financings. ASU 2014-11 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification Topic 605, “Revenue Recognition”, and most industry-specific guidance throughout the Accounting Standards Codification. The amendments require an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new revenue recognition standard sets forth a five step principle-based approach for determining revenue recognition. ASU 2014-09 is effective for United on January 1, 2017. Management is currently evaluating this guidance to determine the impact on the Company’s financial condition or results of operation.
	In January 2014, the FASB issued ASU 2014-04, “Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure.” ASU 2014-04 clarifies when banks and similar institutions should reclassify mortgage loans collateralized by residential real estate properties from the loan portfolio to other real estate owned (OREO). An entity can elect either a retrospective or a prospective transition method, and early adoption is permitted. ASU 2014-04 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In February 2013, the FASB issued ASU 2013-02, “Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income.” ASU 2013-02 is intended to improve the reporting of reclassifications out of accumulated other comprehensive income of various components. ASU 2013-02 requires entities to disclose in a single location, either on the face of financial statement that reports net income or in the notes, the effects of reclassification out of accumulated other comprehensive income (AOCI). For items reclassified out of AOCI and into net income in their entirety, such as realized gains or losses on available-for-sale securities reclassified into net income on sale, entities must disclose the effect on the reclassification on each affected net income item. For AOCI reclassification items that are not reclassified in their entirety into net income, such as actuarial gains or losses amortized into pension cost that may be capitalized into inventory or other assets, entities must provide a cross reference to other required U.S. GAAP disclosures. ASU 2013-02 was effective for United on January 1, 2013 and did not have a significant impact on the Company’s financial condition or results of operation.
	In February 2013, the FASB issued ASU 2013-04, “Obligations Resulting from Joint and Several Liability Arrangements for which the Total Amount of the Obligation is Fixed at the Reporting Date.” ASU 2013-04 addresses the recognition, measurement and disclosure of certain obligations including debt arrangements, other contractual obligations, and settled litigation and judicial ruling. In particular, ASU 2013-04 requires entities to record an obligation resulting from joint and several liability arrangements that are fixed at the reporting date at the greater of the amount that the entity has agreed to pay or the amount the entity expects to pay. The guidance applies retrospectively for obligations that exist at the beginning of an entity’s fiscal year of adoption. ASU 2013-04 was effective for United beginning January 1, 2014 and did not have a significant impact on the Company’s financial condition or results of operation.

Mergers_and_Acquisitions

Mergers and Acquisitions	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Mergers and Acquisitions	'
	2. MERGERS AND ACQUISITIONS
	At the close of business on January 31, 2014 (Acquisition Date), United acquired 100% of the outstanding common stock of Virginia Commerce Bancorp, Inc. (Virginia Commerce), a Virginia corporation headquartered in Arlington, Virginia. The acquisition of Virginia Commerce significantly enhances United’s existing footprint in the Washington, D.C. Metropolitan Statistical Area. The results of operations of Virginia Commerce are included in the consolidated results of operations from the date of acquisition.
	At consummation, Virginia Commerce had assets of approximately $2.77 billion, loans of $2.10 billion and deposits of $2.02 billion. The transaction was accounted for under the purchase acquisition method of accounting and accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at estimated fair value on the Acquisition Date.
	The aggregate purchase price was approximately $585.53 million, including common stock issued valued at $547.89 million, stock options exchanged valued at $4.37 million, $33.263 million paid in cash to redeem the warrant held by the U.S. Department of the Treasury (the Treasury) issued by Virginia Commerce in connection with the TARP Capital Purchase Program and $8 thousand paid in cash to holders of Virginia Commerce common stock and restricted stock in lieu of fractional shares of United common stock. The cash portion of the purchase price was funded by cash on hand. The purchase price of the warrant was based on its fair market as agreed upon by United and the Treasury. As a result of the purchase by United, the warrant has been canceled. The number of shares issued in the transaction was 18,330,347, which were valued based on the closing market price of $29.89 for United’s common shares on January 31, 2014. The preliminary purchase price has been allocated to the identifiable tangible and intangible assets resulting in preliminary additions to goodwill and core deposit intangibles of $335.98 million and $17.14 million, respectively. The core deposit intangibles are expected to be amortized over ten years. Because the consideration paid was greater than the net fair value of the acquired assets and liabilities, the Company recorded goodwill as part of the acquisition. None of the goodwill from the Virginia Commerce acquisition is expected to be deductible for tax purposes. As a result of the merger, United recorded a downward fair value adjustment of $90.39 million on the loans acquired from Virginia Commerce, a downward fair value adjustment of $1.71 million on certain other real estate owned properties, a premium on interest-bearing deposits of $6.01 million, a premium on term securities sold under agreements to repurchase of $3.70 million and a discount of $16.38 million on junior subordinated debt securities. The discount and premium amounts are being amortized or accreted on an accelerated basis over each asset’s or liability’s estimated remaining life at the time of acquisition. At September 30, 2014, the premium on the interest-bearing deposits and the securities sold under agreements to repurchase has an estimated remaining life of 1.25 years and 1.83 years, respectively, while the discount on the junior subordinated debt securities has an estimated remaining life of 21.22 years. United assumed approximately $109 thousand of liabilities to provide severance benefits to terminated employees of Virginia Commerce which has no remaining balance as of September 30, 2014. The estimated fair values of the acquired assets and assumed liabilities, including identifiable intangible assets, are preliminary and subject to refinement as additional information relative to closing date fair values becomes available. Any subsequent adjustments to the fair values of acquired assets and liabilities assumed, identifiable intangible assets, or other purchase accounting adjustments will result in adjustments to goodwill within the first 12 months following the date of acquisition.
	In many cases, determining the estimated fair value of the acquired assets and assumed liabilities required United to estimate cash flows expected to result from those assets and liabilities and to discount those cash flows at appropriate rates of interest. The most significant of those determinations related to the fair valuation of acquired loans. The fair value of the acquired loans was based on the present value of the expected cash flows. Periodic principal and interest cash flows were adjusted for expected losses and prepayments, then discounted to determine the present value and summed to arrive at the estimated fair value. For such loans, the excess of cash flows expected at acquisition over the estimated fair value is recognized as interest income over the remaining lives of the loans. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition reflects the impact of estimated credit losses and other factors, such as prepayments. In accordance with GAAP, there was no carry-over of Virginia Commerce’s previously established allowance for loan losses. As a result, standard industry coverage ratios with regard to the allowance for credit losses are less meaningful after the acquisition of Virginia Commerce.
	The acquired loans were divided into loans with evidence of credit quality deterioration, which are accounted for under ASC topic 310-30 (acquired impaired) and loans that do not meet this criteria, which are accounted for under ASC topic 310-20 (acquired performing). Acquired impaired loans have experienced a deterioration of credit quality from origination to acquisition for which it is probable that United will be unable to collect all contractually required payments receivable, including both principal and interest. Subsequent decreases in the expected cash flows require United to evaluate the need for additions to the Company’s allowance for credit losses. Subsequent improvements in expected cash flows generally result in the recognition of additional interest income over the then remaining lives of the loans.
	In conjunction with the Virginia Commerce merger, the acquired loan portfolio was accounted for at fair value as follows:
			January 31, 2014
	Contractually required principal and interest at acquisition		$	2,683,966
	Contractual cash flows not expected to be collected			(396,983	)
	Expected cash flows at acquisition			2,286,983
	Interest component of expected cash flows			(274,462	)
	Basis in acquired loans at acquisition – estimated fair value		$	2,012,521
	Included in the above table is information related to acquired impaired loans. Specifically, contractually required principal and interest, cash flows expected to be collected and estimated fair value of acquired impaired loans were $405,109, $166,874, and $157,759, respectively.
	The consideration paid for Virginia Commerce’s common equity and the amounts of acquired identifiable assets and liabilities assumed as of the Acquisition Date were as follows:
	Purchase price:
	Value of common shares issued (18,330,347 shares)		$	547,894
	Fair value of stock options assumed			4,368
	Cash to redeem the Treasury warrant			33,263
	Cash for fractional shares			8
	Total purchase price			585,533
	Identifiable assets:
	Cash and cash equivalents			130,569
	Investment securities			476,541
	Loans			2,012,521
	Premises and equipment			10,786
	Core deposit intangibles			17,143
	Other assets			104,589
	Total identifiable assets		$	2,752,149
	Identifiable liabilities:
	Deposits		$	2,024,969
	Short-term borrowings			263,816
	Long-term borrowings			204,335
	Other liabilities			11,393
	Total identifiable liabilities			2,504,513
	Net assets acquired including identifiable intangible assets			247,636
	Resulting goodwill		$	337,897
	The following table provides a reconciliation of goodwill:
	Goodwill at December 31, 2013		$	375,547
	Addition to goodwill from Virginia Commerce acquisition			337,897
	Reduction to goodwill for options exercised from previous acquisitions			(37	)
	Reclassification from goodwill			(1,342	)
	Goodwill at September 30, 2014		$	712,065
	The operating results of United for the nine months ended September 30, 2014 include operating results of acquired assets and assumed liabilities subsequent to the Acquisition Date. The operations of United’s metropolitan Washington D.C. geographic area, which primarily includes the acquired operations of Virginia Commerce, provided approximately $73.66 million in total revenues, which represents net interest income plus other income, and approximately $33.25 million in net income from the period from the Acquisition Date to September 30, 2014. These amounts are included in United’s consolidated financial statements as of and for the nine months ended September 30, 2014. Virginia Commerce’s results of operations prior to the Acquisition Date are not included in United’s consolidated financial statements.
	The following table presents certain unaudited pro forma information for the results of operations for the nine months ended September 30, 2014 and 2013, as if the Virginia Commerce merger had occurred on January 1, 2014 and 2013, respectively. These results combine the historical results of Virginia Commerce into United’s consolidated statement of income and, while certain adjustments were made for the estimated impact of certain fair valuation adjustments and other acquisition-related activity, they are not indicative of what would have occurred had the acquisition taken place on the indicated date nor are they intended to represent or be indicative of future results of operations. In particular, no adjustments have been made to eliminate the amount of Virginia Commerce’s provision for credit losses for 2014 and 2013 that may not have been necessary had the acquired loans been recorded at fair value as of the beginning of 2014 and 2013. Additionally, United expects to achieve operating cost savings and other business synergies as a result of the acquisition which are not reflected in the pro forma amounts.
			Proforma
			Nine Months Ended
			September 30
			2014			2013
	Total Revenues (1)		$	346,594		$	347,419
	Net Income			89,488			89,960
	(1)	Represents net interest income plus other income

Investment_Securities

Investment Securities	9 Months Ended
	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Investment Securities	'
	3. INVESTMENT SECURITIES
	Securities held for indefinite periods of time and all marketable equity securities are classified as available for sale and carried at estimated fair value. The amortized cost and estimated fair values of securities available for sale are summarized as follows.
			September 30, 2014
			Amortized		Gross		Gross		Estimated		Cumulative
			Cost		Unrealized		Unrealized		Fair		OTTI in
					Gains		Losses		Value		AOCI (1)
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	93,439	$	697	$	138	$	93,998	$	0
	State and political subdivisions			132,583		3,260		2		135,841		0
	Residential mortgage-backed securities
	Agency			537,886		5,049		1,303		541,632		0
	Non-agency			12,871		730		0		13,601		458
	Commercial mortgage-backed securities
	Agency			312,582		1,016		4,381		309,217		0
	Asset-backed securities			8,005		26		0		8,031		0
	Trust preferred collateralized debt obligations			52,370		767		14,318		38,819		28,040
	Single issue trust preferred securities			13,747		291		1,828		12,210		0
	Other corporate securities			4,997		162		0		5,159		0
	Marketable equity securities			3,467		584		0		4,051		0
	Total		$	1,171,947	$	12,582	$	21,970	$	1,162,559	$	28,498
			December 31, 2013
			Amortized		Gross		Gross		Estimated		Cumulative
			Cost		Unrealized		Unrealized		Fair		OTTI in
					Gains		Losses		Value		AOCI (1)
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	172,324	$	178	$	748	$	171,754	$	0
	State and political subdivisions			60,861		1,874		26		62,709		0
	Residential mortgage-backed securities
	Agency			215,788		2,491		1,815		216,464		0
	Non-agency			16,369		163		0		16,532		458
	Commercial mortgage-backed securities
	Agency			241,947		225		8,740		233,432		0
	Asset-backed securities			9,257		1		31		9,227		0
	Trust preferred collateralized debt obligations			73,862		210		30,623		43,449		34,299
	Single issue trust preferred securities			14,346		305		2,019		12,632		0
	Other corporate securities			4,996		219		0		5,215		0
	Marketable equity securities			3,299		572		1		3,870		0
	Total		$	813,049	$	6,238	$	44,003	$	775,284	$	34,757
	-1	Other-than-temporary impairment in accumulated other comprehensive income. Amounts are before-tax.
	The following is a summary of securities available-for-sale which were in an unrealized loss position at September 30, 2014 and December 31, 2013.
			Less than 12 months				12 months or longer
			Fair		Unrealized		Fair		Unrealized
			Value		Losses		Value		Losses
	September 30, 2014
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	19,030	$	138	$	0	$	0
	State and political subdivisions			2,783		2		0		0
	Residential mortgage-backed securities
	Agency			164,364		1,303		0		0
	Commercial mortgage-backed securities
	Agency			78,108		526		162,621		3,855
	Asset-backed securities			0		0		0		0
	Trust preferred collateralized debt obligations			0		0		34,148		14,318
	Single issue trust preferred securities			0		0		8,430		1,828
	Marketable equity securities			0		0		0		0
	Total		$	264,285	$	1,969	$	205,199	$	20,001
	December 31, 2013
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	61,517	$	748	$	0	$	0
	State and political subdivisions			2,353		26		0		0
	Residential mortgage-backed securities
	Agency			160,835		1,815		0		0
	Commercial mortgage-backed securities
	Agency			208,979		8,740		0		0
	Asset-backed securities			7,976		31		0		0
	Trust preferred collateralized debt obligations			0		0		27,167		30,623
	Single issue trust preferred securities			502		2		8,210		2,017
Marketable equity securities			0		0		25		1
Total		$	442,162	$	11,362	$	35,402	$	32,641
Marketable equity securities consist mainly of equity securities of financial institutions and mutual funds within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries. The following table shows the proceeds from maturities, sales and calls of available for sale securities and the gross realized gains and losses on sales and calls of those securities that have been included in earnings as a result of those sales and calls. Gains or losses on sales and calls of available for sale securities were recognized by the specific identification method. The realized losses relate to sales of securities within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
		Three Months Ended				Nine Months Ended
		September 30				September 30
		2014		2013		2014		2013
Proceeds from sales and calls		$	64,610	$	183,069	$	500,493	$	587,852
Gross realized gains			1,314		109		2,366		499
Gross realized losses			5		8		232		23
At September 30, 2014, gross unrealized losses on available for sale securities were $21,970 on 95 securities of a total portfolio of 452 available for sale securities. Securities in an unrealized loss position at September 30, 2014 consisted primarily of pooled trust preferred collateralized debt obligations (Trup Cdos) and agency commercial mortgage-backed securities. The Trup Cdos relate mainly to securities of financial institutions. The agency commercial mortgage-backed securities relate mainly to income-producing multifamily properties and provide a guaranty of full and timely payments of principal and interest by either Fannie Mae or Freddie Mac. In determining whether or not a security is other-than-temporarily impaired (OTTI), management considered the severity and the duration of the loss in conjunction with United’s positive intent and the more likely than not ability to hold these securities to recovery of their cost basis or maturity.
Agency mortgage-backed securities
United’s agency mortgage-backed securities portfolio relates to securities issued by Fannie Mae, Freddie Mac, and Ginnie Mae. The total amortized cost of available for sale agency mortgage securities was $850.47 million at September 30, 2014. Of the $850.47 million, $312.58 million was related to agency commercial mortgage securities and $537.89 million was related to agency residential mortgage securities. Each of the agency mortgage securities provides a guarantee of full and timely payments of principal and interest by the issuing agency. Based upon management’s analysis and judgment, it was determined that none of the agency mortgage-backed securities were other-than-temporarily impaired at September 30, 2014.
Non-agency residential mortgage-backed securities
United’s non-agency residential mortgage-backed securities portfolio relates to securities of various private label issuers. The Company has no exposure to real estate investment trusts (REITS) in its investment portfolio. The total amortized cost of available for sale non-agency residential mortgage securities was $12.87 million at September 30, 2014. Of the $12.87 million, $4.03 million was rated above investment grade and $8.84 million was rated below investment grade. Approximately 39% of the portfolio includes collateral that was originated during the year of 2005 or before. The remaining 61% includes collateral that was originated in the years of 2006 and 2007. The entire portfolio of the non-agency residential mortgage securities are either the senior or super-senior tranches of their respective structure. In determining whether or not the non-agency mortgage-backed securities are other-than-temporarily impaired, management performs an in-depth analysis on each non-agency residential mortgage-backed security on a quarterly basis. The analysis includes a review of the following factors: weighted average loan to value, weighted average maturity, average FICO scores, historical collateral performance, geographic concentration, credit subordination, cross-collateralization, coverage ratios, origination year, full documentation percentage, event risk (repricing), and collateral type. Management completes a quarterly stress test to determine the level of loss protection remaining in each individual security and compares the protection remaining to the future expected performance of the underlying collateral. Additionally, management utilizes a third-party cash flow model to perform a cash flow test for each bond below investment grade. The model produces a bond specific set of cash flows based upon assumptions input by management. The input assumptions that are incorporated include the projected constant default rate (CDR) of the underlying mortgages, the loss severity upon default, and the prepayment rate on the underlying mortgage collateral. CDR and loss severities are forecasted by management after full evaluation of the underlying collateral including recent performance statistics. Therefore, based upon management’s analysis and judgment, there was no additional credit-related or noncredit-related other-than-temporary impairment recognized on the non-agency residential mortgage-backed securities at September 30, 2014.
Single issue trust preferred securities
The majority of United’s single-issue trust preferred portfolio consists of obligations from large cap banks (i.e. banks with market capitalization in excess of $10 billion). Management reviews each issuer’s current and projected earnings trends, asset quality, capitalization levels, TARP participation status, and other key factors. Upon completing the review for the third quarter of 2014, it was determined that none of the single issue securities were other-than-temporarily impaired. All single-issue trust preferred securities are currently receiving interest payments. The available for sale single issue trust preferred securities’ ratings ranged from a low of B to a high of BBB-. The amortized cost of available for sale single issue trust preferred securities as of September 30, 2014 consisted of $2.99 million in split-rated bonds and $10.76 million in below investment grade bonds. Of the $10.76 million in below investment grade bonds, $10.26 million was in an unrealized loss position for twelve months or longer as of September 30, 2014.
Trust preferred collateralized debt obligations (Trup Cdos)
At September 30, 2014, United determined that certain Trup Cdos were other-than-temporarily impaired. In order to determine how and when the Company recognizes OTTI, the Company first assesses its intentions regarding any sale of securities as well as the likelihood that it would be required to sell prior to recovery of the amortized cost. As of September 30, 2014, the Company has determined that it does not intend to sell any pooled trust preferred security and that it is not more likely than not that the Company will be required to sell such securities before recovery of their amortized cost.
Although the Company believes it is not more likely than not that it will be required to sell any Trup Cdo, the Company was notified by the Trustee of one Trup Cdo that it had been ordered by the holders of the senior notes to liquidate the underlying collateral of the security. The auction is scheduled to take place during the fourth quarter of 2014. The Company estimates that the proceeds from the auction will be insufficient to cover the amortized cost basis of the security. Due to this estimated shortfall, the Company recognized credit-related other-than-temporary impairment of $4.71 million during the third quarter of 2014 related to this security.
During the third quarter of 2014, the Company sold four Trup Cdos in response to Section 619 of the Dodd-Frank Wall Street Reform and Consumer Protection Act, commonly known as the Volcker Rule. Under the Volcker Rule, these four securities were identified by the Company as covered funds and were required to be divested of before July 21, 2015. The execution of these sales resulted in a total net gain of $1.3 million. The Company does not expect any further direct impact from the Volcker Rule, as the remaining Trup Cdo portfolio is excluded from the scope of the Rule.
To determine a net realizable value and assess whether other-than-temporary impairment existed on securities which the Company is not more likely than not required to sell, management performed detailed cash flow analysis to determine whether, in management’s judgment, it was more likely that United would not recover the entire amortized cost basis of the security. The Company discounts the security-specific cash flow projection at the security-specific interest rate and compares the present value to the amortized cost. Management’s cash flow analysis was performed for each security and considered the current deferrals and defaults within the underlying collateral, the likelihood that current deferrals would cure or ultimately default, potential future deferrals and defaults, potential prepayments, cash reserves, excess interest spread, credit analysis of the underlying collateral and the priority of payments in the cash flow structure. The underlying collateral analysis for each issuer took into consideration multiple factors including TARP participation, capital adequacy, earnings trends and asset quality.
After completing its analysis of estimated cash flows, management determined that none of the Trup Cdos experienced an adverse change in cash flows during the third quarter of 2014, as the expected discounted cash flows from these securities were greater than or equal to the discounted cash flows originally expected at purchase or from the previous date of other-than-temporary impairment (cash flows are discounted at the contractual coupon rate for purposes of assessing OTTI).
Other than the $4.71 million mentioned above, there was no additional credit-related other-than-temporary impairment recognized in earnings for the third quarter of 2014 related to Trup Cdos. There was no credit-related other-than-temporary impairment recognized in earnings for the third quarter of 2013 related to these securities. At September 30, 2014, the balance of the noncredit-related other-than-temporary impairment recognized on United’s Trup Cdo portfolio was $28.04 million as compared to $34.30 million at December 31, 2013. This decline is attributable to improvements in the overall fair values of these securities.
The amortized cost of available for sale Trup Cdos as of September 30, 2014 consisted of $5.00 million in split-rated bonds and $47.37 million in below investment grade bonds.
The following is a summary of the available for sale Trup Cdos as of September 30, 2014:
								Amortized Cost
Class		Amortized		Fair		Unrealized		Investment		Split		Below
		Cost		Value		Loss/(Gain)		Grade		Rated		Investment
												Grade
Senior – Bank		$	7,725	$	6,133	$	1,592	$	0	$	5,000	$	2,725
Mezzanine – Bank (now in senior position)			12,599		9,658		2,941		0		0		12,599
Mezzanine – Bank			26,883		19,045		7,838		0		0		26,883
Mezzanine – Bank & Insurance (combination)			5,163		3,983		1,180		0		0		5,163
Totals		$	52,370	$	38,819	$	13,551	$	0	$	5,000	$	47,370
While a large difference remains between the fair value and amortized cost, the Company believes the remaining unrealized losses are related to the illiquid market for Trup Cdos rather than an adverse change in expected cash flows. The expected future cash flow substantiates the return of the remaining amortized cost of the security. The Company believes the following evidence supports the position that the remaining unrealized loss is related to the illiquid market for Trup Cdos:
	•		The market for new issuance of Trup Cdos was robust from 2000 to 2007 with an estimated $60 billion in new issuance. The new market issuances came to an abrupt halt in 2007.
	•		The secondary market for Trup Cdos ultimately became illiquid and is not reflective of orderly transactions between market participants. In making this determination, the Company holds discussions with institutional traders to identify trends in the number and type of transactions related to the Trup Cdos. Although market conditions for these securities have improved in recent quarters, the Company notes that the overall amount of observable market data is still lacking.
	•		The presence of a below-investment grade rating severely limits the pool of available buyers and contributes to the illiquidity of the market.
	•		Trup Cdos have a more complex structure than most debt instruments, making projections of tranche returns difficult for non-specialists in the product. Deferral features available to the underlying issuers within each pool are unique to these securities. Additionally, it can be difficult for market participants to predict whether deferrals will ultimately cure or ultimately default. Due to the lack of transparency, market participants will require a higher risk premium, thus resulting in higher required discount rates.
	•		The variability of cash flows at the time the securities were originated was expected to be very limited. Due to the financial crisis, Trup Cdos have experienced more substantive variability of cash flows compared to expectations, resulting in a higher risk premium when evaluating discount rates.
	•		The limited, yet relevant, observable inputs indicate that market yield requirements for Trup Cdos, on a credit-adjusted basis, remained very high relative to discount rates at purchase and compared to other similarly rated debt securities.
Overall, the Company believes the lack of new issuances, illiquid secondary market, limited pool of buyers, below investment grade ratings, complex structures and high market discount rates are the key drivers of the remaining unrealized losses in the Company’s Trup Cdos and the robust expected cash flow analysis substantiates the return of the remaining amortized cost under ASC 320.
Management also considered the ratings of the Company’s bonds in its portfolio and the extent of downgrades in United’s impairment analysis. However, due to historical discrepancies in ratings from the various rating agencies, management considered it imperative to independently perform its own credit analysis based on cash flows as described. The ratings of the split-rated Trup Cdos in the table above range from a low of BB+ to a high of Aa1. The below investment grade Trup Cdos range from a low of Ca to a high of Ba1.
The Company has recognized cumulative credit-related other-than-temporary impairment of $48.88 million on certain Trup Cdos since the third quarter of 2009.
On the Trup Cdos that have not been deemed to be other-than-temporarily impaired, the collateralization ratios range from a low of 97.4% to a high of 240.3%, with a median of 135.7%, and a weighted average of 174.8%. The collateralization ratio is defined as the current performing collateral in a security, divided by the current balance of the specific tranche the Company owns, plus any debt which is senior or pari passu with the Company’s security’s priority level. Performing collateral excludes the balance of any issuer that has either defaulted or has deferred its interest payment. It is not uncommon for the collateralization of a security that is not other-than-temporarily impaired to be less than 100% due to the excess spread built into the securitization structure.
Except for the debt securities that have already been deemed to be other-than-temporarily impaired, management does not believe any other individual security with an unrealized loss as of September 30, 2014 is other-than-temporarily impaired. For these securities, United believes the decline in value resulted from changes in market interest rates, credit spreads and liquidity, not a change in the expected contractual cash flows. Based on a review of each of the securities in the investment portfolio, management concluded that it expected to recover the amortized cost basis of the investment in such securities.
Equity securities
The amortized cost of United’s equity securities was $3.47 million at September 30, 2014. For equity securities, management has evaluated the near-term prospects of the investment in relation to the severity and duration of any impairment and based on that evaluation, management determined that no equity securities were other-than-temporarily impaired at September 30, 2014. These securities were in an unrealized gain position of $584 thousand at September 30, 2014.
Other investment securities (cost method)
During the third quarter of 2014, United also evaluated all of its cost method investments to determine if certain events or changes in circumstances during the third quarter of 2014 had a significant adverse effect on the fair value of any of its cost method securities. United determined that there were no events or changes in circumstances during the third quarter which would have an adverse effect on the fair value of any of its cost method securities. Therefore, no impairment was recorded.
Below is a progression of the credit losses on securities which United has recorded other-than-temporary charges through earnings and other comprehensive income.
Balance of cumulative credit losses at December 31, 2013		$	70,446
Additions for credit losses on securities for which OTTI was not previously recognized			0
Additions for additional credit losses on securities for which OTTI was previously recognized			5,774
Balance of cumulative credit losses at September 30, 2014		$	76,220
The amortized cost and estimated fair value of securities available for sale at September 30, 2014 and December 31, 2013 by contractual maturity are shown as follows. Expected maturities may differ from contractual maturities because the issuers may have the right to call or prepay obligations without penalties.
		September 30, 2014				December 31, 2013
				Estimated				Estimated
		Amortized		Fair		Amortized		Fair
		Cost		Value		Cost		Value
Due in one year or less		$	26,751	$	26,981	$	28,837	$	28,960
Due after one year through five years			153,260		153,718		217,415		218,498
Due after five years through ten years			365,664		366,395		292,460		286,534
Due after ten years			622,805		611,414		271,038		237,422
Marketable equity securities			3,467		4,051		3,299		3,870
Total		$	1,171,947	$	1,162,559	$	813,049	$	775,284
The amortized cost and estimated fair values of securities held to maturity are summarized as follows:
		September 30, 2014
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	10,640	$	1,403	$	0	$	12,043
State and political subdivisions			9,989		32		391		9,630
Residential mortgage-backed securities
Agency			42		7		0		49
Single issue trust preferred securities			19,278		0		2,639		16,639
Other corporate securities			20		0		0		20
Total		$	39,969	$	1,442	$	3,030	$	38,381
		December 31, 2013
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
		Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	10,762	$	1,689	$	0	$	12,451
State and political subdivisions			10,367		37		299		10,105
Residential mortgage-backed securities
Agency			50		9		0		59
Single issue trust preferred securities			19,766		0		4,108		15,658
Other corporate securities			20		0		0		20
Total		$	40,965	$	1,735	$	4,407	$	38,293
Even though the market value of the held-to-maturity investment portfolio is less than its cost, the unrealized loss has no impact on the net worth or regulatory capital requirements of United. As of September 30, 2014, the Company’s two largest held-to-maturity single-issue trust preferred exposures were to Wells Fargo ($9.91 million) and SunTrust Bank ($7.40 million). The two held-to-maturity single-issue trust preferred exposures with at least one rating below investment grade included SunTrust Bank ($7.40 million) and Royal Bank of Scotland ($973 thousand). Other corporate securities consist mainly of bonds of corporations.
The following table shows the gross realized gains and losses on calls that have been included in earnings as a result of those calls. Gains or losses on calls of held-to-maturity securities are recognized by the specific identification method.
		Three Months  Ended				Nine Months  Ended
		September 30				September 30
		2014		2013		2014		2013
Gross realized gains		$	9	$	0	$	9	$	114
Gross realized losses			0		0		0		0
The amortized cost and estimated fair value of debt securities held to maturity at September 30, 2014 and December 31, 2013 by contractual maturity are shown on the following page. Expected maturities may differ from contractual maturities because the issuers may have the right to call or prepay obligations without penalties.
		September 30, 2014				December 31, 2013
				Estimated				Estimated
		Amortized		Fair		Amortized		Fair
		Cost		Value		Cost		Value
Due in one year or less		$	570	$	571	$	555	$	556
Due after one year through five years			12,750		14,165		6,683		7,312
Due after five years through ten years			6,444		6,069		13,026		13,821
Due after ten years			20,205		17,576		20,701		16,604
Total		$	39,969	$	38,381	$	40,965	$	38,293
The carrying value of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes as required or permitted by law, approximated $1,017,560 and $640,870 at September 30, 2014 and December 31, 2013, respectively.

Loans

Loans	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Loans	'
	4. LOANS
	Major classes of loans are as follows:
		September 30,			December 31,
		2014			2013
	Commercial, financial and agricultural:
	Owner-occupied commercial real estate	$	1,044,951		$	654,963
	Nonowner-occupied commercial real estate		2,718,821			1,917,785
	Other commercial loans		1,592,606			1,338,355
	Total commercial, financial & agricultural		5,356,378			3,911,103
	Residential real estate		2,229,353			1,821,378
	Construction & land development		1,088,627			670,364
	Consumer:
	Bankcard		10,110			11,023
	Other consumer		346,015			299,731
	Total gross loans	$	9,030,483		$	6,713,599
	The table above does not include loans held for sale of $5,773 and $4,236 at September 30, 2014 and December 31, 2013, respectively. Loans held for sale consist of single-family residential real estate loans originated for sale in the secondary market.
	The outstanding balances in the table above include acquired impaired loans with a recorded investment of $163,473 or 1.81% of total gross loans at September 30, 2014 and $31,099 or less than 1% of total gross loans at December 31, 2013. The contractual principal in these acquired impaired loans was $250,933 and $52,237 at September 30, 2014 and December 31, 2013, respectively. The balances above do not include future accretable net interest (i.e. the difference between the undiscounted expected cash flows and the recorded investment in the loan) on the acquired impaired loans.
	Activity for the accretable yield for the first nine months of 2014 follows:
	Accretable yield at the beginning of the period	$	2,251
	Additions		9,116
	Accretion (including cash recoveries)		(6,051	)
	Net reclassifications to accretable from non-accretable		1,700
	Disposals (including maturities, foreclosures, and charge-offs)		(628	)
	Accretable yield at the ending of the period	$	6,388
	United’s subsidiary banks have made loans, in the normal course of business, to the directors and officers of United and its subsidiaries, and to their affiliates. Such related party loans were made on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with unrelated persons and did not involve more than normal risk of collectibility. The aggregate dollar amount of these loans was $197,380 and $150,798 at September 30, 2014 and December 31, 2013, respectively.

Credit_Quality

Credit Quality	9 Months Ended
	Sep. 30, 2014
Text Block [Abstract]	'
Credit Quality	'
	5. CREDIT QUALITY
	Management monitors the credit quality of its loans on an ongoing basis. Measurement of delinquency and past due status are based on the contractual terms of each loan.
	For all loan classes, past due loans are reviewed on a monthly basis to identify loans for nonaccrual status. Generally, when collection in full of the principal and interest is jeopardized, the loan is placed on nonaccrual status. The accrual of interest income on commercial and most consumer loans generally is discontinued when a loan becomes 90 to 120 days past due as to principal or interest. However, regardless of delinquency status, if a loan is fully secured and in the process of collection and resolution of collection is expected in the near term (generally less than 90 days), then the loan will not be placed on nonaccrual status. When interest accruals are discontinued, unpaid interest recognized in income in the current year is reversed, and unpaid interest accrued in prior years is charged to the allowance for loan losses. United’s method of income recognition for loans that are classified as nonaccrual is to recognize interest income on a cash basis or apply the cash receipt to principal when the ultimate collectibility of principal is in doubt. Management may elect to continue the accrual of interest when the estimated net realizable value of collateral exceeds the principal balance and accrued interest, and the loan is in the process of collection. Nonaccrual loans will not normally be returned to accrual status unless all past due principal and interest has been paid and the borrower has evidenced their ability to meet the contractual provisions of the note.
	A loan is categorized as a troubled debt restructuring (TDR) if a concession is granted and there is deterioration in the financial condition of the borrower. TDRs can take the form of a reduction of the stated interest rate, splitting a loan into separate loans with market terms on one loan and concessionary terms on the other loan, receipts of assets from a debtor in partial or full satisfaction of a loan, the extension of the maturity date or dates at a stated interest rate lower than the current market rate for new debt with similar risk, the reduction of the face amount or maturity amount of the debt as stated in the instrument or other agreement, the reduction of accrued interest or any other concessionary type of renegotiated debt. As of September 30, 2014, United had TDRs of $13,502 as compared to $8,157 as of December 31, 2013. Of the $13,502 aggregate balance of TDRs at September 30, 2014, $820 was on nonaccrual status and included in the “Loans on Nonaccrual Status” on the following page. Of the $8,157 aggregate balance of TDRs at December 31, 2013, $861 was on nonaccrual status and included in the “Loans on Nonaccrual Status” on the following page. As of September 30, 2014, there were no commitments to lend additional funds to debtors owing receivables whose terms have been modified in TDRs. At September 30, 2014, United had restructured loans in the amount of $4,012 that were modified by a reduction in the interest rate, $8,523 that were modified by a combination of a reduction in the interest rate and the principal and $967 that was modified by a change in terms.
	A loan acquired and accounted for under ASC topic 310-30 “Loans and Debt Securities Acquired with Deteriorated Credit Quality” is reported as an accruing loan and a performing asset, even if contractually past due (or if United does not expect to receive payment in full based on the original contractual terms), as United is currently accreting interest income over the expected life of the loans. See Notes 2 and 4 in the Notes to Consolidated Financial Statements for additional information on these loans.
	No loans were restructured during the three months ended September 30, 2014 and 2013. The following table sets forth United’s troubled debt restructurings that have been restructured during the nine months ended September 30, 2014 and 2013, segregated by class of loans:
			Troubled Debt Restructurings
			For the Nine Months Ended
			September 30, 2014						September 30, 2013
			Number of		Pre-Modification		Post-		Number of		Pre-Modification		Post-
			Contracts		Outstanding		Modification		Contracts		Outstanding		Modification
					Recorded		Outstanding				Recorded		Outstanding
					Investment		Recorded				Investment		Recorded
							Investment						Investment
	Commercial real estate:
	Owner-occupied			0	$	0	$	0		4	$	5,143	$	4,590
	Nonowner-occupied			0		0		0		0		0		0
	Other commercial			2		5,630		5,630		0		0		0
	Residential real estate			0		0		0		0		0		0
	Construction & land development			0		0		0		0		0		0
	Consumer:
	Bankcard			0		0		0		0		0		0
	Other consumer			0		0		0		0		0		0
	Total			2	$	5,630	$	5,630		4	$	5,143	$	4,590
	During the first nine months of 2014, $5,630 of restructured loans were modified by a combination of a reduction in the interest rate and an extension of the maturity date. During the first nine months of 2013, a restructured loan of $2,974 was modified by a combination of a reduction in the interest rate and an extension of the maturity date. The remaining $1,616 of loans restructured during the first nine months of 2013 was modified by a reduction in the interest rate. In some instances, the post-modification balance on a restructured loan is larger than the pre-modification balance due to the advancement of monies for items such as delinquent taxes on real estate property. The loans were evaluated individually for allocation within United’s allowance for loan losses. The modifications had an immaterial impact on the financial condition and results of operations for United.
	The following table presents troubled debt restructurings, by class of loan, that had charge-offs during the three months ended September 30, 2014. During the time periods indicated, the loan’s principal was reduced through a charge-off to the value of the underlying collateral. No troubled debt restructurings had charge-offs during the three months ended September 30, 2013.
			Three Months Ended September 30, 2014
	(In thousands)		Number of		Recorded
			Contracts		Investment
	Troubled Debt Restructurings
	Commercial real estate:
	Owner-occupied			0	$	0
	Nonowner-occupied			1		478
	Other commercial			0		0
	Residential real estate			0		0
	Construction & land development			0		0
	Consumer:
	Bankcard			0		0
	Other consumer			0		0
	Total			1	$	478
	The following table presents troubled debt restructurings, by class of loan, that had charge-offs during the nine months ended September 30, 2014 and 2013.
			Nine Months Ended September 30, 2014				Nine Months Ended September 30, 2013
	(In thousands)		Number of		Recorded		Number of		Recorded
			Contracts		Investment		Contracts		Investment
	Troubled Debt Restructurings
	Commercial real estate:
	Owner-occupied			0	$	0		0	$	0
	Nonowner-occupied			1		478		0		0
	Other commercial			0		0		0		0
	Residential real estate			0		0		0		0
	Construction & land development			0		0		1		375
	Consumer:
	Bankcard			0		0		0		0
	Other consumer			0		0		0		0
	Total			1	$	478		1	$	375
	The following table sets forth United’s age analysis of its past due loans, segregated by class of loans:
	Age Analysis of Past Due Loans
	As of September 30, 2014
	(In thousands)		30-89		90 Days or		Total Past		Current &		Total		Recorded
			Days Past		more Past		Due		Other (1)		Loans		Investment
			Due		Due								>90 Days &
													Accruing
	Commercial real estate:
Owner-occupied		$	14,148	$	9,634	$	23,782	$	1,021,169	$	1,044,951	$	674
Nonowner-occupied			27,990		13,849		41,839		2,676,982		2,718,821		1,028
Other commercial			20,239		18,070		38,309		1,554,297		1,592,606		6,197
Residential real estate			41,714		26,957		68,671		2,160,682		2,229,353		6,809
Construction & land development			6,729		14,905		21,634		1,066,993		1,088,627		305
Consumer:
Bankcard			371		185		556		9,554		10,110		185
Other consumer			7,921		1,627		9,548		336,467		346,015		1,494
Total		$	119,112	$	85,227	$	204,339	$	8,826,144	$	9,030,483	$	16,692
-1	Other includes loans with a recorded investment of $163,473 acquired and accounted for under ASC topic 310-30 “Loans and Debt Securities Acquired with Deteriorated Credit Quality”.
Age Analysis of Past Due Loans
As of December 31, 2013
		30-89		90 Days or		Total Past		Current &		Total		Recorded
		Days		more Past		Due		Other (1)		Financing		Investment
		Past Due		Due						Receivables		>90 Days &
												Accruing
Commercial real estate:
Owner-occupied		$	14,144	$	4,537	$	18,681	$	636,282	$	654,963	$	1,383
Nonowner-occupied			30,836		11,725		42,561		1,875,224		1,917,785		186
Other commercial			54,319		11,794		66,113		1,272,242		1,338,355		896
Residential real estate			54,271		25,446		79,717		1,741,661		1,821,378		5,214
Construction & land development			9,921		18,491		28,412		641,952		670,364		1,611
Consumer:
Bankcard			229		128		357		10,666		11,023		128
Age Analysis of Past Due Loans
As of December 31, 2013
		30-89		90 Days or		Total Past		Current &		Total		Recorded
		Days Past		more Past		Due		Other (1)		Financing		Investment
		Due		Due						Receivables		>90 Days &
												Accruing
Other consumer			9,466		1,712		11,178		288,553		299,731		1,626
Total		$	173,186	$	73,833	$	247,019	$	6,466,580	$	6,713,599	$	11,044
-1	Other includes loans with a recorded investment of $31,099 acquired and accounted for under ASC topic 310-30 “Loans and Debt Securities Acquired with Deteriorated Credit Quality”.
The following table sets forth United’s nonaccrual loans, segregated by class of loans:
Loans on Nonaccrual Status
		September 30,		December 31,
		2014		2013
Commercial real estate:
Owner-occupied		$	8,960	$	3,154
Nonowner-occupied			12,821		11,539
Other commercial			11,873		10,898
Residential real estate			20,148		20,232
Construction & land development			14,600		16,880
Consumer:
Bankcard			0		0
Other consumer			133		86
Total		$	68,535	$	62,789
United assigns credit quality indicators of pass, special mention, substandard and doubtful to its loans. For United’s loans with a corporate credit exposure, United internally assigns a grade based on the creditworthiness of the borrower. For loans with a consumer credit exposure, United internally assigns a grade based upon an individual loan’s delinquency status. United reviews and updates these grades on a quarterly basis, as necessary.
Special mention loans, with a corporate credit exposure, have potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loans or in the Company’s credit position at some future date. Borrowers may be experiencing adverse operating trends (declining revenues or margins) or an ill proportioned balance sheet (e.g., increasing inventory without an increase in sales, high leverage, tight liquidity). Adverse economic or market conditions, such as interest rate increases or the entry of a new competitor, may also support a special mention rating. Nonfinancial reasons for rating a credit exposure special mention include management problems, pending litigation, an ineffective loan agreement or other material structural weakness, and any other significant deviation from prudent lending practices. For loans with a consumer credit exposure, loans that are past due 30-89 days are considered special mention.
A substandard loan with a corporate credit exposure is inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness, or weaknesses, that jeopardize the liquidation of the debt by the borrower. They are characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected. They require more intensive supervision by management. Substandard loans are generally characterized by current or expected unprofitable operations, inadequate debt service coverage, inadequate liquidity, or marginal capitalization. Repayment may depend on collateral or other credit risk mitigants. For some substandard loans, the likelihood of full collection of interest and principal may be in doubt and thus, placed on nonaccrual. For loans with a consumer credit exposure, loans that are 90 days or more past due or that have been placed on nonaccrual are considered substandard.
A loan with corporate credit exposure is classified as doubtful if it has all the weaknesses inherent in one classified as substandard with the added characteristic that the weaknesses make collection in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. A doubtful loan has a high probability of total or substantial loss, but because of specific pending events that may strengthen the loan, its classification as loss is deferred. Doubtful borrowers are usually in default, lack adequate liquidity or capital, and lack the resources necessary to remain an operating entity. Pending events can include mergers, acquisitions, liquidations, capital injections, the perfection of liens on additional collateral, the valuation of collateral, and refinancing. Generally, there are not any loans with a consumer credit exposure that are classified as doubtful. Usually, they are charged-off prior to such a classification. Loans classified as doubtful are also considered impaired.
The following tables set forth United’s credit quality indicators information, by class of loans:
Credit Quality Indicators
Corporate Credit Exposure
As of September 30, 2014
		Commercial Real Estate				Other		Construction
						Commercial		& Land
		Owner-		Nonowner-				Development
		occupied		occupied
Grade:
Pass		$	946,727	$	2,539,705	$	1,385,308	$	903,780
Special mention			30,297		56,224		23,794		71,263
Substandard			67,927		122,892		182,181		113,584
Doubtful			0		0		1,323		0
Total		$	1,044,951	$	2,718,821	$	1,592,606	$	1,088,627
As of December 31, 2013
		Commercial Real Estate				Other		Construction
						Commercial		& Land
		Owner-		Nonowner-				Development
		occupied		occupied
Grade:
Pass		$	604,129	$	1,811,915	$	1,206,030	$	510,911
Special mention			27,576		45,617		60,668		63,375
Substandard			23,258		60,253		71,148		96,078
Doubtful			0		0		509		0
Total		$	654,963	$	1,917,785	$	1,338,355	$	670,364
Credit Quality Indicators
Consumer Credit Exposure
As of September 30, 2014
		Residential		Bankcard		Other
		Real Estate				Consumer
Grade:
Pass		$	2,146,423	$	9,554	$	336,157
Special mention			17,668		371		8,042
Substandard			63,787		185		1,816
Doubtful			1,475		0		0
Total		$	2,229,353	$	10,110	$	346,015
As of December 31, 2013
		Residential		Bankcard		Other
		Real Estate				Consumer
Grade:
Pass		$	1,773,244	$	10,666	$	288,401
Special mention			13,006		229		9,466
Substandard			35,128		128		1,712
Doubtful			0		0		152
Total		$	1,821,378	$	11,023	$	299,731
Loans are designated as impaired when, in the opinion of management, based on current information and events, the collection of principal and interest in accordance with the loan contract is doubtful. Typically, United does not consider loans for impairment unless a sustained period of delinquency (i.e. 90 days or more) is noted or there are subsequent events that impact repayment probability (i.e. negative financial trends, bankruptcy filings, eminent foreclosure proceedings, etc.). Impairment is evaluated in total for smaller-balance loans of a similar nature and on an individual loan basis for other loans. Consistent with United’s existing method of income recognition for loans, interest on impaired loans, except those classified as nonaccrual, is recognized as income using the accrual method. Impaired loans, or portions thereof, are charged off when deemed uncollectible.
The following table sets forth United’s impaired loans information, by class of loans:
		Impaired Loans
		September 30, 2014						December 31, 2013
		Recorded		Unpaid		Related		Recorded		Unpaid		Related
		Investment		Principal		Allowance		Investment		Principal		Allowance
				Balance						Balance
With no related allowance recorded:
Commercial real estate:
Owner-occupied		$	35,355	$	35,355	$	0	$	4,672	$	4,672	$	0
Nonowner-occupied			60,329		60,739		0		5,938		6,651		0
Other commercial			18,535		21,910		0		10,292		17,753		0
Residential real estate			28,832		29,501		0		12,009		12,193		0
Construction & land development			43,096		44,676		0		13,866		14,662		0
Consumer:
Bankcard			0		0		0		0		0		0
Other consumer			51		51		0		0		0		0
With an allowance recorded:
Commercial real estate:
Owner-occupied		$	5,036	$	5,036	$	820	$	4,358	$	4,358	$	638
Nonowner-occupied			7,190		7,249		773		9,350		10,563		1,631
Other commercial			13,639		16,639		4,016		13,304		16,240		2,192
Residential real estate			10,239		10,825		2,582		7,669		8,191		4,112
Construction & land development			12,028		15,306		3,775		11,050		14,833		3,752
Consumer:
Bankcard			0		0		0		0		0		0
Other consumer			0		0		0		152		152		152
Total:
Commercial real estate:
Owner-occupied		$	40,391	$	40,391	$	820	$	9,030	$	9,030	$	638
Nonowner-occupied			67,519		67,988		773		15,288		17,214		1,631
Other commercial			32,174		38,549		4,016		23,596		33,993		2,192
Residential real estate			39,071		40,326		2,582		19,678		20,384		4,112
Construction & land development			55,124		59,982		3,775		24,916		29,495		3,752
Consumer:
Bankcard			0		0		0		0		0		0
Other consumer			51		51		0		152		152		152
		Impaired Loans
		For the Three Months Ended
		September 30, 2014				September 30, 2013
		Average		Interest		Average		Interest
		Recorded		Income		Recorded		Income
		Investment		Recognized		Investment		Recognized
With no related allowance recorded:
Commercial real estate:
Owner-occupied		$	37,208	$	129	$	13,661	$	68
Nonowner-occupied			63,035		230		12,035		27
Other commercial			20,679		59		18,947		389
Residential real estate			32,864		46		9,605		30
Construction & land development			44,191		97		8,688		119
Consumer:
Bankcard			0		0		0		0
Other consumer			55		0		152		0
With an allowance recorded:
Commercial real estate:
Owner-occupied		$	4,352	$	114	$	2,313	$	139
Nonowner-occupied			7,332		67		6,562		155
Other commercial			12,537		97		9,390		59
Residential real estate			7,716		8		5,773		105
Construction & land development			11,491		31		14,234		111
Consumer:
Bankcard			0		0		0		0
Other consumer			76		0		0		0
Total:
Commercial real estate:
Owner-occupied		$	41,560	$	243	$	15,974	$	207
Nonowner-occupied			70,367		297		18,597		182
Other commercial			33,216		156		28,337		448
Residential real estate			40,580		54		15,378		135
Construction & land development			55,682		128		22,922		230
Consumer:
Bankcard			0		0		0		0
Other consumer			131		0		152		0
		Impaired Loans
		For the Nine Months Ended
		September 30, 2014				September 30, 2013
		Average		Interest		Average		Interest
		Recorded		Income		Recorded		Income
		Investment		Recognized		Investment		Recognized
With no related allowance recorded:
Commercial real estate:
Owner-occupied		$	35,959	$	617	$	13,530	$	145
Nonowner-occupied			62,205		440		11,637		221
Other commercial			27,454		217		12,268		478
Residential real estate			30,484		195		8,530		197
Construction & land development			46,747		234		8,078		304
Consumer:
Bankcard			0		0		0		0
Other consumer			45		0		152		0
With an allowance recorded:
Commercial real estate:
Owner-occupied		$	4,236	$	189	$	1,935	$	166
Nonowner-occupied			7,606		159		5,518		204
Other commercial			12,751		185		16,616		991
Residential real estate			8,548		101		5,505		186
Construction & land development			10,694		47		13,934		378
Consumer:
Bankcard			0		0		0		0
Other consumer			102		0		0		0
Total:
Commercial real estate:
Owner-occupied		$	40,195	$	806	$	15,465	$	311
Nonowner-occupied			69,811		599		17,155		425
Other commercial			40,205		402		28,884		1,469
Residential real estate			39,032		296		14,035		383
Construction & land development			57,441		281		22,012		682
Consumer:
Bankcard			0		0		0		0
Other consumer			147		0		152		0

Allowance_for_Credit_Losses

Allowance for Credit Losses	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Allowance for Credit Losses	'
	6. ALLOWANCE FOR CREDIT LOSSES
	The allowance for loan losses is management’s estimate of the probable credit losses inherent in the loan portfolio. Management’s evaluation of the adequacy of the allowance for loan losses and the appropriate provision for credit losses is based upon a quarterly evaluation of the portfolio. This evaluation is inherently subjective and requires significant estimates, including the amounts and timing of estimated future cash flows, estimated losses on pools of loans based on historical loss experience, and consideration of current economic trends, all of which are susceptible to constant and significant change. Allocations are made for specific commercial loans based upon management’s estimate of the borrowers’ ability to repay and other factors impacting collectibility. Other commercial loans not specifically reviewed on an individual basis are evaluated based on historical loss percentages applied to loan pools that have been segregated by the type of risk. Allocations for loans other than commercial loans are made based upon historical loss experience adjusted for current environmental conditions. The allowance for credit losses includes estimated probable inherent but undetected losses within the portfolio due to uncertainties in economic conditions, delays in obtaining information, including unfavorable information about a borrower’s financial condition, the difficulty in identifying triggering events that correlate perfectly to subsequent loss rates, and risk factors that have not yet fully manifested themselves in loss allocation factors. In addition, a portion of the allowance accounts for the inherent imprecision in the allowance for credit losses analysis.
	For purposes of determining the general allowance, the loan portfolio is segregated by loan product type to recognize differing risk profiles among loan categories. It is further segregated by credit grade for risk-rated loan pools and delinquency for homogeneous loan pools. The outstanding principal balance within each pool is multiplied by historical loss data and certain qualitative factors to derive the general loss allocation per pool. Specific loss allocations are calculated for loans in excess of $500 thousand in accordance with ASC topic 310. Risk characteristics of owner-occupied commercial real estate loans and other commercial loans are similar in that they are normally dependent upon the borrower’s internal cash flow from operations to service debt. Nonowner-occupied commercial real estate loans differ in that cash flow to service debt is normally dependent on external income from third parties for use of the real estate such as rents, leases and room rates. Residential real estate loans are dependent upon individual borrowers who are affected by changes in general economic conditions, demand for housing and resulting residential real estate valuation. Construction and land development loans are impacted mainly by demand whether for new residential housing or for retail, industrial, office and other types of commercial construction within a given area. Consumer loan pool risk characteristics are influenced by general, regional and local economic conditions. During the first nine months of 2014, there were no material changes to the accounting policy or methodology related to the allowance for loan losses.
	Loans deemed to be uncollectible are charged against the allowance for loan losses, while recoveries of previously charged-off amounts are credited to the allowance for loan losses. For commercial loans, when a loan or a portion of a loan is identified to contain a loss, a charge-off recommendation is directed to management to charge-off all or a portion of that loan. Generally, any unsecured commercial loan more than six months delinquent in payment of interest must be charged-off in full. If secured, the charge-off is generally made to reduce the loan balance to a level equal to the liquidation value of the collateral when payment of principal and interest is six months delinquent. Any commercial loan, secured or unsecured, on which a principal or interest payment has not been made within 90 days, is reviewed monthly for appropriate action.
	For consumer loans, closed-end retail loans that are past due 120 cumulative days delinquent from the contractual due date and open-end loans 180 cumulative days delinquent from the contractual due date are charged-off. Any consumer loan on which a principal or interest payment has not been made within 90 days is reviewed monthly for appropriate action. For a one-to-four family open-end or closed-end residential real estate loan, home equity loan, or high-loan-to-value loan that has reached 180 or more days past due, management evaluates the collateral position and charge-offs any amount that exceeds the value of the collateral. Retail credits for which the borrower is in bankruptcy, all amounts deemed unrecoverable are charged-off within 60 days or before of the receipt of the notification. On retail credits effected by fraud, a loan is charged-off within 90 days of the discovery of the fraud. In the event of the borrower’s death and if repayment within the required timeframe is uncertain, the loan is generally charged-off as soon as the amount of the loss is determined.
	United maintains an allowance for loan losses and a reserve for lending-related commitments such as unfunded loan commitments and letters of credit. The reserve for lending-related commitments of $1,477 and $2,143 at September 30, 2014 and December 31, 2013, respectively, is separately classified on the balance sheet and is included in other liabilities. The combined allowance for loan losses and reserve for lending-related commitments are referred to as the allowance for credit losses.
	A progression of the allowance for loan losses, by portfolio segment, for the periods indicated is summarized as follows.
	Allowance for Loan Losses
	For the Three Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real			& Land				for
										Estate			Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	3,810		$	8,036		$	26,778	$	14,785		$	18,320	$	3,146	$	100		$	74,975
	Charge-offs		726			1,226			1,142		486			457		366		0			4,403
	Recoveries		113			16			132		76			16		48		0			401
	Provision		1,174			1,442			589		(532	)		1,682		313		80			4,748
	Ending balance	$	4,371		$	8,268		$	26,357	$	13,843		$	19,561	$	3,141	$	180		$	75,721
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Nine Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real Estate			& Land				for
													Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	5,653		$	8,992		$	20,917	$	16,694		$	18,953	$	2,945	$	44		$	74,198
	Charge-offs		1,863			2,063			3,233		3,078			5,140		1,618		0			16,995
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Nine Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real Estate			& Land				for
													Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Recoveries		1,611			250			249		340			140		300		0			2,890
	Provision		(1,030	)		1,089			8,424		(113	)		5,608		1,514		136			15,628
	Ending balance	$	4,371		$	8,268		$	26,357	$	13,843		$	19,561	$	3,141	$	180		$	75,721
	Ending Balance: individually evaluated for impairment	$	820		$	773		$	4,016	$	2,582		$	3,775	$	0	$	0		$	11,966
	Ending Balance: collectively evaluated for impairment	$	3,551		$	7,495		$	22,341	$	11,261		$	15,786	$	3,141	$	180		$	63,755
	Ending Balance: loans acquired with deteriorated credit quality	$	0		$	0		$	0	$	0		$	0	$	0	$	0		$	0
	Financing receivables:
	Ending balance	$	1,044,951		$	2,718,821		$	1,592,606	$	2,229,353		$	1,088,627	$	356,125	$	0		$	9,030,483
	Ending Balance: individually evaluated for impairment	$	13,383		$	13,739		$	20,072	$	14,990		$	16,961	$	0	$	0		$	79,145
	Ending Balance: collectively evaluated for impairment	$	1,005,661		$	2,648,094		$	1,561,323	$	2,193,341		$	1,023,381	$	356,065	$	0		$	8,787,865
	Ending Balance: loans acquired with deteriorated credit quality	$	25,907		$	56,988		$	11,211	$	21,022		$	48,285	$	60	$	0		$	163,473
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Year Ended December 31, 2013
	(In thousands)	Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real			& Land				for
										Estate			Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	3,877		$	12,876		$	20,511	$	14,895		$	18,858	$	2,620	$	264		$	73,901
	Charge-offs		5,344			1,164			7,699		4,111			896		1,792		0			21,006
	Recoveries		150			56			641		698			73		418		0			2,036
	Provision		6,970			(2,776	)		7,464		5,212			918		1,699		(220	)		19,267
	Ending balance	$	5,653		$	8,992		$	20,917	$	16,694		$	18,953	$	2,945	$	44		$	74,198
	Ending Balance: individually evaluated for impairment	$	638		$	1,631		$	2,192	$	4,112		$	3,752	$	152	$	0		$	12,477
	Allowance for Loan Losses and Carrying Amount of Loans
For the Year Ended December 31, 2013
(In thousands)	Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
							Commercial		Real Estate			& Land				for
												Development				Estimated
	Owner-			Nonowner-												Imprecision
	occupied			occupied
Ending Balance: collectively evaluated for impairment	$	5,015		$	7,361		$	18,725	$	12,582		$	15,201	$	2,793	$	44		$	61,721
Ending Balance: loans acquired with deteriorated credit quality	$	0		$	0		$	0	$	0		$	0	$	0	$	0		$	0
Financing receivables:
Ending balance	$	654,963		$	1,917,785		$	1,338,355	$	1,821,378		$	670,364	$	310,754	$	0		$	6,713,599
Ending Balance: individually evaluated for impairment	$	7,157		$	13,913		$	22,327	$	16,160		$	21,593	$	152	$	0		$	81,302
Ending Balance: collectively evaluated for impairment	$	646,548		$	1,894,421		$	1,314,543	$	1,802,686		$	632,407	$	310,593	$	0		$	6,601,198
Ending Balance: loans acquired with deteriorated credit quality	$	1,258		$	9,451		$	1,485	$	2,532		$	16,364	$	9	$	0		$	31,099

Intangible_Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Intangible Assets	'
	7. INTANGIBLE ASSETS
	The following is a summary of intangible assets subject to amortization and those not subject to amortization:
		As of September 30, 2014
		Gross Carrying		Accumulated			Net Carrying
		Amount		Amortization			Amount
	Amortized intangible assets:
	Core deposit intangible assets	$	60,577	($	38,263	)	$	22,314
	Goodwill not subject to amortization						$	712,065
		As of December 31, 2013
		Gross Carrying		Accumulated			Net Carrying
		Amount		Amortization			Amount
	Amortized intangible assets:
	Core deposit intangible assets	$	43,434	($	35,296	)	$	8,138
	Goodwill not subject to amortization						$	375,547
	United incurred amortization expense of $1,054 and $2,967 for the quarter and nine months ended September 30, 2014, respectively, and $479 and $1,519 for the quarter and nine months ended September 30, 2013, respectively, related to intangible assets.
	The following table sets forth the anticipated amortization expense for intangible assets for the years subsequent to 2013:
	Year	Amount
	2014	$	4,133
	2015		3,383
	2016		2,943
	2017		2,730
	2018 and thereafter		12,092

ShortTerm_Borrowings

Short-Term Borrowings	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Short-Term Borrowings	'
	8. SHORT-TERM BORROWINGS
	Federal funds purchased and securities sold under agreements to repurchase are a significant source of funds for the Company. United has various unused lines of credit available from certain of its correspondent banks in the aggregate amount of $234,000. These lines of credit, which bear interest at prevailing market rates, permit United to borrow funds in the overnight market, and are renewable annually subject to certain conditions. At September 30, 2014, federal funds purchased were $30,120 while securities sold under agreements to repurchase (REPOs) were $396,818. Included in the $396,818 of total REPOs were wholesale REPOs of $52,713, including purchase accounting amounts, assumed in the Virginia Commerce merger. These wholesale REPOs are scheduled to mature in July of 2018. The securities sold under agreements to repurchase were accounted for as collateralized financial transactions. They were recorded at the amounts at which the securities were acquired or sold plus accrued interest.
	United has a $10,000 line of credit with an unrelated financial institution to provide for general liquidity needs. The line is an unsecured, revolving line of credit. The line will be renewable on a 360 day basis and will carry an indexed, floating-rate of interest. The line requires compliance with various financial and nonfinancial covenants. At September 30, 2014, United had no outstanding balance under this line of credit.

LongTerm_Borrowings

Long-Term Borrowings	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Long-Term Borrowings	'
	9. LONG-TERM BORROWINGS
	United’s subsidiary banks are members of the Federal Home Loan Bank (FHLB). Membership in the FHLB makes available short-term and long-term borrowings from collateralized advances. All FHLB borrowings are collateralized by a mix of single-family residential mortgage loans, commercial loans and investment securities. At September 30, 2014, United had an unused borrowing amount of approximately $2,275,693 available subject to delivery of collateral after certain trigger points. Advances may be called by the FHLB or redeemed by United based on predefined factors and penalties.
	At September 30, 2014, $930,679 of FHLB advances with a weighted-average interest rate of 0.45% are scheduled to mature within the next five years. Overnight funds of $100,000 are included in the $930,679 above at September 30, 2014. The scheduled maturities of these FHLB borrowings are as follows:
	Year	Amount
	2014	$	525,284
	2015		354,397
	2016		654
	2017		344
	2018 and thereafter		50,000
	Total	$	930,679
	At September 30, 2014, United had a total of fifteen statutory business trusts that were formed for the purpose of issuing or participating in pools of trust preferred capital securities (Capital Securities) with the proceeds invested in junior subordinated debt securities (Debentures) of United. The Debentures, which are subordinate and junior in right of payment to all present and future senior indebtedness and certain other financial obligations of United, are the sole assets of the trusts and United’s payment under the Debentures is the sole source of revenue for the trusts. At September 30, 2014, and December 31, 2013, the outstanding balance of the Debentures was $249,863 and $198,628, respectively, and was included in the category of long-term debt on the Consolidated Balance Sheets entitled “Other long-term borrowings.” The Capital Securities are not included as a component of shareholders’ equity in the Consolidated Balance Sheets. United fully and unconditionally guarantees each individual trust’s obligations under the Capital Securities.
	Under the provisions of the subordinated debt, United has the right to defer payment of interest on the subordinated debt at any time, or from time to time, for periods not exceeding five years. If interest payments on the subordinated debt are deferred, the dividends on the Capital Securities are also deferred. Interest on the subordinated debt is cumulative. United has not deferred any payment as of September 30, 2014.
	As part of the acquisition of Virginia Commerce on January 31, 2014, United assumed all the obligations of Virginia Commerce and its subsidiaries. Virginia Commerce has a total of three statutory business trusts that were formed for the purpose of issuing or participating in Capital Securities with the proceeds invested in Debentures of Virginia Commerce. At merger, the outstanding balance of Virginia Commerce’s Debentures was $50,635, including purchase accounting adjustments.
	The Trust Preferred Securities currently qualify as Tier 1 capital of United for regulatory purposes.

Commitments_and_Contingent_Lia

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingent Liabilities	'
	10. COMMITMENTS AND CONTINGENT LIABILITIES
	United is a party to financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers and to alter its own exposure to fluctuations in interest rates. These financial instruments include loan commitments, standby letters of credit, and interest rate swap agreements. The instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the financial statements.
	United’s maximum exposure to credit loss in the event of nonperformance by the counterparty to the financial instrument for the loan commitments and standby letters of credit is the contractual or notional amount of those instruments. United uses the same policies in making commitments and conditional obligations as it does for on-balance sheet instruments. Collateral may be obtained, if deemed necessary, based on management’s credit evaluation of the counterparty.
	Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the commitment contract. Commitments generally have fixed expiration dates or other termination clauses and may require the payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily, and historically do not, represent future cash requirements. The amount of collateral obtained, if deemed necessary upon the extension of credit, is based on management’s credit evaluation of the counterparty. United had approximately $2,641,369 and $1,895,682 of loan commitments outstanding as of September 30, 2014 and December 31, 2013, respectively, substantially all of which expire within one year.
	Commercial and standby letters of credit are agreements used by United’s customers as a means of improving their credit standing in their dealings with others. Under these agreements, United guarantees certain financial commitments of its customers. A commercial letter of credit is issued specifically to facilitate trade or commerce. Typically, under the terms of a commercial letter of credit, a commitment is drawn upon when the underlying transaction is consummated as intended between the customer and a third party. As of September 30, 2014 and December 31, 2013, United had no outstanding commercial letters of credit. A standby letter of credit is generally contingent upon the failure of a customer to perform according to the terms of an underlying contract with a third party. United has issued standby letters of credit of $172,008 and $114,664 as of September 30, 2014 and December 31, 2013, respectively. In accordance with the Contingencies Topic of the FASB Accounting Standards Codification, United has determined that substantially all of its letters of credit are renewed on an annual basis and the fees associated with these letters of credit are immaterial.
	United and its subsidiaries are currently involved in various legal proceedings in the normal course of business. Management is vigorously pursuing all its legal and factual defenses and, after consultation with legal counsel, believes that all such litigation will be resolved with no material effect on United’s financial position.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	11. DERIVATIVE FINANCIAL INSTRUMENTS
	United uses derivative instruments to help manage adverse prices or interest rate movements on the value of certain assets or liabilities and on future cash flows. These derivatives may consist of interest rate swaps, caps, floors, collars, futures, forward contracts, written and purchased options. United also executes derivative instruments with its commercial banking customers to facilitate its risk management strategies.
	United accounts for its derivative financial instruments in accordance with the Derivatives and Hedging topic of the FASB Accounting Standards Codification. The Derivatives and Hedging topic require all derivative instruments to be carried at fair value on the balance sheet. United has designated certain derivative instruments used to manage interest rate risk as hedge relationships with certain assets, liabilities or cash flows being hedged. Certain derivatives used for interest rate risk management are not designated in a hedge relationship.
	Derivative instruments designated in a hedge relationship to mitigate exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivative instruments designated in a hedge relationship to mitigate exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. As of September 30, 2014, United has only fair value hedges.
	For a fair value hedge, the fair value of the interest rate swap is recognized on the balance sheet as either a freestanding asset or liability with a corresponding adjustment to the hedged financial instrument. Subsequent adjustments due to changes in the fair value of a derivative that qualifies as a fair value hedge are offset in current period earnings.
	At inception of a hedge relationship, United formally documents the hedged item, the particular risk management objective, the nature of the risk being hedged, the derivative being used, how effectiveness of the hedge will be assessed and how the ineffectiveness of the hedge will be measured. United also assesses hedge effectiveness at inception and on an ongoing basis using regression analysis. Hedge ineffectiveness is measured by using the change in fair value method. The change in fair value method compares the change in the fair value of the hedging derivative to the change in the fair value of the hedged exposure, attributable to changes in the benchmark rate. The portion of a hedge that is ineffective is recognized immediately in earnings.
	The derivative portfolio also includes derivative financial instruments not included in hedge relationships. These derivatives consist of interest rate swaps used for interest rate management purposes and derivatives executed with commercial banking customers to facilitate their interest rate management strategies. For derivatives that are not designated in a hedge relationship, changes in the fair value of the derivatives are recognized in earnings in the same period as the change in fair value. Gains and losses on other derivative financial instruments are included in noninterest income and noninterest expense, respectively.
	The following table sets forth certain information regarding the interest rate derivatives portfolio used for interest-rate risk management purposes and designated as accounting hedges under the Derivatives and Hedging topic at September 30, 2014.
	Derivative Classifications and Hedging Relationships
	September 30, 2014
			Notional			Average
			Amount			Pay Rate
	Fair Value Hedges:
	Pay Fixed Swaps (Hedging Commercial Loans)		$	40,794			5.07	%
	Total Derivatives Used in Fair Value Hedges		$	40,794
	Total Derivatives Used for Interest Rate Risk Management and Designated as Hedges		$	40,794
	The following tables summarize the fair value of United’s derivative financial instruments.
			Asset Derivatives
			September 30, 2014						December 31, 2013
			Balance			Fair			Balance			Fair
			Sheet			Value			Sheet			Value
			Location						Location
	Derivatives designated as hedging instruments
	Interest rate contracts			Other assets		$	646			Other assets		$	2,179
	Total derivatives designated as hedging instruments					$	646					$	2,179
	Derivatives not designated as hedging instruments
	Interest rate contracts			Other assets		$	618			Other assets		$	1,045
	Total derivatives not designated as hedging instruments					$	618					$	1,045
	Total asset derivatives					$	1,264					$	3,224
			Liability Derivatives
			September 30, 2014						December 31, 2013
			Balance			Fair			Balance			Fair
			Sheet			Value			Sheet			Value
			Location						Location
	Derivatives designated as hedging instruments
	Interest rate contracts			Other liabilities		$	45			Other liabilities		$	149
	Total derivatives designated as hedging instruments					$	45					$	149
	Derivatives not designated as hedging instruments
	Interest rate contracts			Other liabilities		$	618			Other liabilities		$	1,045
	Total derivatives not designated as hedging instruments					$	618					$	1,045
	Total liability derivatives					$	663					$	1,194
	Derivative contracts involve the risk of dealing with both bank customers and institutional derivative counterparties and their ability to meet contractual terms. Credit risk arises from the possible inability of counterparties to meet the terms of their contracts. United’s exposure is limited to the replacement value of the contracts rather than the notional amount of the contract. The Company’s agreements generally contain provisions that limit the unsecured exposure up to an agreed upon threshold. Additionally, the Company attempts to minimize credit risk through certain approval processes established by management.
	The effect of United’s derivative financial instruments on its unaudited Consolidated Statements of Income for the three and nine months ended September 30, 2014 and 2013 are presented as follows:
						Three Months Ended
			Income Statement			September 30,			September 30,
			Location			2014			2013
	Derivatives in fair value hedging relationships
	Interest rate contracts			Interest income/	(expense)	$	(271	)	$	(157	)
	Total derivatives in fair value hedging relationships					$	(271	)	$	(157	)
	Derivatives not designated as hedging instruments
	Interest rate contracts (1)			Other income		$	154		$	218
	Interest rate contracts (2)			Other expense		$	(154	)	$	(218	)
	Total derivatives not designated as hedging instruments					$	0		$	0
	Total derivatives					$	(271	)	$	(157	)
						Nine Months Ended
			Income Statement			September 30,			September 30,
			Location			2014			2013
	Derivatives in fair value hedging relationships
	Interest rate contracts			Interest income/	(expense)	$	(795	)	$	(401	)
	Total derivatives in fair value hedging relationships					$	(795	)	$	(401	)
	Derivatives not designated as hedging instruments
	Interest rate contracts (1)			Other income		$	427		$	1,181
	Interest rate contracts (2)			Other expense		$	(427	)	$	(1,181	)
Total derivatives not designated as hedging instruments					$	0		$	0
Total derivatives					$	(795	)	$	(401	)
-1	Represents net gains from derivative assets not designated as hedging instruments.
-2	Represents net losses from derivative liabilities not designated as hedging instruments.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	12. FAIR VALUE MEASUREMENTS
	United determines the fair values of its financial instruments based on the fair value hierarchy established by ASC topic 820, which also clarifies that fair value of certain assets and liabilities is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants.
	The Fair Value Measurements and Disclosures topic specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect United’s market assumptions.
	The three levels of the fair value hierarchy, based on these two types of inputs, are as follows:
	Level 1			-		Valuation is based on quoted prices in active markets for identical assets and liabilities.
	Level 2			-		Valuation is based on observable inputs including quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets and liabilities in less active markets, and model-based valuation techniques for which significant assumptions can be derived primarily from or corroborated by observable data in the market.
	Level 3			-		Valuation is based on model-based techniques that use one or more significant inputs or assumptions that are unobservable in the market.
	When determining the fair value measurements for assets and liabilities, United looks to active and observable markets to price identical assets or liabilities whenever possible and classifies such items in Level 1. When identical assets and liabilities are not traded in active markets, United looks to market observable data for similar assets and liabilities and classifies such items as Level 2. Nevertheless, certain assets and liabilities are not actively traded in observable markets and United must use alternative valuation techniques using unobservable inputs to determine a fair value and classifies such items as Level 3. For assets and liabilities that are not actively traded, the fair value measurement is based primarily upon estimates that require significant judgment. Therefore, the results may not be realized in an actual sale or immediate settlement of the asset or liability. Additionally, there are inherent weaknesses in any calculation technique, and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the results of current or future values. The level within the fair value hierarchy is based on the lowest level of input that is significant in the fair value measurement.
	In accordance with ASC topic 820, the following describes the valuation techniques used by United to measure certain financial assets and liabilities recorded at fair value on a recurring basis in the financial statements:
	Securities available for sale: Securities available for sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted market prices, when available (Level 1). If quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar securities for which significant assumptions are derived primarily from or corroborated by observable market data. Using a market approach valuation methodology, third party vendors compile prices from various sources and may determine the fair value of identical or similar securities by using pricing models that considers observable market data (Level 2). Management internally reviews the fair values provided by third party vendors on a monthly basis. Management’s review consists of comparing fair values assigned by third party vendors to trades and offerings observed by management. The review requires some degree of judgment as to the number or percentage of securities to review on the part of management which could fluctuate based on results of past reviews and in comparison to current expectations. As part of management’s review, any items that exceed the scope of expected values are further investigated. Additionally, to assess the reliability of the information received from third party vendors, management obtains documentation from third party vendors related to the sources, methodologies, and inputs utilized in valuing securities classified as Level 2. Management analyzes this information to ensure the underlying assumptions appear reasonable. Management also obtains an independent service auditor’s report from third party vendors to provide reasonable assurance that appropriate controls are in place over the valuation process. Upon completing its review of the pricing from third party vendors at September 30, 2014, management determined that the prices provided by its third party pricing source were reasonable and in line with management’s expectations for the market values of these securities. Therefore, prices obtained from third party vendors that did not reflect forced liquidation or distressed sales were not adjusted by management at September 30, 2014. Management utilizes a number of factors to determine if a market is inactive, all of which may require a significant level of judgment. Factors that management considers include: a significant widening of the bid-ask spread, a considerable decline in the volume and level of trading activity in the instrument, a significant variance in prices among market participants, and a significant reduction in the level of observable inputs. Any securities available for sale not valued based upon quoted market prices or third party pricing models that consider observable market data are considered Level 3. Currently, United considers its valuation of available-for-sale Trup Cdos as Level 3. The Fair Value Measurements and Disclosures topic assumes that fair values of financial assets are determined in an orderly transaction and not a forced liquidation or distressed sale at the measurement date. Based on financial market conditions, United feels that the fair values obtained from its third party vendor reflect forced liquidation or distressed sales for these Trup Cdos due to decreased volume and trading activity. Additionally, management held discussions with institutional traders to identify trends in the number and type of transactions related to the Trup Cdos sector. Based upon management’s review of the market conditions for Trup Cdos, it was determined that an income approach valuation technique (present value technique) that maximizes the use of relevant observable inputs and minimizes the use of unobservable inputs is more representative of fair value than the valuation technique used by United’s third party vendor. The present value technique discounts expected future cash flows of a security to arrive at a present value. Management considers the following items when calculating the appropriate discount rate: the implied rate of return when the market was last active, changes in the implied rate of return as markets moved from very active to inactive, recent changes in credit ratings, and recent activity showing that the market has built in increased liquidity and credit premiums. Management’s internal credit review of each security was also factored in to determine the appropriate discount rate. The credit review considered each security’s collateral, subordination, excess spread, priority of claims, principal and interest. Discount margins used in the valuation at September 30, 2014 ranged from LIBOR plus 3.50% to LIBOR plus 9.75%. Management completed a sensitivity analysis on the fair value of its TRUP CDOs. Given a comprehensive 200 basis point increase in the discount rates, the total fair value of these securities would decline by approximately 19%, or $7.5 million.
	Derivatives: United utilizes interest rate swaps to hedge exposure to interest rate risk and variability of cash flows associated to changes in the underlying interest rate of the hedged item. These hedging interest rate swaps are classified as either a fair value hedge or a cash flow hedge. United’s derivative portfolio also includes derivative financial instruments not included in hedge relationships. These derivatives consist of interest rate swaps used for interest rate management purposes and derivatives executed with commercial banking customers to facilitate their interest rate management strategies. United utilizes third-party vendors for derivative valuation purposes. These vendors determine the appropriate fair value based on a net present value calculation of the cash flows related to the interest rate swaps using primarily observable market inputs such as interest rate yield curves (Level 2). Valuation adjustments to derivative fair values for liquidity and credit risk are also taken into consideration, as well as the likelihood of default by United and derivative counterparties, the net counterparty exposure and the remaining maturities of the positions. Values obtained from third party vendors are typically not adjusted by management. Management internally reviews the derivative values provided by third party vendors on a quarterly basis. All derivative values are tested for reasonableness by management utilizing a net present value calculation.
	For a fair value hedge, the fair value of the interest rate swap is recognized on the balance sheet as either a freestanding asset or liability with a corresponding adjustment to the hedged financial instrument. Subsequent adjustments due to changes in the fair value of a derivative that qualifies as a fair value hedge are offset in current period earnings either in interest income or interest expense depending on the nature of the hedged financial instrument. For a cash flow hedge, the fair value of the interest rate swap is recognized on the balance sheet as either a freestanding asset or liability with a corresponding adjustment to other comprehensive income within shareholders’ equity, net of tax. Subsequent adjustments due to changes in the fair value of a derivative that qualifies as a cash flow hedge are offset to other comprehensive income, net of tax. The portion of a hedge that is ineffective is recognized immediately in earnings. For derivatives that are not designated in a hedge relationship, changes in the fair value of the derivatives are recognized in earnings in the same period as the change in the fair value. Unrealized gains and losses due to changes in the fair value of other derivative financial instruments not in hedge relationship are included in noninterest income and noninterest expense, respectively.
	The following tables present the balances of financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2014 and December 31, 2013, segregated by the level of the valuation inputs within the fair value hierarchy.
						Fair Value at September 30, 2014 Using
	Description		Balance as of			Quoted Prices			Significant		Significant
			September 30,			in Active			Other		Unobservable
			2014			Markets for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Available for sale debt securities:
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	93,998		$	0		$	93,998	$	0
	State and political subdivisions			135,841			0			135,841		0
	Residential mortgage-backed securities
	Agency			541,632			0			541,632		0
	Non-agency			13,601			0			13,601		0
	Asset-backed securities			8,031			0			8,031		0
	Commercial mortgage-backed securities
	Agency			309,217			0			309,217		0
	Trust preferred collateralized debt obligations			38,819			0			0		38,819
	Single issue trust preferred securities			12,210			0			12,210		0
	Other corporate securities			5,159			0			5,159		0
	Total available for sale debt securities			1,158,508			0			1,119,689		38,819
	Available for sale equity securities:
	Financial services industry			2,329			703			1,626		0
	Equity mutual funds (1)			558			558			0		0
	Other equity securities			1,164			1,164			0		0
	Total available for sale equity securities			4,051			2,425			1,626		0
	Total available for sale securities			1,162,559			2,425			1,121,315		38,819
	Derivative financial assets:
	Interest rate contracts			1,264			0			1,264		0
	Liabilities
	Derivative financial liabilities:
	Interest rate contracts			663			0			663		0
	-1	The equity mutual funds are within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
						Fair Value at December 31, 2013 Using
	Description		Balance as of			Quoted Prices			Significant		Significant
			December 31,			in  Active			Other		Unobservable
			2013			Markets  for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Available for sale debt securities:
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	171,754		$	0		$	171,754	$	0
	State and political subdivisions			62,709			0			62,709		0
	Residential mortgage-backed securities
	Agency			216,464			0			216,464		0
	Non-agency			16,532			0			16,532		0
	Asset-backed securities			9,227			0			9,227		0
	Commercial mortgage-backed securities
	Agency			233,432			0			233,432		0
Trust preferred collateralized debt obligations			43,449			0			0		43,449
Single issue trust preferred securities			12,632			502			12,130		0
Other corporate securities			5,215			0			5,215		0
Total available for sale debt securities			771,414			502			727,463		43,449
Available for sale equity securities:
Financial services industry			2,292			716			1,576		0
Equity mutual funds (1)			434			434			0		0
Other equity securities			1,144			1,144			0		0
Total available for sale equity securities			3,870			2,294			1,576		0
Total available for sale securities			775,284			2,796			729,039		43,449
Derivative financial assets:
Interest rate contracts			3,224			0			3,224		0
Liabilities
Derivative financial liabilities:
Interest rate contracts			1,194			0			1,194		0
-1	The equity mutual funds are within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
The following table presents additional information about financial assets and liabilities measured at fair value at September 30, 2014 and December 31, 2013 on a recurring basis and for which United has utilized Level 3 inputs to determine fair value:
		Available-for-sale
		Securities
		Trust preferred
		collateralized debt obligations
		September 30,			December 31,
		2014			2013
Balance, beginning of period		$	43,449		$	40,613
Total gains or losses (realized/unrealized):
Included in earnings (or changes in net assets)			(4,539	)		(6,456	)
Included in other comprehensive income			15,400			14,520
Purchases, issuances, and settlements			(15,491	)		(5,228	)
Transfers in and/or out of Level 3			0			0
Balance, ending of period		$	38,819		$	43,449
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at reporting date			0			0
Certain financial assets are measured at fair value on a nonrecurring basis in accordance with GAAP. Adjustments to the fair value of these assets usually result from the application of lower-of-cost-or-market accounting or write-downs of individual assets.
The following describes the valuation techniques used by United to measure certain financial assets recorded at fair value on a non-recurring basis in the financial statements.
Loans held for sale: Loans held for sale are carried at the lower of cost or fair value. These loans currently consist of one-to-four family residential loans originated for sale in the secondary market. Fair value is based on the price secondary markets are currently offering for similar loans using observable market data which is not materially different than cost due to the short duration between origination and sale (Level 2). As such, United records any fair value adjustments on a nonrecurring basis. No nonrecurring fair value adjustments were recorded on loans held for sale during the quarter ended September 30, 2014. Gains and losses on sale of loans are recorded within income from mortgage banking on the Consolidated Statements of Income.
Impaired Loans: Loans are designated as impaired when, in the judgment of management based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. Impairment is measured based upon the present value of expected future cash flows from the loan discounted at the loan’s effective rate and the loan’s observable market price or the fair value of collateral, if the loan is collateral dependent. Fair value is measured using a market approach based on the value of the collateral securing the loans. Collateral may be in the form of real estate or business assets including equipment, inventory, and accounts receivable. The vast majority of the collateral is real estate. The value of real estate collateral is determined utilizing an appraisal conducted by an independent, licensed appraiser outside of the Company using comparable property sales (Level 2). However, if the collateral is a house or building in the process of construction or if an appraisal of the real estate property is over two years old, then the fair value is considered Level 3. The value of business equipment is based upon an outside appraisal if deemed significant, or the net book value on the applicable business’ financial statements if not considered significant using observable market data. Likewise, values for inventory and accounts receivables collateral are based on financial statement balances or aging reports (Level 3). For impaired loans, a specific reserve is established through the Allowance for Loan Losses, if necessary, by estimating the fair value of the underlying collateral on a nonrecurring basis. Any fair value adjustments are recorded in the period incurred as provision for credit losses expense on the Consolidated Statements of Income.
OREO: OREO consists of real estate acquired in foreclosure or other settlement of loans. Such assets are carried on the balance sheet at the lower of the investment in the assets or the fair value of the assets less estimated selling costs. Fair value is determined by one of two market approach methods depending on whether the property has been vacated and an appraisal can be conducted. If the property has yet to be vacated and thus an appraisal cannot be performed, a Brokers Price Opinion (i.e. BPO), is obtained. A BPO represents a best estimate valuation performed by a realtor based on knowledge of current property values and a visual examination of the exterior condition of the property. Once the property is subsequently vacated, a formal appraisal is obtained and the recorded asset value appropriately adjusted. On the other hand, if the OREO property has been vacated and an appraisal can be conducted, the fair value of the property is determined based upon the appraisal using a market approach. An authorized independent appraiser conducts appraisals for United. Appraisals for property other than ongoing construction are based on consideration of comparable property sales (Level 2). In contrast, valuation of ongoing construction assets requires some degree of professional judgment. In conducting an appraisal for ongoing construction property, the appraiser develops two appraised amounts: an “as is” appraised value and a “completed” value. Based on professional judgment and their knowledge of the particular situation, management determines the appropriate fair value to be utilized for such property (Level 3). As a matter of policy, valuations are reviewed at least annually and appraisals are generally updated on a bi-annual basis with values lowered as necessary.
Intangible Assets: For United, intangible assets consist of goodwill and core deposit intangibles. Goodwill is tested for impairment at least annually or sooner if indicators of impairment exist. Goodwill impairment would be defined as the difference between the recorded value of goodwill (i.e. book value) and the implied fair value of goodwill. In determining the implied fair value of goodwill for purposes of evaluating goodwill impairment, United determines the fair value of the reporting unit using a market approach and compares the fair value to its carrying value. If the carrying value exceeds the fair value, a step two test is performed whereby the implied fair value is computed by deducting the fair value of all tangible and intangible net assets from the fair value of the reporting unit. Core deposit intangibles relate to the estimated value of the deposit base of acquired institutions. Management reviews core deposit intangible assets on an annual basis, or sooner if indicators of impairment exist, and evaluates changes in facts and circumstances that may indicate impairment in the carrying value. Other than those intangible assets recorded in the acquisition of Virginia Commerce, no fair value measurement of intangible assets was made during the first nine months of 2014.
The following table summarizes United’s financial assets that were measured at fair value on a nonrecurring basis during the period:
Description		Balance as of			Fair Value Measurements							YTD
		September 30,			at September 30, 2014 Using							Losses
		2014			Quoted Prices			Significant		Significant
					in Active			Other		Unobservable
					Markets for			Observable		Inputs
					Identical			Inputs		(Level 3)
					Assets			(Level 2)
					(Level 1)
Assets
Impaired Loans		$	48,132		$	0		$	18,587	$	29,545	$	1,935
OREO			42,432			0			42,273		159		2,966
Description		Balance as of			at December 31, 2013 Using							YTD
		December 31,										Losses
		2013			Quoted Prices			Significant		Significant
					in Active			Other		Unobservable
					Markets for			Observable		Inputs
					Identical			Inputs		(Level 3)
					Assets			(Level 2)
					(Level 1)
Assets
Impaired Loans		$	45,883		$	0		$	13,081	$	32,802	$	1,886
OREO			38,182			0			38,107		75		2,548
The following methods and assumptions were used by United in estimating its fair value disclosures for other financial instruments:
Cash and Cash Equivalents: The carrying amounts reported in the balance sheet for cash and cash equivalents approximate those assets’ fair values.
Securities held to maturity and other securities: The estimated fair values of held to maturity are based on quoted market prices, where available. If quoted market prices are not available, fair values are measured utilizing independent valuation techniques of identical or similar securities for which significant assumptions are derived primarily from or corroborated by observable market data. Third party vendors compile prices from various sources and may determine the fair value of identical or similar securities by using pricing models that considers observable market data. Any securities held to maturity not valued based upon the methods above are valued based on a discounted cash flow methodology using appropriately adjusted discount rates reflecting nonperformance and liquidity risks. Other securities consist mainly of shares of Federal Home Loan Bank and Federal Reserve Bank stock that do not have readily determinable fair values and are carried at cost.
Loans: The fair values of certain mortgage loans (e.g., one-to-four family residential), credit card loans, and other consumer loans are based on quoted market prices of similar loans sold in conjunction with securitization transactions, adjusted for differences in loan characteristics. The fair values of other loans (e.g., commercial real estate and rental property mortgage loans, commercial and industrial loans, financial institution loans and agricultural loans) are estimated using discounted cash flow analyses, using market interest rates currently being offered for loans with similar terms to borrowers of similar creditworthiness, which include adjustments for liquidity concerns.
Deposits: The fair values of demand deposits (e.g., interest and noninterest checking, regular savings and certain types of money market accounts) are, by definition, equal to the amount payable on demand at the reporting date (i.e., their carrying amounts). The carrying amounts of variable-rate, fixed-term money market accounts and certificates of deposit approximate their fair values at the reporting date. Fair values of fixed-rate certificates of deposit are estimated using a discounted cash flow calculation that applies interest rates currently being offered on certificates to a schedule of aggregated expected monthly maturities on time deposits.
Short-term Borrowings: The carrying amounts of federal funds purchased, borrowings under repurchase agreements and other short-term borrowings approximate their fair values.
Long-term Borrowings: The fair values of United’s Federal Home Loan Bank borrowings and trust preferred securities are estimated using discounted cash flow analyses, based on United’s current incremental borrowing rates for similar types of borrowing arrangements.
The estimated fair values of United’s financial instruments are summarized below:
								Fair Value Measurements
		Carrying			Fair Value			Quoted Prices		Significant		Significant
		Amount						in Active		Other		Unobservable
								Markets for		Observable		Inputs
								Identical		Inputs		(Level 3)
								Assets		(Level 2)
								(Level 1)
September 30, 2014
Cash and cash equivalents		$	591,270		$	591,270		$	0	$	591,270	$	0
Securities available for sale			1,162,559			1,162,559			2,425		1,121,315		38,819
Securities held to maturity			39,969			38,381			0		36,361		2,020
Other securities			104,714			99,478			0		0		99,478
Loans held for sale			5,773			5,773			0		5,773		0
Loans			8,940,182			8,988,058			0		0		8,988,058
Derivative financial assets			1,264			1,264			0		1,264		0
Deposits			8,753,257			8,754,110			0		8,754,110		0
Short-term borrowings			474,225			474,225			0		474,225		0
Long-term borrowings			1,133,255			1,115,046			0		1,115,046		0
Derivative financial liabilities			663			663			0		663		0
December 31, 2013
Cash and cash equivalents		$	416,617		$	416,617		$	0	$	416,617	$	0
Securities available for sale			775,284			775,284			2,796		729,039		43,449
Securities held to maturity			40,965			38,293			0		35,773		2,520
Other securities			73,093			70,072			0		0		70,072
Loans held for sale			4,236			4,236			0		4,236		0
Loans			6,630,385			6,657,376			0		0		6,657,376
Derivative financial assets			3,224			3,224			0		3,224		0
Deposits			6,621,571			6,641,070			0		6,641,070		0
Short-term borrowings			430,754			430,754			0		430,754		0
Long-term borrowings			575,697			553,796			0		553,796		0
Derivative financial liabilities			1,194			1,194			0		1,194		0

Stock_Based_Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock Based Compensation	'
	13. STOCK BASED COMPENSATION
	On May 16, 2011, United’s shareholders approved the 2011 Long-Term Incentive Plan (2011 LTI Plan). The 2011 LTI Plan became effective as of July 1, 2011. An award granted under the 2011 LTI Plan may consist of any non-qualified stock options or incentive stock options, stock appreciation rights, restricted stock, or restricted stock units. These awards all relate to the common stock of United. The maximum number of shares of United common stock which may be issued under the 2011 LTI Plan is 1,500,000. Any and all shares may be issued in respect of any of the types of awards, provided that (1) the aggregate number of shares that may be issued in respect of restricted stock awards, and restricted stock units awards which are settled in shares is 350,000, and (2) the aggregate number of shares that may be issued pursuant to stock options is 1,150,000. The shares to be offered under the 2011 LTI Plan may be authorized and unissued shares or treasury shares. With respect to awards that are intended to satisfy the requirements for performance-based compensation under Code Section 162(m), the maximum number of options and stock appreciation rights, in the aggregate, which may be awarded pursuant to the 2011 LTI Plan to any individual participant during any calendar year is 100,000, and the maximum number of shares of restricted stock and/or shares subject to a restricted stock units award that may be granted pursuant to the 2011 LTI Plan to any individual participant during any calendar year is 50,000 shares. A participant may be any key employee of United or its affiliates or a non-employee member of United’s Board of Directors. Subject to certain change in control provisions, stock options, SARs, restricted stock and restricted stock units will vest in 25% increments over the first four anniversaries of the awards unless the Committee specifies otherwise in the award agreement. No award will vest sooner than 1/3 per year over the first three anniversaries of the award. A Form S-8 was filed on September 2, 2011 with the Securities and Exchange Commission to register all the shares which were available for the 2011 LTI Plan. During the first nine months of 2014, a total of 204,800 non-qualified stock options and 66,949 shares of restricted stock were granted under the 2011 LTI Plan.
	Compensation expense of $433 and $1,593 related to the nonvested awards under the 2011 LTI Plan and the 2006 Stock Option Plan was incurred for the third quarter and first nine months of 2014, respectively, as compared to the compensation expense of $466 and $1,320 related to the nonvested awards under the 2006 Stock Option Plan incurred for the third quarter and first nine months of 2013, respectively. Compensation expense was included in employee compensation in the unaudited Consolidated Statements of Income.
	Stock Options
	United currently has options outstanding from various option plans other than the 2006 Stock Option Plan (the “Prior Plans”); however, no common shares of United stock are available for grants under the Prior Plans as these plans have expired. Awards outstanding under the Prior Plans will remain in effect in accordance with their respective terms. The maximum term for options granted under the plans is ten (10) years.
	A summary of activity under United’s stock option plans as of September 30, 2014, and the changes during the first nine months of 2014 are presented below:
		Nine Months Ended September 30, 2014
							Weighted Average
					Aggregate		Remaining
					Intrinsic		Contractual		Exercise
		Shares			Value		Term (Yrs.)		Price
	Outstanding at January 1, 2014		1,447,997						$	29.33
	Assumed in Virginia Commerce merger		440,813							19.55
	Granted		204,800							28.89
	Exercised		(368,856	)						19.5
	Forfeited or expired		(69,529	)						32.3
	Outstanding at September 30, 2014		1,655,225		$	5,745		5.1	$	28.74
	Exercisable at September 30, 2014		1,254,236		$	4,629		4	$	28.92
	The following table summarizes the status of United’s nonvested stock option awards during the first nine months of 2014:
		Shares			Weighted-Average
					Grant Date Fair Value
					Per Share
	Nonvested at January 1, 2014		589,197		$	7.01
	Granted		204,800			6.42
	Vested		(383,475	)		7.46
	Forfeited or expired		(9,533	)		6.48
	Nonvested at September 30, 2014		400,989		$	6.29
	During the nine months ended September 30, 2014 and 2013, 368,856 and 70,570 shares, respectively, were issued in connection with stock option exercises. Of the 368,856 shares issued in connection with stock option exercises, 342,382 were issued from available treasury stock while 26,474 shares were issued from authorized and unissued stock for the nine months ended September 30, 2014. All shares issued in connection with stock options exercises for the nine months ended September 30, 2013 were issued from available treasury stock. The total intrinsic value of options exercised under the Plans during the nine months ended September 30, 2014 and 2013 was $3,977 and $363, respectively.
	Restricted Stock
	Under the 2011 LTI Plan, United may award restricted common shares to key employees and non-employee directors. Restricted shares granted to participants have a four-year time-based vesting period. Recipients of restricted shares do not pay any consideration to United for the shares, have the right to vote all shares subject to such grant and receive all dividends with respect to such shares, whether or not the shares have vested. Presently, these nonvested participating securities have an immaterial impact on diluted earnings per share.
	The following summarizes the changes to United’s restricted common shares for the period ended September 30, 2014:
		Number			Weighted-Average
		of Shares			Grant Date Fair Value
					Per Share
	Outstanding at January 1, 2014		85,497		$	27.53
	Assumed in Virginia Commerce merger		34,538			29.89
	Granted		66,949			28.89
	Vested		(57,204	)		28.83
	Forfeited		(2,338	)		28.11
	Outstanding at September 30, 2014		127,442		$	28.29

Employee_Benefit_Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plans	'
	14. EMPLOYEE BENEFIT PLANS
	United has a defined benefit retirement plan covering some of its employees. Pension benefits are based on years of service and the average of the employee’s highest five consecutive plan years of basic compensation paid during the ten plan years preceding the date of determination. Contributions are intended to provide not only for benefits attributed to service to date, but also for those expected to be earned in the future.
	In September of 2007, after a recommendation by United’s Pension Committee and approval by United’s Board of Directors, the United Bankshares, Inc. Pension Plan (the Plan) was amended to change the participation rules. The decision to change the participation rules for the Plan followed current industry trends, as many large and medium size companies had taken similar steps. The amendment provides that employees hired on or after October 1, 2007, will not be eligible to participate in the Plan. However, new employees, including those retained in the Virginia Commerce acquisition, will be eligible to participate in United’s Savings and Stock Investment 401(k) plan. This change had no impact on current employees hired prior to October 1, 2007 as they will continue to participate in the Plan, with no change in benefit provisions, and will continue to be eligible to participate in United’s Savings and Stock Investment 401(k) plan.
	Included in accumulated other comprehensive income at December 31, 2013 are the following amounts that have not yet been recognized in net periodic pension cost: unrecognized prior service costs of $2 ($1 net of tax) and unrecognized actuarial losses of $31,151 ($20,248 net of tax). The amortization of these items expected to be recognized in net periodic pension cost during the fiscal year ended December 31, 2014 is $1 ($1 net of tax), and $4,821 ($3,134 net of tax), respectively.
	Net periodic pension cost for the three and nine months ended September 30, 2014 and 2013 included the following components:
		Three Months  Ended						Nine Months Ended
		September 30						September 30
		2014			2013			2014			2013
	Service cost	$	579		$	777		$	1,720		$	2,304
	Interest cost		1,361			1,235			4,039			3,665
	Expected return on plan assets		(2,293	)		(2,097	)		(6,806	)		(6,223	)
	Amortization of transition asset		0			0			0			0
	Recognized net actuarial loss		491			1,184			1,458			3,515
	Amortization of prior service cost		1			1			1			1
	Net periodic pension (benefit) cost	$	139		$	1,100		$	412		$	3,262
	Weighted-Average Assumptions:
	Discount rate		5.2	%		4.4	%		5.2	%		4.4	%
	Expected return on assets		7.5	%		8	%		7.5	%		8	%
	Rate of compensation increase (prior to age 45)		3.5	%		3.75	%		3.5	%		3.75	%
	Rate of compensation increase		3	%		2.75	%		3	%		2.75	%

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	15. INCOME TAXES
	United records a liability for uncertain income tax positions based on a recognition threshold of more-likely-than-not, and a measurement attribute for all tax positions taken on a tax return, in order for those tax positions to be recognized in the financial statements.
	As of September 30, 2014, United has provided a liability for $3,449 of unrecognized tax benefits related to various federal and state income tax matters. The entire amount of unrecognized tax benefits, if recognized, would impact United’s effective tax rate. Over the next 12 months, the statute of limitations will close on certain income tax periods. However, at this time, United cannot reasonably estimate the amount of tax benefits it may recognize over the next 12 months.
	United is currently open to audit under the statute of limitations by the Internal Revenue Service for the years ended December 31, 2011, 2012 and 2013 and State Taxing authorities for the years ended December 31, 2010 through 2013.
	As of September 30, 2014 and 2013, the total amount of accrued interest related to uncertain tax positions was $540 and $427, respectively. United accounts for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes.

Comprehensive_Income

Comprehensive Income	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Comprehensive Income	'
	16. COMPREHENSIVE INCOME
	The components of total comprehensive income for the three and nine months ended September 30, 2014 and 2013 are as follows:
			Three Months Ended						Nine Months Ended
			September 30						September 30
			2014			2013			2014			2013
	Net Income		$	33,260		$	22,170		$	96,631		$	65,968
	Available for sale (“AFS”) securities:
	AFS securities with OTTI charges during the period			(4,714	)		0			(5,774	)		(1,172	)
	Related income tax effect			1,650			0			2,021			410
	Less : OTTI charges recognized in net income			4,714			0			5,774			971
	Related income tax benefit			(1,650	)		0			(2,021	)		(340	)
	Reclassification of previous noncredit OTTI to credit OTTI			4,153			0			6,259			1,458
	Related income tax benefit			(1,453	)		0			(2,190	)		(510	)
	Net unrealized (losses) gains on AFS securities with OTTI			2,700			0			4,069			817
	AFS securities – all other:
	Change in net unrealized gain on AFS securities arising during the period			(339	)		4,680			24,242			1,080
	Related income tax effect			119			(1,638	)		(8,485	)		(378	)
	Net reclassification adjustment for (gains) losses included in net income			(1,300	)		(101	)		(2,125	)		(476	)
	Related income tax expense (benefit)			455			36			744			167
				(1,065	)		2,977			14,376			393
	Net effect of AFS securities on other comprehensive income			1,635			2,977			18,445			1,210
	Held to maturity (“HTM”) securities:
	Accretion on the unrealized loss for securities transferred from			2			2			6			6
	AFS to the HTM investment portfolio prior to call or maturity
	Related income tax expense			(0	)		0			(2	)		(2	)
	Net effect of HTM securities on other comprehensive income			2			2			4			4
	Pension plan:
	Amortization of prior service cost			1			1			1			1
	Related income tax benefit			0			0			0			0
	Recognized net actuarial loss			491			1,184			1,458			3,515
	Related income tax benefit			(183	)		(445	)		(531	)		(1,293	)
	Net effect of change in pension plan asset on other comprehensive income			309			740			928			2,223
	Total change in other comprehensive income			1,946			3,719			19,377			3,437
	Total Comprehensive Income		$	35,206		$	25,889		$	116,008		$	69,405
	The components of accumulated other comprehensive income for the nine months ended September 30, 2014 are as follows:
	Changes in Accumulated Other Comprehensive Income (AOCI) by Component (a)
	For the Nine Months Ended September 30, 2014
	(Dollars in thousands)		Unrealized			Accretion on			Defined			Total
			Gains/Losses			the unrealized			Benefit
			on AFS			loss for			Pension
			Securities			securities			Items
						transferred
						from AFS to
						the HTM
	Balance at January 1, 2014		($	23,235	)	($	67	)	($	19,745	)	($	43,047	)
	Other comprehensive income before reclassification			15,757			4			0			15,761
	Amounts reclassified from accumulated other comprehensive income			2,688			0			928			3,616
	Net current-period other comprehensive income, net of tax			18,445			4			928			19,377
	Balance at September 30, 2014		($	4,790	)	($	63	)	($	18,817	)	($	23,670	)
	(a)	All amounts are net-of-tax.
	Reclassifications out of Accumulated Other Comprehensive Income (AOCI)
	For the Nine Months Ended September 30, 2014
	(Dollars in thousands)		Amount			Affected Line Item in the Statement Where
			Reclassified			Net Income is Presented
	Details about AOCI Components		from AOCI
	Available for sale (“AFS”) securities:
	Reclassification of previous noncredit OTTI to credit OTTI		$	6,259		Total other-than-temporary impairment losses
	Net reclassification adjustment for losses (gains) included in net income			(2,125	)	Net gains on sales/calls of investment securities
				4,134		Total before tax
	Related income tax effect			(1,446	)	Tax expense
				2,688		Net of tax
	Pension plan:
	Amortization of transition asset			1	(a)
Recognized net actuarial loss			1,458	(a)
			1,459		Total before tax
Related income tax effect			(531	)	Tax expense
			928		Net of tax
Total reclassifications for the period		$	3,616
(a)	This AOCI component is included in the computation of net periodic pension cost (see Note 14, Employee Benefit Plans)

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	17. EARNINGS PER SHARE
	The reconciliation of the numerator and denominator of basic earnings per share with that of diluted earnings per share is presented as follows:
		Three Months Ended				Nine Months Ended
		September 30				September 30
		2014		2013		2014		2013
	Distributed earnings allocated to common stock	$	22,101	$	15,597	$	66,261	$	46,760
	Undistributed earnings allocated to common stock		11,102		6,538		30,194		19,104
	Net earnings allocated to common shareholders	$	33,203	$	22,135	$	96,455	$	65,864
	Average common shares outstanding		69,044,876		50,378,613		66,836,396		50,336,741
	Equivalents from stock options		224,433		94,346		232,956		65,714
	Average diluted shares outstanding		69,269,309		50,472,959		67,069,352		50,402,455
	Earnings per basic common share	$	0.48	$	0.44	$	1.45	$	1.31
	Earnings per diluted common share	$	0.48	$	0.44	$	1.44	$	1.31

Variable_Interest_Entities

Variable Interest Entities

9 Months Ended

Sep. 30, 2014

Equity Method Investments and Joint Ventures [Abstract]

'

Variable Interest Entities

'

18. VARIABLE INTEREST ENTITIES

Variable interest entities (VIEs) are entities that either have a total equity investment that is insufficient to permit the entity to finance its activities without additional subordinated financial support or whose equity investors lack the characteristics of a controlling financial interest (i.e., ability to make significant decisions, through voting rights, right to receive the expected residual returns of the entity, and obligation to absorb the expected losses of the entity). VIEs can be structured as corporations, trusts, partnerships, or other legal entities. United’s business practices include relationships with certain VIEs. For United, the business purpose of these relationships primarily consists of funding activities in the form of issuing trust preferred securities.

United currently sponsors fifteen statutory business trusts that were created for the purpose of raising funds that qualify for Tier I regulatory capital. These trusts, of which several were acquired through bank acquisitions, issued or participated in pools of trust preferred capital securities to third-party investors with the proceeds invested in junior subordinated debt securities of United. The Company, through a small capital contribution, owns 100% of the voting equity shares of each trust. The assets, liabilities, operations, and cash flows of each trust are solely related to the issuance, administration, and repayment of the preferred equity securities held by third-party investors. United fully and unconditionally guarantees the obligations of each trust and is obligated to redeem the junior subordinated debentures upon maturity.

The trusts utilized in these transactions are VIEs as the third-party equity holders lack a controlling financial interest in the trusts through their inability to make decisions that have a significant effect on the operations and success of the entities. United does not consolidate these trusts as it is not the primary beneficiary of these entities because United’s equity interest does not absorb the majority of the trusts’ expected losses or receive a majority of their expected residual returns.

Information related to United’s statutory trusts is presented in the table below:

Description

Issuance Date

Amount of

Interest Rate

Maturity Date

Capital

Securities

Issued

Century Trust

March 23, 2000

$

8,800

10.875% Fixed

March 8, 2030

Sequoia Trust I

28-Mar-01

$

2,000

10.18% Fixed

8-Jun-31

United Statutory Trust III

December 17, 2003

$

20,000

3-month LIBOR + 2.85%

December 17, 2033

United Statutory Trust IV

19-Dec-03

$

25,000

3-month LIBOR + 2.85%

23-Jan-34

United Statutory Trust V

12-Jul-07

$

50,000

3-month LIBOR + 1.55%

1-Oct-37

United Statutory Trust VI

September 20, 2007

$

30,000

3-month LIBOR + 1.30%

15-Dec-37

Premier Statutory Trust II

25-Sep-03

$

6,000

3-month LIBOR + 3.10%

8-Oct-33

Premier Statutory Trust III

16-May-05

$

8,000

3-month LIBOR + 1.74%

15-Jun-35

Premier Statutory Trust IV

20-Jun-06

$

14,000

3-month LIBOR + 1.55%

September 23, 2036

Premier Statutory Trust V

14-Dec-06

$

10,000

3-month LIBOR + 1.61%

1-Mar-37

Centra Statutory Trust I

20-Sep-04

$

10,000

3-month LIBOR + 2.29%

20-Sep-34

Centra Statutory Trust II

15-Jun-06

$

10,000

3-month LIBOR + 1.65%

7-Jul-36

Virginia Commerce Trust II

19-Dec-02

$

15,000

6-month LIBOR + 3.30%

19-Dec-32

Virginia Commerce Trust III

20-Dec-05

$

25,000

3-month LIBOR + 1.42%

23-Feb-36

Virginia Commerce Trust IV

24-Sep-08

$

25,000

10.20% Fixed

30-Sep-38

On November 7, 2014, UBV Holding Company, Inc., a wholly-owned subsidiary of United, submitted redemption notices to Wilmington Trust Company, as Trustee, to redeem the trust preferred securities listed below. Under applicable regulatory capital guidelines issued by bank regulatory agencies, upon notice of the redemption, the amount of trust preferred securities that will be redeemed will no longer qualify as Tier 1 capital for United. The Federal Reserve Board did not object to the redemption of the securities. The redemptions will be funded with excess cash currently available to United.

Trust

Interest Rate

Redemption

Principal Amount

Principal Amount

Redemption Date

Price

Outstanding

to be Redeemed

Sequoia Capital Trust I

10.18

%

103.563

%

$

2,000

$

2,000

December 8, 2014

VCBI Capital Trust IV

10.2

%

100

%

$

25,000

$

25,000

December 30, 2014

United, through its banking subsidiaries, also makes limited partner equity investments in various low income housing and community development partnerships sponsored by independent third-parties. United invests in these partnerships to either realize tax credits on its consolidated federal income tax return or for purposes of earning a return on its investment. These partnerships are considered VIEs as the limited partners lack a controlling financial interest in the entities through their inability to make decisions that have a significant effect on the operations and success of the partnerships. United’s limited partner interests in these entities is immaterial, however; these partnerships are not consolidated as United is not deemed to be the primary beneficiary.

The following table summarizes quantitative information about United’s significant involvement in unconsolidated VIEs:

As of September 30, 2014

As of December 31, 2013

Aggregate

Aggregate

Risk Of

Aggregate

Aggregate

Risk Of

Assets

Liabilities

Loss (1)

Assets

Liabilities

Loss (1)

Trust preferred securities

$

268,315

$

259,454

$

8,861

$

201,186

$

194,453

$

6,733

-1

Represents investment in VIEs.

General_Policies

General (Policies)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
New Accounting Standards	'
	New Accounting Standards
	In August 2014, the FASB issued ASU 2014-14, “Receivables-Troubled Debt Restructurings by Creditors (Subtopic 310-40), Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure.” ASU 2014-14 was issued to clarify the classification and measurement of certain foreclosed residential and nonresidential mortgage loans that are either fully or partially guaranteed under government programs. Specifically, creditors should reclassify loans that are within the scope of ASU 2014-14 to “other receivables” upon foreclosure, rather than reclassifying them to other real estate owned (OREO). ASU 2014-14 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In June 2014, the FASB issued ASU 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period.” ASU 2014-12 amends the guidance in FASB ASC 718, “Compensation-Stock Compensation”, to bring consistency to the accounting for share-based payment awards that require a specific performance target to be achieved in order for employees to become eligible to vest in the awards. The amendments affect all entities that grant their employees share-based payments in which the terms of the award provide that a performance target that affects vesting could be achieved after the requisite service period. ASU 2014-12 is effective for United on January 1, 2016, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In June 2014, the FASB issued ASU 2014-11, “Transfers and Servicing (Topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures.” ASU 2014-11 modifies accounting for repurchase-to-maturity transactions and repurchase financing arrangements, as well as modifies required disclosures. Under ASU 2014-11, repurchase-to-maturity transactions, repurchase agreements executed as repurchase financings, and other typical repurchase agreements are accounted for as secured borrowings. ASU 2014-11 also eliminates off-balance-sheet accounting for transfers of financial assets with contemporaneous repurchase financings. ASU 2014-11 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 supersedes the revenue recognition requirements in Accounting Standards Codification Topic 605, “Revenue Recognition”, and most industry-specific guidance throughout the Accounting Standards Codification. The amendments require an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new revenue recognition standard sets forth a five step principle-based approach for determining revenue recognition. ASU 2014-09 is effective for United on January 1, 2017. Management is currently evaluating this guidance to determine the impact on the Company’s financial condition or results of operation.
	In January 2014, the FASB issued ASU 2014-04, “Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure.” ASU 2014-04 clarifies when banks and similar institutions should reclassify mortgage loans collateralized by residential real estate properties from the loan portfolio to other real estate owned (OREO). An entity can elect either a retrospective or a prospective transition method, and early adoption is permitted. ASU 2014-04 is effective for United on January 1, 2015, and is not expected to have a significant impact on the Company’s financial condition or results of operation.
	In February 2013, the FASB issued ASU 2013-02, “Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income.” ASU 2013-02 is intended to improve the reporting of reclassifications out of accumulated other comprehensive income of various components. ASU 2013-02 requires entities to disclose in a single location, either on the face of financial statement that reports net income or in the notes, the effects of reclassification out of accumulated other comprehensive income (AOCI). For items reclassified out of AOCI and into net income in their entirety, such as realized gains or losses on available-for-sale securities reclassified into net income on sale, entities must disclose the effect on the reclassification on each affected net income item. For AOCI reclassification items that are not reclassified in their entirety into net income, such as actuarial gains or losses amortized into pension cost that may be capitalized into inventory or other assets, entities must provide a cross reference to other required U.S. GAAP disclosures. ASU 2013-02 was effective for United on January 1, 2013 and did not have a significant impact on the Company’s financial condition or results of operation.
	In February 2013, the FASB issued ASU 2013-04, “Obligations Resulting from Joint and Several Liability Arrangements for which the Total Amount of the Obligation is Fixed at the Reporting Date.” ASU 2013-04 addresses the recognition, measurement and disclosure of certain obligations including debt arrangements, other contractual obligations, and settled litigation and judicial ruling. In particular, ASU 2013-04 requires entities to record an obligation resulting from joint and several liability arrangements that are fixed at the reporting date at the greater of the amount that the entity has agreed to pay or the amount the entity expects to pay. The guidance applies retrospectively for obligations that exist at the beginning of an entity’s fiscal year of adoption. ASU 2013-04 was effective for United beginning January 1, 2014 and did not have a significant impact on the Company’s financial condition or results of operation.
Fair Value Measurement	'
	United determines the fair values of its financial instruments based on the fair value hierarchy established by ASC topic 820, which also clarifies that fair value of certain assets and liabilities is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants.
	The Fair Value Measurements and Disclosures topic specifies a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect United’s market assumptions.
	The three levels of the fair value hierarchy, based on these two types of inputs, are as follows:
	Level 1	-	Valuation is based on quoted prices in active markets for identical assets and liabilities.
	Level 2	-	Valuation is based on observable inputs including quoted prices in active markets for similar assets and liabilities, quoted prices for identical or similar assets and liabilities in less active markets, and model-based valuation techniques for which significant assumptions can be derived primarily from or corroborated by observable data in the market.
	Level 3	-	Valuation is based on model-based techniques that use one or more significant inputs or assumptions that are unobservable in the market.
	When determining the fair value measurements for assets and liabilities, United looks to active and observable markets to price identical assets or liabilities whenever possible and classifies such items in Level 1. When identical assets and liabilities are not traded in active markets, United looks to market observable data for similar assets and liabilities and classifies such items as Level 2. Nevertheless, certain assets and liabilities are not actively traded in observable markets and United must use alternative valuation techniques using unobservable inputs to determine a fair value and classifies such items as Level 3. For assets and liabilities that are not actively traded, the fair value measurement is based primarily upon estimates that require significant judgment. Therefore, the results may not be realized in an actual sale or immediate settlement of the asset or liability. Additionally, there are inherent weaknesses in any calculation technique, and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the results of current or future values. The level within the fair value hierarchy is based on the lowest level of input that is significant in the fair value measurement.

Mergers_and_Acquisitions_Table

Mergers and Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Schedule of Acquired Loans Accounted for at Fair value	'
	In conjunction with the Virginia Commerce merger, the acquired loan portfolio was accounted for at fair value as follows:
			January 31, 2014
	Contractually required principal and interest at acquisition		$	2,683,966
	Contractual cash flows not expected to be collected			(396,983	)
	Expected cash flows at acquisition			2,286,983
	Interest component of expected cash flows			(274,462	)
	Basis in acquired loans at acquisition – estimated fair value		$	2,012,521
Schedule of Acquired Identifiable Assets and Liabilities Assumed	'
	The consideration paid for Virginia Commerce’s common equity and the amounts of acquired identifiable assets and liabilities assumed as of the Acquisition Date were as follows:
	Purchase price:
	Value of common shares issued (18,330,347 shares)		$	547,894
	Fair value of stock options assumed			4,368
	Cash to redeem the Treasury warrant			33,263
	Cash for fractional shares			8
	Total purchase price			585,533
	Identifiable assets:
	Cash and cash equivalents			130,569
	Investment securities			476,541
	Loans			2,012,521
	Premises and equipment			10,786
	Core deposit intangibles			17,143
	Other assets			104,589
	Total identifiable assets		$	2,752,149
	Identifiable liabilities:
	Deposits		$	2,024,969
	Short-term borrowings			263,816
	Long-term borrowings			204,335
	Other liabilities			11,393
	Total identifiable liabilities			2,504,513
	Net assets acquired including identifiable intangible assets			247,636
	Resulting goodwill		$	337,897
Schedule of Acquired Reconciliation of Goodwill	'
	The following table provides a reconciliation of goodwill:
	Goodwill at December 31, 2013		$	375,547
	Addition to goodwill from Virginia Commerce acquisition			337,897
	Reduction to goodwill for options exercised from previous acquisitions			(37	)
	Reclassification from goodwill			(1,342	)
	Goodwill at September 30, 2014		$	712,065
Schedule of Business Acquisition Pro Forma Information	'
	The following table presents certain unaudited pro forma information for the results of operations for the nine months ended September 30, 2014 and 2013, as if the Virginia Commerce merger had occurred on January 1, 2014 and 2013, respectively.
			Proforma
			Nine Months Ended
			September 30
			2014			2013
	Total Revenues (1)		$	346,594		$	347,419
	Net Income			89,488			89,960
	(1)	Represents net interest income plus other income

Investment_Securities_Tables

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2014
Summary of Amortized Cost and Estimated Fair Values of Available for Sale Securities	'
	The amortized cost and estimated fair values of securities available for sale are summarized as follows.
			September 30, 2014
			Amortized		Gross		Gross		Estimated		Cumulative
			Cost		Unrealized		Unrealized		Fair		OTTI in
					Gains		Losses		Value		AOCI (1)
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	93,439	$	697	$	138	$	93,998	$	0
	State and political subdivisions			132,583		3,260		2		135,841		0
	Residential mortgage-backed securities
	Agency			537,886		5,049		1,303		541,632		0
	Non-agency			12,871		730		0		13,601		458
	Commercial mortgage-backed securities
	Agency			312,582		1,016		4,381		309,217		0
	Asset-backed securities			8,005		26		0		8,031		0
	Trust preferred collateralized debt obligations			52,370		767		14,318		38,819		28,040
	Single issue trust preferred securities			13,747		291		1,828		12,210		0
	Other corporate securities			4,997		162		0		5,159		0
	Marketable equity securities			3,467		584		0		4,051		0
	Total		$	1,171,947	$	12,582	$	21,970	$	1,162,559	$	28,498
			December 31, 2013
			Amortized		Gross		Gross		Estimated		Cumulative
			Cost		Unrealized		Unrealized		Fair		OTTI in
					Gains		Losses		Value		AOCI (1)
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	172,324	$	178	$	748	$	171,754	$	0
	State and political subdivisions			60,861		1,874		26		62,709		0
	Residential mortgage-backed securities
	Agency			215,788		2,491		1,815		216,464		0
	Non-agency			16,369		163		0		16,532		458
	Commercial mortgage-backed securities
	Agency			241,947		225		8,740		233,432		0
	Asset-backed securities			9,257		1		31		9,227		0
	Trust preferred collateralized debt obligations			73,862		210		30,623		43,449		34,299
	Single issue trust preferred securities			14,346		305		2,019		12,632		0
	Other corporate securities			4,996		219		0		5,215		0
	Marketable equity securities			3,299		572		1		3,870		0
	Total		$	813,049	$	6,238	$	44,003	$	775,284	$	34,757
	-1	Other-than-temporary impairment in accumulated other comprehensive income. Amounts are before-tax.
Summary of Securities Available for Sale in an Unrealized Loss Position	'
	The following is a summary of securities available-for-sale which were in an unrealized loss position at September 30, 2014 and December 31, 2013.
			Less than 12 months				12 months or longer
			Fair		Unrealized		Fair		Unrealized
			Value		Losses		Value		Losses
	September 30, 2014
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	19,030	$	138	$	0	$	0
	State and political subdivisions			2,783		2		0		0
	Residential mortgage-backed securities
	Agency			164,364		1,303		0		0
	Commercial mortgage-backed securities
	Agency			78,108		526		162,621		3,855
	Asset-backed securities			0		0		0		0
	Trust preferred collateralized debt obligations			0		0		34,148		14,318
	Single issue trust preferred securities			0		0		8,430		1,828
	Marketable equity securities			0		0		0		0
	Total		$	264,285	$	1,969	$	205,199	$	20,001
	December 31, 2013
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	61,517	$	748	$	0	$	0
	State and political subdivisions			2,353		26		0		0
	Residential mortgage-backed securities
	Agency			160,835		1,815		0		0
	Commercial mortgage-backed securities
	Agency			208,979		8,740		0		0
	Asset-backed securities			7,976		31		0		0
	Trust preferred collateralized debt obligations			0		0		27,167		30,623
	Single issue trust preferred securities			502		2		8,210		2,017
	Marketable equity securities			0		0		25		1
	Total		$	442,162	$	11,362	$	35,402	$	32,641
Summary of Gains or Losses on Proceeds from Maturities, Sales and Calls of Available for Sale Securities by Specific Identification Method	'
	The realized losses relate to sales of securities within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
			Three Months Ended				Nine Months Ended
			September 30				September 30
			2014		2013		2014		2013
	Proceeds from sales and calls		$	64,610	$	183,069	$	500,493	$	587,852
	Gross realized gains			1,314		109		2,366		499
	Gross realized losses			5		8		232		23
Summary of Available for Sale TRUP CDOs	'
	The following is a summary of the available for sale Trup Cdos as of September 30, 2014:
									Amortized Cost
	Class		Amortized		Fair		Unrealized		Investment		Split		Below
			Cost		Value		Loss/(Gain)		Grade		Rated		Investment
													Grade
	Senior – Bank		$	7,725	$	6,133	$	1,592	$	0	$	5,000	$	2,725
	Mezzanine – Bank (now in senior position)			12,599		9,658		2,941		0		0		12,599
	Mezzanine – Bank			26,883		19,045		7,838		0		0		26,883
	Mezzanine – Bank & Insurance (combination)			5,163		3,983		1,180		0		0		5,163
	Totals		$	52,370	$	38,819	$	13,551	$	0	$	5,000	$	47,370
Roll Forward of Credit Losses on Securities	'
	Below is a progression of the credit losses on securities which United has recorded other-than-temporary charges through earnings and other comprehensive income.
	Balance of cumulative credit losses at December 31, 2013		$	70,446
	Additions for credit losses on securities for which OTTI was not previously recognized			0
	Additions for additional credit losses on securities for which OTTI was previously recognized			5,774
	Balance of cumulative credit losses at September 30, 2014		$	76,220
Summary of Amortized Cost and Estimated Fair Values of Securities Held to Maturity	'
	The amortized cost and estimated fair values of securities held to maturity are summarized as follows:
			September 30, 2014
					Gross		Gross		Estimated
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gains		Losses		Value
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	10,640	$	1,403	$	0	$	12,043
	State and political subdivisions			9,989		32		391		9,630
	Residential mortgage-backed securities
	Agency			42		7		0		49
	Single issue trust preferred securities			19,278		0		2,639		16,639
	Other corporate securities			20		0		0		20
	Total		$	39,969	$	1,442	$	3,030	$	38,381
			December 31, 2013
					Gross		Gross		Estimated
			Amortized		Unrealized		Unrealized		Fair
			Cost		Gains		Losses		Value
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	10,762	$	1,689	$	0	$	12,451
	State and political subdivisions			10,367		37		299		10,105
	Residential mortgage-backed securities
	Agency			50		9		0		59
	Single issue trust preferred securities			19,766		0		4,108		15,658
	Other corporate securities			20		0		0		20
	Total		$	40,965	$	1,735	$	4,407	$	38,293
Summary of Gross Realized Gains and Losses on Calls That Have Been Included in Earnings as a Result of Calls of Held-to-maturity Securities	'
	The following table shows the gross realized gains and losses on calls that have been included in earnings as a result of those calls. Gains or losses on calls of held-to-maturity securities are recognized by the specific identification method.
			Three Months  Ended				Nine Months  Ended
			September 30				September 30
			2014		2013		2014		2013
	Gross realized gains		$	9	$	0	$	9	$	114
	Gross realized losses			0		0		0		0
Available-for-sale Securities [Member]	'
Summary of Maturities of Debt Securities Held to Maturity by Amortized Cost and Estimated Fair Value	'
	The amortized cost and estimated fair value of securities available for sale at September 30, 2014 and December 31, 2013 by contractual maturity are shown as follows. Expected maturities may differ from contractual maturities because the issuers may have the right to call or prepay obligations without penalties.
			September 30, 2014				December 31, 2013
					Estimated				Estimated
			Amortized		Fair		Amortized		Fair
			Cost		Value		Cost		Value
	Due in one year or less		$	26,751	$	26,981	$	28,837	$	28,960
	Due after one year through five years			153,260		153,718		217,415		218,498
	Due after five years through ten years			365,664		366,395		292,460		286,534
	Due after ten years			622,805		611,414		271,038		237,422
	Marketable equity securities			3,467		4,051		3,299		3,870
	Total		$	1,171,947	$	1,162,559	$	813,049	$	775,284
Held-to-maturity Securities [Member]	'
Summary of Maturities of Debt Securities Held to Maturity by Amortized Cost and Estimated Fair Value	'
	The amortized cost and estimated fair value of debt securities held to maturity at September 30, 2014 and December 31, 2013 by contractual maturity are shown on the following page. Expected maturities may differ from contractual maturities because the issuers may have the right to call or prepay obligations without penalties.
			September 30, 2014				December 31, 2013
					Estimated				Estimated
			Amortized		Fair		Amortized		Fair
			Cost		Value		Cost		Value
	Due in one year or less		$	570	$	571	$	555	$	556
	Due after one year through five years			12,750		14,165		6,683		7,312
	Due after five years through ten years			6,444		6,069		13,026		13,821
	Due after ten years			20,205		17,576		20,701		16,604
	Total		$	39,969	$	38,381	$	40,965	$	38,293

Loans_Tables

Loans (Tables)	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Major Classes of Loans	'
	Major classes of loans are as follows:
		September 30,			December 31,
		2014			2013
	Commercial, financial and agricultural:
	Owner-occupied commercial real estate	$	1,044,951		$	654,963
	Nonowner-occupied commercial real estate		2,718,821			1,917,785
	Other commercial loans		1,592,606			1,338,355
	Total commercial, financial & agricultural		5,356,378			3,911,103
	Residential real estate		2,229,353			1,821,378
	Construction & land development		1,088,627			670,364
	Consumer:
	Bankcard		10,110			11,023
	Other consumer		346,015			299,731
	Total gross loans	$	9,030,483		$	6,713,599
Activity for Accretable Yield	'
	Activity for the accretable yield for the first nine months of 2014 follows:
	Accretable yield at the beginning of the period	$	2,251
	Additions		9,116
	Accretion (including cash recoveries)		(6,051	)
	Net reclassifications to accretable from non-accretable		1,700
	Disposals (including maturities, foreclosures, and charge-offs)		(628	)
	Accretable yield at the ending of the period	$	6,388

Credit_Quality_Tables

Credit Quality (Tables)	9 Months Ended
	Sep. 30, 2014
Text Block [Abstract]	'
Schedule of Troubled Debt Restructurings, Segregated by Class of Loans	'
	The following table sets forth United’s troubled debt restructurings that have been restructured during the nine months ended September 30, 2014 and 2013, segregated by class of loans:
			Troubled Debt Restructurings
			For the Nine Months Ended
			September 30, 2014						September 30, 2013
			Number of		Pre-Modification		Post-		Number of		Pre-Modification		Post-
			Contracts		Outstanding		Modification		Contracts		Outstanding		Modification
					Recorded		Outstanding				Recorded		Outstanding
					Investment		Recorded				Investment		Recorded
							Investment						Investment
	Commercial real estate:
	Owner-occupied			0	$	0	$	0		4	$	5,143	$	4,590
	Nonowner-occupied			0		0		0		0		0		0
	Other commercial			2		5,630		5,630		0		0		0
	Residential real estate			0		0		0		0		0		0
	Construction & land development			0		0		0		0		0		0
	Consumer:
	Bankcard			0		0		0		0		0		0
	Other consumer			0		0		0		0		0		0
	Total			2	$	5,630	$	5,630		4	$	5,143	$	4,590
Schedule of Charged-off Troubled Debt Restructurings on Financing Receivables	'
	The following table presents troubled debt restructurings, by class of loan, that had charge-offs during the three ended September 30, 2014.
			Three Months Ended
			September 30, 2014
	(In thousands)		Number of		Recorded
			Contracts		Investment
	Troubled Debt Restructurings
	Commercial real estate:
	Owner-occupied			0	$	0
	Nonowner-occupied			1		478
	Other commercial			0		0
	Residential real estate			0		0
	Construction & land development			0		0
	Consumer:
	Bankcard			0		0
	Other consumer			0		0
	Total			1	$	478
	The following table presents troubled debt restructurings, by class of loan, that had charge-offs during the nine months ended September 30, 2014 and 2013.
			Nine Months Ended				Nine Months Ended
			September 30, 2014				September 30, 2013
	(In thousands)		Number of		Recorded		Number of		Recorded
			Contracts		Investment		Contracts		Investment
	Troubled Debt Restructurings
	Commercial real estate:
	Owner-occupied			0	$	0		0	$	0
	Nonowner-occupied			1		478		0		0
	Other commercial			0		0		0		0
	Residential real estate			0		0		0		0
	Construction & land development			0		0		1		375
	Consumer:
	Bankcard			0		0		0		0
	Other consumer			0		0		0		0
	Total			1	$	478		1	$	375
Schedule of Age Analysis of Past Due Loans, Segregated by Class of Loans	'
	The following table sets forth United’s age analysis of its past due loans, segregated by class of loans:
	Age Analysis of Past Due Loans
	As of September 30, 2014
	(In thousands)		30-89		90 Days or		Total Past		Current &		Total		Recorded
			Days Past		more Past		Due		Other (1)		Loans		Investment
			Due		Due								>90 Days &
													Accruing
	Commercial real estate:
	Owner-occupied		$	14,148	$	9,634	$	23,782	$	1,021,169	$	1,044,951	$	674
	Nonowner-occupied			27,990		13,849		41,839		2,676,982		2,718,821		1,028
	Other commercial			20,239		18,070		38,309		1,554,297		1,592,606		6,197
	Residential real estate			41,714		26,957		68,671		2,160,682		2,229,353		6,809
	Construction & land development			6,729		14,905		21,634		1,066,993		1,088,627		305
	Consumer:
	Bankcard			371		185		556		9,554		10,110		185
	Other consumer			7,921		1,627		9,548		336,467		346,015		1,494
	Total		$	119,112	$	85,227	$	204,339	$	8,826,144	$	9,030,483	$	16,692
	-1	Other includes loans with a recorded investment of $163,473 acquired and accounted for under ASC topic 310-30 “Loans and Debt Securities Acquired with Deteriorated Credit Quality”.
	Age Analysis of Past Due Loans
	As of December 31, 2013
			30-89		90 Days or		Total Past		Current &		Total		Recorded
			Days		more Past		Due		Other (1)		Financing		Investment
			Past Due		Due						Receivables		>90 Days &
													Accruing
	Commercial real estate:
	Owner-occupied		$	14,144	$	4,537	$	18,681	$	636,282	$	654,963	$	1,383
	Nonowner-occupied			30,836		11,725		42,561		1,875,224		1,917,785		186
	Other commercial			54,319		11,794		66,113		1,272,242		1,338,355		896
	Residential real estate			54,271		25,446		79,717		1,741,661		1,821,378		5,214
	Construction & land development			9,921		18,491		28,412		641,952		670,364		1,611
	Consumer:
	Bankcard			229		128		357		10,666		11,023		128
	Age Analysis of Past Due Loans
	As of December 31, 2013
			30-89		90 Days or		Total Past		Current &		Total		Recorded
			Days Past		more Past		Due		Other (1)		Financing		Investment
			Due		Due						Receivables		>90 Days &
													Accruing
	Other consumer			9,466		1,712		11,178		288,553		299,731		1,626
	Total		$	173,186	$	73,833	$	247,019	$	6,466,580	$	6,713,599	$	11,044
	-1	Other includes loans with a recorded investment of $31,099 acquired and accounted for under ASC topic 310-30 “Loans and Debt Securities Acquired with Deteriorated Credit Quality”.
Schedule of Nonaccrual Loans, Segregated by Class of Loans	'
	The following table sets forth United’s nonaccrual loans, segregated by class of loans:
	Loans on Nonaccrual Status
			September 30,		December 31,
			2014		2013
	Commercial real estate:
	Owner-occupied		$	8,960	$	3,154
	Nonowner-occupied			12,821		11,539
	Other commercial			11,873		10,898
	Residential real estate			20,148		20,232
	Construction & land development			14,600		16,880
	Consumer:
	Bankcard			0		0
	Other consumer			133		86
	Total		$	68,535	$	62,789
Schedule of Credit Quality Indicators Information, by Class of Loans	'
	The following tables set forth United’s credit quality indicators information, by class of loans:
	Credit Quality Indicators
	Corporate Credit Exposure
	As of September 30, 2014
			Commercial Real Estate				Other		Construction
							Commercial		& Land
			Owner-		Nonowner-				Development
			occupied		occupied
	Grade:
	Pass		$	946,727	$	2,539,705	$	1,385,308	$	903,780
	Special mention			30,297		56,224		23,794		71,263
	Substandard			67,927		122,892		182,181		113,584
	Doubtful			0		0		1,323		0
	Total		$	1,044,951	$	2,718,821	$	1,592,606	$	1,088,627
	As of December 31, 2013
			Commercial Real Estate				Other		Construction
							Commercial		& Land
			Owner-		Nonowner-				Development
			occupied		occupied
	Grade:
	Pass		$	604,129	$	1,811,915	$	1,206,030	$	510,911
	Special mention			27,576		45,617		60,668		63,375
	Substandard			23,258		60,253		71,148		96,078
	Doubtful			0		0		509		0
	Total		$	654,963	$	1,917,785	$	1,338,355	$	670,364
	Credit Quality Indicators
	Consumer Credit Exposure
	As of September 30, 2014
			Residential		Bankcard		Other
			Real Estate				Consumer
	Grade:
	Pass		$	2,146,423	$	9,554	$	336,157
	Special mention			17,668		371		8,042
	Substandard			63,787		185		1,816
	Doubtful			1,475		0		0
	Total		$	2,229,353	$	10,110	$	346,015
	As of December 31, 2013
			Residential		Bankcard		Other
			Real Estate				Consumer
	Grade:
	Pass		$	1,773,244	$	10,666	$	288,401
	Special mention			13,006		229		9,466
	Substandard			35,128		128		1,712
	Doubtful			0		0		152
	Total		$	1,821,378	$	11,023	$	299,731
Schedule of Impaired Loans Information by Class of Loans	'
	The following table sets forth United’s impaired loans information, by class of loans:
			Impaired Loans
			September 30, 2014						December 31, 2013
			Recorded		Unpaid		Related		Recorded		Unpaid		Related
			Investment		Principal		Allowance		Investment		Principal		Allowance
					Balance						Balance
	With no related allowance recorded:
	Commercial real estate:
	Owner-occupied		$	35,355	$	35,355	$	0	$	4,672	$	4,672	$	0
	Nonowner-occupied			60,329		60,739		0		5,938		6,651		0
	Other commercial			18,535		21,910		0		10,292		17,753		0
	Residential real estate			28,832		29,501		0		12,009		12,193		0
	Construction & land development			43,096		44,676		0		13,866		14,662		0
	Consumer:
	Bankcard			0		0		0		0		0		0
	Other consumer			51		51		0		0		0		0
	With an allowance recorded:
	Commercial real estate:
	Owner-occupied		$	5,036	$	5,036	$	820	$	4,358	$	4,358	$	638
	Nonowner-occupied			7,190		7,249		773		9,350		10,563		1,631
	Other commercial			13,639		16,639		4,016		13,304		16,240		2,192
	Residential real estate			10,239		10,825		2,582		7,669		8,191		4,112
	Construction & land development			12,028		15,306		3,775		11,050		14,833		3,752
	Consumer:
	Bankcard			0		0		0		0		0		0
	Other consumer			0		0		0		152		152		152
	Total:
	Commercial real estate:
	Owner-occupied		$	40,391	$	40,391	$	820	$	9,030	$	9,030	$	638
	Nonowner-occupied			67,519		67,988		773		15,288		17,214		1,631
	Other commercial			32,174		38,549		4,016		23,596		33,993		2,192
	Residential real estate			39,071		40,326		2,582		19,678		20,384		4,112
	Construction & land development			55,124		59,982		3,775		24,916		29,495		3,752
	Consumer:
	Bankcard			0		0		0		0		0		0
	Other consumer			51		51		0		152		152		152
			Impaired Loans
			For the Three Months Ended
			September 30, 2014				September 30, 2013
			Average		Interest		Average		Interest
			Recorded		Income		Recorded		Income
			Investment		Recognized		Investment		Recognized
	With no related allowance recorded:
	Commercial real estate:
	Owner-occupied		$	37,208	$	129	$	13,661	$	68
	Nonowner-occupied			63,035		230		12,035		27
	Other commercial			20,679		59		18,947		389
	Residential real estate			32,864		46		9,605		30
	Construction & land development			44,191		97		8,688		119
	Consumer:
	Bankcard			0		0		0		0
	Other consumer			55		0		152		0
	With an allowance recorded:
	Commercial real estate:
	Owner-occupied		$	4,352	$	114	$	2,313	$	139
	Nonowner-occupied			7,332		67		6,562		155
	Other commercial			12,537		97		9,390		59
	Residential real estate			7,716		8		5,773		105
	Construction & land development			11,491		31		14,234		111
	Consumer:
	Bankcard			0		0		0		0
	Other consumer			76		0		0		0
	Total:
Commercial real estate:
Owner-occupied		$	41,560	$	243	$	15,974	$	207
Nonowner-occupied			70,367		297		18,597		182
Other commercial			33,216		156		28,337		448
Residential real estate			40,580		54		15,378		135
Construction & land development			55,682		128		22,922		230
Consumer:
Bankcard			0		0		0		0
Other consumer			131		0		152		0
		Impaired Loans
		For the Nine Months Ended
		September 30, 2014				September 30, 2013
		Average		Interest		Average		Interest
		Recorded		Income		Recorded		Income
		Investment		Recognized		Investment		Recognized
With no related allowance recorded:
Commercial real estate:
Owner-occupied		$	35,959	$	617	$	13,530	$	145
Nonowner-occupied			62,205		440		11,637		221
Other commercial			27,454		217		12,268		478
Residential real estate			30,484		195		8,530		197
Construction & land development			46,747		234		8,078		304
Consumer:
Bankcard			0		0		0		0
Other consumer			45		0		152		0
With an allowance recorded:
Commercial real estate:
Owner-occupied		$	4,236	$	189	$	1,935	$	166
Nonowner-occupied			7,606		159		5,518		204
Other commercial			12,751		185		16,616		991
Residential real estate			8,548		101		5,505		186
Construction & land development			10,694		47		13,934		378
Consumer:
Bankcard			0		0		0		0
Other consumer			102		0		0		0
Total:
Commercial real estate:
Owner-occupied		$	40,195	$	806	$	15,465	$	311
Nonowner-occupied			69,811		599		17,155		425
Other commercial			40,205		402		28,884		1,469
Residential real estate			39,032		296		14,035		383
Construction & land development			57,441		281		22,012		682
Consumer:
Bankcard			0		0		0		0
Other consumer			147		0		152		0

Allowance_for_Credit_Losses_Ta

Allowance for Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2014
Receivables [Abstract]	'
Schedule of Allowance for Loan Losses and Carrying Amount of Loans	'
	A progression of the allowance for loan losses, by portfolio segment, for the periods indicated is summarized as follows.
	Allowance for Loan Losses
	For the Three Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real			& Land				for
										Estate			Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	3,810		$	8,036		$	26,778	$	14,785		$	18,320	$	3,146	$	100		$	74,975
	Charge-offs		726			1,226			1,142		486			457		366		0			4,403
	Recoveries		113			16			132		76			16		48		0			401
	Provision		1,174			1,442			589		(532	)		1,682		313		80			4,748
	Ending balance	$	4,371		$	8,268		$	26,357	$	13,843		$	19,561	$	3,141	$	180		$	75,721
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Nine Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real Estate			& Land				for
													Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	5,653		$	8,992		$	20,917	$	16,694		$	18,953	$	2,945	$	44		$	74,198
	Charge-offs		1,863			2,063			3,233		3,078			5,140		1,618		0			16,995
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Nine Months Ended September 30, 2014
		Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real Estate			& Land				for
													Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Recoveries		1,611			250			249		340			140		300		0			2,890
	Provision		(1,030	)		1,089			8,424		(113	)		5,608		1,514		136			15,628
	Ending balance	$	4,371		$	8,268		$	26,357	$	13,843		$	19,561	$	3,141	$	180		$	75,721
	Ending Balance: individually evaluated for impairment	$	820		$	773		$	4,016	$	2,582		$	3,775	$	0	$	0		$	11,966
	Ending Balance: collectively evaluated for impairment	$	3,551		$	7,495		$	22,341	$	11,261		$	15,786	$	3,141	$	180		$	63,755
	Ending Balance: loans acquired with deteriorated credit quality	$	0		$	0		$	0	$	0		$	0	$	0	$	0		$	0
	Financing receivables:
	Ending balance	$	1,044,951		$	2,718,821		$	1,592,606	$	2,229,353		$	1,088,627	$	356,125	$	0		$	9,030,483
	Ending Balance: individually evaluated for impairment	$	13,383		$	13,739		$	20,072	$	14,990		$	16,961	$	0	$	0		$	79,145
	Ending Balance: collectively evaluated for impairment	$	1,005,661		$	2,648,094		$	1,561,323	$	2,193,341		$	1,023,381	$	356,065	$	0		$	8,787,865
	Ending Balance: loans acquired with deteriorated credit quality	$	25,907		$	56,988		$	11,211	$	21,022		$	48,285	$	60	$	0		$	163,473
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Year Ended December 31, 2013
	(In thousands)	Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real			& Land				for
										Estate			Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
	Allowance for Loan Losses:
	Beginning balance	$	3,877		$	12,876		$	20,511	$	14,895		$	18,858	$	2,620	$	264		$	73,901
	Charge-offs		5,344			1,164			7,699		4,111			896		1,792		0			21,006
	Recoveries		150			56			641		698			73		418		0			2,036
	Provision		6,970			(2,776	)		7,464		5,212			918		1,699		(220	)		19,267
	Ending balance	$	5,653		$	8,992		$	20,917	$	16,694		$	18,953	$	2,945	$	44		$	74,198
	Ending Balance: individually evaluated for impairment	$	638		$	1,631		$	2,192	$	4,112		$	3,752	$	152	$	0		$	12,477
	Allowance for Loan Losses and Carrying Amount of Loans
	For the Year Ended December 31, 2013
	(In thousands)	Commercial Real Estate						Other		Residential			Construction		Consumer		Allowance			Total
								Commercial		Real Estate			& Land				for
													Development				Estimated
		Owner-			Nonowner-												Imprecision
		occupied			occupied
Ending Balance: collectively evaluated for impairment	$	5,015		$	7,361		$	18,725	$	12,582		$	15,201	$	2,793	$	44		$	61,721
Ending Balance: loans acquired with deteriorated credit quality	$	0		$	0		$	0	$	0		$	0	$	0	$	0		$	0
Financing receivables:
Ending balance	$	654,963		$	1,917,785		$	1,338,355	$	1,821,378		$	670,364	$	310,754	$	0		$	6,713,599
Ending Balance: individually evaluated for impairment	$	7,157		$	13,913		$	22,327	$	16,160		$	21,593	$	152	$	0		$	81,302
Ending Balance: collectively evaluated for impairment	$	646,548		$	1,894,421		$	1,314,543	$	1,802,686		$	632,407	$	310,593	$	0		$	6,601,198
Ending Balance: loans acquired with deteriorated credit quality	$	1,258		$	9,451		$	1,485	$	2,532		$	16,364	$	9	$	0		$	31,099

Intangible_Assets_Tables

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Summary of Intangible Assets	'
	The following is a summary of intangible assets subject to amortization and those not subject to amortization:
		As of September 30, 2014
		Gross Carrying		Accumulated			Net Carrying
		Amount		Amortization			Amount
	Amortized intangible assets:
	Core deposit intangible assets	$	60,577	($	38,263	)	$	22,314
	Goodwill not subject to amortization						$	712,065
		As of December 31, 2013
		Gross Carrying		Accumulated			Net Carrying
		Amount		Amortization			Amount
	Amortized intangible assets:
	Core deposit intangible assets	$	43,434	($	35,296	)	$	8,138
	Goodwill not subject to amortization						$	375,547
Schedule of Anticipated Amortization Expense	'
	The following table sets forth the anticipated amortization expense for intangible assets for the years subsequent to 2013:
	Year	Amount
	2014	$	4,133
	2015		3,383
	2016		2,943
	2017		2,730
	2018 and thereafter		12,092

LongTerm_Borrowings_Tables

Long-Term Borrowings (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of Maturities of FHLB Borrowings	'
	The scheduled maturities of these FHLB borrowings are as follows:
	Year	Amount
	2014	$	525,284
	2015		354,397
	2016		654
	2017		344
	2018 and thereafter		50,000
	Total	$	930,679

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Schedule of Derivative Instruments	'
	The following table sets forth certain information regarding the interest rate derivatives portfolio used for interest-rate risk management purposes and designated as accounting hedges under the Derivatives and Hedging topic at September 30, 2014.
	Derivative Classifications and Hedging Relationships
	September 30, 2014
			Notional			Average
			Amount			Pay Rate
	Fair Value Hedges:
	Pay Fixed Swaps (Hedging Commercial Loans)		$	40,794			5.07	%
	Total Derivatives Used in Fair Value Hedges		$	40,794
	Total Derivatives Used for Interest Rate Risk Management and Designated as Hedges		$	40,794
Schedule of Fair Value Derivative Financial Instruments	'
	The following tables summarize the fair value of United’s derivative financial instruments.
			Asset Derivatives
			September 30, 2014						December 31, 2013
			Balance			Fair			Balance			Fair
			Sheet			Value			Sheet			Value
			Location						Location
	Derivatives designated as hedging instruments
	Interest rate contracts			Other assets		$	646			Other assets		$	2,179
	Total derivatives designated as hedging instruments					$	646					$	2,179
	Derivatives not designated as hedging instruments
	Interest rate contracts			Other assets		$	618			Other assets		$	1,045
	Total derivatives not designated as hedging instruments					$	618					$	1,045
	Total asset derivatives					$	1,264					$	3,224
			Liability Derivatives
			September 30, 2014						December 31, 2013
			Balance			Fair			Balance			Fair
			Sheet			Value			Sheet			Value
			Location						Location
	Derivatives designated as hedging instruments
	Interest rate contracts			Other liabilities		$	45			Other liabilities		$	149
	Total derivatives designated as hedging instruments					$	45					$	149
	Derivatives not designated as hedging instruments
	Interest rate contracts			Other liabilities		$	618			Other liabilities		$	1,045
	Total derivatives not designated as hedging instruments					$	618					$	1,045
	Total liability derivatives					$	663					$	1,194
Schedule of Derivative Financial Instruments on Statement of Income	'
	The effect of United’s derivative financial instruments on its unaudited Consolidated Statements of Income for the three and nine months ended September 30, 2014 and 2013 are presented as follows:
						Three Months Ended
			Income Statement			September 30,			September 30,
			Location			2014			2013
	Derivatives in fair value hedging relationships
	Interest rate contracts			Interest income/	(expense)	$	(271	)	$	(157	)
	Total derivatives in fair value hedging relationships					$	(271	)	$	(157	)
	Derivatives not designated as hedging instruments
	Interest rate contracts (1)			Other income		$	154		$	218
	Interest rate contracts (2)			Other expense		$	(154	)	$	(218	)
	Total derivatives not designated as hedging instruments					$	0		$	0
	Total derivatives					$	(271	)	$	(157	)
						Nine Months Ended
			Income Statement			September 30,			September 30,
			Location			2014			2013
	Derivatives in fair value hedging relationships
	Interest rate contracts			Interest income/	(expense)	$	(795	)	$	(401	)
	Total derivatives in fair value hedging relationships					$	(795	)	$	(401	)
	Derivatives not designated as hedging instruments
	Interest rate contracts (1)			Other income		$	427		$	1,181
	Interest rate contracts (2)			Other expense		$	(427	)	$	(1,181	)
	Total derivatives not designated as hedging instruments					$	0		$	0
	Total derivatives					$	(795	)	$	(401	)
	-1	Represents net gains from derivative assets not designated as hedging instruments.
	-2	Represents net losses from derivative liabilities not designated as hedging instruments.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Financial Assets and Liabilities Measured at Fair Value	'
	The following tables present the balances of financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2014 and December 31, 2013, segregated by the level of the valuation inputs within the fair value hierarchy.
						Fair Value at September 30, 2014 Using
	Description		Balance as of			Quoted Prices			Significant		Significant
			September 30,			in Active			Other		Unobservable
			2014			Markets for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Available for sale debt securities:
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	93,998		$	0		$	93,998	$	0
	State and political subdivisions			135,841			0			135,841		0
	Residential mortgage-backed securities
	Agency			541,632			0			541,632		0
	Non-agency			13,601			0			13,601		0
	Asset-backed securities			8,031			0			8,031		0
	Commercial mortgage-backed securities
	Agency			309,217			0			309,217		0
	Trust preferred collateralized debt obligations			38,819			0			0		38,819
	Single issue trust preferred securities			12,210			0			12,210		0
	Other corporate securities			5,159			0			5,159		0
	Total available for sale debt securities			1,158,508			0			1,119,689		38,819
	Available for sale equity securities:
	Financial services industry			2,329			703			1,626		0
	Equity mutual funds (1)			558			558			0		0
	Other equity securities			1,164			1,164			0		0
	Total available for sale equity securities			4,051			2,425			1,626		0
	Total available for sale securities			1,162,559			2,425			1,121,315		38,819
	Derivative financial assets:
	Interest rate contracts			1,264			0			1,264		0
	Liabilities
	Derivative financial liabilities:
	Interest rate contracts			663			0			663		0
	-1	The equity mutual funds are within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
						Fair Value at December 31, 2013 Using
	Description		Balance as of			Quoted Prices			Significant		Significant
			December 31,			in  Active			Other		Unobservable
			2013			Markets  for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Available for sale debt securities:
	U.S. Treasury securities and obligations of U.S. Government corporations and agencies		$	171,754		$	0		$	171,754	$	0
	State and political subdivisions			62,709			0			62,709		0
	Residential mortgage-backed securities
	Agency			216,464			0			216,464		0
	Non-agency			16,532			0			16,532		0
	Asset-backed securities			9,227			0			9,227		0
	Commercial mortgage-backed securities
	Agency			233,432			0			233,432		0
	Trust preferred collateralized debt obligations			43,449			0			0		43,449
	Single issue trust preferred securities			12,632			502			12,130		0
	Other corporate securities			5,215			0			5,215		0
	Total available for sale debt securities			771,414			502			727,463		43,449
	Available for sale equity securities:
	Financial services industry			2,292			716			1,576		0
	Equity mutual funds (1)			434			434			0		0
	Other equity securities			1,144			1,144			0		0
	Total available for sale equity securities			3,870			2,294			1,576		0
	Total available for sale securities			775,284			2,796			729,039		43,449
	Derivative financial assets:
	Interest rate contracts			3,224			0			3,224		0
Liabilities
Derivative financial liabilities:
Interest rate contracts			1,194			0			1,194		0
-1	The equity mutual funds are within a rabbi trust for the payment of benefits under a deferred compensation plan for certain key officers of United and its subsidiaries.
Schedule of Additional Information about Financial Assets and Liabilities Measured at Fair Value Utilized Level 3	'
	The following table presents additional information about financial assets and liabilities measured at fair value at September 30, 2014 and December 31, 2013 on a recurring basis and for which United has utilized Level 3 inputs to determine fair value:
			Available-for-sale
			Securities
			Trust preferred
			collateralized debt obligations
			September 30,			December 31,
			2014			2013
	Balance, beginning of period		$	43,449		$	40,613
	Total gains or losses (realized/unrealized):
	Included in earnings (or changes in net assets)			(4,539	)		(6,456	)
	Included in other comprehensive income			15,400			14,520
	Purchases, issuances, and settlements			(15,491	)		(5,228	)
	Transfers in and/or out of Level 3			0			0
	Balance, ending of period		$	38,819		$	43,449
	The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at reporting date			0			0
Summary of Financial Assets Measured at Fair Value on Nonrecurring Basis	'
	The following table summarizes United’s financial assets that were measured at fair value on a nonrecurring basis during the period:
	Description		Balance as of			Fair Value Measurements							YTD
			September 30,			at September 30, 2014 Using							Losses
			2014			Quoted Prices			Significant		Significant
						in Active			Other		Unobservable
						Markets for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Impaired Loans		$	48,132		$	0		$	18,587	$	29,545	$	1,935
	OREO			42,432			0			42,273		159		2,966
	Description		Balance as of			at December 31, 2013 Using							YTD
			December 31,										Losses
			2013			Quoted Prices			Significant		Significant
						in Active			Other		Unobservable
						Markets for			Observable		Inputs
						Identical			Inputs		(Level 3)
						Assets			(Level 2)
						(Level 1)
	Assets
	Impaired Loans		$	45,883		$	0		$	13,081	$	32,802	$	1,886
	OREO			38,182			0			38,107		75		2,548
Summary of Estimated Fair Values of Financial Instruments	'
	The estimated fair values of United’s financial instruments are summarized below:
									Fair Value Measurements
			Carrying			Fair Value			Quoted Prices		Significant		Significant
			Amount						in Active		Other		Unobservable
									Markets for		Observable		Inputs
									Identical		Inputs		(Level 3)
									Assets		(Level 2)
									(Level 1)
	September 30, 2014
	Cash and cash equivalents		$	591,270		$	591,270		$	0	$	591,270	$	0
	Securities available for sale			1,162,559			1,162,559			2,425		1,121,315		38,819
	Securities held to maturity			39,969			38,381			0		36,361		2,020
	Other securities			104,714			99,478			0		0		99,478
	Loans held for sale			5,773			5,773			0		5,773		0
	Loans			8,940,182			8,988,058			0		0		8,988,058
	Derivative financial assets			1,264			1,264			0		1,264		0
	Deposits			8,753,257			8,754,110			0		8,754,110		0
	Short-term borrowings			474,225			474,225			0		474,225		0
	Long-term borrowings			1,133,255			1,115,046			0		1,115,046		0
	Derivative financial liabilities			663			663			0		663		0
	December 31, 2013
	Cash and cash equivalents		$	416,617		$	416,617		$	0	$	416,617	$	0
	Securities available for sale			775,284			775,284			2,796		729,039		43,449
	Securities held to maturity			40,965			38,293			0		35,773		2,520
	Other securities			73,093			70,072			0		0		70,072
	Loans held for sale			4,236			4,236			0		4,236		0
	Loans			6,630,385			6,657,376			0		0		6,657,376
	Derivative financial assets			3,224			3,224			0		3,224		0
	Deposits			6,621,571			6,641,070			0		6,641,070		0
	Short-term borrowings			430,754			430,754			0		430,754		0
	Long-term borrowings			575,697			553,796			0		553,796		0
	Derivative financial liabilities			1,194			1,194			0		1,194		0

Stock_Based_Compensation_Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of Stock Option Plans	'
	A summary of activity under United’s stock option plans as of September 30, 2014, and the changes during the first nine months of 2014 are presented below:
		Nine Months Ended September 30, 2014
							Weighted Average
					Aggregate		Remaining
					Intrinsic		Contractual		Exercise
		Shares			Value		Term (Yrs.)		Price
	Outstanding at January 1, 2014		1,447,997						$	29.33
	Assumed in Virginia Commerce merger		440,813							19.55
	Granted		204,800							28.89
	Exercised		(368,856	)						19.5
	Forfeited or expired		(69,529	)						32.3
	Outstanding at September 30, 2014		1,655,225		$	5,745		5.1	$	28.74
	Exercisable at September 30, 2014		1,254,236		$	4,629		4	$	28.92
Status of United's Nonvested Stock Option Awards	'
	The following table summarizes the status of United’s nonvested stock option awards during the first nine months of 2014:
		Shares			Weighted-Average
					Grant Date Fair Value
					Per Share
	Nonvested at January 1, 2014		589,197		$	7.01
	Granted		204,800			6.42
	Vested		(383,475	)		7.46
	Forfeited or expired		(9,533	)		6.48
	Nonvested at September 30, 2014		400,989		$	6.29
Changes to United's Restricted Common Shares	'
	The following summarizes the changes to United’s restricted common shares for the period ended September 30, 2014:
		Number			Weighted-Average
		of Shares			Grant Date Fair Value
					Per Share
	Outstanding at January 1, 2014		85,497		$	27.53
	Assumed in Virginia Commerce merger		34,538			29.89
	Granted		66,949			28.89
	Vested		(57,204	)		28.83
	Forfeited		(2,338	)		28.11
	Outstanding at September 30, 2014		127,442		$	28.29

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Net Periodic Pension Cost	'
	Net periodic pension cost for the three and nine months ended September 30, 2014 and 2013 included the following components:
		Three Months  Ended						Nine Months Ended
		September 30						September 30
		2014			2013			2014			2013
	Service cost	$	579		$	777		$	1,720		$	2,304
	Interest cost		1,361			1,235			4,039			3,665
	Expected return on plan assets		(2,293	)		(2,097	)		(6,806	)		(6,223	)
	Amortization of transition asset		0			0			0			0
	Recognized net actuarial loss		491			1,184			1,458			3,515
	Amortization of prior service cost		1			1			1			1
	Net periodic pension (benefit) cost	$	139		$	1,100		$	412		$	3,262
	Weighted-Average Assumptions:
	Discount rate		5.2	%		4.4	%		5.2	%		4.4	%
	Expected return on assets		7.5	%		8	%		7.5	%		8	%
	Rate of compensation increase (prior to age 45)		3.5	%		3.75	%		3.5	%		3.75	%
	Rate of compensation increase		3	%		2.75	%		3	%		2.75	%

Comprehensive_Income_Tables

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Components of Total Comprehensive Income	'
	The components of total comprehensive income for the three and nine months ended September 30, 2014 and 2013 are as follows:
			Three Months Ended						Nine Months Ended
			September 30						September 30
			2014			2013			2014			2013
	Net Income		$	33,260		$	22,170		$	96,631		$	65,968
	Available for sale (“AFS”) securities:
	AFS securities with OTTI charges during the period			(4,714	)		0			(5,774	)		(1,172	)
	Related income tax effect			1,650			0			2,021			410
	Less : OTTI charges recognized in net income			4,714			0			5,774			971
	Related income tax benefit			(1,650	)		0			(2,021	)		(340	)
	Reclassification of previous noncredit OTTI to credit OTTI			4,153			0			6,259			1,458
	Related income tax benefit			(1,453	)		0			(2,190	)		(510	)
	Net unrealized (losses) gains on AFS securities with OTTI			2,700			0			4,069			817
	AFS securities – all other:
	Change in net unrealized gain on AFS securities arising during the period			(339	)		4,680			24,242			1,080
	Related income tax effect			119			(1,638	)		(8,485	)		(378	)
	Net reclassification adjustment for (gains) losses included in net income			(1,300	)		(101	)		(2,125	)		(476	)
	Related income tax expense (benefit)			455			36			744			167
				(1,065	)		2,977			14,376			393
	Net effect of AFS securities on other comprehensive income			1,635			2,977			18,445			1,210
	Held to maturity (“HTM”) securities:
	Accretion on the unrealized loss for securities transferred from			2			2			6			6
	AFS to the HTM investment portfolio prior to call or maturity
	Related income tax expense			(0	)		0			(2	)		(2	)
	Net effect of HTM securities on other comprehensive income			2			2			4			4
	Pension plan:
	Amortization of prior service cost			1			1			1			1
	Related income tax benefit			0			0			0			0
	Recognized net actuarial loss			491			1,184			1,458			3,515
	Related income tax benefit			(183	)		(445	)		(531	)		(1,293	)
	Net effect of change in pension plan asset on other comprehensive income			309			740			928			2,223
	Total change in other comprehensive income			1,946			3,719			19,377			3,437
	Total Comprehensive Income		$	35,206		$	25,889		$	116,008		$	69,405
Components of Accumulated Other Comprehensive Income	'
	The components of accumulated other comprehensive income for the nine months ended September 30, 2014 are as follows:
	Changes in Accumulated Other Comprehensive Income (AOCI) by Component (a)
	For the Nine Months Ended September 30, 2014
	(Dollars in thousands)		Unrealized			Accretion on			Defined			Total
			Gains/Losses			the unrealized			Benefit
			on AFS			loss for			Pension
			Securities			securities			Items
						transferred
						from AFS to
						the HTM
	Balance at January 1, 2014		($	23,235	)	($	67	)	($	19,745	)	($	43,047	)
	Other comprehensive income before reclassification			15,757			4			0			15,761
	Amounts reclassified from accumulated other comprehensive income			2,688			0			928			3,616
	Net current-period other comprehensive income, net of tax			18,445			4			928			19,377
	Balance at September 30, 2014		($	4,790	)	($	63	)	($	18,817	)	($	23,670	)
	(a)	All amounts are net-of-tax.
Reclassifications Out of Accumulated Other Comprehensive Income	'
	Reclassifications out of Accumulated Other Comprehensive Income (AOCI)
	For the Nine Months Ended September 30, 2014
	(Dollars in thousands)		Amount			Affected Line Item in the Statement Where
			Reclassified			Net Income is Presented
	Details about AOCI Components		from AOCI
	Available for sale (“AFS”) securities:
	Reclassification of previous noncredit OTTI to credit OTTI		$	6,259		Total other-than-temporary impairment losses
	Net reclassification adjustment for losses (gains) included in net income			(2,125	)	Net gains on sales/calls of investment securities
				4,134		Total before tax
	Related income tax effect			(1,446	)	Tax expense
				2,688		Net of tax
	Pension plan:
	Amortization of transition asset			1	(a)
	Recognized net actuarial loss			1,458	(a)
				1,459		Total before tax
	Related income tax effect			(531	)	Tax expense
				928		Net of tax
	Total reclassifications for the period		$	3,616
	(a)	This AOCI component is included in the computation of net periodic pension cost (see Note 14, Employee Benefit Plans)

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Reconciliation of Numerator and Denominator of Basic Earnings Per Share with that of Diluted Earnings Per Share	'
	The reconciliation of the numerator and denominator of basic earnings per share with that of diluted earnings per share is presented as follows:
		Three Months Ended				Nine Months Ended
		September 30				September 30
		2014		2013		2014		2013
	Distributed earnings allocated to common stock	$	22,101	$	15,597	$	66,261	$	46,760
	Undistributed earnings allocated to common stock		11,102		6,538		30,194		19,104
	Net earnings allocated to common shareholders	$	33,203	$	22,135	$	96,455	$	65,864
	Average common shares outstanding		69,044,876		50,378,613		66,836,396		50,336,741
	Equivalents from stock options		224,433		94,346		232,956		65,714
	Average diluted shares outstanding		69,269,309		50,472,959		67,069,352		50,402,455
	Earnings per basic common share	$	0.48	$	0.44	$	1.45	$	1.31
	Earnings per diluted common share	$	0.48	$	0.44	$	1.44	$	1.31

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)

9 Months Ended

Sep. 30, 2014

Equity Method Investments and Joint Ventures [Abstract]

'

Information Related to Statutory Trusts

'

Information related to United’s statutory trusts is presented in the table below:

Description

Issuance Date

Amount of

Interest Rate

Maturity Date

Capital

Securities Issued

Century Trust

23-Mar-00

$

8,800

10.875% Fixed

8-Mar-30

Sequoia Trust I

28-Mar-01

$

2,000

10.18% Fixed

8-Jun-31

United Statutory Trust III

17-Dec-03

$

20,000

3-month LIBOR + 2.85%

17-Dec-33

United Statutory Trust IV

19-Dec-03

$

25,000

3-month LIBOR + 2.85%

23-Jan-34

United Statutory Trust V

12-Jul-07

$

50,000

3-month LIBOR + 1.55%

1-Oct-37

United Statutory Trust VI

20-Sep-07

$

30,000

3-month LIBOR + 1.30%

15-Dec-37

Premier Statutory Trust II

25-Sep-03

$

6,000

3-month LIBOR + 3.10%

8-Oct-33

Premier Statutory Trust III

16-May-05

$

8,000

3-month LIBOR + 1.74%

15-Jun-35

Premier Statutory Trust IV

20-Jun-06

$

14,000

3-month LIBOR + 1.55%

23-Sep-36

Premier Statutory Trust V

14-Dec-06

$

10,000

3-month LIBOR + 1.61%

1-Mar-37

Centra Statutory Trust I

20-Sep-04

$

10,000

3-month LIBOR + 2.29%

20-Sep-34

Centra Statutory Trust II

15-Jun-06

$

10,000

3-month LIBOR + 1.65%

7-Jul-36

Virginia Commerce Trust II

19-Dec-02

$

15,000

6-month LIBOR + 3.30%

19-Dec-32

Virginia Commerce Trust III

20-Dec-05

$

25,000

3-month LIBOR + 1.42%

23-Feb-36

Virginia Commerce Trust IV

24-Sep-08

$

25,000

10.20% Fixed

30-Sep-38

Schedule of Trust Prefferred Securities Redemption

'

On November 7, 2014, UBV Holding Company, Inc., a wholly-owned subsidiary of United, submitted redemption notices to Wilmington Trust Company, as Trustee, to redeem the trust preferred securities listed below.

Trust

Interest Rate

Redemption

Principal Amount

Principal Amount

Redemption Date

Price

Outstanding

to be Redeemed

Sequoia Capital Trust I

10.18

%

103.563

%

$

2,000

$

2,000

December 8, 2014

VCBI Capital Trust IV

10.2

%

100

%

$

25,000

$

25,000

December 30, 2014

Summary of Quantitative Information Related to Significant Involvement in Unconsolidated Variable Interest Entities

'

The following table summarizes quantitative information about United’s significant involvement in unconsolidated VIEs:

As of September 30, 2014

As of December 31, 2013

Aggregate

Aggregate

Risk Of

Aggregate

Aggregate

Risk Of

Assets

Liabilities

Loss (1)

Assets

Liabilities

Loss (1)

Trust preferred securities

$

268,315

$

259,454

$

8,861

$

201,186

$

194,453

$

6,733

-1

Represents investment in VIEs.

Mergers_and_Acquisitions_Addit

Mergers and Acquisitions - Additional Information (Detail) (USD $)	0 Months Ended	9 Months Ended
	Jan. 31, 2014	Sep. 30, 2014	Jan. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]	'	'	'	'
Outstanding common stock acquired	100.00%	'	100.00%	'
Business acquisition date	'	31-Jan-14	'	'
Total assets at consummation	'	$12,085,063,000	'	$8,735,324,000
Loans at consummation	'	9,030,483,000	'	6,713,599,000
Deposits at consummation	'	8,753,257,000	'	6,621,571,000
Goodwill arising from acquisition	'	712,065,000	'	375,547,000
Contractually required principal and interest at acquisition	405,109,000	'	405,109,000	'
Expected cash flows at acquisition	166,874,000	'	166,874,000	'
Estimated fair value of acquired impaired loans at acquisition	157,759,000	'	157,759,000	'
Virginia Commerce Bancorp, Inc. [Member]	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'
Total assets at consummation	'	'	'	2,770,000,000
Loans at consummation	'	'	'	2,100,000,000
Deposits at consummation	'	'	'	2,020,000,000
Common stock paid in cash	585,533,000	8,000	'	'
Common stock value	547,894,000	'	'	'
Stock options exchanged value	4,368,000	4,370,000	'	'
Cash paid cash to redeem the warrant	'	33,263,000	33,263,000	'
Number of shares issued in the transaction	'	440,813	'	'
Goodwill arising from acquisition	'	335,980,000	337,897,000	'
Goodwill from acquisition expected to be tax deductible	'	0	'	'
Downward fair value adjustment on loans acquired	'	90,390,000	'	'
Downward fair value adjustment on real state properties	'	1,710,000	'	'
Premium on interest-bearing deposits acquired	'	6,010,000	'	'
Premium on term securities to purchase	'	3,700,000	'	'
Discount on junior subordinated debt securities acquired	'	16,380,000	'	'
Estimated remaining life of premium on interest-bearing deposits acquired	'	'1 year 3 months	'	'
Estimated remaining life on premium of term securities to purchase	'	'1 year 9 months 29 days	'	'
Estimated remaining life of discount on junior subordinated debt securities acquired	'	'21 years 2 months 19 days	'	'
Assumed liabilities to provide severance benefits	'	109,000	'	'
Liabilities to provide severance benefits	'	0	'	'
Revenue since acquisition included in consolidated results	'	73,660,000	'	'
Revenue since acquisition included in consolidated results	'	33,250,000	'	'
Virginia Commerce Bancorp, Inc. [Member] | Common Stock [Member]	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'
Common stock value	'	547,890,000	'	'
Number of shares issued in the transaction	18,330,347	'	'	'
Closing market price per common share	$29.89	'	'	'
Virginia Commerce Bancorp, Inc. [Member] | Core Deposit Intangible Assets [Member]	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'
Purchase price allocation of Identifiable Intangible assets	'	$17,140,000	'	'
Estimated period of amortization of core deposit intangibles	'10 years	'	'	'

Mergers_and_Acquisitions_Sched

Mergers and Acquisitions - Schedule of Acquired Loans Accounted for at Fair value (Detail) (USD $)	Jan. 31, 2014
In Thousands, unless otherwise specified
Business Acquisition [Line Items]	'
Contractually required principal and interest at acquisition	$405,109
Expected cash flows at acquisition	166,874
Basis in acquired loans at acquisition - estimated fair value	157,759
Virginia Commerce Bancorp, Inc. [Member]	'
Business Acquisition [Line Items]	'
Contractually required principal and interest at acquisition	2,683,966
Contractual cash flows not expected to be collected	-396,983
Expected cash flows at acquisition	2,286,983
Interest component of expected cash flows	-274,462
Basis in acquired loans at acquisition - estimated fair value	$2,012,521

Mergers_and_Acquisitions_Sched1

Mergers and Acquisitions - Schedule of Acquired Identifiable Assets and Liabilities Assumed (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Jan. 31, 2014	Sep. 30, 2014	Jan. 31, 2014	Jan. 31, 2014
In Thousands, unless otherwise specified			Virginia Commerce Bancorp, Inc. [Member]	Virginia Commerce Bancorp, Inc. [Member]	Virginia Commerce Bancorp, Inc. [Member]	Virginia Commerce Bancorp, Inc. [Member]
						Core Deposit Intangible Assets [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Value of common shares issued (18,330,347 shares)	'	'	$547,894	'	'	'
Fair value of stock options assumed	'	'	4,368	4,370	'	'
Cash to redeem the Treasury warrant	'	'	'	33,263	33,263	'
Cash for fractional shares	'	'	8	'	'	'
Total purchase price	'	'	585,533	8	'	'
Cash and cash equivalents	'	'	'	'	130,569	'
Investment securities	'	'	'	'	476,541	'
Loans	'	'	'	'	2,012,521	'
Premises and equipment	'	'	'	'	10,786	'
Core deposit intangibles	'	'	'	'	'	17,143
Other assets	'	'	'	'	104,589	'
Total identifiable assets	'	'	'	'	2,752,149	'
Deposits	'	'	'	'	2,024,969	'
Short-term borrowings	'	'	'	'	263,816	'
Long-term borrowings	'	'	'	'	204,335	'
Other liabilities	'	'	'	'	11,393	'
Total identifiable liabilities	'	'	'	'	2,504,513	'
Net assets acquired including identifiable intangible assets	'	'	'	'	247,636	'
Resulting goodwill	$712,065	$375,547	'	$335,980	$337,897	'

Mergers_and_Acquisitions_Sched2

Mergers and Acquisitions - Schedule of Acquired Identifiable Assets and Liabilities Assumed (Parenthetical) (Detail)	Sep. 30, 2014	Dec. 31, 2013	Jan. 31, 2014
			Virginia Commerce Bancorp, Inc. [Member]
Business Acquisition [Line Items]	'	'	'
Common stock, shares issued	69,224,451	50,867,630	18,330,347

Mergers_and_Acquisitions_Sched3

Mergers and Acquisitions - Schedule of Acquired Reconciliation of Goodwill (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Goodwill [Line Items]	'
Beginning balance	$375,547
Reduction to goodwill for options exercised from previous acquisitions	-37
Reclassification from goodwill	-1,342
Ending balance	712,065
Virginia Commerce Bancorp, Inc. [Member]	'
Goodwill [Line Items]	'
Addition to goodwill from Virginia Commerce acquisition	$337,897

Mergers_and_Acquisitions_Sched4

Mergers and Acquisitions - Schedule of Business Acquisition Pro Forma Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Business Combinations [Abstract]	'	'
Total Revenues	$346,594	$347,419
Net Income	$89,488	$89,960

Investment_Securities_Summary_

Investment Securities - Summary of Amortized Cost and Estimated Fair Values of Available for Sale Securities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]	'	'
Amortized Cost	$1,171,947	$813,049
Gross Unrealized Gains	12,582	6,238
Gross Unrealized Losses	21,970	44,003
Estimated Fair Value	1,162,559	775,284
Cumulative OTTI in AOCI	28,498	34,757
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	93,439	172,324
Gross Unrealized Gains	697	178
Gross Unrealized Losses	138	748
Estimated Fair Value	93,998	171,754
Cumulative OTTI in AOCI	0	0
State and Political Subdivisions [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	132,583	60,861
Gross Unrealized Gains	3,260	1,874
Gross Unrealized Losses	2	26
Estimated Fair Value	135,841	62,709
Cumulative OTTI in AOCI	0	0
Residential Mortgage-Backed Securities, Agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	537,886	215,788
Gross Unrealized Gains	5,049	2,491
Gross Unrealized Losses	1,303	1,815
Estimated Fair Value	541,632	216,464
Cumulative OTTI in AOCI	0	0
Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	12,871	16,369
Gross Unrealized Gains	730	163
Gross Unrealized Losses	0	0
Estimated Fair Value	13,601	16,532
Cumulative OTTI in AOCI	458	458
Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	312,582	241,947
Gross Unrealized Gains	1,016	225
Gross Unrealized Losses	4,381	8,740
Estimated Fair Value	309,217	233,432
Cumulative OTTI in AOCI	0	0
Asset-Backed Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	8,005	9,257
Gross Unrealized Gains	26	1
Gross Unrealized Losses	0	31
Estimated Fair Value	8,031	9,227
Cumulative OTTI in AOCI	0	0
Trust Preferred Collateralized Debt Obligations [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	52,370	73,862
Gross Unrealized Gains	767	210
Gross Unrealized Losses	14,318	30,623
Estimated Fair Value	38,819	43,449
Cumulative OTTI in AOCI	28,040	34,299
Single Issue Trust Preferred Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	13,747	14,346
Gross Unrealized Gains	291	305
Gross Unrealized Losses	1,828	2,019
Estimated Fair Value	12,210	12,632
Cumulative OTTI in AOCI	0	0
Other Corporate Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	4,997	4,996
Gross Unrealized Gains	162	219
Gross Unrealized Losses	0	0
Estimated Fair Value	5,159	5,215
Cumulative OTTI in AOCI	0	0
Marketable Equity Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	3,467	3,299
Gross Unrealized Gains	584	572
Gross Unrealized Losses	0	1
Estimated Fair Value	4,051	3,870
Cumulative OTTI in AOCI	$0	$0

Investment_Securities_Summary_1

Investment Securities - Summary of Securities Available for Sale in an Unrealized Loss Position (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	$264,285	$442,162
Less than 12 months, Unrealized Losses	1,969	11,362
12 months or longer, Fair Value	205,199	35,402
12 months or longer, Unrealized Losses	20,001	32,641
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	19,030	61,517
Less than 12 months, Unrealized Losses	138	748
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
State and Political Subdivisions [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	2,783	2,353
Less than 12 months, Unrealized Losses	2	26
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
Residential Mortgage-Backed Securities, Agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	164,364	160,835
Less than 12 months, Unrealized Losses	1,303	1,815
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	78,108	208,979
Less than 12 months, Unrealized Losses	526	8,740
12 months or longer, Fair Value	162,621	0
12 months or longer, Unrealized Losses	3,855	0
Asset-Backed Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	0	7,976
Less than 12 months, Unrealized Losses	0	31
12 months or longer, Fair Value	0	0
12 months or longer, Unrealized Losses	0	0
Trust Preferred Collateralized Debt Obligations [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	0	0
Less than 12 months, Unrealized Losses	0	0
12 months or longer, Fair Value	34,148	27,167
12 months or longer, Unrealized Losses	14,318	30,623
Single Issue Trust Preferred Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	0	502
Less than 12 months, Unrealized Losses	0	2
12 months or longer, Fair Value	8,430	8,210
12 months or longer, Unrealized Losses	1,828	2,017
Marketable Equity Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Less than 12 months, Fair Value	0	0
Less than 12 months, Unrealized Losses	0	0
12 months or longer, Fair Value	0	25
12 months or longer, Unrealized Losses	$0	$1

Investment_Securities_Summary_2

Investment Securities - Summary of Gains or Losses on Proceeds from Maturities, Sales and Calls of Available for Sale Securities by Specific Identification Method (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'
Proceeds from sales and calls	$64,610	$183,069	$500,493	$587,852
Gross realized gains	1,314	109	2,366	499
Gross realized losses	$5	$8	$232	$23

Investment_Securities_Addition

Investment Securities - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
	Securities		Securities
Schedule of Investments [Line Items]	'	'	'	'	'
Gross unrealized losses on available for sale securities	$21,970,000	'	$21,970,000	'	$44,003,000
Available for sale securities in unrealized loss position	95	'	95	'	'
Available for sale securities in portfolio, number	452	'	452	'	'
Amortized cost agency residential mortgage securities	1,171,947,000	'	1,171,947,000	'	813,049,000
Capitalization of banks, equal to or greater than, in the single-issue trust preferred portfolio	10,000,000,000	'	10,000,000,000	'	'
Net gain on sales of securities	1,309,000	101,000	2,134,000	589,000	'
New issuance of Preferred Stock estimated	'	'	60,000,000,000	'	'
Recognized cumulative credit-related other-than-temporary impairment	4,714,000	0	5,774,000	971,000	'
Other-than-temporarily impaired, the collateralization ratios low	'	'	97.40%	'	'
Other-than-temporarily impaired, the collateralization ratios high	'	'	240.30%	'	'
Other-than-temporarily impaired, the collateralization ratios median	'	'	135.70%	'	'
Other-than-temporarily impaired, the collateralization ratios weighted average	'	'	174.80%	'	'
Security other-than-temporarily impaired	'	'	100.00%	'	'
Carrying value of securities pledged	1,017,560	'	1,017,560	'	640,870
Wells Fargo [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of trust preferred securities	9,910,000	'	9,910,000	'	'
SunTrust Bank [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of trust preferred securities	7,400,000	'	7,400,000	'	'
Royal Bank of Scotland [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of trust preferred securities	973,000	'	973,000	'	'
Split Rated [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of available for sale single issue trust preferred securities	2,990,000	'	2,990,000	'	'
Below Investment Grade [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of available for sale single issue trust preferred securities	10,760,000	'	10,760,000	'	'
TRUP CDOs [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Credit-related other-than-temporary impairment	4,710,000	'	'	'	'
Net gain on sales of securities	'	'	1,300,000	'	'
Issue of Trup Cdos securities	'	'	4	'	'
Credit-related other-than-temporary impairment recognized in earnings	'	'	0	0	'
Noncredit-related other-than-temporary impairment recognized	28,040,000	'	28,040,000	'	34,300,000
Recognized cumulative credit-related other-than-temporary impairment	'	'	48,880,000	'	'
TRUP CDOs [Member] | Split Rated [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost agency residential mortgage securities	5,000,000	'	5,000,000	'	'
TRUP CDOs [Member] | Below Investment Grade [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost agency residential mortgage securities	47,370,000	'	47,370,000	'	'
Originated Prior to 2005 [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Percentage of portfolio of non-agency mortgage backed securities with collateral	'	'	39.00%	'	'
Originated in 2006 and 2007 [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Percentage of portfolio of non-agency mortgage backed securities with collateral	'	'	61.00%	'	'
Agency Mortgage Backed Securities [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost agency residential mortgage securities	850,470,000	'	850,470,000	'	'
Commercial Mortgage-Backed Securities, Agency [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Gross unrealized losses on available for sale securities	4,381,000	'	4,381,000	'	8,740,000
Amortized cost agency residential mortgage securities	312,582,000	'	312,582,000	'	241,947,000
Residential Mortgage-Backed Securities, Agency [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Gross unrealized losses on available for sale securities	1,303,000	'	1,303,000	'	1,815,000
Amortized cost agency residential mortgage securities	537,886,000	'	537,886,000	'	215,788,000
Residential Mortgage-Backed Securities, Non-agency [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Gross unrealized losses on available for sale securities	0	'	0	'	0
Amortized cost agency residential mortgage securities	12,871,000	'	12,871,000	'	16,369,000
Amortized cost above investment grade	4,030,000	'	4,030,000	'	'
Amortized cost below investment grade	8,840,000	'	8,840,000	'	'
Single Issue Trust Preferred [Member] | Below Investment Grade [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Amortized cost of available for sale TRUP CDOs and single issue trust preferred securities in an unrealized loss position 12 months or longer	10,260,000	'	10,260,000	'	'
Marketable Equity Securities [Member]	'	'	'	'	'
Schedule of Investments [Line Items]	'	'	'	'	'
Gross unrealized losses on available for sale securities	0	'	0	'	1,000
Amortized cost agency residential mortgage securities	3,467,000	'	3,467,000	'	3,299,000
Amortized cost	3,470,000	'	3,470,000	'	'
Number of equity securities other-than-temporarily impaired	0	'	0	'	'
Mortgage backed securities net unrealized gains	'	'	$584,000	'	'

Investment_Securities_Summary_3

Investment Securities - Summary of Available for Sale TRUP CDOs (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	$1,171,947	$813,049
Fair Value	1,162,559	775,284
Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	52,370	'
Fair Value	38,819	'
Unrealized Loss/(Gain)	13,551	'
Senior - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	7,725	'
Fair Value	6,133	'
Unrealized Loss/(Gain)	1,592	'
Mezzanine - Bank (now in senior position) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	12,599	'
Fair Value	9,658	'
Unrealized Loss/(Gain)	2,941	'
Mezzanine - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	26,883	'
Fair Value	19,045	'
Unrealized Loss/(Gain)	7,838	'
Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	5,163	'
Fair Value	3,983	'
Unrealized Loss/(Gain)	1,180	'
Investment Grade [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Investment Grade [Member] | Senior - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Investment Grade [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Investment Grade [Member] | Mezzanine - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Investment Grade [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Split Rated [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	5,000	'
Split Rated [Member] | Senior - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	5,000	'
Split Rated [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Split Rated [Member] | Mezzanine - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Split Rated [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	0	'
Below Investment Grade [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	47,370	'
Below Investment Grade [Member] | Senior - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	2,725	'
Below Investment Grade [Member] | Mezzanine - Bank (now in senior position) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	12,599	'
Below Investment Grade [Member] | Mezzanine - Bank [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	26,883	'
Below Investment Grade [Member] | Mezzanine - Bank & Insurance (combination) [Member] | Trup CDOs and Single Issue Trust Preferred Securities [Member]	'	'
Assumptions Utilized In Other Than Temporary Impairment Analysis Of Securities [Line Items]	'	'
Amortized Cost	$5,163	'

Investment_Securities_Roll_For

Investment Securities - Roll Forward of Credit Losses on Securities (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]	'
Cumulative credit losses, Beginning Balance	$70,446
Additions for credit losses on securities for which OTTI was not previously recognized	0
Additions for additional credit losses on securities for which OTTI was previously recognized	5,774
Cumulative credit losses, Ending Balance	$76,220

Investment_Securities_Summary_4

Investment Securities - Summary of Maturities of Securities Available for Sale by Amortized Cost and Estimated Fair Value (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Due in one year or less, Amortized Cost	$26,751	$28,837
Due after one year through five years, Amortized Cost	153,260	217,415
Due after five years through ten years, Amortized Cost	365,664	292,460
Due after ten years, Amortized Cost	622,805	271,038
Marketable equity securities, Amortized Cost	3,467	3,299
Amortized Cost, Total	1,171,947	813,049
Due in one year or less, Estimated Fair Value	26,981	28,960
Due after one year through five years, Estimated Fair Value	153,718	218,498
Due after five years through ten years, Estimated Fair Value	366,395	286,534
Due after ten years, Estimated Fair Value	611,414	237,422
Marketable equity securities, Estimated Fair Value	4,051	3,870
Total available for sale securities	$1,162,559	$775,284

Investment_Securities_Summary_5

Investment Securities - Summary of Amortized Cost and Estimated Fair Values of Securities Held to Maturity (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]	'	'
Amortized Cost	$39,969	$40,965
Gross Unrealized Gains	1,442	1,735
Gross Unrealized Losses	3,030	4,407
Estimated Fair Value	38,381	38,293
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	10,640	10,762
Gross Unrealized Gains	1,403	1,689
Gross Unrealized Losses	0	0
Estimated Fair Value	12,043	12,451
State and Political Subdivisions [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	9,989	10,367
Gross Unrealized Gains	32	37
Gross Unrealized Losses	391	299
Estimated Fair Value	9,630	10,105
Residential Mortgage-Backed Securities, Agency [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	42	50
Gross Unrealized Gains	7	9
Gross Unrealized Losses	0	0
Estimated Fair Value	49	59
Single Issue Trust Preferred Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	19,278	19,766
Gross Unrealized Gains	0	0
Gross Unrealized Losses	2,639	4,108
Estimated Fair Value	16,639	15,658
Other Corporate Securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Amortized Cost	20	20
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$20	$20

Investment_Securities_Summary_6

Investment Securities - Summary of Gross Realized Gains and Losses on Calls and Sales of Held to Maturity Securities Included in Earnings (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'	'	'	'
Gross realized gains	$9	$0	$9	$114
Gross realized losses	$0	$0	$0	$0

Investment_Securities_Summary_7

Investment Securities - Summary of Maturities of Debt Securities Held to Maturity by Amortized Cost and Estimated Fair Value (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Due in one year or less, Amortized Cost	$570	$555
Due after one year through five years, Amortized Cost	12,750	6,683
Due after five years through ten years, Amortized Cost	6,444	13,026
Due after ten years, Amortized Cost	20,205	20,701
Amortized Cost, Total	39,969	40,965
Due in one year or less, Estimated Fair Value	571	556
Due after one year through five years, Estimated Fair Value	14,165	7,312
Due after five years through ten years, Estimated Fair Value	6,069	13,821
Due after ten years, Estimated Fair Value	17,576	16,604
Estimated Fair Value, Total	$38,381	$38,293

Loans_Major_Classes_of_Loans_D

Loans - Major Classes of Loans (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Commercial, financial and agricultural:	'	'
Total commercial, financial & agricultural	$5,356,378	$3,911,103
Residential real estate	2,229,353	1,821,378
Construction & land development	1,088,627	670,364
Consumer:	'	'
Bankcard	10,110	11,023
Other consumer	346,015	299,731
Total gross loans	9,030,483	6,713,599
Owner-Occupied Commercial Real Estate [Member]	'	'
Commercial, financial and agricultural:	'	'
Total commercial, financial & agricultural	1,044,951	654,963
Nonowner-Occupied Commercial Real Estate [Member]	'	'
Commercial, financial and agricultural:	'	'
Total commercial, financial & agricultural	2,718,821	1,917,785
Other Commercial Loans [Member]	'	'
Commercial, financial and agricultural:	'	'
Total commercial, financial & agricultural	$1,592,606	$1,338,355

Loans_Additional_Information_D

Loans - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loans held for sale	$5,773	$4,236
Acquired impaired loans from merger	163,473	31,099
Percentage of acquired impaired loans from merger on total gross loans	1.81%	'
Recorded investment in acquired impaired loans	250,933	52,237
Related party loans	$197,380	$150,798
Maximum [Member]	'	'
Percentage of acquired impaired loans from merger on total gross loans	'	1.00%

Loans_Activity_for_Accretable_

Loans - Activity for Accretable Yield (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Loans [Abstract]	'
Accretable yield at the beginning of the period	$2,251
Additions	9,116
Accretion (including cash recoveries)	-6,051
Net reclassifications to accretable from non-accretable	1,700
Disposals (including maturities, foreclosures, and charge-offs)	-628
Accretable yield at the ending of the period	$6,388

Credit_Quality_Additional_Info

Credit Quality - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Dec. 31, 2013
	SecurityLoan	SecurityLoan
Receivables [Abstract]	'	'	'	'
Minimum days for discontinue of accrual interest on commercial and consumer loan	'	'	'90 days	'
Maximum days for discontinue of accrual interest on commercial and consumer loan	'	'	'120 days	'
Troubled debt restructuring	'	'	$13,502	$8,157
Loans on nonaccrual status	820	'	820	861
Restructured loans modified by reduction in interest	4,012	1,616	4,012	'
Restructured loan and interest	8,523	'	8,523	'
Restructured loans modified by reduction in interest	967	'	967	'
Number of loans restructured	0	0	'	'
Restructured loans modified by reduction in interest and extension of maturity	$5,630	$2,974	$5,630	'
Loans restructured subsequently defaulted, resulting in principal charge-off	'	0	'	'
Number of days required for special mention	'	'	'30 days	'
Number of days required for special mention	'	'	'89 days	'
Number of days required for substandard	'	'	'90 days	'

Credit_Quality_Schedule_of_Tro

Credit Quality - Schedule of Troubled Debt Restructurings, Segregated by Class of Loans (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
	Contract	Contract
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	2	4
Pre-Modification Outstanding Recorded Investment	$5,630	$5,143
Post-Modification Outstanding Recorded Investment	5,630	4,590
Owner-Occupied Commercial Real Estate [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	4
Pre-Modification Outstanding Recorded Investment	0	5,143
Post-Modification Outstanding Recorded Investment	0	4,590
Nonowner-Occupied Commercial Real Estate [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Outstanding Recorded Investment	0	0
Other Commercial [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	2	0
Pre-Modification Outstanding Recorded Investment	5,630	0
Post-Modification Outstanding Recorded Investment	5,630	0
Residential Real Estate [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Outstanding Recorded Investment	0	0
Construction & Land Development [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Outstanding Recorded Investment	0	0
Bankcard [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Outstanding Recorded Investment	0	0
Other Consumer [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Number of Contracts	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Outstanding Recorded Investment	$0	$0

Credit_Quality_Schedule_of_Cha

Credit Quality - Schedule of Charged-off Troubled Debt Restructurings on Financing Receivables (Detail) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013
	Contract	Contract	Contract
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	1	1	1
Recorded Investment	$478	$478	$375
Owner-Occupied [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	0
Recorded Investment	0	0	0
Nonowner-Occupied [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	1	1	0
Recorded Investment	478	478	0
Other Commercial [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	0
Recorded Investment	0	0	0
Residential Real Estate [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	0
Recorded Investment	0	0	0
Construction & Land Development [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	1
Recorded Investment	0	0	375
Bankcard [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	0
Recorded Investment	0	0	0
Other Consumer [Member]	'	'	'
Financing Receivable, Modifications [Line Items]	'	'	'
Number of Contracts	0	0	0
Recorded Investment	$0	$0	$0

Credit_Quality_Schedule_of_Age

Credit Quality - Schedule of Age Analysis of its Past Due Loans, Segregated by Class of Loans (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	$119,112	$173,186
Loans, 90 Days or more Past Due	85,227	73,833
Loans, Total Past Due	204,339	247,019
Loans, Current & Other	8,826,144	6,466,580
Total gross loans	9,030,483	6,713,599
Loans, Recorded Investment >90 Days & Accruing	16,692	11,044
Owner-Occupied [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	14,148	14,144
Loans, 90 Days or more Past Due	9,634	4,537
Loans, Total Past Due	23,782	18,681
Loans, Current & Other	1,021,169	636,282
Total gross loans	1,044,951	654,963
Loans, Recorded Investment >90 Days & Accruing	674	1,383
Nonowner-Occupied [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	27,990	30,836
Loans, 90 Days or more Past Due	13,849	11,725
Loans, Total Past Due	41,839	42,561
Loans, Current & Other	2,676,982	1,875,224
Total gross loans	2,718,821	1,917,785
Loans, Recorded Investment >90 Days & Accruing	1,028	186
Other Commercial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	20,239	54,319
Loans, 90 Days or more Past Due	18,070	11,794
Loans, Total Past Due	38,309	66,113
Loans, Current & Other	1,554,297	1,272,242
Total gross loans	1,592,606	1,338,355
Loans, Recorded Investment >90 Days & Accruing	6,197	896
Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	41,714	54,271
Loans, 90 Days or more Past Due	26,957	25,446
Loans, Total Past Due	68,671	79,717
Loans, Current & Other	2,160,682	1,741,661
Total gross loans	2,229,353	1,821,378
Loans, Recorded Investment >90 Days & Accruing	6,809	5,214
Construction & Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	6,729	9,921
Loans, 90 Days or more Past Due	14,905	18,491
Loans, Total Past Due	21,634	28,412
Loans, Current & Other	1,066,993	641,952
Total gross loans	1,088,627	670,364
Loans, Recorded Investment >90 Days & Accruing	305	1,611
Bankcard [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	371	229
Loans, 90 Days or more Past Due	185	128
Loans, Total Past Due	556	357
Loans, Current & Other	9,554	10,666
Total gross loans	10,110	11,023
Loans, Recorded Investment >90 Days & Accruing	185	128
Other Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Loans, 30-89 Days Past Due	7,921	9,466
Loans, 90 Days or more Past Due	1,627	1,712
Loans, Total Past Due	9,548	11,178
Loans, Current & Other	336,467	288,553
Total gross loans	346,015	299,731
Loans, Recorded Investment >90 Days & Accruing	$1,494	$1,626

Credit_Quality_Schedule_of_Age1

Credit Quality - Schedule of Age Analysis of its Past Due Loans, Segregated by Class of Loans (Parenthetical) (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Acquired impaired loans from merger	$163,473	$31,099
Loans and Debt Securities Acquired with Deteriorated Credit Quality [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Acquired impaired loans from merger	$163,473	$31,099

Credit_Quality_Schedule_of_Non

Credit Quality - Schedule of Nonaccrual Loans, Segregated by Class of Loans (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	$68,535	$62,789
Owner-Occupied [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	8,960	3,154
Nonowner-Occupied [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	12,821	11,539
Other Commercial [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	11,873	10,898
Residential Real Estate [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	20,148	20,232
Construction & Land Development [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	14,600	16,880
Bankcard [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	0	0
Other Consumer [Member]	'	'
Non Accrual Loans Segregated By Class Of Loans [Line Items]	'	'
Loans on Nonaccrual Status	$133	$86

Credit_Quality_Schedule_of_Cre

Credit Quality - Schedule of Credit Quality Indicators Information, by Class of Loans (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	$9,030,483	$6,713,599
Owner-Occupied [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,044,951	654,963
Owner-Occupied [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	946,727	604,129
Owner-Occupied [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	30,297	27,576
Owner-Occupied [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	67,927	23,258
Owner-Occupied [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	0	0
Nonowner-Occupied [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	2,718,821	1,917,785
Nonowner-Occupied [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	2,539,705	1,811,915
Nonowner-Occupied [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	56,224	45,617
Nonowner-Occupied [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	122,892	60,253
Nonowner-Occupied [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	0	0
Other Commercial [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,592,606	1,338,355
Other Commercial [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,385,308	1,206,030
Other Commercial [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	23,794	60,668
Other Commercial [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	182,181	71,148
Other Commercial [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,323	509
Construction & Land Development [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,088,627	670,364
Construction & Land Development [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	903,780	510,911
Construction & Land Development [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	71,263	63,375
Construction & Land Development [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	113,584	96,078
Construction & Land Development [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	0	0
Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	2,229,353	1,821,378
Residential Real Estate [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	2,146,423	1,773,244
Residential Real Estate [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	17,668	13,006
Residential Real Estate [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	63,787	35,128
Residential Real Estate [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,475	0
Bankcard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	10,110	11,023
Bankcard [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	9,554	10,666
Bankcard [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	371	229
Bankcard [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	185	128
Bankcard [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	0	0
Other Consumer [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	346,015	299,731
Other Consumer [Member] | Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	336,157	288,401
Other Consumer [Member] | Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	8,042	9,466
Other Consumer [Member] | Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	1,816	1,712
Other Consumer [Member] | Doubtful [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Financing receivable, credit quality indicators information	$0	$152

Credit_Quality_Schedule_of_Imp

Credit Quality - Schedule of Impaired Loans Information by Class of Loans (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Owner-Occupied [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	$35,355	'	$35,355	'	$4,672
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	35,355	'	35,355	'	4,672
Impaired Loans, Recorded Investment, With an allowance recorded	5,036	'	5,036	'	4,358
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	5,036	'	5,036	'	4,358
Impaired Loans, Related Allowance	820	'	820	'	638
Impaired Loans, Recorded Investment	40,391	'	40,391	'	9,030
Impaired Loans, Unpaid Principal Balance	40,391	'	40,391	'	9,030
Impaired Loans, Related Allowance	820	'	820	'	638
Impaired Loans, Average Recorded Investment, With no related allowance recorded	37,208	13,661	35,959	13,530	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	129	68	617	145	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	4,352	2,313	4,236	1,935	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	114	139	189	166	'
Impaired Loans, Average Recorded Investment	41,560	15,974	40,195	15,465	'
Impaired Loans, Interest Income Recognized	243	207	806	311	'
Nonowner-Occupied [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	60,329	'	60,329	'	5,938
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	60,739	'	60,739	'	6,651
Impaired Loans, Recorded Investment, With an allowance recorded	7,190	'	7,190	'	9,350
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	7,249	'	7,249	'	10,563
Impaired Loans, Related Allowance	773	'	773	'	1,631
Impaired Loans, Recorded Investment	67,519	'	67,519	'	15,288
Impaired Loans, Unpaid Principal Balance	67,988	'	67,988	'	17,214
Impaired Loans, Related Allowance	773	'	773	'	1,631
Impaired Loans, Average Recorded Investment, With no related allowance recorded	63,035	12,035	62,205	11,637	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	230	27	440	221	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	7,332	6,562	7,606	5,518	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	67	155	159	204	'
Impaired Loans, Average Recorded Investment	70,367	18,597	69,811	17,155	'
Impaired Loans, Interest Income Recognized	297	182	599	425	'
Other Commercial [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	18,535	'	18,535	'	10,292
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	21,910	'	21,910	'	17,753
Impaired Loans, Recorded Investment, With an allowance recorded	13,639	'	13,639	'	13,304
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	16,639	'	16,639	'	16,240
Impaired Loans, Related Allowance	4,016	'	4,016	'	2,192
Impaired Loans, Recorded Investment	32,174	'	32,174	'	23,596
Impaired Loans, Unpaid Principal Balance	38,549	'	38,549	'	33,993
Impaired Loans, Related Allowance	4,016	'	4,016	'	2,192
Impaired Loans, Average Recorded Investment, With no related allowance recorded	20,679	18,947	27,454	12,268	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	59	389	217	478	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	12,537	9,390	12,751	16,616	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	97	59	185	991	'
Impaired Loans, Average Recorded Investment	33,216	28,337	40,205	28,884	'
Impaired Loans, Interest Income Recognized	156	448	402	1,469	'
Residential Real Estate [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	28,832	'	28,832	'	12,009
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	29,501	'	29,501	'	12,193
Impaired Loans, Recorded Investment, With an allowance recorded	10,239	'	10,239	'	7,669
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	10,825	'	10,825	'	8,191
Impaired Loans, Related Allowance	2,582	'	2,582	'	4,112
Impaired Loans, Recorded Investment	39,071	'	39,071	'	19,678
Impaired Loans, Unpaid Principal Balance	40,326	'	40,326	'	20,384
Impaired Loans, Related Allowance	2,582	'	2,582	'	4,112
Impaired Loans, Average Recorded Investment, With no related allowance recorded	32,864	9,605	30,484	8,530	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	46	30	195	197	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	7,716	5,773	8,548	5,505	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	8	105	101	186	'
Impaired Loans, Average Recorded Investment	40,580	15,378	39,032	14,035	'
Impaired Loans, Interest Income Recognized	54	135	296	383	'
Construction & Land Development [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	43,096	'	43,096	'	13,866
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	44,676	'	44,676	'	14,662
Impaired Loans, Recorded Investment, With an allowance recorded	12,028	'	12,028	'	11,050
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	15,306	'	15,306	'	14,833
Impaired Loans, Related Allowance	3,775	'	3,775	'	3,752
Impaired Loans, Recorded Investment	55,124	'	55,124	'	24,916
Impaired Loans, Unpaid Principal Balance	59,982	'	59,982	'	29,495
Impaired Loans, Related Allowance	3,775	'	3,775	'	3,752
Impaired Loans, Average Recorded Investment, With no related allowance recorded	44,191	8,688	46,747	8,078	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	97	119	234	304	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	11,491	14,234	10,694	13,934	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	31	111	47	378	'
Impaired Loans, Average Recorded Investment	55,682	22,922	57,441	22,012	'
Impaired Loans, Interest Income Recognized	128	230	281	682	'
Bankcard [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	0	'	0	'	0
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	0	'	0	'	0
Impaired Loans, Recorded Investment, With an allowance recorded	0	'	0	'	0
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	0	'	0	'	0
Impaired Loans, Related Allowance	0	'	0	'	0
Impaired Loans, Recorded Investment	0	'	0	'	0
Impaired Loans, Unpaid Principal Balance	0	'	0	'	0
Impaired Loans, Related Allowance	0	'	0	'	0
Impaired Loans, Average Recorded Investment, With no related allowance recorded	0	0	0	0	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	0	0	0	0	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	0	0	0	0	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	0	0	0	0	'
Impaired Loans, Average Recorded Investment	0	0	0	0	'
Impaired Loans, Interest Income Recognized	0	0	0	0	'
Other Consumer [Member]	'	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'	'
Impaired Loans, Recorded Investment, With no related allowance recorded	51	'	51	'	0
Impaired Loans, Unpaid Principal Balance, With no related allowance recorded	51	'	51	'	0
Impaired Loans, Recorded Investment, With an allowance recorded	0	'	0	'	152
Impaired Loans, Unpaid Principal Balance, With an allowance recorded	0	'	0	'	152
Impaired Loans, Related Allowance	0	'	0	'	152
Impaired Loans, Recorded Investment	51	'	51	'	152
Impaired Loans, Unpaid Principal Balance	51	'	51	'	152
Impaired Loans, Related Allowance	0	'	0	'	152
Impaired Loans, Average Recorded Investment, With no related allowance recorded	55	152	45	152	'
Impaired Loans, Interest Income Recognized, With no related allowance recorded	0	0	0	0	'
Impaired Loans, Average Recorded Investment, With an allowance recorded	76	0	102	0	'
Impaired Loans, Interest Income Recognized, With an allowance recorded	0	0	0	0	'
Impaired Loans, Average Recorded Investment	131	152	147	152	'
Impaired Loans, Interest Income Recognized	$0	$0	$0	$0	'

Allowance_for_Credit_Losses_Ad

Allowance for Credit Losses - Additional Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Specific loss allocations are calculated for loans in excess	$500	'
Number of days for collecting principal or interest on consumer loans	'90 days	'
Minimum collection period for home equity loan or high loan to value loan	'180 days	'
Retail credits amount deemed unrecoverable charged-off period	'60 days	'
Retail credits charged off period after discovery of the fraud	'90 days	'
Reserve for lending-related commitments	$1,477	$2,143
Closed-End Retail Loans [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Number of days delinquent from contractual due date	'120 days	'
Open-End Loans [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Number of days delinquent from contractual due date	'180 days	'

Allowance_for_Credit_Losses_Sc

Allowance for Credit Losses - Schedule of Allowance for Loan Losses and Carrying Amount of Loans (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	$74,975	'	$74,198	$73,901	$73,901
Charge-offs	4,403	'	16,995	'	21,006
Recoveries	401	'	2,890	'	2,036
Provision	4,748	4,777	15,628	14,924	19,267
Ending balance	75,721	'	75,721	'	74,198
Ending Balance: individually evaluated for impairment	11,966	'	11,966	'	12,477
Ending Balance: collectively evaluated for impairment	63,755	'	63,755	'	61,721
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	9,030,483	'	9,030,483	'	6,713,599
Ending Balance: individually evaluated for impairment	79,145	'	79,145	'	81,302
Ending Balance: collectively evaluated for impairment	8,787,865	'	8,787,865	'	6,601,198
Ending Balance: loans acquired with deteriorated credit quality	163,473	'	163,473	'	31,099
Owner-Occupied [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	3,810	'	5,653	3,877	3,877
Charge-offs	726	'	1,863	'	5,344
Recoveries	113	'	1,611	'	150
Provision	1,174	'	-1,030	'	6,970
Ending balance	4,371	'	4,371	'	5,653
Ending Balance: individually evaluated for impairment	820	'	820	'	638
Ending Balance: collectively evaluated for impairment	3,551	'	3,551	'	5,015
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	1,044,951	'	1,044,951	'	654,963
Ending Balance: individually evaluated for impairment	13,383	'	13,383	'	7,157
Ending Balance: collectively evaluated for impairment	1,005,661	'	1,005,661	'	646,548
Ending Balance: loans acquired with deteriorated credit quality	25,907	'	25,907	'	1,258
Nonowner-Occupied [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	8,036	'	8,992	12,876	12,876
Charge-offs	1,226	'	2,063	'	1,164
Recoveries	16	'	250	'	56
Provision	1,442	'	1,089	'	-2,776
Ending balance	8,268	'	8,268	'	8,992
Ending Balance: individually evaluated for impairment	773	'	773	'	1,631
Ending Balance: collectively evaluated for impairment	7,495	'	7,495	'	7,361
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	2,718,821	'	2,718,821	'	1,917,785
Ending Balance: individually evaluated for impairment	13,739	'	13,739	'	13,913
Ending Balance: collectively evaluated for impairment	2,648,094	'	2,648,094	'	1,894,421
Ending Balance: loans acquired with deteriorated credit quality	56,988	'	56,988	'	9,451
Other Commercial [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	26,778	'	20,917	20,511	20,511
Charge-offs	1,142	'	3,233	'	7,699
Recoveries	132	'	249	'	641
Provision	589	'	8,424	'	7,464
Ending balance	26,357	'	26,357	'	20,917
Ending Balance: individually evaluated for impairment	4,016	'	4,016	'	2,192
Ending Balance: collectively evaluated for impairment	22,341	'	22,341	'	18,725
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	1,592,606	'	1,592,606	'	1,338,355
Ending Balance: individually evaluated for impairment	20,072	'	20,072	'	22,327
Ending Balance: collectively evaluated for impairment	1,561,323	'	1,561,323	'	1,314,543
Ending Balance: loans acquired with deteriorated credit quality	11,211	'	11,211	'	1,485
Residential Real Estate [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	14,785	'	16,694	14,895	14,895
Charge-offs	486	'	3,078	'	4,111
Recoveries	76	'	340	'	698
Provision	-532	'	-113	'	5,212
Ending balance	13,843	'	13,843	'	16,694
Ending Balance: individually evaluated for impairment	2,582	'	2,582	'	4,112
Ending Balance: collectively evaluated for impairment	11,261	'	11,261	'	12,582
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	2,229,353	'	2,229,353	'	1,821,378
Ending Balance: individually evaluated for impairment	14,990	'	14,990	'	16,160
Ending Balance: collectively evaluated for impairment	2,193,341	'	2,193,341	'	1,802,686
Ending Balance: loans acquired with deteriorated credit quality	21,022	'	21,022	'	2,532
Construction & Land Development [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	18,320	'	18,953	18,858	18,858
Charge-offs	457	'	5,140	'	896
Recoveries	16	'	140	'	73
Provision	1,682	'	5,608	'	918
Ending balance	19,561	'	19,561	'	18,953
Ending Balance: individually evaluated for impairment	3,775	'	3,775	'	3,752
Ending Balance: collectively evaluated for impairment	15,786	'	15,786	'	15,201
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	1,088,627	'	1,088,627	'	670,364
Ending Balance: individually evaluated for impairment	16,961	'	16,961	'	21,593
Ending Balance: collectively evaluated for impairment	1,023,381	'	1,023,381	'	632,407
Ending Balance: loans acquired with deteriorated credit quality	48,285	'	48,285	'	16,364
Consumer [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	3,146	'	2,945	2,620	2,620
Charge-offs	366	'	1,618	'	1,792
Recoveries	48	'	300	'	418
Provision	313	'	1,514	'	1,699
Ending balance	3,141	'	3,141	'	2,945
Ending Balance: individually evaluated for impairment	0	'	0	'	152
Ending Balance: collectively evaluated for impairment	3,141	'	3,141	'	2,793
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	356,125	'	356,125	'	310,754
Ending Balance: individually evaluated for impairment	0	'	0	'	152
Ending Balance: collectively evaluated for impairment	356,065	'	356,065	'	310,593
Ending Balance: loans acquired with deteriorated credit quality	60	'	60	'	9
Allowance for Estimated Imprecision [Member]	'	'	'	'	'
Allowance for Loan Losses:	'	'	'	'	'
Beginning balance	100	'	44	264	264
Charge-offs	0	'	0	'	0
Recoveries	0	'	0	'	0
Provision	80	'	136	'	-220
Ending balance	180	'	180	'	44
Ending Balance: individually evaluated for impairment	0	'	0	'	0
Ending Balance: collectively evaluated for impairment	180	'	180	'	44
Ending Balance: loans acquired with deteriorated credit quality	0	'	0	'	0
Financing receivables:	'	'	'	'	'
Ending balance	0	'	0	'	0
Ending Balance: individually evaluated for impairment	0	'	0	'	0
Ending Balance: collectively evaluated for impairment	0	'	0	'	0
Ending Balance: loans acquired with deteriorated credit quality	$0	'	$0	'	$0

Intangible_Assets_Summary_of_I

Intangible Assets - Summary of Intangible Assets (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Goodwill not subject to amortization	$712,065	$375,547
Core Deposit Intangible Assets [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Gross Carrying Amount	60,577	43,434
Accumulated Amortization	-38,263	-35,296
Net Carrying Amount	$22,314	$8,138

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Intangible Liability Disclosure [Abstract]	'	'	'	'
Amortization expense	$1,054	$479	$2,967	$1,519

Intangible_Assets_Schedule_of_

Intangible Assets - Schedule of Anticipated Amortization Expense (Detail) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
2014	$4,133
2015	3,383
2016	2,943
2017	2,730
2018 and thereafter	$12,092

ShortTerm_Borrowings_Additiona

Short-Term Borrowings - Additional Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Short-term Debt [Line Items]	'	'
Unused lines of credit	$234,000	'
Federal funds purchased	30,120	27,685
Repurchase agreements	396,818	'
Wholesale REPO	52,713	'
Maturity date of wholesale REPO	'2018-07	'
Unrelated Financial Institution [Member]	'	'
Short-term Debt [Line Items]	'	'
Unused lines of credit	10,000	'
Renewal period of line of credit	'360 days	'
Amount of outstanding balance under line of credit	$0	'

LongTerm_Borrowings_Additional

Long-Term Borrowings - Additional Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Jan. 31, 2014
	Trust		Virginia Commerce Bancorp, Inc. [Member]	Virginia Commerce Bancorp, Inc. [Member]
			Trust
Debt Instrument [Line Items]	'	'	'	'
Unused borrowing amount	$2,275,693	'	'	'
FHLB advances	930,679	592,069	'	'
FHLB advances, weighted-average interest rate	0.45%	'	'	'
FHLB advances, maximum maturity period	'5 years	'	'	'
Overnight funds	100,000	'	'	'
Number of statutory business trusts	15	'	3	'
Outstanding balances of Debentures	$249,863	$198,628	'	$50,635
Maximum time to defer payment of interest on subordinate debt	'5 years	'	'	'

LongTerm_Borrowings_Schedule_o

Long-Term Borrowings - Schedule of Maturities of FHLB Borrowings (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]	'	'
2014	$525,284	'
2015	354,397	'
2016	654	'
2017	344	'
2018 and thereafter	50,000	'
Total	$930,679	$592,069

Commitments_and_Contingent_Lia1

Commitments and Contingent Liabilities - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]	'	'
Loan commitments outstanding	$2,641,369,000	$1,895,682,000
Loan commitments expiry period	'1 year	'
Commercial Letters of Credit [Member]	'	'
Loss Contingencies [Line Items]	'	'
Letters of credit issued	0	0
Standby Letters of Credit [Member]	'	'
Loss Contingencies [Line Items]	'	'
Letters of credit issued	$172,008,000	$114,664,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Schedule of Derivative Instruments (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]	'
Total Derivatives Used for Interest Rate Risk Management and Designated as Hedges	$40,794
Average Pay Rate	5.07%
Fair Value Hedging [Member] | Interest Rate Contracts [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Amount, Pay Fixed Swap (Hedging Commercial Loans)	40,794
Cash Flow Hedging [Member] | Interest Rate Contracts [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Amount, Pay Fixed Swap (Hedging Commercial Loans)	$40,794

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Schedule of Fair Value Derivative Financial Instruments (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Derivatives designated as hedging instruments	$646	$2,179
Derivatives not designated as hedging instruments	618	1,045
Total asset derivatives	1,264	3,224
Derivatives designated as hedging instruments	45	149
Derivatives not designated as hedging instruments	618	1,045
Total liability derivatives	663	1,194
Interest Rate Contracts [Member] | Other Assets [Member]	'	'
Derivative [Line Items]	'	'
Derivatives designated as hedging instruments	646	2,179
Derivatives not designated as hedging instruments	618	1,045
Interest Rate Contracts [Member] | Other Liabilities [Member]	'	'
Derivative [Line Items]	'	'
Derivatives designated as hedging instruments	45	149
Derivatives not designated as hedging instruments	$618	$1,045

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Schedule of Derivative Financial Instruments on Statement of Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest Rate Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives in fair value hedging relationships	($271)	($157)	($795)	($401)
Interest Income/ (Expense) [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives in fair value hedging relationships	-271	-157	-795	-401
Interest Income/ (Expense) [Member] | Interest Rate Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivatives in fair value hedging relationships	-271	-157	-795	-401
Other Income [Member] | Interest Rate Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivative instruments not designated as hedging instruments, gain	154	218	427	1,181
Other Expense [Member] | Interest Rate Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivative instruments not designated as hedging instruments, loss	-154	-218	-427	-1,181
Other Income/ (Expense) [Member] | Interest Rate Contracts [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Derivative instruments not designated as hedging instruments, net	$0	$0	$0	$0

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Discount rates utilized, minimum	3.50%	3.50%
Discount rates utilized, maximum	9.75%	9.75%
Amount of decrease in fair value of securities	'	$7,500,000
Nonrecurring fair value adjustments on loans held for sale	0	'
Fair value measurement of intangible assets	$0	$0
Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Decrease in fair value of securities	'	19.00%
Increase in discount rates, basis point	200	200

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	$4,051	$3,870
Total available for sale securities	1,162,559	775,284
Derivative financial assets	1,264	3,224
Derivative financial liabilities	663	1,194
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	93,998	171,754
State and Political Subdivisions [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	135,841	62,709
Residential Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	541,632	216,464
Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	13,601	16,532
Asset-Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	8,031	9,227
Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	309,217	233,432
Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	38,819	43,449
Single Issue Trust Preferred Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	12,210	12,632
Other Corporate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	5,159	5,215
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	1,158,508	771,414
Available for sale equity securities	4,051	3,870
Total available for sale securities	1,162,559	775,284
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	93,998	171,754
Fair Value, Measurements, Recurring [Member] | State and Political Subdivisions [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	135,841	62,709
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	541,632	216,464
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	13,601	16,532
Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	8,031	9,227
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	309,217	233,432
Fair Value, Measurements, Recurring [Member] | Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	38,819	43,449
Fair Value, Measurements, Recurring [Member] | Single Issue Trust Preferred Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	12,210	12,632
Fair Value, Measurements, Recurring [Member] | Other Corporate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	5,159	5,215
Fair Value, Measurements, Recurring [Member] | Financial Services Industry [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	2,329	2,292
Fair Value, Measurements, Recurring [Member] | Equity Mutual Funds [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	558	434
Fair Value, Measurements, Recurring [Member] | Other Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	1,164	1,144
Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Derivative financial assets	1,264	3,224
Derivative financial liabilities	663	1,194
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	2,425	2,796
Derivative financial assets	0	0
Derivative financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	502
Available for sale equity securities	2,425	2,294
Total available for sale securities	2,425	2,796
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | State and Political Subdivisions [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Single Issue Trust Preferred Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	502
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Other Corporate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Financial Services Industry [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	703	716
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Mutual Funds [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	558	434
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Other Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	1,164	1,144
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Derivative financial assets	0	0
Derivative financial liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	1,121,315	729,039
Derivative financial assets	1,264	3,224
Derivative financial liabilities	663	1,194
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	1,119,689	727,463
Available for sale equity securities	1,626	1,576
Total available for sale securities	1,121,315	729,039
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	93,998	171,754
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | State and Political Subdivisions [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	135,841	62,709
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	541,632	216,464
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	13,601	16,532
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	8,031	9,227
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	309,217	233,432
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Single Issue Trust Preferred Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	12,210	12,130
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Other Corporate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	5,159	5,215
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Financial Services Industry [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	1,626	1,576
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Mutual Funds [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Other Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Derivative financial assets	1,264	3,224
Derivative financial liabilities	663	1,194
Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total available for sale securities	38,819	43,449
Derivative financial assets	0	0
Derivative financial liabilities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	38,819	43,449
Available for sale equity securities	0	0
Total available for sale securities	38,819	43,449
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | State and Political Subdivisions [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities, Non-agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Asset-Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities, Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Trust Preferred Collateralized Debt Obligations [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	38,819	43,449
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Single Issue Trust Preferred Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Other Corporate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Financial Services Industry [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Equity Mutual Funds [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Other Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available for sale equity securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member] | Interest Rate Contracts [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Derivative financial assets	0	0
Derivative financial liabilities	$0	$0

Fair_Value_Measurements_Schedu1

Fair Value Measurements - Schedule of Additional Information about Financial Assets and Liabilities Measured at Fair Value Utilized Level 3 (Detail) (Trust Preferred Collateralized Debt Obligations [Member], Fair Value, Measurements, Recurring [Member], USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Trust Preferred Collateralized Debt Obligations [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Balance, beginning of period	$43,449	$40,613
Included in earnings (or changes in net assets)	-4,539	-6,456
Included in other comprehensive income	15,400	14,520
Purchases, issuances, and settlements	-15,491	-5,228
Transfers in and/or out of Level 3	0	0
Balance, ending of period	38,819	43,449
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at reporting date	$0	$0

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
YTD Losses, Impaired Loans	$1,935	$1,886
YTD Losses, OREO	2,966	2,548
Impaired Loans	48,132	45,883
OREO	42,432	38,182
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Impaired Loans	0	0
OREO	0	0
Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Impaired Loans	18,587	13,081
OREO	42,273	38,107
Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Impaired Loans	29,545	32,802
OREO	$159	$75

Fair_Value_Measurements_Summar1

Fair Value Measurements - Summary of Estimated Fair Values of Financial Instruments (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	$591,270	$416,617
Securities available for sale	1,162,559	775,284
Securities held to maturity	39,969	40,965
Other securities	104,714	73,093
Loans held for sale	5,773	4,236
Loans	9,015,903	6,704,583
Derivative financial assets	1,264	3,224
Deposits	8,753,257	6,621,571
Derivative financial liabilities	663	1,194
Carrying Amount [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	591,270	416,617
Securities available for sale	1,162,559	775,284
Securities held to maturity	39,969	40,965
Other securities	104,714	73,093
Loans held for sale	5,773	4,236
Loans	8,940,182	6,630,385
Derivative financial assets	1,264	3,224
Deposits	8,753,257	6,621,571
Short-term borrowings	474,225	430,754
Long-term borrowings	1,133,255	575,697
Derivative financial liabilities	663	1,194
Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	591,270	416,617
Securities available for sale	1,162,559	775,284
Securities held to maturity	38,381	38,293
Other securities	99,478	70,072
Loans held for sale	5,773	4,236
Loans	8,988,058	6,657,376
Derivative financial assets	1,264	3,224
Deposits	8,754,110	6,641,070
Short-term borrowings	474,225	430,754
Long-term borrowings	1,115,046	553,796
Derivative financial liabilities	663	1,194
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	0	0
Securities available for sale	2,425	2,796
Securities held to maturity	0	0
Other securities	0	0
Loans held for sale	0	0
Loans	0	0
Derivative financial assets	0	0
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Derivative financial liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	591,270	416,617
Securities available for sale	1,121,315	729,039
Securities held to maturity	36,361	35,773
Other securities	0	0
Loans held for sale	5,773	4,236
Loans	0	0
Derivative financial assets	1,264	3,224
Deposits	8,754,110	6,641,070
Short-term borrowings	474,225	430,754
Long-term borrowings	1,115,046	553,796
Derivative financial liabilities	663	1,194
Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Cash and cash equivalents	0	0
Securities available for sale	38,819	43,449
Securities held to maturity	2,020	2,520
Other securities	99,478	70,072
Loans held for sale	0	0
Loans	8,988,058	6,657,376
Derivative financial assets	0	0
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Derivative financial liabilities	$0	$0

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	16-May-11	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	16-May-11
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Authorized shares of stock, option plan, maximum	'	'	'	'	'	1,500,000
Aggregate number of shares issued in respect of restricted stock awards	350,000	'	'	'	'	'
Options available for award each plan year	'	'	'	'	'	1,150,000
Maximum number of shares of restricted stock or shares subject to a restricted stock units award granted	'	'	'	50,000	'	'
Maximum number of options and stock appreciation rights	'	'	'	100,000	'	'
Percentage of restricted stock and restricted stock units vest	'	'	'	25.00%	'	'
Vesting period of awards	'	'	'	'1/3 per year	'	'
Recognition of compensation expense	'	$433	$466	$1,593	$1,320	'
Number of share available for grant for prior plans	'	0	'	0	'	'
Maximum term for awards granted (years)	'	'	'	'10 years	'	'
Shares issued related stock option exercises	'	'	'	368,856	70,570	'
Total intrinsic value of options exercised	'	'	'	$3,977	$363	'
Treasury Stock [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Shares issued related stock option exercises	'	'	'	342,382	'	'
Authorized and Unissued Stock [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Shares issued related stock option exercises	'	'	'	26,474	'	'
Restricted Stock [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Shares, Granted	'	'	'	66,949	'	'
Vesting period	'	'	'	'4 years	'	'
Non-qualified Stock Options [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Shares, Granted	'	'	'	204,800	'	'

Stock_Based_Compensation_Summa

Stock Based Compensation - Summary of Stock Option Plans (Detail) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Schedule Of Stock Options [Line Items]	'	'
Shares, Outstanding, Beginning balance	1,447,997	'
Shares, Granted	204,800	'
Shares, Exercised	-368,856	-70,570
Shares, Forfeited or expired	-69,529	'
Shares, Outstanding, Ending balance	1,655,225	'
Shares, Exercisable at September 30, 2014	1,254,236	'
Aggregate Intrinsic Value, Outstanding at September 30, 2014	$5,745	'
Aggregate Intrinsic Value, Exercisable at September 30, 2014	$4,629	'
Weighted Average Remaining Contractual Term, Outstanding at September 30, 2014	'5 years 1 month 6 days	'
Weighted Average Remaining Contractual Term, Exercisable at September 30, 2014	'4 years	'
Weighted Average Exercise Price, Outstanding, Beginning balance	$29.33	'
Weighted Average Exercise Price, Granted	$28.89	'
Weighted Average Exercise Price, Exercised	$19.50	'
Weighted Average Exercise Price, Forfeited or expired	$32.30	'
Weighted Average Exercise Price, Outstanding, Ending balance	$28.74	'
Weighted Average Exercise Price, Exercisable	$28.92	'
Virginia Commerce Bancorp, Inc. [Member]	'	'
Schedule Of Stock Options [Line Items]	'	'
Assumed in Virginia Commerce merger	440,813	'
Weighted Average Exercise Price, Exercisable	$19.55	'

Stock_Based_Compensation_Statu

Stock Based Compensation - Status of United's Nonvested Stock Option Awards (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Shares, Nonvested, Beginning balance	589,197
Shares, Granted	204,800
Shares, Vested	-383,475
Shares, Forfeited or expired	-9,533
Shares, Nonvested, Ending balance	400,989
Weighted-Average Grant Date Fair Value Per Share, Nonvested Beginning balance	$7.01
Weighted-Average Grant Date Fair Value Per Share, Granted	$6.42
Weighted-Average Grant Date Fair Value Per Share, Vested	$7.46
Weighted-Average Grant Date Fair Value Per Share, Forfeited or expired	$6.48
Weighted-Average Grant Date Fair Value Per Share, Nonvested Ending balance	$6.29

Stock_Based_Compensation_Chang

Stock Based Compensation - Changes to United's Restricted Common Shares (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Assumed in Virginia Commerce merger	$6.42
Virginia Commerce Bancorp, Inc. [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Assumed in Virginia Commerce merger	440,813
Restricted Stock [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of Shares, Outstanding, Beginning balance	85,497
Shares, Granted	66,949
Shares, Vested	-57,204
Shares, Forfeited	-2,338
Number of Shares, Outstanding, Ending balance	127,442
Weighted-Average Grant Date Fair Value Per Share, Outstanding, Beginning balance	$27.53
Weighted-Average Grant Date Fair Value Per Share, Granted	$28.89
Weighted-Average Grant Date Fair Value Per Share, Vested	$28.83
Weighted-Average Grant Date Fair Value Per Share, Forfeited	$28.11
Weighted-Average Grant Date Fair Value Per Share, Outstanding, Ending balance	$28.29
Restricted Stock [Member] | Virginia Commerce Bancorp, Inc. [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Assumed in Virginia Commerce merger	34,538
Assumed in Virginia Commerce merger	$29.89

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'	'	'	'	'
Unrecognized prior service costs, before tax	'	'	'	'	$2
Unrecognized prior service costs, net of tax	'	'	'	'	1
Unrecognized actuarial losses, before tax	'	'	'	'	31,151
Unrecognized actuarial losses, net of tax	'	'	'	'	20,248
Amortization of transition asset, before tax, expected for fiscal year ended December 31, 2014	0	0	0	0	1
Amortization of transition asset, net of tax, expected for fiscal year ended December 31, 2014	'	'	'	'	1
Amortization of actuarial losses, before tax, expected for fiscal year ended December 31, 2014	'	'	'	'	4,821
Amortization of actuarial losses, net of tax, expected for fiscal year ended December 31, 2014	'	'	'	'	$3,134

Employee_Benefit_Plans_Net_Per

Employee Benefit Plans - Net Periodic Pension Cost (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'	'
Service cost	$579	$777	$1,720	$2,304	'
Interest cost	1,361	1,235	4,039	3,665	'
Expected return on plan assets	-2,293	-2,097	-6,806	-6,223	'
Amortization of transition asset	0	0	0	0	1
Recognized net actuarial loss	491	1,184	1,458	3,515	'
Amortization of prior service cost	1	1	1	1	'
Net periodic pension (benefit) cost	$139	$1,100	$412	$3,262	'
Weighted-Average Assumptions:	'	'	'	'	'
Discount rate	5.20%	4.40%	5.20%	4.40%	'
Expected return on assets	7.50%	8.00%	7.50%	8.00%	'
Rate of compensation increase	3.00%	2.75%	3.00%	2.75%	'
Prior to Age 45 [Member]	'	'	'	'	'
Weighted-Average Assumptions:	'	'	'	'	'
Rate of compensation increase	3.50%	3.75%	3.50%	3.75%	'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'
Liability of unrecognized tax benefits	$3,449	'
Estimate of unrecognized tax benefits, reasonable possible	'United cannot reasonably estimate the amount of tax benefits it may recognize over the next 12 months	'
Accrued interest related to uncertain tax positions	$540	$427

Comprehensive_Income_Component

Comprehensive Income - Components of Total Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]	'	'	'	'
Net income	$33,260	$22,170	$96,631	$65,968
Available for sale ("AFS") securities:	'	'	'	'
AFS securities with OTTI charges during the period	-4,714	0	-5,774	-1,172
Related income tax effect	1,650	0	2,021	410
Less : OTTI charges recognized in net income	4,714	0	5,774	971
Related income tax benefit	-1,650	0	-2,021	-340
Reclassification of previous noncredit OTTI to credit OTTI	4,153	0	6,259	1,458
Related income tax benefit	-1,453	0	-2,190	-510
Net unrealized (losses) gains on AFS securities with OTTI	2,700	0	4,069	817
AFS securities - all other:	'	'	'	'
Change in net unrealized gain on AFS securities arising during the period	-339	4,680	24,242	1,080
Related income tax effect	119	-1,638	-8,485	-378
Net reclassification adjustment for (gains) losses included in net income	-1,300	-101	-2,125	-476
Related income tax expense (benefit)	455	36	744	167
Total AFS securities - all other	-1,065	2,977	14,376	393
Net effect of AFS securities on other comprehensive income	1,635	2,977	18,445	1,210
Held to maturity ("HTM") securities:	'	'	'	'
Accretion on the unrealized loss for securities transferred from AFS to the HTM investment portfolio prior to call or maturity	2	2	6	6
Related income tax expense	0	0	-2	-2
Net effect of HTM securities on other comprehensive income	2	2	4	4
Pension plan:	'	'	'	'
Amortization of prior service cost	1	1	1	1
Related income tax benefit	0	0	0	0
Recognized net actuarial loss	491	1,184	1,458	3,515
Related income tax benefit	-183	-445	-531	-1,293
Net effect of change in pension plan asset on other comprehensive income	309	740	928	2,223
Net current-period other comprehensive income, net of tax	1,946	3,719	19,377	3,437
Total Comprehensive Income	$35,206	$25,889	$116,008	$69,405

Comprehensive_Income_Component1

Comprehensive Income - Components of Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Balance at January 1, 2014	'	'	($43,047)	'
Other comprehensive income before reclassification	'	'	15,761	'
Amounts reclassified from accumulated other comprehensive income	'	'	3,616	'
Net current-period other comprehensive income, net of tax	1,946	3,719	19,377	3,437
Balance at September 30, 2014	-23,670	'	-23,670	'
Unrealized Gains/Losses on AFS Securities [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Balance at January 1, 2014	'	'	-23,235	'
Other comprehensive income before reclassification	'	'	15,757	'
Amounts reclassified from accumulated other comprehensive income	'	'	2,688	'
Net current-period other comprehensive income, net of tax	'	'	18,445	'
Balance at September 30, 2014	-4,790	'	-4,790	'
Accretion on the Unrealized Loss for Securities Transferred from AFS to the HTM [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Balance at January 1, 2014	'	'	-67	'
Other comprehensive income before reclassification	'	'	4	'
Amounts reclassified from accumulated other comprehensive income	'	'	0	'
Net current-period other comprehensive income, net of tax	'	'	4	'
Balance at September 30, 2014	-63	'	-63	'
Defined Benefit Pension Items [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Balance at January 1, 2014	'	'	-19,745	'
Other comprehensive income before reclassification	'	'	0	'
Amounts reclassified from accumulated other comprehensive income	'	'	928	'
Net current-period other comprehensive income, net of tax	'	'	928	'
Balance at September 30, 2014	($18,817)	'	($18,817)	'

Comprehensive_Income_Reclassif

Comprehensive Income - Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Available for sale ("AFS") securities:	'	'	'	'
Reclassification of previous noncredit OTTI to credit OTTI	$4,153	$0	$6,259	$1,458
Net reclassification adjustment for losses (gains) included in net income	'	'	-2,125	'
Total before tax	'	'	4,134	'
Related income tax effect	'	'	-1,446	'
Net of tax	'	'	2,688	'
Pension plan:	'	'	'	'
Amortization of transition asset	'	'	1	'
Recognized net actuarial loss	'	'	1,458	'
Total before tax	'	'	1,459	'
Related income tax effect	'	'	-531	'
Net of tax	309	740	928	2,223
Total reclassifications for the period	'	'	$3,616	'

Earnings_Per_Share_Reconciliat

Earnings Per Share - Reconciliation of Numerator and Denominator of Basic Earnings Per Share with that of Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Distributed earnings allocated to common stock	$22,101	$15,597	$66,261	$46,760
Undistributed earnings allocated to common stock	11,102	6,538	30,194	19,104
Net earnings allocated to common shareholders	$33,203	$22,135	$96,455	$65,864
Average common shares outstanding	69,044,876	50,378,613	66,836,396	50,336,741
Equivalents from stock options	224,433	94,346	232,956	65,714
Average diluted shares outstanding	69,269,309	50,472,959	67,069,352	50,402,455
Earnings per basic common share	$0.48	$0.44	$1.45	$1.31
Earnings per diluted common share	$0.48	$0.44	$1.44	$1.31

Variable_Interest_Entities_Add

Variable Interest Entities - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
	Trust
Variable Interest Entity, Not Primary Beneficiary, Disclosures [Abstract]	'
Number of statutory business trust sponsored	15
Percentage of equity shares of each trust owned by the company	100.00%

Variable_Interest_Entities_Inf

Variable Interest Entities - Information Related to Statutory Trusts (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Century Trust [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	23-Mar-00
Amount of Capital Securities Issued	$8,800
Interest Rate	'10.875% Fixed
Maturity Date	8-Mar-30
Sequoia Trust I [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	28-Mar-01
Amount of Capital Securities Issued	2,000
Interest Rate	'10.18% Fixed
Maturity Date	8-Jun-31
United Statutory Trust III [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	17-Dec-03
Amount of Capital Securities Issued	20,000
Interest Rate	'3-month LIBOR + 2.85%
Maturity Date	17-Dec-33
United Statutory Trust IV [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	19-Dec-03
Amount of Capital Securities Issued	25,000
Interest Rate	'3-month LIBOR + 2.85%
Maturity Date	23-Jan-34
United Statutory Trust V [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	12-Jul-07
Amount of Capital Securities Issued	50,000
Interest Rate	'3-month LIBOR + 1.55%
Maturity Date	1-Oct-37
United Statutory Trust VI [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	20-Sep-07
Amount of Capital Securities Issued	30,000
Interest Rate	'3-month LIBOR + 1.30%
Maturity Date	15-Dec-37
Premier Statutory Trust II [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	25-Sep-03
Amount of Capital Securities Issued	6,000
Interest Rate	'3-month LIBOR + 3.10%
Maturity Date	8-Oct-33
Premier Statutory Trust III [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	16-May-05
Amount of Capital Securities Issued	8,000
Interest Rate	'3-month LIBOR + 1.74%
Maturity Date	15-Jun-35
Premier Statutory Trust IV [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	20-Jun-06
Amount of Capital Securities Issued	14,000
Interest Rate	'3-month LIBOR + 1.55%
Maturity Date	23-Sep-36
Premier Statutory Trust V [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	14-Dec-06
Amount of Capital Securities Issued	10,000
Interest Rate	'3-month LIBOR + 1.61%
Maturity Date	1-Mar-37
Centra Statutory Trust I [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	20-Sep-04
Amount of Capital Securities Issued	10,000
Interest Rate	'3-month LIBOR + 2.29%
Maturity Date	20-Sep-34
Centra Statutory Trust II [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	15-Jun-06
Amount of Capital Securities Issued	10,000
Interest Rate	'3-month LIBOR + 1.65%
Maturity Date	7-Jul-36
Virginia Commerce Trust II [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	19-Dec-02
Amount of Capital Securities Issued	15,000
Interest Rate	'6-month LIBOR + 3.30%
Maturity Date	19-Dec-32
Virginia Commerce Trust III [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	20-Dec-05
Amount of Capital Securities Issued	25,000
Interest Rate	'3-month LIBOR + 1.42%
Maturity Date	23-Feb-36
Virginia Commerce Trust IV [Member]	'
Variable Interest Entity [Line Items]	'
Issuance Date	24-Sep-08
Amount of Capital Securities Issued	$25,000
Interest Rate	'10.20% Fixed
Maturity Date	30-Sep-38

Variable_Interest_Entities_Sch

Variable Interest Entities - Schedule of Trust preferred Securities Redemption (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Sequoia Capital Trust I [Member]	'
Debt Instrument, Redemption [Line Items]	'
Redemption rate	10.18%
Redemption price	103.56%
Principal amount outstanding	$2,000
Principal amount to be redeemed	2,000
Redemption date	8-Dec-14
VCBI Capital Trust IV [Member]	'
Debt Instrument, Redemption [Line Items]	'
Redemption rate	10.20%
Redemption price	100.00%
Principal amount outstanding	25,000
Principal amount to be redeemed	$25,000
Redemption date	30-Dec-14

Variable_Interest_Entities_Sum

Variable Interest Entities - Summary of Quantitative Information Related to Significant Involvement in Unconsolidated Variable Interest Entities (Detail) (Trust Preferred Securities [Member], USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Trust Preferred Securities [Member]	'	'
Variable Interest Entity [Line Items]	'	'
Aggregate Assets	$268,315	$201,186
Aggregate Liabilities	259,454	194,453
Risk Of Loss	$8,861	$6,733