Western Alliance Bancorporation (WAL) 10-Q31 Oct 132013 Q3 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2013	Oct. 25, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Entity Registrant Name	'WESTERN ALLIANCE BANCORPORATION	'
Entity Central Index Key	'0001212545	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	87,198,769

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets:	'	'
Cash and due from banks	$142,625	$141,789
Securities purchased under agreement to resell	128,102	'
Interest-bearing deposits in other financial institutions	238,306	62,836
Cash and cash equivalents	509,033	204,625
Money market investments	4,176	664
Investment securities-measured at fair value	3,621	5,061
Investment securities-available-for-sale, at fair value; amortized cost of $1,095,942 at September 30, 2013 and $926,050 at December 31, 2012	1,073,886	939,590
Investment securities-held-to-maturity, at amortized cost; fair value of $287,543 at September 30, 2013 and $292,819 at December 31, 2012	289,108	291,333
Investments in restricted stock, at cost	30,186	30,936
Loans-held for sale	25,413	31,124
Loans-held for investment, net of deferred fees	6,490,870	5,678,194
Less: allowance for credit losses	-97,851	-95,427
Total loans held for investment	6,393,019	5,582,767
Premises and equipment, net	105,925	107,910
Other assets acquired through foreclosure, net	76,475	77,247
Bank owned life insurance	139,658	138,336
Goodwill	23,224	23,224
Other intangible assets, net	4,747	6,539
Deferred tax assets, net	79,570	51,757
Prepaid expenses	5,236	12,029
Other assets	158,152	119,495
Total assets	8,921,429	7,622,637
Deposits:	'	'
Non-interest-bearing demand	1,972,474	1,933,169
Interest-bearing	5,302,837	4,522,008
Total deposits	7,275,311	6,455,177
Customer repurchase agreements	55,524	79,034
Securities sold short	126,664	'
Other borrowings	394,105	193,717
Junior subordinated debt, at fair value	39,447	36,218
Other liabilities	204,090	98,875
Total liabilities	8,095,141	6,863,021
Commitments and contingencies (Note 7)	'	'
Stockholders' equity:	'	'
Preferred stock-par value $0.0001 and liquidation value per share of $1,000; 20,000,000 authorized; 141,000 shares issued and outstanding at September 30, 2013 and December 31, 2012	141,000	141,000
Common stock-par value $0.0001; 200,000,000 authorized; 87,098,782 shares issued and outstanding at September 30, 2013 and 86,465,050 at December 31, 2012	9	9
Additional paid in capital	792,140	784,852
Accumulated deficit	-92,357	-174,471
Accumulated other comprehensive (loss) income	-14,504	8,226
Total stockholders' equity	826,288	759,616
Total liabilities and stockholders' equity	$8,921,429	$7,622,637

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]	'	'
Amortized cost of investment securities available for sale	$1,095,942	$926,050
Amortized cost of investment securities held to maturity	$287,543	$292,819
Preferred stock, par value	$0.00	$0.00
Preferred stock, liquidation value	$1,000	$1,000
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	141,000	141,000
Preferred stock, shares outstanding	141,000	141,000
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	87,098,782	86,465,050
Common stock, shares outstanding	87,098,782	86,465,050

Consolidated_Income_Statements

Consolidated Income Statements (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest income:	'	'	'	'
Loans, including fees	$83,994	$69,580	$239,812	$205,682
Investment securities-taxable	3,977	5,295	11,523	17,522
Investment securities-tax exempt	3,356	2,723	9,712	7,491
Dividends-taxable	286	305	909	899
Dividends-tax exempt	667	711	2,122	2,096
Other	400	55	995	262
Total interest income	92,680	78,669	265,073	233,952
Interest expense:	'	'	'	'
Deposits	4,232	3,974	11,893	12,904
Other borrowings	3,409	2,225	8,808	6,624
Junior subordinated debt	460	487	1,381	1,458
Customer repurchase agreements	20	37	77	158
Total interest expense	8,121	6,723	22,159	21,144
Net interest income	84,559	71,946	242,914	212,808
Provision for credit losses	'	8,932	8,920	35,343
Net interest income after provision for credit losses	84,559	63,014	233,994	177,465
Non-interest income:	'	'	'	'
Service charges and fees	2,425	2,412	7,408	7,014
Income from bank owned life insurance	1,832	1,116	3,904	3,359
Amortization of affordable housing investments	-1,504	-651	-3,304	-710
(Loss) gain on sales of securities, net	-1,679	1,031	-1,537	2,502
Mark to market (losses) gains, net	-7	470	-3,865	701
Bargain purchase gain from acquisition	0	'	10,044	'
Other income	1,558	2,604	4,736	7,397
Total noninterest income	2,625	6,982	17,386	20,263
Non-interest expense:	'	'	'	'
Salaries and employee benefits	28,689	25,500	83,363	78,159
Occupancy	4,901	4,655	14,500	14,046
Legal, professional and directors' fees	3,006	2,291	8,017	6,380
Data processing	1,872	1,390	5,912	3,678
Insurance	1,884	2,121	6,350	6,323
Marketing	1,599	1,231	4,970	4,061
Loan and repossessed asset expenses	1,136	1,236	3,453	4,573
Customer service	677	653	2,037	1,926
Net loss (gain) on sales / valuations of repossesed assets and bank premises, net	371	126	-234	3,678
Intangible amortization	597	880	1,791	2,660
Goodwill and intangible impairment	'	3,435	'	3,435
Merger / restructure expenses	1,018	113	3,833	113
Other expense	3,925	3,912	11,143	10,839
Total non-interest expense	49,675	47,543	145,135	139,871
Income from continuing operations before provision for income taxes	37,509	22,453	106,245	57,857
Income tax expense	9,288	6,752	22,913	16,452
Income from continuing operations	28,221	15,701	83,332	41,405
Loss from discontinued operations, net of tax benefit	-29	-243	-160	-686
Net income	28,192	15,458	83,172	40,719
Dividends on preferred stock	352	352	1,058	3,440
Net income available to common shareholders	$27,840	$15,106	$82,114	$37,279
Earnings per share from continuing operations:	'	'	'	'
Basic	$0.32	$0.19	$0.96	$0.47
Diluted	$0.32	$0.19	$0.95	$0.46
Loss per share from discontinued operations:	'	'	'	'
Basic	'	$0	'	($0.01)
Diluted	'	$0	'	($0.01)
Earnings per share applicable to common shareholders:	'	'	'	'
Basic	$0.32	$0.18	$0.96	$0.46
Diluted	$0.32	$0.18	$0.95	$0.45
Weighted average number of common shares outstanding:	'	'	'	'
Basic	85,799	81,758	85,596	81,570
Diluted	86,769	82,294	86,428	82,159
Dividends declared per common share	'	'	'	'

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive (Loss) Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income	$28,192	$15,458	$83,172	$40,719
Other comprehensive (loss) income, net:	'	'	'	'
Unrealized (loss) gain on securities available-for-sale (AFS), net (tax effect of $2,887, $(4,607), $14,327, $(10,637) for each respective period presented)	-4,770	8,478	-23,670	18,803
Unrealized (loss) gain on cash flow hedge, net (tax effect of $18, $(5), $10, $(10) for each respective period presented)	-30	9	-17	17
Realized loss (gain) on sale of securities AFS included in income, net (tax effect of $(633), $363, $(580), $904 for each respective period presented)	1,046	-668	957	-2,117
Net other comprehensive (loss) income	-3,754	7,819	-22,730	16,703
Comprehensive income	24,438	23,277	60,442	57,422
Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Other comprehensive (loss) income, net:	'	'	'	'
Realized gain on cash flow hedge, net (tax effect of $314 for the respective period presented)	'	'	'	-519
Realized loss (gain) on sale of securities AFS included in income, net (tax effect of $(633), $363, $(580), $904 for each respective period presented)	1,046	-668	957	-1,598
Unrealized Holding Gains (Losses) on AFS [Member]	'	'	'	'
Other comprehensive (loss) income, net:	'	'	'	'
Realized loss (gain) on sale of securities AFS included in income, net (tax effect of $(633), $363, $(580), $904 for each respective period presented)	$1,046	($668)	$957	($1,598)

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive (Loss) Income (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Unrealized gain on securities available-for-sale securities, net of tax	$2,887	($4,607)	$14,327	($10,637)
Unrealized gain on cash flow hedge, net of tax	18	-5	10	-10
Realized gain on cash flow hedge, net of tax	'	'	'	294
Realized gain on sale of securities, net of tax	($633)	$363	($580)	$904

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
In Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2012	$759,616	$141,000	$9	$784,852	$8,226	($174,471)
Beginning balance, shares at Dec. 31, 2012	'	141	86,465	'	'	'
Net income	83,172	'	'	'	'	83,172
Exercise of stock options	2,924	'	'	2,924	'	'
Exercise of stock options, shares	'	'	332	'	'	'
Stock-based compensation	1,608	'	'	1,608	'	'
Stock-based compensation, shares	'	'	111	'	'	'
Restricted stock grants, net	2,756	'	'	2,756	'	'
Restricted stock grants, net, shares	'	'	191	'	'	'
Dividends on preferred stock	-1,058	'	'	'	'	-1,058
Other comprehensive loss, net	-22,730	'	'	'	-22,730	'
Ending balance at Sep. 30, 2013	$826,288	$141,000	$9	$792,140	($14,504)	($92,357)
Ending balance, shares at Sep. 30, 2013	'	141	87,099	'	'	'

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net income	$83,172	$40,719
Adjustments to reconcile net income to cash provided by operating activities:	'	'
Provision for credit losses	8,920	35,343
Depreciation and amortization	6,655	7,319
Stock-based compensation	4,364	4,725
Deferred income taxes and income taxes receivable	1,761	16,125
Net amortization of discounts and premiums for investment securities	7,658	8,027
Goodwill and intangible impairment	'	3,435
Accretion and amortization of fair market value adjustments due to acquisitions	-10,285	'
(Gains) / Losses on:	'	'
Sales of securities, AFS	1,537	-2,502
Acquisition of Centennial Bank	-10,044	'
Other assets acquired through foreclosure, net	-2,388	-317
Valuation adjustments of other repossessed assets, net	2,279	4,060
Sale of premises and equipment, net	-125	-65
Sale of minority interest in Miller / Russell & Associates, Inc.	'	-776
Changes in, net of acquisitions:	'	'
Other assets/liabilities, net	26,437	9,554
Fair value of assets and liabilities measured at fair value	3,865	-701
Net cash provided by operating activities	123,806	124,946
Cash flows from investing activities:	'	'
Investment securities - measured at fair value Principal pay downs and maturities	1,358	954
Investment securities - available-for-sale	'	'
Proceeds from sales	63,153	143,553
Principal pay downs and maturities	161,394	304,428
Purchases	-373,485	-277,619
Investment securities - held-to-maturity Principal pay downs and maturities	'	735
Purchase of investment tax credits	-28,172	-17,901
(Purchase) /sale of money market investments, net	-3,512	1,577
Liquidation of restricted stock	750	676
Loan fundings and principal collections, net	-388,259	-612,929
Proceeds from loan sales	'	3,435
Sale and purchase of premises and equipment, net	-2,472	-5,951
Proceeds from sale of other real estate owned and repossessed assets, net	20,513	26,650
Cash and cash equivalents acquired in acquisition, net	21,204	'
Net cash used in investing activities	-527,528	-432,392
Cash flows from financing activities:	'	'
Net increase in deposits	481,989	503,464
Net decrease in customer repurchases	-23,510	'
Proceeds from securities sold short	126,664	'
Net increase (decrease) in borrowings	121,121	-42,276
Proceeds from exercise of common stock options	2,924	2,620
Cash dividends paid on preferred stock	-1,058	-3,440
Net cash provided by financing activities	708,130	460,368
Net increase in cash and cash equivalents	304,408	152,922
Cash and cash equivalents at beginning of year	204,625	154,995
Cash and cash equivalents at end of period	509,033	307,917
Cash paid during the period for:	'	'
Interest	22,648	22,263
Income taxes	20,245	1,290
Non-cash investing and financing activity:	'	'
Transfers to other assets acquired through foreclosure, net	14,010	19,522
Unfunded commitments to purchase investment tax credits	21,828	34,599
Assets acquired in Centennial merger transaction	410,827	'
Liabilities assumed in Centennial merger transaction	421,987	'
Change in unrealized (loss) gain on AFS securities, net of tax	-23,670	18,803
Change in unrealized gain on cash flow hedge, net of tax	($17)	$17

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Nature of operations
	Western Alliance Bancorporation (“WAL” or “the Company”), incorporated under the laws of the state of Nevada, is a bank holding company providing full service banking and related services to locally owned businesses, professional firms, real estate developers and investors, local non-profit organizations, high net worth individuals and other consumers through its three wholly owned subsidiary banks: Bank of Nevada (“BON”), operating in Southern Nevada; Western Alliance Bank (“WAB”), operating in Arizona and Northern Nevada; and Torrey Pines Bank (“TPB”), operating in California. In addition, there are two non-bank subsidiaries, Western Alliance Equipment Finance (“WAEF”), which offers equipment finance services nationwide, and Las Vegas Sunset Properties (“LVSP”), which holds certain non-performing assets. These entities are collectively referred to herein as the Company.
	Basis of presentation
	The accounting and reporting policies of the Company are in accordance with accounting principles generally accepted in the United States (“GAAP”) and conform to practices within the financial services industry. The accounts of the Company and its consolidated subsidiaries are included in these Consolidated Financial Statements. All intercompany balances and transactions have been eliminated.
	Use of estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant changes in the near term relate to the determination of the allowance for credit losses; fair value determinations related to acquisitions, including loans acquired with deteriorated credit quality; fair value of other assets acquired through foreclosure; determination of the valuation allowance related to deferred tax assets; impairment of goodwill and other intangible assets and other than temporary impairment of securities. Although the Company’s management (“Management”) believes these estimates to be reasonably accurate, actual amounts may differ. In the opinion of Management, all adjustments considered necessary have been reflected in the Consolidated Financial Statements.
	Principles of consolidation
	WAL has eleven wholly owned subsidiaries: BON, WAB, TPB, which are all banking subsidiaries; WAEF, which provides equipment finance services; LVSP, which holds certain non-performing assets; and six unconsolidated subsidiaries used as business trusts in connection with the issuance of trust-preferred securities. In addition, until October 31, 2012, WAL maintained an 80% interest in Shine Investment Advisory Services Inc. (“Shine”), a registered investment advisor. WAL divested its 80% interest in Shine as of October 31, 2012. On April 30, 2013, the Company completed its acquisition of Centennial Bank (“Centennial”) and merged Centennial into WAB effective as of the acquisition date. The assets and liabilities of Centennial are included in the Company’s Consolidated Financial Statements as of April 30, 2013. See Note 2, “Acquisitions and Dispositions” for further discussion.
	BON has three wholly owned subsidiaries: BW Real Estate, Inc., which operates as a real estate investment trust and holds certain of BON’s real estate loans and related securities; BON Investments, Inc., which holds certain investment securities, municipal loans and leases; and BW Nevada Holdings, LLC, which owns the Company’s 2700 West Sahara Avenue, Las Vegas, Nevada office building.
	WAB has one wholly owned subsidiary, WAB Investments, Inc., which holds certain investment securities, municipal loans and leases, and TPB has one wholly owned subsidiary, TPB Investments, Inc., which holds certain investment securities and leases.
	The Company does not have any other entities that should be considered for consolidation. All intercompany balances and transactions have been eliminated in consolidation.
	Reclassifications
	Certain amounts in the Consolidated Financial Statements as of December 31, 2012 and for the three and nine months ended September 30, 2013 have been reclassified to conform to the current presentation. The reclassifications have no effect on net income or stockholders’ equity as previously reported.
	Interim financial information
	The accompanying unaudited Consolidated Financial Statements as of September 30, 2013 and 2012 have been prepared in condensed format and, therefore, do not include all of the information and footnotes required by GAAP for complete financial statements. These statements have been prepared on a basis that is substantially consistent with the accounting principles applied to the Company’s Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

	The information furnished in these interim statements reflects all adjustments which are, in the opinion of Management, necessary for a fair statement of the results for each respective period presented. Such adjustments are of a normal, recurring nature. The results of operations in the interim statements are not necessarily indicative of the results that may be expected for any other quarter or for the full year. The interim financial information should be read in conjunction with the Company’s audited Consolidated Financial Statements.
	Business combinations
	Acquisitions are accounted for in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations (“ASC 805”), which requires that all identified assets acquired and liabilities assumed are recorded at their estimated fair value as of the acquisition date. Any excess of the purchase price over amounts allocated to assets acquired, including identifiable intangible assets, and liabilities assumed, is recorded as goodwill. Where amounts allocated to assets acquired and liabilities assumed is greater than the purchase price, a bargain purchase gain is recognized. Acquisition-related costs are expensed as incurred.
	Fair values are determined in accordance with FASB ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). In many cases, the determination of these fair values required Management to make estimates about discount rates, future expected cash flows, market conditions and other future events that are subjective in nature and subject to change. Determining the fair value of the assets and liabilities, especially the loan portfolio and other real estate owned (“OREO”), is a complex process involving significant judgment regarding the methods and assumptions used to calculate estimated fair values. The fair value of loans acquired is estimated based on discounted cash flows, which take into consideration current portfolio interest rates and repricing characteristics as well as assumptions related to prepayment speeds and credit losses. Loans acquired with credit deterioration are considered to be impaired and are accounted for in accordance with GAAP (see the policy note, “Loans Acquired with Deteriorated Credit Quality,” for further discussion).
	Investment securities
	Investment securities may be classified as held-to-maturity (“HTM”), available-for-sale (“AFS”) or trading. The appropriate classification is initially decided at the time of purchase. Securities classified as HTM are those debt securities that the Company has both the intent and ability to hold to maturity regardless of changes in market conditions, liquidity needs or general economic conditions. These securities are carried at amortized cost. The sale of a security within three months of its maturity date or after the majority of the principal outstanding has been collected is considered a maturity for purposes of classification and disclosure.
	Securities classified as AFS or trading are reported on the Consolidated Balance Sheets at their estimated fair value. As the fair value of AFS securities changes, the changes are reported net of income tax as an element of other comprehensive income (“OCI”), except for impaired securities. When AFS securities are sold, the unrealized gain or loss is reclassified from OCI to non-interest income. Changes in the fair values of trading securities are reported in non-interest income. Securities classified as AFS are securities that the Company intends to hold for an indefinite period of time, but not necessarily to maturity. Any decision to sell a security classified as AFS would be based on various factors, including significant movements in interest rates, changes in the maturity mix of the Company’s assets and liabilities, liquidity needs, decline in credit quality, and regulatory capital considerations.
	Interest income is recognized based on the coupon rate and increased by accretion of discounts earned or decreased by the amortization of premiums paid, over the contractual life of the security, using the interest method. For mortgage-backed securities, estimates of prepayments are considered in the constant yield calculations.
	In estimating whether there are any other than temporary impairment (“OTTI”) losses, Management considers (1) the length of time and the extent to which the fair value has been less than amortized cost, (2) the financial condition and near term prospects of the issuer, (3) the impact of changes in market interest rates, and (4) the intent and ability of the Company to retain its investment for a period of time sufficient to allow for any anticipated recovery in fair value and whether it is not more likely than not the Company would be required to sell the security prior to recovery.
	Declines in the fair value of individual debt securities classified as AFS that are deemed to be other than temporary are reflected in earnings when identified. The fair value of the security then becomes the new cost basis. For individual debt securities where the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the other than temporary decline in fair value of the debt security related to (1) credit loss is recognized in earnings, and (2) market or other factors is recognized in other comprehensive income or loss. Credit losses are recorded if the present value of cash flows is less than amortized cost.
	For individual debt securities where the Company intends to sell the security or more likely than not, will not recover all of its amortized cost, the OTTI is recognized in earnings equal to the entire difference between the securities cost basis and its fair value at the balance sheet date. For individual debt securities for which a credit loss has been recognized in earnings, interest accruals and amortization and accretion of premiums and discounts are suspended when the credit loss is recognized. Interest received after accruals have been suspended is recognized on a cash basis.

	Allowance for credit losses
	Credit risk is inherent in the business of extending loans and leases to borrowers. Like other financial institutions, the Company must maintain an adequate allowance for credit losses. The allowance for credit losses is established through a provision for credit losses charged to expense. Loans are charged against the allowance for credit losses when Management believes that the contractual principal or interest will not be collected. Subsequent recoveries, if any, are credited to the allowance. The allowance is an amount believed adequate to absorb probable losses on existing loans that may become uncollectable, based on evaluation of the collectability of loans and prior credit loss experience, together with other factors. The Company formally re-evaluates and establishes the appropriate level of the allowance for credit losses on a quarterly basis.
	The Company’s allowance for credit loss methodology incorporates several quantitative and qualitative risk factors used to establish the appropriate allowance for credit losses at each reporting date. Quantitative factors include the Company’s historical loss experience, delinquency and charge-off trends, collateral values, changes in the level of nonperforming loans and other factors. Qualitative factors include the economic condition of the Company’s operating markets and the state of certain industries. Specific changes in the risk factors are based on actual loss experience, as well as perceived risk of similar groups of loans classified by collateral type and loan grade. An internal one-year and five-year loss history are also incorporated into the allowance calculation model. Due to the credit concentration of the Company’s loan portfolio in real estate secured loans, the value of collateral is heavily dependent on real estate values in Nevada, Arizona and California. While Management uses the best information available to make its evaluation, future adjustments to the allowance may be necessary if there are significant changes in economic or other conditions. In addition, the Federal Deposit Insurance Corporation (“FDIC”) and state bank regulatory agencies, as an integral part of their examination processes, periodically review the Company’s subsidiary banks’ allowances for credit losses, and may require the subsidiary banks to make additions to the allowance based on their judgment about information available to them at the time of their examinations. Management regularly reviews the assumptions and formulas used in determining the allowance and makes adjustments if required to reflect the current risk profile of the portfolio.
	The allowance consists of specific and general components. The specific allowance relates to impaired loans. In general, impaired loans include non-accrual loans, loans 90 days past due and still accruing, and other criticized and classified loans. For such loans, an allowance is established when the discounted cash flows, collateral value or observable market price of the impaired loan are lower than the carrying value of that loan, pursuant to FASB ASC 310, Receivables (“ASC 310”). Loans not collateral dependent are evaluated based on the expected future cash flows discounted at the original contractual interest rate. The amount to which the present value falls short of the current loan obligation is recorded as a reserve or charge-off.
	The Company uses an appraised value method to determine the need for a reserve or charge-off on impaired, collateral dependent loans and further discounts the appraisal for disposition costs. The Company obtains an independent collateral valuation analysis for each impaired loan, at least annually.
	Loans acquired with deteriorated credit quality
	FASB ASC 310-30, Accounting for Certain Loans or Debt Securities Acquired in a Transfer (“ASC 310-30”), applies to a loan with evidence of deterioration of credit quality since its origination, and for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. For these loans, accounted for under ASC 310-30, Management determines the value of the loan portfolio based, in part, on work provided by an appraiser. Factors considered in the valuation are projected cash flows for the loans, type of loan and related collateral, loan grade, delinquency and loan to value. Loans are grouped together according to similar characteristics and are treated in the aggregate when applying various valuation techniques. Loans are first evaluated individually to determine if there has been credit deterioration since origination. Once acquired loans are determined to have deteriorated credit quality, the Company evaluates such loans for common risk characteristics and aggregation into one or more pools. Common risk characteristics for pooling acquired loans may include credit ratings, loan type, collateral type, delinquency status, geographic location, loan to value, or combinations thereof. Management also estimates the amount of credit losses that are expected to be realized for individual loans by estimating the probability of default and the loss given default, which incorporates the liquidation value of collateral securing loans. These estimates are subjective. The accretion of the fair value adjustments attributable to interest rates on loans acquired with deteriorated credit quality is recorded in interest income in the Consolidated Income Statements over the estimated life of the pool. The fair value adjustment attributable to credit losses on these loans is non-accretable. When a loan is sold, paid off or transferred to OREO and liquidated, any remaining non-accretable yield is recorded in interest income.

	Adjustments to these loan values in future periods may occur based on Management’s expectation of future cash flows to be collected over the lives of the loans. Estimating cash flows is performed at a pool level and incorporates analysis of historical cash flows, delinquencies, and charge-offs as well as assumptions about future cash flows. Performance can vary from period to period, causing changes in estimates of the expected cash flows. If based on the review of a pool of loans, it is probable that a significant increase or improvement in cash flows previously expected to be collected, any valuation allowance established for the pool of loans is first reduced for the increase in the present value of cash flows expected to be collected, and any remaining increase in estimated cash flows increases the accretable yield and is recognized over the remaining estimated life of the loan pool. If based on the review of a pool of loans, it is probable that a decrease or impairment in cash flows previously expected to be collected or if actual cash flows are less than cash flows previously expected, the allowance for credit losses is increased for the decrease in the present value of the cash flows expected to be collected.
	Other assets acquired through foreclosure
	Other assets acquired through foreclosure consist primarily of properties acquired as a result of, or in-lieu-of, foreclosure. Properties or other assets (primarily repossessed assets formerly leased) are classified as other real estate owned and other repossessed property and are initially reported at fair value of the asset less estimated selling costs. Subsequent adjustments are based on the lower of carrying value or fair value, less estimated costs to sell the property. Costs relating to the development or improvement of the assets are capitalized and costs relating to holding the assets are charged to non-interest expense. Property is evaluated regularly to ensure the recorded amount is supported by its current fair value and valuation allowances.
	Derivative financial instruments
	The Company uses interest-rate swaps to mitigate interest-rate risk associated with changes to (1) the fair value of certain fixed-rate financial instruments (fair value hedges) and (2) certain cash flows related to future interest payments on variable rate financial instruments (cash flow hedges).
	The Company recognizes derivatives as assets or liabilities in the Consolidated Balance Sheets at their fair value in accordance with FASB ASC 815, Derivatives and Hedging (“ASC 815”). The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. On the date the derivative contract is entered into, the Company designates the derivative as a fair value hedge or cash flow hedge. Derivative instruments designated in a hedge relationship to mitigate exposure to changes in the fair value of an asset or liability 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.
	For a fair value hedge, the change in the fair value of the derivative instrument is recognized in earnings. For a cash flow hedge, the effective portion of the change in the fair value of the derivative is recorded in accumulated other comprehensive income (loss) (“AOCI”) and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Any ineffective portion of the change in fair value of a cash flow hedge is recognized immediately in non-interest income in the Consolidated Income Statement. Under both the fair value and cash flow hedge scenarios, changes in the fair value of derivatives not considered to be highly effective in hedging the change in fair value or the expected cash flows of the hedged item are recognized in earnings as non-interest income during the period of the change.
	The Company documents its hedge relationships, including identification of the hedging instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transaction at the time the derivative contract is executed. Both at inception and at least quarterly thereafter, the Company assesses whether the derivatives used in hedging transactions are highly effective (as defined in the guidance) in offsetting changes in either the fair value or cash flows of the hedged item. Retroactive effectiveness is assessed, as well as the continued expectation that the hedge will remain effective prospectively. The Company discontinues hedge accounting prospectively when it is determined that a hedge is no longer highly effective. When hedge accounting is discontinued on a fair value hedge that no longer qualifies as an effective hedge, the derivative continues to be reported at fair value on the Consolidated Balance Sheets, but the carrying amount of the hedged item is no longer adjusted for future changes in fair value. The adjustment to the carrying amount of the hedged item that existed at the date hedge accounting is discontinued is amortized over the remaining life of the hedged item into earnings.
	Derivative instruments that are not designated as hedges per the accounting guidance are reported in the Consolidated Balance Sheets at fair value and the changes in fair value are recognized in earnings as non-interest income during the period of change.

	The Company occasionally purchases a financial instrument or originates a loan that contains an embedded derivative instrument. Upon purchasing the instrument or originating the loan, the Company assesses whether the economic characteristics of the embedded derivative are clearly and closely related to the economic characteristics of the remaining component of the financial instrument (i.e., the host contract) and whether a separate instrument with the same terms as the embedded instrument would meet the definition of a derivative instrument. When it is determined that (1) the embedded derivative possesses economic characteristics that are not clearly and closely related to the economic characteristics of the host contract, and (2) a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is separated from the host contract and carried at fair value. However, in cases where (1) the host contract is measured at fair value, with changes in fair value reported in current earnings, or (2) the Company is unable to reliably identify and measure an embedded derivative for separation from its host contract, the entire contract is carried on the Consolidated Balance Sheet at fair value and is not designated as a hedging instrument.
	Commitments and letters of credit
	In the ordinary course of business, the Company enters into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the Consolidated Financial Statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for credit losses.
	Income taxes
	The Company and its subsidiaries, other than BW Real Estate, Inc., file a consolidated federal tax return. Due to tax regulations, several items of income and expense are recognized in different periods for tax return purposes than for financial reporting purposes. These items represent “temporary differences.” Deferred taxes are provided on an asset and liability method, whereby deferred tax assets are recognized for deductible temporary differences and tax credit carry-forwards and deferred tax liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of Management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effect of changes in tax laws and rates on the date of enactment.
	Fair values of financial instruments
	The Company uses fair value measurements to record fair value adjustments to certain assets and liabilities. ASC 820 establishes a framework for measuring fair value, establishes a three-level valuation hierarchy for disclosure of fair value measurement and enhances disclosure requirements for fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The Company uses various valuation approaches, including market, income and/or cost approaches. ASC 820 establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would consider in pricing the asset or liability developed based on the best information available in the circumstances. The hierarchy is broken down into three levels based on the reliability of inputs, as follows:

		•	Level 1 — Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

		•	Level 2 — Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, prepayment speeds, volatilities, etc.) or model-based valuation techniques where all significant assumptions are observable, either directly or indirectly, in the market.

		•	Level 3 — Valuation is generated from model-based techniques where one or more significant inputs are not observable, either directly or indirectly, in the market. These unobservable assumptions reflect the Company’s own estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques may include use of matrix pricing, discounted cash flow models and similar techniques.
	The availability of observable inputs varies based on the nature of the specific financial instrument. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety.
	Fair value is a market-based measure considered from the perspective of a market participant who holds the asset or owes the liability rather than an entity-specific measure. When market assumptions are available, ASC 820 requires the Company to make assumptions regarding the assumptions that market participants would use to estimate the fair value of the financial instrument at the measurement date.

FASB ASC 825, Financial Instruments (“ASC 825”), requires disclosure of fair value information about financial instruments, whether or not recognized in the balance sheet, for which it is practicable to estimate that value.
Management uses its best judgment in estimating the fair value of the Company’s financial instruments; however, there are inherent limitations in any estimation technique. Therefore, for substantially all financial instruments, the fair value estimates presented herein are not necessarily indicative of the amounts the Company could have realized in a sales transaction at September 30, 2013 or December 31, 2012. The estimated fair value amounts for September 30, 2013 and December 31, 2012 have been measured as of period-end, and have not been reevaluated or updated for purposes of these Consolidated Financial Statements subsequent to those dates. As such, the estimated fair values of these financial instruments subsequent to the reporting date may be different than the amounts reported at the period-end.
The information in Note 11, “Fair Value Accounting,” should not be interpreted as an estimate of the fair value of the entire Company since a fair value calculation is only required for a limited portion of the Company’s assets and liabilities.
Due to the wide range of valuation techniques and the degree of subjectivity used in making the estimate, comparisons between the Company’s disclosures and those of other companies or banks may not be meaningful.
The following methods and assumptions were used by the Company in estimating the fair value of its financial instruments:
Cash and cash equivalents
The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks approximate their fair value.
Money market and certificates of deposit investments
The carrying amounts reported in the Consolidated Balance Sheets for money market investments approximate their fair value.
Investment securities
The fair values of U.S. Treasuries, corporate bonds, mutual funds, and exchange-listed preferred stock are based on quoted market prices and are categorized as Level 1 in the fair value hierarchy.
The fair value of other investment securities were determined based on matrix pricing. Matrix pricing is a mathematical technique that utilizes observable market inputs including, for example, yield curves, credit ratings and prepayment speeds. Fair values determined using matrix pricing are generally categorized as Level 2 in the fair value hierarchy.
The Company owns certain collateralized debt obligations (“CDOs”) for which quoted prices are not available. Quoted prices for similar assets are also not available for these investment securities. In order to determine the fair value of these securities, the Company has estimated the future cash flows and discount rate using observable market inputs adjusted based on assumptions regarding the adjustments a market participant would assume necessary for each specific security. As a result, the resulting fair values have been categorized as Level 3 in the fair value hierarchy.
Restricted stock
The Company’s subsidiary banks are members of the Federal Home Loan Bank (“FHLB”) system and maintain an investment in capital stock of the FHLB. The Company’s subsidiary banks also maintain an investment in their primary correspondent bank. These investments are carried at cost since no ready market exists for them, and they have no quoted market value. The Company conducts a periodic review and evaluation of its FHLB stock to determine if any impairment exists. The fair values have been categorized as Level 2 in the fair value hierarchy.
Loans
Fair value for loans is estimated based on discounted cash flows using interest rates currently being offered for loans with similar terms to borrowers with similar credit quality with adjustments that the Company believes a market participant would consider in determining fair value based on a third party independent valuation. As a result, the fair value for loans disclosed in Note 11, “Fair Value Accounting,” is categorized as Level 2 in the fair value hierarchy.
Accrued interest receivable and payable
The carrying amounts reported in the Consolidated Balance Sheets for accrued interest receivable and payable approximate their fair value. Accrued interest receivable and payable fair value measurements are classified as Level 3 in the fair value hierarchy.
Derivative financial instruments
All derivatives are recognized in the Consolidated Balance Sheet at their fair value. The fair value for derivatives is determined based on market prices, broker-dealer quotations on similar products or other related input parameters. As a result, the fair values have been categorized as Level 2 in the fair value hierarchy.

Deposits
The fair value disclosed for demand and savings deposits is by definition equal to the amount payable on demand at their reporting date (that is, their carrying amount), which the Company believes a market participant would consider in determining fair value. The carrying amount for variable-rate deposit accounts approximates their fair value. Fair values for 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 these deposits. The fair value measurement of the deposit liabilities disclosed in Note 11, “Fair Value Accounting,” is categorized as Level 2 in the fair value hierarchy.
Federal Home Loan Bank advances and other borrowings
The fair values of the Company’s borrowings are estimated using discounted cash flow analyses, based on the market rates for similar types of borrowing arrangements. The FHLB advances have been categorized as Level 2 in the fair value hierarchy due to their short durations. The other borrowings have been categorized as Level 3 in the fair value hierarchy.
Junior subordinated debt
Junior subordinated debt and subordinated debt are valued by comparing interest rates and spreads to benchmark indices offered to institutions with similar credit profiles to the Company and discounting the contractual cash flows on the Company’s debt using these market rates. The junior subordinated debt has been categorized as Level 3 in the fair value hierarchy.
Off-balance sheet instruments
Fair values for the Company’s off-balance sheet instruments (lending commitments and standby letters of credit) are based on quoted fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the counterparties’ credit standing.
Recent accounting pronouncements
In January 2013, the FASB issued guidance within Accounting Standards Update (“ASU”) 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities. The amendments in ASU 2013-01 to Topic 210, Balance Sheet, clarify that the scope of ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, would apply to derivatives, including bifurcated embedded derivatives, repurchase and reverse agreements, and securities borrowing and lending transactions that are either offset or subject to a master netting arrangement. The amendments are effective for fiscal years beginning on or after January 1, 2013, and interim periods within those annual periods. The adoption of this guidance did not have a material impact on the Company’s Consolidated Income Statement, Consolidated Balance Sheet, or Consolidated Cash Flows.
In February 2013, the FASB issued guidance within ASU 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. The amendments in ASU 2013-02 to Topic 220, Comprehensive Income, update, supersede and replace the presentation requirements for reclassifications out of accumulated other comprehensive income in ASUs 2011-05 and 2011-12. The amendments require an entity to provide additional information about reclassifications out of accumulated other comprehensive income. The amendments are effective prospectively for reporting periods beginning after December 15, 2012. The adoption of this guidance did not have a material impact on the Company’s Consolidated Income Statement, Consolidated Balance Sheet, or Consolidated Cash Flows and only impacted the presentation of other comprehensive income in the Consolidated Financial Statements.
In February 2013, the FASB issued guidance within 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. The amendments in ASU 2013-04 to Topic 405, Liabilities, provide guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation within the scope of the Update is fixed at the reporting date, except for obligations addressed with existing GAAP. The guidance requires an entity to measure those obligations as the sum of the amount the reporting entity agreed to pay on behalf of its co-obligors. The guidance also requires an entity to disclose the nature and amount of the obligation, as well as other information about those obligations. The amendment is effective retrospectively for reporting periods beginning after December 15, 2013. Early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company’s Consolidated Income Statement, Consolidated Balance Sheet, or Consolidated Cash Flows.
In July 2013, the FASB issued guidance within ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The amendments in ASU 2013-11 to Topic 740, Income Taxes, provide guidance on the financial statement presentation of unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendments are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this guidance is not expected to have a material impact on the Company’s Consolidated Financial Statements.

Acquisitions_and_Dispositions

Acquisitions and Dispositions	9 Months Ended
Acquisitions and Dispositions	Sep. 30, 2013
Text Block [Abstract]	'
Acquisitions and Dispositions	'
	2. ACQUISITIONS AND DISPOSITIONS
	Acquisitions
	On April 30, 2013, the Company completed its acquisition of Centennial Bank (“Centennial”). Under the terms of the merger, the Company paid $57.5 million in cash for all equity interests in Centennial. The Company merged Centennial into WAB effective April 30, 2013, reporting combined assets for the resulting bank of $3.16 billion and deposits of $2.76 billion. The merger was undertaken, in part, because the purchase price of Centennial was at a discount to its tangible book value and was accretive to capital at close of the transaction.
	Centennial’s results of operations are included in the Company’s results beginning April 30, 2013. Merger / restructure expenses related to the Centennial acquisition of $0.2 million and $2.7 million for the three and nine months ended September 30, 2013, respectively, have been included in non-interest expense, of which, $1.0 million are acquisition related costs as defined by ASC 805. The acquisition was accounted for under the acquisition method of accounting in accordance with ASC 805. Assets purchased and liabilities assumed were all recorded at their respective acquisition date fair values. A bargain purchase gain of $10.0 million resulted from the acquisition and is included as a component of non-interest income in the Consolidated Income Statement. The amount of gain is equal to the amount by which the estimated fair value of net assets purchased exceeded the consideration paid. Pursuant to the terms of the transaction, $12.7 million in loan receivables were not acquired by the Company.
	The recognized amounts of identifiable assets acquired and liabilities assumed are as follows:


			(in thousands)
	Assets:
	Cash and cash equivalents ⁽¹⁾		$	70,349
	Federal funds sold ⁽¹⁾			8,355
	Investment securities - avaialable-for-sale			26,014
	Loans			351,474
	Deferred tax assets, net			21,666
	Premises and equipment			44
	Other assets acquired through foreclosure, net			5,622
	Other assets			6,007

	Total assets acquired			489,531

	Liabilities:
	Deposits			338,811
	FHLB advances			79,943
	Other liabilities			3,233
	Total liabilities assumed		$	421,987

	Net assets acquired			67,544

	Consideration paid ⁽¹⁾			57,500

	Bargain purchase gain from acquisition		$	10,044


	-1	Cash acquired, net of cash consideration paid of $57.5 million represents the net cash and cash equivalents acquired of $21.2 million as part of the acquisition.
	The fair values of assets acquired and liabilities assumed are subject to adjustment during the first twelve months after the acquisition date if additional information becomes available to indicate a more accurate or appropriate value for an asset or liability. Accordingly, the estimated fair value of net assets are preliminary and subject to measurement period adjustments. Assets that are particularly susceptible to adjustment include certain loans and other assets acquired through foreclosure. However, these adjustments are not expected to be significant. The fair value of net assets acquired includes fair value adjustments to certain receivables that were not considered impaired as of the acquisition date. The fair value adjustments were determined using discounted contractual cash flows. However, the Company believes that all contractual cash flows related to these financial instruments will be collected. As such, these receivables were not considered impaired at the acquisition date and were not subject to the guidance relating to acquired loans which have shown evidence of credit deterioration since origination.
	On October 17, 2012, the Company acquired Western Liberty Bancorp (“Western Liberty”), which included two wholly owned subsidiaries, Service 1^st Bank of Nevada and LVSP. Service 1^st Bank of Nevada was merged into the Company’s wholly owned subsidiary, BON, effective October 19, 2012. LVSP remains a wholly owned subsidiary of WAL.

	The following table presents pro forma information as if the Centennial and Western Liberty acquisitions had occurred as of January 1, 2012. The pro forma information is not necessarily indicative of the results of operations as they would have been had the transactions been effected on the assumed dates.


			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands, except per share amounts)
	Net Interest income ⁽¹⁾		$	81,093		$	85,151		$	238,430		$	254,535
	Non Interest income ⁽²⁾			2,625			8,138			7,468			22,147
	Net income ⁽³⁾			25,820			13,549			69,435			36,012
	Earnings per share—basic		$	0.3		$	0.17		$	0.81		$	0.44
	Earnings per share—diluted		$	0.3		$	0.16		$	0.8		$	0.44

	-1	Excludes accretion (or amortization) of fair market value adjustments for loans, deposits and other borrowings advances of $3,466 for the three months ended September 30, 2013 and $10,285 for the nine months ended September 30, 2013.
	-2	Excludes bargain purchase gain of $10,044 related to the Centennial acquisition.
	-3	Excludes merger / restructure related costs incurred by the Company($181 for the three months ended September 30, 2013 and $2,660 for the nine months ended September 30, 2013) and Centennial ($0 for the three months ended September 30, 2013 and $1,000 for the nine months ended September 30, 2013) and footnotes 1 and 2 noted above as well as the related tax effects.
	Discontinued Operations
	The Company has discontinued its affinity credit card business, PartnersFirst, and has presented these activities as discontinued operations. At September 30, 2013 and December 31, 2012, the outstanding credit card loans held for sale were $25.4 million and $31.1 million, respectively. As discussed in Note 14, “Subsequent Events,” certain receivables in this portfolio were sold on October 1, 2013.
	The following table summarizes the operating results of the discontinued operations for the periods indicated:


			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands)
	Operating revenue		$	1,105		$	315		$	3,376		$	947
Non-interest expenses			(1,155	)		(734	)		(3,653	)		(2,130	)

Loss before income taxes			(50	)		(419	)		(277	)		(1,183	)
Income tax benefit			(21	)		(176	)		(117	)		(497	)

Net loss		$	(29	)	$	(243	)	$	(160	)	$	(686	)

Investment_Securities

Investment Securities	9 Months Ended
Investment Securities	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Investment Securities	'
	3. INVESTMENT SECURITIES
	Carrying amounts and fair values of investment securities at September 30, 2013 and December 31, 2012 are summarized as follows:


			September 30, 2013
						Gross			Gross
			Amortized			Unrealized			Unrealized				Fair
			Cost			Gains			(Losses)				Value
			(in thousands)
	Held-to-maturity
	Collateralized debt obligations		$	50		$	578		$	—			$	628
	Corporate bonds			97,778			647			(4,586	)			93,839
	Municipal obligations			189,680			3,531			(1,735	)			191,476
	Other			1,600			—			—				1,600

			$	289,108		$	4,756		$	(6,321	)		$	287,543



						OTTI
						Recognized
						in Other			Gross				Gross
			Amortized			Comprehensive			Unrealized				Unrealized				Fair
			Cost			Income			Gains				(Losses)				Value
			(in thousands)
	Available-for-sale
	U.S. government sponsored agency securities		$	28,694		$	—		$	—			$	(1,317	)		$	27,377
	Municipal obligations			110,081			—			302				(4,838	)			105,545
	Adjustable-rate preferred stock			66,093			—			864				(5,568	)			61,389
	Mutual funds			32,422			—			123				(222	)			32,323
	Direct U.S. obligations and GSE residential mortgage-backed securities			769,983			—			5,748				(7,253	)			768,478
	Private label residential mortgage-backed securities			27,683			—			8				(1,544	)			26,147
	Trust preferred securities			32,000			—			—				(8,166	)			23,834
	CRA investments			23,703			—			—				(403	)			23,300
	Collateralized mortgage-backed securities			5,283			—			210				—				5,493

			$	1,095,942		$	—		$	7,255			$	(29,311	)		$	1,073,886

	Measured at fair value
	Direct U.S. obligations and GSE residential mortgage-backed securities																$	3,621



			December 31, 2012
						Gross			Gross
			Amortized			Unrealized			Unrealized				Fair
			Cost			Gains			(Losses)				Value
			(in thousands)
	Held-to-maturity
	Collateralized debt obligations		$	50		$	1,401		$	—			$	1,451
	Corporate bonds			97,781			984			(6,684	)			92,081
	Municipal obligations			191,902			5,887			(102	)			197,687
	CRA investments			1,600			—			—				1,600

			$	291,333		$	8,272		$	(6,786	)		$	292,819



						OTTI
						Recognized
						in Other			Gross				Gross
			Amortized			Comprehensive			Unrealized				Unrealized				Fair
			Cost			Income			Gains				(Losses)				Value
		(in thousands)
Available-for-sale
Municipal obligations		$	71,777		$	—		$	1,578			$	(184	)		$	73,171
Adjustable-rate preferred stock			72,717			—			3,591				(753	)			75,555
Mutual funds			36,314			—			1,647				—				37,961
Direct U.S. obligations and GSE residential mortgage-backed securities			648,641			—			14,573				(10	)			663,204
Private label residential mortgage-backed securities			35,868			(1,811	)		2,067				(517	)			35,607
Private label commercial mortgage-backed securities			5,365			—			376				—				5,741
Trust preferred securities			32,000			—			—				(7,865	)			24,135
CRA investments			23,368			—			848				—				24,216

		$	926,050		$	(1,811	)	$	24,680			$	(9,329	)		$	939,590

Measured at fair value
Direct U.S. obligations and GSE residential mortgage-backed securities (3)																$	5,061


During the second quarter 2013, a private label mortgage-backed security with a $1.8 million balance of OTTI recognized in other comprehensive income was sold. Accordingly, there is no OTTI balance recognized in other comprehensive income as of September 30, 2013. For additional information on the fair value changes of the securities measured at fair value, see the trading securities table in Note 11, “Fair Value Accounting.”
The Company conducts an OTTI analysis on a quarterly basis. The initial indication of OTTI for both debt and equity securities is a decline in the market value below the amount recorded for an investment, and the severity and duration of the decline. Another potential indication of OTTI is a downgrade below investment grade. In determining whether an impairment is OTTI, the Company considers the length of time and the extent to which the market value has been below cost, recent events specific to the issuer, including investment downgrades by rating agencies and economic conditions of its industry, and the Company’s ability and intent to hold the investment for a period of time sufficient to allow for any anticipated recovery. For marketable equity securities, the Company also considers the issuer’s financial condition, capital strength, and near-term prospects.
For debt securities and adjustable-rate preferred stock (“ARPS”) that are treated as debt securities for the purpose of OTTI analysis, the Company also considers the cause of the price decline (general level of interest rates and industry- and issuer-specific factors), the issuer’s financial condition, near-term prospects and current ability to make future payments in a timely manner, the issuer’s ability to service debt, and any change in agencies’ ratings at evaluation date from acquisition date and any likely imminent action. For ARPS with a fair value below cost that is not attributable to the credit deterioration of the issuer, such as a decline in cash flows from the security or a downgrade in the security’s rating below investment grade, the Company does not recognize an OTTI charge where determines that it has the intent and ability to retain its investment for a period of time sufficient to allow for any anticipated recovery in fair value.
Gross unrealized losses at September 30, 2013 and December 31, 2012 are primarily caused by interest rate fluctuations, credit spread widening and reduced liquidity in applicable markets. The Company has reviewed securities on which there is an unrealized loss in accordance with its accounting policy for OTTI described above and determined there were no securities impairment charges needed for the three and nine months ended September 30, 2013 and 2012.
The Company does not consider any other securities to be other-than-temporarily impaired as of September 30, 2013 and December 31, 2012. No assurance can be made that additional OTTI will not occur in future periods.
Information pertaining to securities with gross unrealized losses at September 30, 2013 and December 31, 2012, aggregated by investment category and length of time that individual securities have been in a continuous loss position follows:


		September 30, 2013
		Less Than Twelve Months						More Than Twelve Months								Total
		Gross						Gross								Gross
		Unrealized			Fair			Unrealized				Fair				Unrealized			Fair
		Losses			Value			Losses				Value				Losses			Value
		(in thousands)
Held-to-maturity
Corporate bonds		$	—		$	—		$	4,586			$	80,414			$	4,586		$	80,414
Municipal obligations			1,735			41,505			—				—				1,735			41,505

		$	1,735		$	41,505		$	4,586			$	80,414			$	6,321		$	121,919

Available-for-sale
U.S. Government-sponsored agency securities		$	1,317		$	17,377		$	—			$	—			$	1,317		$	17,377
Adjustable-rate preferred stock			5,568			43,599			—				—				5,568			43,599
Mutual funds			222			25,862			—				—				222			25,862
Direct U.S obligations and GSE residential mortgage-backed securities			7,242			358,092			11				1,528				7,253			359,620
Municipal obligations			4,838			79,308			—				—				4,838			79,308
Private label residential mortgage-backed securities			1,500			20,322			44				3,460				1,544			23,782
Trust preferred securities			—			—			8,166				23,834				8,166			23,834
Other			403			23,299			—				—				403			23,299

		$	21,090		$	567,859		$	8,221			$	28,822			$	29,311		$	596,681


		December 31, 2012
		Less Than Twelve Months						More Than Twelve Months								Total
		Gross						Gross								Gross
		Unrealized			Fair			Unrealized				Fair				Unrealized			Fair
		Losses			Value			Losses				Value				Losses			Value
		(in thousands)
Held-to-maturity
Corporate bonds		$	206		$	14,794		$	6,478			$	63,522			$	6,684		$	78,316
Municipal obligations			102			10,908			—				—				102			10,908

		$	308		$	25,702		$	6,478			$	63,522			$	6,786		$	89,224

Available-for-sale
Adjustable-rate preferred stock		$	110		$	7,811		$	643			$	8,723			$	753		$	16,534
Mutual funds			—			—			—				—				—			—
Corporate bonds			—			—			—				—				—			—
Direct U.S obligations and GSE residential mortgage-backed securities			2			557			8				1,938				10			2,495
Municipal obligations			184			15,713			—				—				184			15,713
Private label residential mortgage-backed securities			120			16,901			397				6,986				517			23,887
Trust preferred securities			—			—			7,865				24,135				7,865			24,135

		$	416		$	40,982		$	8,913			$	41,782			$	9,329		$	82,764


The total number of securities in an unrealized loss position at September 30, 2013 was 202, compared to 66 at December 31, 2012. In analyzing an issuer’s financial condition, Management considers whether the securities are issued by the federal government or its agencies, whether downgrades by bond rating agencies have occurred, and industry analysis reports. Since material downgrades have not occurred and Management does not intend to sell the debt securities for the foreseeable future, none of the securities described in the above table or in this paragraph were deemed to be other than temporarily impaired.
At September 30, 2013 and December 31, 2012, the gross unrealized loss on trust preferred securities classified as AFS was $8.2 million and $7.9 million, respectively. The Company actively monitors its debt and other structured securities portfolios classified as AFS for declines in fair value. At September 30, 2013, the gross unrealized loss on the corporate bond portfolio classified as HTM was $4.6 million, compared to $6.7 million at December 31, 2012. During the prior year, the Federal Reserve announced its intention to keep interest rates at historically low levels into 2015. The yields of most of the bonds in the portfolio are tied to LIBOR, thus, negatively affecting their anticipated returns. Additionally, Moody’s had downgraded certain bonds held in the portfolio during 2012. However, all of the bonds remain investment grade.
The amortized cost and fair value of securities as of September 30, 2013 and December 31, 2012, by contractual maturities, are shown below. The actual maturities of the mortgage-backed securities may differ from their contractual maturities because the loans underlying the securities may be repaid without any penalties due to borrowers that have the right to call or prepay obligations with or without call or prepayment penalties. These securities are included in the after ten years category in the following table.


		September 30, 2013						December 31, 2012
		Amortized			Estimated			Amortized				Estimated
		Cost			Fair Value			Cost				Fair Value
		(in thousands)
Held-to-maturity
Due in one year or less		$	2,517		$	2,534		$	1,600			$	1,600
After one year through five years			15,400			15,760			13,596				13,934
After five years through ten years			147,897			144,898			121,238				116,020
After ten years			123,294			124,351			154,899				161,265

		$	289,108		$	287,543		$	291,333			$	292,819

Available-for-sale
Due in one year or less		$	56,226		$	55,725		$	65,190			$	67,794
After one year through five years			23,694			24,216			24,261				25,906
After five years through ten years			34,019			32,661			8,165				8,000
After ten years (1)			982,003			961,284			828,434				837,890

		$	1,095,942		$	1,073,886		$	926,050			$	939,590


-1	Includes mortgage-backed securities.
The following table summarizes the Company’s investment ratings position as of September 30, 2013:


		As of September 30, 2013
		AAA			Split-rated			AA+ to AA-				A+ to A-				BBB+ to BBB-			BB+ and below		Totals
		AAA			AAA/AA+			AA+ to AA-				A+ to A-				BBB+ to BBB-			BB+ and below		Totals
		(in thousands)
Municipal obligations		$	8,006		$	—		$	130,149			$	149,477			$	7,323		$	270	$	295,225
Direct U.S. obligations & GSE residential mortgage-backed securities			—			772,098			—				—				—			—		772,098
Private label residential mortgage-backed securities			12,396			—			151				5,563				4,145			3,892		26,147
Mutual funds (3)			—			—			—				—				32,323			—		32,323
U.S. Government-sponsored agency securities			—			27,377			—				—				—			—		27,377
Adjustable-rate preferred stock			—			—			—				—				45,970			13,371		59,341
Trust preferred securities			—			—			—				—				23,834			—		23,834
Collateralized debt obligations			—			—			—				—				—			50		50
Corporate bonds			—			—			2,697				40,105				54,976			—		97,778
Collarteralized mortgage-backed securities			5,493			—			—				—				—			—		5,493

Total (1) (2)		$	25,895		$	799,475		$	132,997			$	195,145			$	168,571		$	17,583	$	1,339,666


-1	The Company used the average credit rating of the combination of S&P, Moody’s and Fitch in the above table where ratings differed.
-2	Securities values are shown at carrying value as of September 30, 2013. Unrated securities consist of CRA investments with a carrying value of $23.3 million, ARPS with a carrying value of $2.0 million and an other investment of $1.6 million.
-3	At least 80% of mutual funds are investment grade corporate bonds.

The following table summarizes the Company’s investment ratings position as of December 31, 2012:


		As of December 31, 2012
		AAA			Split-rated			AA+ to AA-				A+ to A-				BBB+ to BBB-			BB+ and below		Totals
		AAA			AAA/AA+			AA+ to AA-				A+ to A-				BBB+ to BBB-			BB+ and below		Totals
		(in thousands)
Municipal obligations		$	8,120		$	—		$	149,352			$	92,401			$	14,922		$	278	$	265,073
Direct U.S. obligations & GSE residential mortgage-backed securities			—			668,265			—				—				—			—		668,265
Private label residential mortgage-backed securities			15,219			—			1,649				6,069				5,249			7,421		35,607
Private label commercial mortgage-backed securities			5,741			—			—				—				—			—		5,741
Mutual funds (3)			—			—			—				—				37,961			—		37,961
U.S. Government-sponsored agency securities			—			—			—				—				—			—		—
Adjustable-rate preferred stock			—			—			826				—				60,807			10,838		72,471
Trust preferred securities			—			—			—				—				24,135			—		24,135
Collateralized debt obligations			—			—			—				—				—			50		50
Corporate bonds			—			—			2,696				40,116				54,969			—		97,781

Total (1) (2)		$	29,080		$	668,265		$	154,523			$	138,586			$	198,043		$	18,587	$	1,207,084


-1	The Company used the average credit rating of the combination of S&P, Moody’s and Fitch in the above table where ratings differed.
-2	Securities values are shown at carrying value as of December 31, 2012. Unrated securities consist of CRA investments with a carrying value of $24.2 million, one ARPS security with a carrying value of $3.1 million and an other investment of $1.6 million.
-3	At least 80% of mutual funds are investment grade corporate bonds.
Securities with carrying amounts of approximately $638.5 million and $711.7 million at September 30, 2013 and December 31, 2012, respectively, were pledged for various purposes as required or permitted by law.
The following table presents gross gains and (losses) on sales of investment securities:


		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013				2012
		(in thousands)
Gross gains		$	602		$	1,073		$	870			$	2,786
Gross (losses)			(2,281	)		(42	)		(2,407	)			(284	)

		$	(1,679	)	$	1,031		$	(1,537	)		$	2,502

Loans_Leases_and_Allowance_For

Loans, Leases and Allowance For Credit Losses	9 Months Ended
Loans, Leases and Allowance For Credit Losses	Sep. 30, 2013
Receivables [Abstract]	'
Loans, Leases and Allowance For Credit Losses	'
	4. LOANS, LEASES AND ALLOWANCE FOR CREDIT LOSSES
	The composition of the Company’s loans held for investment portfolio is as follows:


			September 30,				December 31,
			2013				2012
			(in thousands)
	Commercial and industrial		$	1,990,568			$	1,659,003
	Commercial real estate—non-owner occupied			1,864,333				1,505,600
	Commercial real estate—owner occupied			1,551,187				1,396,797
	Construction and land development			459,764				394,319
	Residential real estate			358,962				407,937
	Commercial leases			244,312				288,747
	Consumer			29,850				31,836
	Deferred fees and unearned income, net			(8,106	)			(6,045	)

				6,490,870				5,678,194
	Allowance for credit losses			(97,851	)			(95,427	)

	Total		$	6,393,019			$	5,582,767


	The following table presents the contractual aging of the recorded investment in past due loans by class of loans including loans held for sale and excluding deferred fees:


			September 30, 2013
			Current				30-59 Days				60-89 Days			Over 90 days			Total			Total
			Current				Past Due				Past Due			Past Due			Past Due			Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,538,589			$	2,123			$	—		$	10,475		$	12,598		$	1,551,187
	Non-owner occupied			1,629,045				1,475				12,607			7,294			21,376			1,650,421
	Multi-family			213,912				—				—			—			—			213,912
	Commercial and industrial
	Commercial			1,986,782				1,094				817			1,875			3,786			1,990,568
	Leases			243,959				—				—			353			353			244,312
	Construction and land development
	Construction			264,145				—				—			—			—			264,145
	Land			194,218				56				—			1,345			1,401			195,619
	Residential real estate			342,382				560				127			15,893			16,580			358,962
	Consumer			54,195				309				248			511			1,068			55,263

	Total loans		$	6,467,227			$	5,617			$	13,799		$	37,746		$	57,162		$	6,524,389



			December 31, 2012
			Current				30-59 Days				60-89 Days			Over 90 days			Total			Total
			Current				Past Due				Past Due			Past Due			Past Due			Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,372,550			$	13,153			$	1,757		$	9,337		$	24,247		$	1,396,797
	Non-owner occupied			1,327,481				917				4,416			8,573			13,906			1,341,387
	Multi-family			164,213				—				—			—			—			164,213
	Commercial and industrial
	Commercial			1,654,787				3,109				121			986			4,216			1,659,003
	Leases			287,768				515				—			464			979			288,747
	Construction and land development
	Construction			215,597				—				—			—			—			215,597
	Land			171,919				826				571			5,406			6,803			178,722
	Residential real estate			387,641				3,525				1,837			14,934			20,296			407,937
	Consumer			62,271				524				—			165			689			62,960

Total loans		$	5,644,227			$	22,569			$	8,702		$	39,865		$	71,136		$	5,715,363


The following table presents the recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing interest by class of loans:


		September 30, 2013														December 31, 2012
													Loans past											Loans past
		Non-accrual loans											due 90 days			Non-accrual loans								due 90 days
						Past Due/				Total			or more and						Past Due/			Total		or more and
		Current				Delinquent				Non-accrual			still accruing			Current			Delinquent			Non-accrual		still accruing
		(in thousands)
Commercial real estate
Owner occupied		$	10,222			$	10,391			$	20,613		$	388		$	14,392		$	18,394		$	32,786	$	1,272
Non-owner occupied			12,761				12,885				25,646			4,553			18,299			8,572			26,871		—
Multi-family			—				—				—			—			318			—			318		—
Commercial and industrial
Commercial			1,909				2,092				4,001			4			2,549			3,194			5,743		15
Leases			114				353				467			—			—			979			979		—
Construction and land development
Construction			—				—				—			—			—			—			—		—
Land			5,241				1,401				6,642			—			4,375			6,718			11,093		—
Residential real estate			3,350				15,894				19,244			—			11,561			15,161			26,722		101
Consumer			28				—				28			511			39			165			204		—

Total		$	33,625			$	43,016			$	76,641		$	5,456		$	51,533		$	53,183		$	104,716	$	1,388

The reduction in interest income associated with loans on nonaccrual status was approximately $1.3 million and $3.8 million for the three and nine months ended September 30, 2013, respectively, and $1.3 million and $4.1 million for the three and nine months ended September 30, 2012, respectively.
The Company utilizes an internal asset classification system as a means of reporting problem and potential problem loans. Under the Company’s risk rating system, the Company classifies problem and potential problem loans as “Special Mention,” “Substandard,” “Doubtful,” and “Loss.” Substandard loans include those characterized by well-defined weaknesses and carry the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected. Loans classified as Doubtful have all the weaknesses inherent in those classified Substandard with the added characteristic that the weaknesses present make collection or liquidation in full, on the basis of currently existing facts, conditions and values, highly questionable and improbable. The final rating of Loss covers loans considered uncollectible and having such little recoverable value that it is not practical to defer writing off the asset. Loans that do not currently expose the Company to sufficient risk to warrant classification in one of the aforementioned categories, but possess weaknesses that deserve Management’s close attention, are deemed to be Special Mention. Risk ratings are updated, at a minimum, quarterly. The following tables present the recorded investment and delinquency status by class of loans including loans held for sale and excluding deferred fees by risk rating:


		September 30, 2013
		Pass				Special				Substandard			Doubtful			Loss			Total
		Pass				Mention				Substandard			Doubtful			Loss			Total
		(in thousands)
Commercial real estate
Owner occupied		$	1,465,697			$	35,217			$	49,293		$	980		$	—		$	1,551,187
Non-owner occupied			1,490,250				64,405				95,766			—			—			1,650,421
Multi-family			206,586				5,618				1,708			—			—			213,912
Commercial and industrial
Commercial			1,964,491				9,661				14,904			1,512			—			1,990,568
Leases			239,002				4,843				467			—			—			244,312
Construction and land development
Construction			256,037				8,108				—			—			—			264,145
Land			167,523				4,676				23,420			—			—			195,619
Residential real estate			324,254				3,865				30,843			—			—			358,962
Consumer			53,518				853				892			—			—			55,263

Total		$	6,167,358			$	137,246			$	217,293		$	2,492		$	—		$	6,524,389



		September 30, 2013
		Pass				Special				Substandard			Doubtful			Loss			Total
		Pass				Mention				Substandard			Doubtful			Loss			Total
		(in thousands)
Current (up to 29 days past due)		$	6,164,416			$	136,297			$	165,836		$	678		$	—		$	6,467,227
Past due 30—59 days			2,622				378				2,617			—			—			5,617
Past due 60—89 days			320				571				12,908			—			—			13,799
Past due 90 days or more			—				—				35,932			1,814			—			37,746

Total		$	6,167,358			$	137,246			$	217,293		$	2,492		$	—		$	6,524,389



		December 31, 2012
		Pass				Special				Substandard			Doubtful			Loss			Total
		Pass				Mention				Substandard			Doubtful			Loss			Total
		(in thousands)
Commercial real estate
Owner occupied		$	1,280,337			$	50,552			$	65,908		$	—		$	—		$	1,396,797
Non-owner occupied			1,257,011				21,065				63,311			—			—			1,341,387
Multi-family			163,895				—				318			—			—			164,213
Commercial and industrial
Commercial			1,630,166				12,370				15,499			968			—			1,659,003
Leases			282,075				5,693				979			—			—			288,747
Construction and land development
Construction			215,395				202				—			—			—			215,597
Land			141,436				5,641				31,645			—			—			178,722
Residential real estate			365,042				7,559				32,446			2,890			—			407,937
Consumer			61,469				469				1,022			—			—			62,960

Total		$	5,396,826			$	103,551			$	211,128		$	3,858		$	—		$	5,715,363


		31-Dec-12
		Pass				Special				Substandard			Doubtful			Loss			Total
		Pass				Mention				Substandard			Doubtful			Loss			Total
		(in thousands)
Current (up to 29 days past due)		$	5,387,543			$	100,549			$	152,827		$	3,308		$	—		$	5,644,227
Past due 30—59 days			4,410				1,310				16,849			—			—			22,569
Past due 60—89 days			4,450				1,692				2,560			—			—			8,702
Past due 90 days or more			423				—				38,892			550			—			39,865

Total		$	5,396,826			$	103,551			$	211,128		$	3,858		$	—		$	5,715,363

The table below reflects recorded investment in loans classified as impaired:


		September 30,				December 31,
		2013				2012
		(in thousands)
Impaired loans with a specific valuation allowance under ASC 310		$	20,717			$	51,538
Impaired loans without a specific valuation allowance under ASC 310			153,514				146,617

Total impaired loans		$	174,231			$	198,155

Valuation allowance related to impaired loans		$	(5,909	)		$	(12,866	)


The following table presents the impaired loans by class:


		September 30,				December 31,
		2013				2012
		(in thousands)
Commercial real estate
Owner occupied		$	45,516			$	58,074
Non-owner occupied			54,052				52,146
Multi-family			—				318
Commercial and industrial
Commercial			14,106				15,531
Leases			467				979
Construction and land development
Construction			—				—
Land			26,748				32,492
Residential real estate			32,811				37,851
Consumer			531				764

Total		$	174,231			$	198,155

An allowance for credit loss is established for an impaired loan when the fair value of the loan is less than the recorded investment. In certain cases, portions of impaired loans are charged-off to realizable value instead of establishing a valuation allowance and, are included, when applicable in the table above as “Impaired loans without specific valuation allowance under ASC 310.” The valuation allowance disclosed above is included in the allowance for credit losses reported in the Consolidated Balance Sheets as of September 30, 2013 and December 31, 2012.
The following table presents average investment in impaired loans by loan class:


		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013			2012
		(in thousands)
Commercial real estate
Owner occupied		$	46,108			$	61,223			$	52,030		$	55,881
Non-owner occupied			54,211				60,207				54,553			57,433
Multi-family			—				882				118			983
Commercial and industrial
Commercial			13,786				25,616				14,558			26,097
Leases			565				1,030				817			839
Construction and land development
Construction			—				—				—			1,315
Land			27,418				35,215				28,268			37,440
Residential real estate			34,616				37,814				34,972			34,567
Consumer			564				794				629			1,256

Total		$	177,268			$	222,781			$	185,945		$	215,811


The following table presents interest income on impaired loans by class:


		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013			2012
		(in thousands)
Commercial real estate
Owner occupied		$	426			$	841			$	1,182		$	1,696
Non-owner occupied			458				649				1,283			1,661
Multi-family			—				—				—			—
Commercial and industrial
Commercial			185				406				454			920
Leases			—				—				—			—
Construction and land development
Construction			—				—				—			—
Land			328				171				874			867
Residential real estate			21				78				45			199
Consumer			7				13				22			31

Total		$	1,425			$	2,158			$	3,860		$	5,374

The Company is not committed to lend significant additional funds on these impaired loans.
The following table summarizes nonperforming assets:


		September 30,				December 31,
		2013				2012
		(in thousands)
Nonaccrual loans		$	76,641			$	104,716
Loans past due 90 days or more on accrual status			5,456				1,388
Troubled debt restructured loans			87,387				84,609

Total nonperforming loans			169,484				190,713
Other assets acquired through foreclosure, net			76,475				77,247

Total nonperforming assets		$	245,959			$	267,960

Loans Acquired with Deteriorated Credit Quality
The following table presents information regarding the contractually required payments receivable, cash flows expected to be collected and the estimated fair value of loans acquired in the Centennial acquisition, as of April 30, 2013, the closing date of the transaction:


		April 30, 2013
		Commercial				Residential
		Real Estate				Real Estate				Total
		(in thousands)
Contractually required payments:
Loans with credit deterioration since origination		$	253,419			$	—			$	253,419
Purchased non-credit impaired loans			368,040				2,136				370,176

Total loans acquired		$	621,459			$	2,136			$	623,595

Cash flows expected to be collected:
Loans with credit deterioration since origination		$	145,346			$	—			$	145,346
Purchased non-credit impaired loans			304,818				1,352				306,170

Total loans acquired		$	450,164			$	1,352			$	451,516

Fair value of loans acquired:
Loans with credit deterioration since origination		$	108,863			$	—			$	108,863
Purchased non-credit impaired loans			241,541				1,070				242,611

Total loans acquired		$	350,404			$	1,070			$	351,474


Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows:


		September 30, 2013
		Three Months				Nine Months
		Ended				Ended
		(in thousands)
Balance, at beginning of period		$	26,073			$	7,072
Addition due to acquisition			—				22,318
Reclassification from nonaccretable difference			4,804				5,851
Accretion to interest income			(2,044	)			(6,408	)

Balance, at end of period		$	28,833			$	28,833

The addition during the nine months ended September 30, 2013 reflected in the above table relate to the acquisition of Centennial. The primary drivers of reclassification from nonaccretable to accretable yield resulted from changes in estimated cash flows.
Allowance for Credit Losses
The following table summarizes the changes in the allowance for credit losses by portfolio type:


		For the Three Months Ended September 30,
		Construction and				Commercial				Residential			Commercial
		Land Development				Real Estate				Real Estate			and Industrial			Consumer			Total
		(in thousands)
2013
Beginning Balance		$	9,614			$	34,583			$	13,847		$	37,383		$	896		$	96,323
Charge-offs			—				(864	)			(1,138	)		(544	)		(712	)		(3,258	)
Recoveries			966				422				430			2,242			726			4,786
Provision			(533	)			(278	)			(247	)		354			704			—

Ending balance		$	10,047			$	33,863			$	12,892		$	39,435		$	1,614		$	97,851

2012
Beginning Balance		$	13,378			$	36,733			$	16,957		$	26,132		$	4,312		$	97,512
Charge-offs			(2,315	)			(1,470	)			(2,242	)		(4,100	)		(799	)		(10,926	)
Recoveries			567				633				153			501			38			1,892
Provision			18				2,324				(82	)		5,611			1,061			8,932

Ending balance		$	11,648			$	38,220			$	14,786		$	28,144		$	4,612		$	97,410


		For the Nine Months Ended September 30,
		Construction and				Commercial				Residential			Commercial			Consumer			Total
		Land Development				Real Estate				Real Estate			and Industrial			Consumer			Total
		(in thousands)
2013
Beginning Balance		$	10,554			$	34,982			$	15,237		$	32,860		$	1,794		$	95,427
Charge-offs			(852	)			(6,142	)			(5,641	)		(3,379	)		(1,005	)		(17,019	)
Recoveries			1,787				1,997				1,548			4,440			751			10,523
Provision			(1,442	)			3,026				1,748			5,514			74			8,920

Ending balance		$	10,047			$	33,863			$	12,892		$	39,435		$	1,614		$	97,851

2012
Beginning Balance		$	14,195			$	35,031			$	19,134		$	25,535		$	5,275		$	99,170
Charge-offs			(10,587	)			(12,023	)			(5,756	)		(12,687	)		(3,571	)		(44,624	)
Recoveries			870				2,897				765			2,695			294			7,521
Provision			7,170				12,315				643			12,601			2,614			35,343

Ending balance		$	11,648			$	38,220			$	14,786		$	28,144		$	4,612		$	97,410


The following table presents impairment method information related to loans and allowance for credit losses by loan portfolio segment:


		Commercial				Commercial
		Real Estate-				Real Estate-				Commercial			Residential			Construction
		Owner				Non-Owner				and			Real			and Land			Commercial					Total
		Occupied				Occupied				Industrial			Estate			Development			Leases			Consumer		Loans
		(in thousands)
Loans Held for Investment as of September 30, 2013:
Recorded Investment:
Impaired loans with an allowance recorded		$	2,440			$	7,654			$	2,285		$	6,018		$	2,178		$	114		$	28	$	20,717
Impaired loans with no allowance recorded			43,076				46,398				11,821			26,793			24,570			353			503		153,514

Total loans individually evaluated for impairment			45,516				54,052				14,106			32,811			26,748			467			531		174,231
Loans collectively evaluated for impairment			1,482,207				1,709,255				1,976,080			323,942			432,521			243,845			29,319		6,197,169
Loans acquired with deteriorated credit quality			23,464				101,026				382			2,209			495			—			—		127,576

Total loans held for investment		$	1,551,187			$	1,864,333			$	1,990,568		$	358,962		$	459,764		$	244,312		$	29,850	$	6,498,976

Unpaid Principal Balance
Impaired loans with an allowance recorded		$	2,933			$	8,169			$	2,498		$	6,082		$	2,178		$	114		$	28		22,002
Impaired loans with no allowance recorded			49,720				48,656				12,325			33,706			25,223			505			515		170,650

Total loans individually evaluated for impairment			52,653				56,825				14,823			39,788			27,401			619			543		192,652
Loans collectively evaluated for impairment			1,482,207				1,709,255				1,976,080			323,942			432,521			243,845			29,319		6,197,169
Loans acquired with deteriorated credit quality			33,112				145,235				1,513			3,750			827			—			—		184,437

Total loans held for investment		$	1,567,972			$	1,911,315			$	1,992,416		$	367,480		$	460,749		$	244,464		$	29,862	$	6,574,258

Related Allowance for Credit Losses
Impaired loans with an allowance recorded		$	580			$	810			$	1,004		$	2,594		$	831		$	86		$	4		5,909
Impaired loans with no allowance recorded			—				—				—			—			—			—			—		—

Total loans individually evaluated for impairment			580				810				1,004			2,594			831			86			4		5,909
Loans collectively evaluated for impairment			14,255				16,845				35,482			10,298			9,216			2,863			1,610		90,569
Loans acquired with deteriorated credit quality			—				1,373				—			—			—			—			—		1,373

Total loans held for investment		$	14,835			$	19,028			$	36,486		$	12,892		$	10,047		$	2,949		$	1,614	$	97,851



		Commercial				Commercial
		Real Estate-				Real Estate-				Commercial			Residential			Construction
		Owner				Non-Owner				and			Real			and Land			Commercial					Total
		Occupied				Occupied				Industrial			Estate			Development			Leases			Consumer		Loans
		(in thousands)
Loans Held for Investment as of December 31, 2012:
Recorded Investment:
Impaired loans with an allowance recorded		$	13,615			$	15,217			$	4,700		$	16,482		$	844		$	515		$	165	$	51,538
Impaired loans with no allowance recorded			44,459				37,247				10,831			21,369			31,648			464			599		146,617

Total loans individually evaluated for impairment			58,074				52,464				15,531			37,851			32,492			979			764		198,155
Loans collectively evaluated for impairment			1,332,185				1,440,214				1,642,313			368,034			361,074			287,768			31,072		5,462,660
Loans acquired with deteriorated credit quality			6,538				12,922				1,159			2,052			753			—			—		23,424

Total loans held for investment		$	1,396,797			$	1,505,600			$	1,659,003		$	407,937		$	394,319		$	288,747		$	31,836	$	5,684,239

Unpaid Principal Balance
Impaired loans with an allowance recorded		$	13,634			$	18,746			$	9,877		$	17,837		$	848		$	515		$	540	$	61,997
Impaired loans with no allowance recorded			54,947				43,208				11,248			27,098			35,669			464			612		173,246

Total loans individually evaluated for impairment			68,581				61,954				21,125			44,935			36,517			979			1,152		235,243
Loans collectively evaluated for impairment			1,332,185				1,440,214				1,642,313			368,034			361,074			287,768			31,072		5,462,660
Loans acquired with deteriorated credit quality			11,893				18,397				3,730			3,811			1,170			—			—		39,001

Total loans held for investment		$	1,412,659			$	1,520,565			$	1,667,168		$	416,780		$	398,761		$	288,747		$	32,224	$	5,736,904

Related Allowance for Credit Losses
Impaired loans with an allowance recorded		$	2,815			$	1,602			$	2,314		$	5,448		$	284		$	238		$	165	$	12,866
Impaired loans with no allowance recorded			—				—				—			—			—			—			—		—

Total loans individually evaluated for impairment			2,815				1,602				2,314			5,448			284			238			165		12,866
Loans collectively evaluated for impairment			15,118				15,447				27,546			9,789			10,270			2,762			1,629		82,561
Loans acquired with deteriorated credit quality			—				—				—			—			—			—			—		—

Total loans held for investment		$	17,933			$	17,049			$	29,860		$	15,237		$	10,554		$	3,000		$	1,794	$	95,427

As of September 30, 2013, there was $1.4 million of allowance for credit losses on loans acquired with credit deterioration. At December 31, 2012, there was no allowance for credit losses on loans acquired with credit deterioration.
In the first quarter of 2012, the Company modified its allowance for credit losses calculation to exclude cash secured loans. Additionally, for internally participated loans, historical loss factors have been revised as follows. Previously the loss factors utilized were based on those of the bank which held the participation. Under the revised methodology, loss characteristics of the originating bank are utilized by the participating bank for the first four quarters after origination, during which time the loan becomes seasoned. The net effect of these changes compared to the calculation method used at December 31, 2011 was to decrease the provision and allowance for credit losses by approximately $2.6 million. The net effect by portfolio segment was to the decrease provision for credit losses for the commercial real estate, commercial and industrial, consumer and residential real estate portfolios by $1.5 million, $0.8 million, $0.2 million and $41,000, respectively.

During the second quarter of 2013, the Company further revised its methodology for calculating the allowance for credit losses. Previously, the Company calculated historical loss factors based on net charge-offs. During the second quarter of 2013, the Company recognized elevated recoveries primarily related to earlier charge-offs stemming from the economic downturn. The Company believes that gross charge-offs is a better representation of the loss characteristics for the current economic environment. This change in methodology resulted in an increase of the allowance for credit losses of $7.2 million for the quarter ended June 30, 2013.
Troubled Debt Restructurings (TDR)
A troubled debt restructured loan is a loan on which the Company, for reasons related to a borrower’s financial difficulties, grants a concession to the borrower that the Company would not otherwise consider. The loan terms that have been modified or restructured due to a borrower’s financial situation include, but are not limited to, a reduction in the stated interest rate, an extension of the maturity or renewal of the loan at an interest rate below current market, a reduction in the face amount of the debt, a reduction in the accrued interest, extensions, deferrals, renewals and rewrites. The majority of the Company’s modifications are extensions in terms or deferral of payments which result in no lost principal or interest followed by reductions in interest rates or accrued interest. A troubled debt restructured loan is also considered impaired. Generally, a loan that is modified at an effective market rate of interest may no longer be disclosed as a troubled debt restructuring in years subsequent to the restructuring if it is not impaired based on the terms specified by the restructuring agreement.
The following table presents information on the financial effects of troubled debt restructured loans by class for the periods presented:


		Three Months Ended
		September 30, 2013
		Number				Pre-Modification				Forgiven			Lost			Post-Modification			Waived Fees
		of Loans				Outstanding				Principal			Interest			Outstanding			and Other
						Recorded Investment				Balance			Income (1)			Recorded Investment			Expenses
		(dollars in thousands)
Commercial real estate
Owner occupied			—			$	—			$	—		$	—		$	—		$	—
Non-owner occupied			—				—				—			—			—			—
Multi-family			—				—				—			—			—			—
Commercial and industrial
Commercial			3				1,253				—			10			1,243			—
Leases			—				—				—			—			—			—
Construction and land development
Construction			—				—				—			—			—			—
Land			—				—				—			—			—			—
Residential real estate			3				2,304				267			613			1,424			9
Consumer			—				—				—			—			—			—

Total			6			$	3,557			$	267		$	623		$	2,667		$	9


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


		Nine Months Ended
		September 30, 2013
						Pre-Modification				Forgiven			Lost			Post-Modification			Waived Fees
		Number				Outstanding				Principal			Interest			Outstanding			and Other
		of Loans				Recorded Investment				Balance			Income (1)			Recorded Investment			Expenses
		(dollars in thousands)
Commercial real estate
Owner occupied			7			$	3,506			$	—		$	54		$	3,452		$	28
Non-owner occupied			5				10,735				1,030			63			9,642			14
Multi-family			—				—				—			—			—			—
Commercial and industrial
Commercial			11				3,611				—			19			3,592			11
Leases			—				—				—			—			—			—
Construction and land development
Construction			—				—				—			—			—			—
Land			2				286				—			—			286			1
Residential real estate			12				5,308				267			887			4,154			24
Consumer			2				74				—			5			69			3

Total			39			$	23,520			$	1,297		$	1,028		$	21,195		$	81


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


		Three Months Ended
		30-Sep-12
						Pre-Modification				Forgiven			Lost			Post-Modification			Waived Fees
		Number				Outstanding				Principal			Interest			Outstanding			and Other
		of Loans				Recorded Investment				Balance			Income (1)			Recorded Investment			Expenses
		(dollars in thousands)
Commercial real estate
Owner occupied			2			$	3,111			$	—		$	28		$	3,083		$	11
Non-owner occupied			10				19,773				10			194			19,569			5
Multi-family			—				—				—			—			—			—
Commercial and industrial
Commercial			—				—				—			—			—			—
Leases			—				—				—			—			—			—
Construction and land development
Construction			—				—				—			—			—			—
Land			1				2,581				—			26			2,555			—
Residential real estate			4				4,113				—			163			3,950			1
Consumer			1				46				—			3			43			2

Total			18			$	29,624			$	10		$	414		$	29,200		$	19


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


		Nine Months Ended
		30-Sep-12
						Pre-Modification				Forgiven			Lost			Post-Modification			Waived Fees
		Number				Outstanding				Principal			Interest			Outstanding			and Other
		of Loans				Recorded Investment				Balance			Income (1)			Recorded Investment			Expenses
		(dollars in thousands)
Commercial real estate
Owner occupied			14			$	21,740			$	750		$	493		$	20,497		$	71
Non-owner occupied			15				33,629				440			321			32,868			16
Multi-family			—				—				—			—			—			—
Commercial and industrial
Commercial			14				7,707				—			26			7,681			37
Leases			—				—				—			—			—			—
Construction and land development
Construction			—				—				—			—			—			—
Land			6				6,460				—			259			6,201			12
Residential real estate			19				10,306				40			1,148			9,118			8
Consumer			3				114				—			3			111			2

Total			71			$	79,956			$	1,230		$	2,250		$	76,476		$	146


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.

The following table presents TDR loans by class for which there was a payment default during the period:


		Three Months Ended														Nine Months Ended
		September 30,														September 30,
		2013								2012						2013						2012
		Number				Recorded				Number			Recorded			Number			Recorded			Number		Recorded
		of Loans				Investment				of Loans			Investment			of Loans			Investment			of Loans		Investment
		(dollars in thousands)
Commercial real estate
Owner occupied			—			$	—				5		$	4,263			3		$	2,506			10	$	10,611
Non-owner occupied			2				1,330				1			1,049			3			1,490			3		4,442
Multi-family			—				—				—			—			—			—			1		193
Commercial and industrial
Commercial			1				307				3			1,794			3			1,089			7		6,700
Leases			—				—				—			—			—			—			—		—
Construction and land development
Construction			—				—				—			—			—			—			—		—
Land			—				—				1			347			2			330			5		4,013
Residential real estate			—				—				3			3,823			2			655			5		4,143
Consumer			—				—				—			—			—			—			1		375

Total			3			$	1,637				13		$	11,276			13		$	6,070			32	$	30,477

A TDR loan is deemed to have a payment default when it becomes past due 90 days, goes on nonaccrual, or is re-structured again.
At September 30, 2013 and December 31, 2012, loan commitments outstanding on TDR loans were $0 and $0.2 million, respectively.
Loan Purchases and Sales
In the third quarter of 2013, the Company had secondary market loan purchases of $87.3 million, consisting of commercial and industrial loans. In the first nine months of 2013, the Company had secondary market loan purchases of $217.8 million, consisting of $213.4 million of commercial and industrial loans and $4.5 million of commercial real estate loans. In the first nine months of 2012, the Company had secondary market loan purchases of $132.3 million, consisting of $66.1 million of commercial leases, $65.2 million of commercial and industrial loans and $1.0 million of commercial real estate loans. In addition, the Company periodically acquires newly originated loans at closing through participations or loan syndications.
The Company had no significant loan sales in the first nine months of 2013 or 2012. The Company held $25.4 million and $31.1 million of credit card loans classified as held for sale at September 30, 2013 and December 31, 2012, respectively.

Other_Assets_Acquired_through_

Other Assets Acquired through Foreclosure	9 Months Ended
Other Assets Acquired through Foreclosure	Sep. 30, 2013
Text Block [Abstract]	'
Other Assets Acquired through Foreclosure	'
	5. OTHER ASSETS ACQUIRED THROUGH FORECLOSURE
	The following table presents the changes in other assets acquired through foreclosure:


			For the Three Months Ended September 30,
			2013									2012
			Gross Balance			Valuation			Net Balance			Gross Balance			Valuation			Net Balance
			Gross Balance			Allowance			Net Balance			Gross Balance			Allowance			Net Balance
			(in thousands)
	Balance, beginning of the period		$	102,923		$	(26,424	)	$	76,499		$	120,391		$	(43,397	)	$	76,994
	Transfers to other assets acquired through foreclosure, net			2,737			—			2,737			10,807			—			10,807
	Proceeds from sale of other real estate owned and repossessed assets, net			(3,411	)		1,055			(2,356	)		(13,733	)		4,335			(9,398	)
	Valuation adjustments, net			—			(697	)		(697	)		—			(781	)		(781	)
	Gains (losses), net ⁽¹⁾			292			—			292			611			—			611

	Balance, end of period		$	102,541		$	(26,066	)	$	76,475		$	118,076		$	(39,843	)	$	78,233


	-1	Included in gains (losses), net are gains related to transfers to other assets of $62 thousand during the quarter ended September 30, 2013 and $249 thousand during the quarter ended September 30, 2012 pursuant to accounting guidance.


			For the Nine Months Ended September 30,
			2013									2012
			Gross Balance			Valuation			Net Balance			Gross Balance			Valuation			Net Balance
			Gross Balance			Allowance			Net Balance			Gross Balance			Allowance			Net Balance
			(in thousands)
	Balance, beginning of the period		$	113,474		$	(36,227	)	$	77,247		$	135,148		$	(46,044	)	$	89,104
	Transfers to other assets acquired through foreclosure, net			14,010			—			14,010			19,522			—			19,522
	Additions from acquisition of Centennial			5,622			—			5,622			—			—			—
	Proceeds from sale of other real estate owned and repossessed assets, net			(32,953	)		12,440			(20,513	)		(36,911	)		10,261			(26,650	)
	Valuation adjustments, net			—			(2,279	)		(2,279	)		—			(4,060	)		(4,060	)
	Gains (losses), net ⁽¹⁾			2,388			—			2,388			317			—			317

	Balance, end of period		$	102,541		$	(26,066	)	$	76,475		$	118,076		$	(39,843	)	$	78,233


	-1	Included in gains (losses), net are gains related to transfers to other assets of $407 thousand during the nine month period ended September 30, 2013 and $291 thousand during the nine month period ended September 30, 2012 pursuant to accounting guidance.
	At September 30, 2013 and 2012, the majority of the Company’s repossessed assets were properties located in Nevada.

Other_Borrowings_and_Other_Lia

Other Borrowings and Other Liabilities	9 Months Ended
Other Borrowings and Other Liabilities	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Other Borrowings and Other Liabilities	'
	6. OTHER BORROWINGS AND OTHER LIABILITIES
	The following table summarizes the Company’s borrowings as of September 30, 2013 and December 31, 2012:


		September 30,		December 31,
		2013		2012
		(in thousands)
	Short Term:
	Federal funds purchased	$	13,285	$	—
	Revolving line of credit		32,500		—
	FHLB advances		—		120,000

	Total short term debt	$	45,785	$	120,000

	Long Term:
	FHLB advances	$	274,277	$	—
	Other long term debt		74,043		73,717

		$	348,320	$	73,717

	Federal funds purchased consist of unsecured advances of excess balances in reserve accounts held at the Federal Reserve Bank (“FRB”) provided by third parties. During the third quarter of 2013, the Company purchased federal funds to enhance efficiency. As of September 30, 2013, federal funds purchased totaled $13.3 million.
	At September 30, 2013, the Company had revolving lines of credit with other institutions, with outstanding advances totaling $32.5 million. The interest rates on these advances range from 1.75% to 4.70% and have a weighted average interest rate of 2.43%.
	The Company maintains lines of credit with the FHLB and FRB. The Company’s borrowing capacity is determined based on collateral pledged, generally consisting of investment securities and loans, at the time of the borrowing. The Company also maintains credit lines with other sources secured by pledged securities. As of September 30, 2013, the Company had no short-term FHLB or FRB advances.
	In 2010, the Company completed a public offering of $75.0 million, at a discount, in principal Senior Notes due in 2015, bearing interest of 10%. In the first quarter of 2013, the Company executed a long-term FHLB advance for $200.0 million, bearing interest of 1.04%, due January 2, 2018. As part of the Centennial acquisition, the Company acquired long-term FHLB advances of $77.2 million, of which, $5.0 million was repaid during the second quarter 2013. These advances were purchased at a premium of $2.5 million, with interest rates ranging from 1.56% to 3.05% and a weighted average interest rate of 2.67%. The weighted average cost on all long-term debt was 3.30% for the three and nine months ended September 30, 2013, and 10.80% and 10.81% for the three and nine months ended September 30, 2012, respectively.
	As of September 30, 2013 and December 31, 2012, the Company had additional available credit with the FHLB of approximately $1.05 billion and $952.8 million, respectively, and with the FRB of approximately $598.3 million and $600.6 million, respectively.

	During the first three quarters of 2013, the Company entered into a Treasury short transaction to mitigate the Company’s modest liability sensitive interest rate risk profile. The Company sold short fixed-rate Treasury securities and invested the proceeds in a short-term repurchase agreement with a balance of $126.7 million as of September 30, 2013.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	7. COMMITMENTS AND CONTINGENCIES
	Unfunded Commitments and Letters of Credit
	The Company is party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. They involve, to varying degrees, elements of credit risk in excess of amounts recognized in the Consolidated Balance Sheets.
	Lines of credit are obligations to lend money to a borrower. Credit risk arises when the borrower’s current financial condition may indicate less ability to pay than when the commitment was originally made. In the case of standby letters of credit, the risk arises from the possibility of the failure of the customer to perform according to the terms of a contract. In such a situation, the third party might draw on the standby letter of credit to pay for completion of the contract and the Company would look to its customer to repay these funds with interest. To minimize the risk, the Company uses the same credit policies in making commitments and conditional obligations as it would for a loan to that customer.
	Standby letters of credit and financial guarantees are commitments issued by the Company to guarantee the performance of a customer to a third party in borrowing arrangements. The Company generally has recourse to recover from the customer any amounts paid under the guarantees. Typically, letters of credit issued have expiration dates within one year.
	A summary of the contractual amounts for unfunded commitments and letters of credit are as follows:


		September 30		December 31,
		2013		2012
		(in thousands)
	Commitments to extend credit, including unsecured loan commitments of $266,189 at September 30, 2013 and $172,002 at December 31, 2012	$	1,692,150	$	1,096,264
	Credit card commitments and financial guarantees		287,186		295,506
	Standby letters of credit, including unsecured letters of credit of $4,032 at September 30, 2013 and $3,915 at December 31, 2012		28,105		32,757

	Total	$	2,007,441	$	1,424,527

	Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. The Company enters into credit arrangements that generally provide for the termination of advances in the event of a covenant violation or other event of default. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on Management’s credit evaluation of the party. The commitments are collateralized by the same types of assets used as loan collateral. The unfunded commitments on the credit cards loans held for sale at September 30, 2013 and December 31, 2012 was $2.8 million and $262.6 million, respectively.
	The Company has exposure to credit losses from unfunded commitments and letters of credit. As funds have not been disbursed on these commitments, they are not reported as loans outstanding. Credit losses related to these commitments are not included in the allowance for credit losses reported in Note 4, “Loans, Leases and Allowance for Credit Losses” of these Consolidated Financial Statements and are accounted for as a separate loss contingency as a liability. This loss contingency for unfunded loan commitments and letters of credit was $2.0 million and $1.3 million as of September 30, 2013 and December 31, 2012, respectively. Changes to this liability are adjusted through other non-interest expense.
	Concentrations of Lending Activities
	The Company’s lending activities are primarily driven by the customers served in the market areas where the Company has branch offices in the states of Nevada, California and Arizona. The Company monitors concentrations within five broad categories: geography, industry, product, call code, and collateral. The Company grants commercial, construction, real estate and consumer loans to customers through branch offices located in the Company’s primary markets. The Company’s business is concentrated in these areas and the loan portfolio includes significant credit exposure to the commercial real estate market of these areas. As of September 30, 2013 and December 31, 2012, commercial real estate related loans accounted for approximately 59% and 58% of total loans, respectively, and approximately 1% and 3% of these loans are secured by undeveloped land, respectively. Substantially all of these loans are secured by first liens with an initial loan to value ratio of generally not more than 75%. Approximately 40% and 48% of these commercial real estate loans, excluding construction and land loans, were owner occupied at September 30, 2013 and December 31, 2012, respectively. In addition, approximately 3% and 4% of total loans were unsecured as of September 30, 2013 and December 31, 2012, respectively.

	Contingencies
	The Company is involved in various lawsuits of a routine nature that are being handled and defended in the ordinary course of the Company’s business. Expenses are being incurred in connection with defending the Company, but in the opinion of Management, based in part on consultation with legal counsel, the resolution of these lawsuits and associated defense costs will not have a material impact on the Company’s financial position, results of operations, or cash flows.
	Lease Commitments
	The Company leases the majority of its office locations and many of these leases contain multiple renewal options and provisions for increased rents. Total rent expense of $1.8 million and $1.5 million was included in occupancy expenses for the three months ended September 30, 2013 and 2012, respectively. For the nine months ended September 30, 2013 and 2012, total rent expense included in occupancy expenses was $5.5 million and $4.4 million, respectively.

Stockholders_Equity

Stockholders' Equity	9 Months Ended
Stockholders' Equity	Sep. 30, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	8. STOCKHOLDERS’ EQUITY
	Stock-based Compensation
	For the three and nine months ended September 30, 2013, 17,600 and 537,125 shares of restricted stock were granted to Company employees, respectively. The Company estimates the compensation cost for restricted stock grants based upon the grant date fair value. Generally, these restricted stock grants have a three year vesting period. The aggregate grant date fair value for the restricted stock issued in the three and nine month periods ended September 30, 2013 was $0.3 million and $6.7 million, respectively. In addition, the Company granted 56,311 shares during the nine months ended September 30, 2013 to non-employee WAL and subsidiary directors that vested immediately. There were no grants to non-employee WAL and subsidiary directors during the three months ended September 30, 2013.
	There were 1,255,640 and 1,469,285 restricted shares outstanding at September 30, 2013 and December 31, 2012, respectively. For the three and nine months ended September 30, 2013, the Company recognized stock-based compensation related to restricted stock grants of $1.3 million and $2.8 million, respectively, compared to $1.1 million and $3.4 million, respectively, for the three and nine months ended September 30, 2012.
	As of September 30, 2013 and 2012, there were 1.2 million and 1.7 million, respectively, of stock options outstanding.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
Accumulated Other Comprehensive Income	Sep. 30, 2013
Equity [Abstract]	'
Accumulated Other Comprehensive Income	'
	9. ACCUMULATED OTHER COMPREHENSIVE INCOME
	The following table summarizes the changes in accumulated other comprehensive income by component, net of tax for the period indicated:


		Three Months Ended September 30,
		2013									2012
		Unrealized			Unrealized gain			Total			Unrealized			Unrealized gain			Total
		holding gains			on cash flow						holding gains			on cash flow
		(losses) on AFS			hedge						(losses) on AFS			hedge
		(in thousands)
	Beginning balance	$	(10,780	)	$	30		$	(10,750	)	$	4,283		$	8		$	4,291
	Other comprehensive income before reclassifications		(4,770	)		(30	)		(4,800	)		8,478			9			8,487
	Amounts reclassified from accumulated other comprehensive income		1,046			—			1,046			(668	)		—			(668	)

	Net current-period other comprehensive income		(3,724	)		(30	)		(3,754	)		7,810			9			7,819

	Ending balance	$	(14,504	)	$	—		$	(14,504	)	$	12,093		$	17		$	12,110



		Nine Months Ended September 30,
		2013									2012
		Unrealized			Unrealized gain						Unrealized			Unrealized gain
		holding gains			on cash flow						holding gains			on cash flow
		(losses) on AFS			hedge			Total			(losses) on AFS			hedge			Total
		(in thousands)
	Beginning balance	$	8,209		$	17		$	8,226		$	(5,112	)	$	519		$	(4,593	)
	Other comprehensive income before reclassifications		(23,670	)		(17	)		(23,687	)		18,803			17			18,820
	Amounts reclassified from accumulated other comprehensive income		957			—			957			(1,598	)		(519	)		(2,117	)

	Net current-period other comprehensive income		(22,713	)		(17	)		(22,730	)		17,205			(502	)		16,703

	Ending balance	$	(14,504	)	$	—		$	(14,504	)	$	12,093		$	17		$	12,110

	The following table presents reclassifications out of accumulated other comprehensive income:


		Amount reclassified from accumulated
		other comprehensive income
	Details about accumulated other	Three Months Ended						Affected line item in the statement
	Details about accumulated other	September 30,						Affected line item in the statement
	comprehensive income components	2013			2012			where net income is presented
		(in thousands)
	Unrealized gains and losses on AFS
		$	(1,679	)	$	1,031		Realized gain on sale of Investment securities
			633			(363	)	Income tax expense

		$	(1,046	)	$	668		Net of tax


		Amount reclassified from accumulated
		other comprehensive income
	Details about accumulated other	Nine Months Ended						Affected line item in the statement
	Details about accumulated other	September 30,						Affected line item in the statement
	comprehensive income components	2013			2012			where net income is presented
		(in thousands)
	Unrealized gains and losses on AFS
		$	(1,537	)	$	2,502		Realized gain on sale of Investment securities
			580			(904	)	Income tax expense

		$	(957	)	$	1,598		Net of tax

Earnings_Per_Share

Earnings Per Share	9 Months Ended
Earnings Per Share	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	10. EARNINGS PER SHARE
	Diluted earnings per share is based on the weighted average outstanding common shares during each period, including common stock equivalents. Basic earnings per share is based on the weighted average outstanding common shares during the period.
	Basic and diluted earnings per share, based on the weighted average outstanding shares, are summarized as follows:


		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands,except per share amounts)
	Weighted average shares—basic		85,799		81,758		85,596		81,570
	Dilutive effect of stock awards		970		536		832		589

	Weighted average shares—diluted		86,769		82,294		86,428		82,159

	Net income available to common shareholders	$	27,840	$	15,106	$	82,114	$	37,279
	Earnings per share—basic		0.32		0.18		0.96		0.46
	Earnings per share—diluted		0.32		0.18		0.95		0.45
	The Company had 216,310 and 1,053,045 stock options outstanding as of September 30, 2013 and December 31, 2012, respectively, that were not included in the computation of diluted earnings per common share because their effect would be anti-dilutive.

Fair_Value_Accounting

Fair Value Accounting	9 Months Ended
Fair Value Accounting	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Accounting	'
	11. FAIR VALUE ACCOUNTING
	The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, the Company utilizes valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy under ASC 825 are described in Note 1, “Summary of Significant Accounting Policies.”
	In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and the Company’s creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. The Company’s valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While Management believes the Company’s valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein. Transfers between levels in the fair value hierarchy are recognized at the end of the reporting period.
	Under ASC 825, the Company elected the fair value option (“FVO”) treatment for the junior subordinated debt and certain investment securities. This election is generally irrevocable and unrealized gains and losses on these items must be reported in earnings at each reporting date. The Company continues to account for these items under the FVO. Since adoption, there were no financial instruments purchased by the Company which met the ASC 825 fair value election criteria, and therefore, no additional instruments have been added under the FVO election.
	All securities for which the fair value measurement option had been elected are included in a separate line item in the Consolidated Balance Sheet titled “Investment securities—measured at fair value.”

	For the three and nine months ended September 30, 2013 and 2012, gains and losses from fair value changes included in the Consolidated Income Statements were as follows:


			Changes in Fair Values for Items Measured at Fair
			Value Pursuant to Election of the FVO
			Unrealized											Total
			Gain/(Loss) on							Interest				Changes
			Assets and							Expense on				Included in
			Liabilities				Interest			Junior				Current-
			Measured at				Income on			Subordinated				Period
	Description		Fair Value, Net				Securities			Debt				Earnings
			(in thousands)
	Three Months Ended September 30, 2013
	Securities measured at fair value		$	(142	)		$	1		$	—			$	(141	)
	Junior subordinated debt			478				—			329				149

			$	336			$	1		$	329			$	8

	Nine Months Ended September 30, 2013
	Securities measured at fair value		$	(196	)		$	7		$	—			$	(189	)
	Junior subordinated debt			(3,229	)			—			1,012				(4,241	)

			$	(3,425	)		$	7		$	1,012			$	(4,430	)


			Changes in Fair Values for Items Measured at Fair
			Value Pursuant to Election of the FVO
			Unrealized											Total
			Gain/(Loss) on							Interest				Changes
			Assets and							Expense on				Included in
			Liabilities				Interest			Junior				Current-
			Measured at				Income on			Subordinated				Period
	Description		Fair Value, Net				Securities			Debt				Earnings
			(in thousands)
	Three Months Ended September 30, 2012
	Securities measured at fair value		$	—			$	3		$	—			$	3
	Junior subordinated debt			469				—			329				140

			$	469			$	3		$	329			$	143

	Nine Months Ended September 30, 2012
	Securities measured at fair value		$	(66	)		$	10		$	—			$	(56	)
	Junior subordinated debt			767				—			981				(214	)

			$	701			$	10		$	981			$	(270	)

	The following table presents gains and losses from fair value changes on securities measured at fair value:


			Three Months Ended							Nine Months Ended
			September 30,							September 30,
			2013				2012			2013				2012
			(in thousands)
	Net losses for the period on trading securities included in earnings		$	(142	)		$	—		$	(196	)		$	(66	)
	Less: net gains and (losses) recognized during the period on trading securities sold during the period			—				—			—				—

	Change in unrealized gains or (losses) for the period included in earnings for trading securities held at the end of the reporting period		$	(142	)		$	—		$	(196	)		$	(66	)

The difference between the aggregate fair value of junior subordinated debt of $39.4 million and the aggregate unpaid principal balance of $66.5 million was $27.1 million at September 30, 2013. The difference between the aggregate fair value of junior subordinated debt of $36.2 million and the aggregate unpaid principal balance of $66.5 million was $30.3 million at December 31, 2012.

Interest income on securities measured at fair value is accounted for similarly to those classified as AFS and HTM. Any premiums or discounts are recognized in interest income over the term of the securities. Interest expense on junior subordinated debt is also determined under a constant yield calculation.
Fair value on a recurring basis
Financial assets and financial liabilities measured at fair value on a recurring basis include the following:
AFS Securities: Adjustable-rate preferred securities, corporate debt securities and CRA mutual fund investments are reported at fair value utilizing Level 1 inputs. Other securities classified as AFS are reported at fair value utilizing Level 2 inputs. For these securities, the Company obtains fair value measurements from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things.
Securities measured at fair value: All of the Company’s securities measured at fair value, the majority of which are mortgage-backed securities, are reported at fair value utilizing Level 2 inputs in the same manner as described above for securities available-for-sale.
Independent pricing service: Management independently evaluates all of the fair value measurements received from its third party pricing service through multiple review steps. First, Management reviews what has transpired in the market- place with respect to interest rates, credit spreads, volatility, mortgage rates, etc., and makes an expectation on changes to the securities valuations from the previous quarter. Then, Management compares expected changes to the actual valuation changes provided to it by its pricing service. Next, Management compares a robust sampling of safekeeping marks on securities with the marks provided by the Company’s third party pricing service and determines whether there are any notable differences. Then, Management compares the prices on Level 1 priced securities to publicly available prices to verify those prices are similar. Finally, Management discusses the assumptions used for Level 2 priced securities with its pricing service. The pricing service provides Management with observable market data including interest rate curves and mortgage prepayment speed grids, as well as dealer quote sheets, new bond offering sheets, and historical trade documentation. Management reviews the assumptions and decides whether they are reasonable. Management may compare interest rates, credit spreads and prepayments speeds used as part of the assumptions to those that Management believes are reasonable. Management may price securities using the provided assumptions to determine whether they can develop similar prices on like securities. Any discrepancies with Management’s review and the prices provided by the vendor are discussed with the vendor and the Company’s other valuation advisors. Management has formally challenged the prices on several securities, but has found that the vendor prices are reasonable.
Annually, the Company receives a SSAE 16 report from its independent pricing service attesting to the controls placed on the operations of the service from its auditor.
Interest rate swap: Interest rate swaps are reported at fair value utilizing Level 2 inputs. The Company obtains dealer quotations to value its interest rate swaps.
Junior subordinated debt: The Company estimates the fair value of its junior subordinated debt using a discounted cash flow model which incorporates the effect of the Company’s own credit risk in the fair value of the liabilities (Level 3). The Company’s cash flow assumptions were based on the contractual cash flows as the Company anticipates that it will pay the debt according to its contractual terms. The Company’s practice of determining the discount rate as of March 31, 2013 and prior was to use a Peer Index derived from market data available for similar non-investment grade trust preferred securities. As of June 30, 2013 the available market data contracted and the small population of similar non-investment grade trust preferred securities was no longer adequately diversified to ensure an accurate representation of change in the discount rate. As a result, the Company replaced the Peer Index with the BB 20 Year Index relative to the 10 Year Treasury (BB Corporate Bond over Treasury Index), which provides a broader base and correlates similarly with the credit and maturity characteristics of the junior subordinated debt. As of September 30, 2013, the discount rate was determined to be 6.280%, which is a 603 basis point spread over 3 month LIBOR (0.250% as of September 30, 2013). As of September 30, 2012, the Company estimated the discount rate at 6.530%, which was a 617 basis point spread over 3 month LIBOR (0.359%). As of December 31, 2012, the Company estimated the discount rate at 6.846%, which was a 654 basis point spread over 3 month LIBOR (0.306%).
Securities sold short: Securities sold short, comprised of entirely U.S. Treasury bonds, are reported at fair value utilizing Level 1 inputs.

The fair value of these assets and liabilities were determined using the following inputs at the periods presented:


		Fair Value Measurements at the End of the Reporting Period Using:
		Quoted Prices
		in Active				Significant
		Markets for				Other			Significant
		Identical				Observable			Unobservable
		Assets				Inputs			Inputs				Fair
September 30, 2013		(Level 1)				(Level 2)			(Level 3)				Value
		(in thousands)
Assets:
Measured at fair value
Direct U.S. obligations and GSE residential mortgage- backed securities		$	—			$	3,621		$	—			$	3,621

Available-for-sale
U.S. Government-sponsored agency securities		$	—			$	27,377		$	—			$	27,377
Municipal obligations			—				105,545			—				105,545
Direct U.S. obligations and GSE residential mortgage-backed securities			—				768,478			—				768,478
Mutual funds			32,323				—			—				32,323
Private label residential mortgage-backed securities			—				26,147			—				26,147
Adjustable-rate preferred stock			61,389				—			—				61,389
Trust preferred			—				23,834			—				23,834
Collateralized mortgage-backed securities			—				5,493			—				5,493
Other			23,300				—			—				23,300

		$	117,012			$	956,874		$	—			$	1,073,886

Interest rate swaps		$	—			$	39		$	—			$	39

Liabilities:
Securities sold short		$	126,664			$	—		$	—			$	126,664

Junior subordinated debt		$	—			$	—		$	39,447			$	39,447

Interest rate swaps		$	—			$	2,188		$	—			$	2,188



		Fair Value Measurements at the End of the Reporting Period Using:
December 31, 2012		Quoted Prices				Significant			Significant				Fair
		in Active				Other			Unobservable				Value
		Markets for				Observable			Inputs
		Identical				Inputs			(Level 3)
		Assets				(Level 2)
		(Level 1)
		(in thousands)
Assets:
Measured at fair value
Direct U.S. obligations and GSE residential mortgage- backed securities		$	—			$	5,061		$	—			$	5,061

Available-for-sale
Municipal obligations		$	—			$	73,171		$	—			$	73,171
Direct U.S. obligations and GSE residential mortgage-backed securities			—				663,204			—				663,204
Mutual funds			37,961				—			—				37,961
Private label residential mortgage-backed securities			—				35,607			—				35,607
Private label commercial mortgage-backed securities			—				5,741							5,741
Adjustable-rate preferred stock			75,555				—			—				75,555
Trust preferred			24,135				—			—				24,135
Other			24,216				—			—				24,216

		$	161,867			$	777,723		$	—			$	939,590

Interest rate swaps		$	—			$	777		$	—			$	777

Liabilities:
Junior subordinated debt		$	—			$	—		$	36,218			$	36,218

Interest rate swaps		$	—			$	751		$	—			$	751

As of June 30, 2013, trust preferred securities transferred from Level 1 to Level 2 due to the unavailability of active trade information. Per the Company’s policy, the transfer is deemed to have occurred at the end of the reporting period.
For the three and nine months ended September 30, 2013, the change in Level 3 liabilities measured at fair value on a recurring basis was as follows:


Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
		Junior Subordinated Debt
		Three Months Ended
		September 30,
		2013				2012
		(in thousands)
Opening balance		$	(39,925	)		$	(36,687	)
Transfers into Level 3			—				—
Transfers out of Level 3			—				—
Total gains or losses for the period
Included in earnings (or changes in net assets) (1)			478				469
Included in other comprehensive income			—				—
Purchases, sales, and settlements
Purchases			—				—
Sales			—				—
Settlements			—				—

Closing balance		$	(39,447	)		$	(36,218	)

Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.		$	478			$	469


-1	Total gains (losses) for the period are included in the non-interest income line, mark to market (losses) gains, net.


		Junior Subordinated Debt
		Nine Months Ended
		September 30,
		2013				2012
		(in thousands)
Opening balance		$	(36,218	)		$	(36,985	)
Transfers into Level 3			—				—
Transfers out of Level 3			—				—
Total gains or losses for the period
Included in earnings (or changes in net assets) (1)			(3,229	)			767
Included in other comprehensive income			—				—
Purchases, sales, and settlements
Purchases			—				—
Sales			—				—
Settlements			—				—

Closing balance		$	(39,447	)		$	(36,218	)

Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.		$	(3,229	)		$	767


-1	Total gains (losses) for the period are included in the non-interest income line, mark to market (losses) gains, net.
For Level 3 liabilities measured at fair value on a recurring basis, the significant unobservable inputs used in the fair value measurements as of the periods presented, were as follows:


		Fair Value at
		September 30,				Valuation		Significant	Input Value
		2013				Technique		Unobservable Inputs	Input Value
		(dollars in thousands)
Junior subordinated debt		$	39,447			Discounted cash flow		BB Corporate Bond over Treasury Index		6.28	%
Junior subordinated debt		$	39,447			Discounted cash flow		with comparable credit spread		6.28	%

		Fair Value at
		December 31,				Valuation		Significant	Input Value
		2012				Technique		Unobservable Inputs	Input Value
		(dollars in thousands)
Junior subordinated debt		$	36,218			Discounted cash flow		Median market spreads on publicly issued trust preferreds with comparable credit risk		6.846	%
The significant unobservable inputs used in the fair value measurement of the Company’s junior subordinated debt as of September 30, 2013 are the BB Corporate Bond over Treasury Index with comparable credit risk and, as of December 31, 2012, are the calculated or estimated credit spreads on comparable publicly traded company trust preferred issuances which were non-investment grade and non-rated. Significant increases (decreases) in these inputs could result in a significantly higher (lower) fair value measurement.

Fair value on a nonrecurring basis
Certain assets are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). The following table presents such assets carried on the Consolidated Balance Sheet by caption and by level within the ASC 825 hierarchy:


		Fair Value Measurements at the End of the Reporting Period Using
		Total				Quoted Prices			Active				Unobservable
						in Active			Markets for				Inputs
						Markets for			Similar Assets				(Level 3)
						Identical Assets			(Level 2)
						(Level 1)
		(in thousands)
As of September 30, 2013:
Impaired loans with specific valuation allowance		$	14,808			$	—		$	—			$	14,808
Impaired loans without specific valuation allowance			95,843				—			—				95,843
Other assets acquired through foreclosure, net			76,475				—			—				76,475
As of December 31, 2012:
Impaired loans with specific valuation allowance		$	38,672			$	—		$	—			$	38,672
Impaired loans without specific valuation allowance			67,207				—			—				67,207
Other assets acquired through foreclosure, net			77,247				—			—				77,247
Impaired loans: The specific reserves for collateral dependent impaired loans are based on the fair value of the collateral. The fair value of collateral is determined based on third-party appraisals. Appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach. Fair value is determined, where possible, using market prices derived from an appraisal or evaluation, which are considered to be Level 2. However, certain assumptions and unobservable inputs are often used by the appraiser; therefore, qualifying the assets as Level 3 in the fair value hierarchy. In some cases, adjustments are made to the appraised values due to various factors, including age of the appraisal (which are generally obtained every twelve months), age of comparables included in the appraisal, and known changes in the market and in the collateral. When significant adjustments are based on unobservable inputs, such as when a current appraised value is not available or Management determines the fair value of the collateral is further impaired below appraised value and there is no observable market price, the resulting fair value measurement has been categorized as a Level 3 measurement. These Level 3 impaired loans had an aggregate carrying amount of $20.7 million and $51.5 million and specific reserves in the allowance for credit losses of $5.9 million and $12.9 million at September 30, 2013 and December 31, 2012, respectively.
Other assets acquired through foreclosure: Other assets acquired through foreclosure consist of properties acquired as a result of, or in-lieu-of, foreclosure. Properties or other assets classified as other assets acquired through foreclosure and other repossessed property are initially reported at the fair value determined by independent appraisals using appraised value, less cost to sell. Such properties are generally re-appraised every twelve months. There is risk for subsequent volatility. Costs relating to the development or improvement of the assets are capitalized and costs relating to holding the assets are charged to expense. The Company had $76.5 million and $77.2 million of such assets at September 30, 2013 and December 31, 2012, respectively. Fair value is determined, where possible, using market prices derived from an appraisal or evaluation, which are considered to be Level 2. However, certain assumptions and unobservable inputs are often used by the appraiser; therefore, qualifying the assets as Level 3 in the fair value hierarchy. When significant adjustments are based on unobservable inputs, such as when a current appraised value is not available or Management determines the fair value of the collateral is further impaired below appraised value and there is no observable market price, the resulting fair value measurement has been categorized as a Level 3 measurement.
Credit vs. non-credit losses
The Company applies the provisions of ASC 320 to its AFS and HTM investment securities portfolios. The OTTI was separated into (1) the amount of total impairment related to the credit loss, and (2) the amount of the total impairment related to all other factors. The amount of the total OTTI related to the credit loss was recognized in earnings. The amount of the total impairment related to all other factors was recognized in OCI. The OTTI was presented in the Consolidated Income Statement with an offset for the amount of the total OTTI that was recognized in OCI.

For the three and nine months ended September 30, 2013 and 2012, the Company determined that no securities contained credit losses.


		Private Label
		Mortgage-Backed
		Securities
		Nine Months Ended
		September 30,
		2013				2012
		(in thousands)
Beginning balance of impairment losses held in other comprehensive income		$	(1,811	)		$	(1,811	)
Current period other-than temporary impairment credit losses recognized through earnings			—				—
Reductions for securities sold during the period			1,811				—
Additions or reductions in credit losses due to change of intent to sell			—				—
Reductions for increases in cash flows to be collected on impaired securities			—				—

Ending balance of net unrealized gains and (losses) held in other comprehensive income		$	—			$	(1,811	)

FAIR VALUE OF FINANCIAL INSTRUMENTS
The estimated fair value of the Company’s financial instruments is as follows:


		September 30, 2013
		Carrying				Fair Value
		Amount				Level 1			Level 2				Level 3				Total
		(in thousands)
Financial assets:
Investment securities		$	1,366,615			$	176,570		$	1,188,472			$	8			$	1,365,050
Derivatives (1)			39				—			39				—				39
Loans, net			6,418,432				—			5,876,917				110,651				5,987,568
Financial liabilities:
Deposits			7,275,311				—			7,349,886				—				7,349,886
Customer repurchases			55,524				—			55,524				—				55,524
Securities sold short			126,664				126,664			—				—				126,664
Other borrowings			394,105				45,785			274,277				82,500				402,562
Junior subordinated debt			39,447				—			—				39,447				39,447
Derivatives (2)			2,188				—			2,188				—				2,188

-1	Included in other assets.
-2	Included in other liabilities.


		31-Dec-12
		Carrying				Fair Value
		Amount				Level 1			Level 2				Level 3				Total
		(in thousands)
Financial assets:
Investment securities		$	1,235,984			$	216,337		$	1,021,133			$	—			$	1,237,470
Derivatives (1)			777				—			777				—				777
Loans, net			5,613,891				—			5,156,776				105,879				5,262,655
Financial liabilities:
Deposits			6,455,177				—			6,458,100				—				6,458,100
Customer repurchases			79,034				—			79,034				—				79,034
Other borrowings			193,717				—			120,000				85,125				205,125
Junior subordinated debt			36,218				—			—				36,218				36,218
Derivatives (2)			751				—			751				—				751

-1	Included in other assets.
-2	Included in other liabilities.

Interest rate risk
The Company assumes interest rate risk (the risk to the Company’s earnings and capital from changes in interest rate levels) as a result of its normal operations. As a result, the fair values of the Company’s financial instruments as well as its future net interest income will change when interest rate levels change and that change may be either favorable or unfavorable to the Company.
Interest rate risk exposure is measured using interest rate sensitivity analysis to determine the change in net portfolio value and net interest income resulting from hypothetical changes in interest rates. If potential changes to net portfolio value and net interest income resulting from hypothetical interest rate changes are not within the limits established by the Board of Directors, the Board of Directors may direct Management to adjust the asset and liability mix to bring interest rate risk within Board-approved limits. As of September 30, 2013, the Company’s interest rate risk profile was within Board-approved limits.
Each of the Company’s subsidiary banks has an Asset and Liability Management Committee charged with managing interest rate risk within Board-approved limits. Such limits may vary by bank based on local strategy and other considerations, but in all cases, are structured to prohibit an interest rate risk profile that is significantly asset or liability sensitive. There also exists an Asset and Liability Management Committee at the holding company level that reviews the interest rate risk of each subsidiary bank, as well as an aggregated position for the entire Company.
Fair value of commitments
The estimated fair value of standby letters of credit outstanding at September 30, 2013 and December 31, 2012 was insignificant. Loan commitments on which the committed interest rates were less than the current market rate are also insignificant at September 30, 2013 and December 31, 2012.

Income_Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	12. INCOME TAXES
	Deferred tax assets and liabilities are included in the Consolidated Financial Statements at currently enacted income tax rates applicable to the period in which the deferred tax assets or liabilities are expected to be realized or settled. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes.
	Although realization is not assured, the Company believes that the realization of the recognized net deferred tax asset of $79.6 million at September 30, 2013 is more likely than not based on expectations as to future taxable income and based on available tax planning strategies as defined in FASB ASC 740, Income Taxes (“ASC 740”), that could be implemented if necessary to prevent a carryforward from expiring.
	Based on its internal analysis, the Company believes that it is more likely than not that the Company will fully utilize deferred federal tax assets pertaining to the existing net operating loss carryforwards and any net operating loss (“NOL”) that would be created by the reversal of the future net deductions that have not yet been taken on a tax return.
	The Company’s effective tax rate was 24.8% and 30.1% for the three months ended September 30, 2013 and 2012, respectively, and 21.6% and 28.4% for the nine months ended September 30, 2013 and 2012, respectively. The reduction in the effective tax rate from the first three quarters of 2012, compared to the first three quarters of 2013 is primarily due to the bargain purchase gain related to the Centennial acquisition, low income housing tax credits, an increase in tax exempt income from revenue from municipal obligations, as well as a reduction in the deferred tax valuation allowance for capital loss carryovers arising from transactions that resulted in capital gains.
	At September 30, 2013, the Company has a deferred tax valuation allowance of $5.2 million (compared to $8.0 million at December 31, 2012).
	The deferred tax asset related to state net operating loss carryovers outstanding at September 30, 2013 is comprised of $1.9 million of tax benefits from Arizona net operating loss carryovers that began to expire in 2013. All of the Company’s remaining California net operating loss carryforwards have been utilized in 2013.
	Uncertain Tax Position
	The Company files income tax returns in the U.S. federal jurisdiction and in various states. With few exceptions, the Company is no longer subject to U.S. federal, state or local tax examinations by tax authorities for years before 2008.
	The Company would recognize interest accrued related to unrecognized tax benefits in tax expense. The Company has not recognized or accrued any interest or penalties for the three and nine month periods ended September 30, 2013 and 2012.

	Management believes that the Company has appropriate support for the income tax positions taken and to be taken on its tax returns and that its accruals for tax liabilities are adequate for all open years based on an assessment of many factors, including past experience and interpretation of tax law applied to the facts of each matter.

Segments

Segments	9 Months Ended
Segments	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segments	'
	13. SEGMENTS
	The Company provides a full range of banking and related financial services through its consolidated subsidiaries. Applicable guidance provides that the identification of reportable segments be on the basis of discrete business units and their financial information to the extent such units are reviewed by the entity’s chief decision maker.
	At September 30, 2013, the Company consists of the following segments: “Western Alliance Bank,” “Bank of Nevada,” “Torrey Pines Bank” and “Other” (Western Alliance Bancorporation holding company, WAEF, LVSP, Shine Investment Advisory Services, Inc. until October 31, 2012, and the discontinued operations).
	Transactions between segments consist primarily of borrowed funds and loan participations. Federal funds purchased and sold and other borrowed funding transactions that resulted in inter-segment profits were eliminated for reporting consolidated results of operations. Loan participations were recorded at par value with no resulting gain or loss. The Company allocated centrally provided services to the operating segments based upon estimated usage of those services.
	The following is a summary of selected operating segment information as of and for the three and nine month periods ended September 30, 2013 and 2012:

	Western Alliance Bancorporation and Subsidiaries
	Operating Segment Results
	Unaudited


																			Inter-
																			segment				Consoli-
			Western				Bank				Torrey								elimi-				dated
			Alliance Bank				of Nevada				Pines Bank*				Other				nations				Company
			(dollars in millions)
	At September 30, 2013
	Assets		$	3,346.70			$	3,288.10			$	2,076.20			$	1,127.80			$	(917.4	)		$	8,921.40
	Held for sale loans			—				—				25.4				—				—				25.4
	Gross loans and deferred fees, net			2,589.20				2,387.10				1,498.70				58.9				(43.0	)			6,490.90
	Less: Allowance for credit losses			(28.0	)			(51.0	)			(18.3	)			(0.6	)			—				(97.9	)

	Loans, net			2,561.20				2,336.10				1,480.40				58.3				(43.0	)			6,393.00

	Goodwill and intangible assets			2.8				25.1				—				—				—				27.9
	Deposits			2,832.00				2,613.50				1,844.70				—				(14.9	)			7,275.30
	Borrowings			81.4				203				3.2				106.5				—				394.1
	Stockholders’ equity			291.5				373.7				171.8				844.7				(855.4	)			826.3
	No. of branches			18				12				12				—				—				42

			(in thousands)
	Three Months Ended September 30, 2013:
	Net interest income (expense)		$	33,755			$	31,888			$	21,055			$	(2,139	)		$	—			$	84,559
	Provision for (recovery of) credit losses			6,277				(6,918	)			2,387				(1,746	)			—				—

	Net interest income (expense) after provision for credit losses			27,478				38,806				18,668				(393	)			—				84,559
	Non-interest income			1,816				2,314				108				2,914				(4,527	)			2,625
	Non-interest expense			(15,520	)			(18,799	)			(11,949	)			(7,934	)			4,527				(49,675	)

	Income (loss) from continuing operations before income taxes			13,774				22,321				6,827				(5,413	)			—				37,509
	Income tax expense (benefit)			3,977				6,027				2,230				(2,946	)			—				9,288

	Income (loss) from continuing operations			9,797				16,294				4,597				(2,467	)			—				28,221
	Loss from discontinued operations, net			—				—				—				(29	)			—				(29	)

	Net income (loss)		$	9,797			$	16,294			$	4,597			$	(2,496	)		$	—			$	28,192


			(in thousands)
	Nine Months Ended September 30, 2013:
	Net interest income (expense)		$	92,920			$	91,821			$	62,435			$	(4,262	)		$	—			$	242,914
	Provision for (recovery of) credit losses			9,921				(5,514	)			3,219				1,294				—				8,920

	Net interest income (expense) after provision for credit losses			82,999				97,335				59,216				(5,556	)			—				233,994
	Non-interest income			14,520				9,383				1,312				4,325				(12,154	)			17,386
	Non-interest expense			(45,688	)			(52,724	)			(35,876	)			(23,001	)			12,154				(145,135	)

	Income (loss) from continuing operations before income taxes			51,831				53,994				24,652				(24,232	)			—				106,245
	Income tax expense (benefit)			13,066				14,292				7,898				(12,343	)			—				22,913

	Income (loss) from continuing operations			38,765				39,702				16,754				(11,889	)			—				83,332
	Loss from discontinued operations, net			—				—				—				(160	)			—				(160	)

Net income (loss)		$	38,765			$	39,702			$	16,754			$	(12,049	)		$	—			$	83,172


*	Excludes discontinued operations.

Western Alliance Bancorporation and Subsidiaries
Operating Segment Results
Unaudited


																		Inter-
																		segment				Consoli-
		Western				Bank				Torrey								elimi-				dated
		Alliance Bank				of Nevada				Pines Bank*				Other				nations				Company
		(dollars in millions)
At September 30, 2012
Assets		$	2,429.80			$	2,918.00			$	1,888.70			$	961.3			$	(794.2	)		$	7,403.60
Gross loans and deferred fees, net			1,871.40				2,061.00				1,430.60				12.8				(42.9	)			5,332.90
Less: Allowance for credit losses			(20.4	)			(59.5	)			(17.5	)			—				—				(97.4	)

Loans, net			1,851.00				2,001.50				1,413.10				12.8				(42.9	)			5,235.50

Goodwill and intangible assets			—				23.2				—				—				—				23.2
Deposits			2,150.50				2,408.50				1,613.80				—				(10.8	)			6,162.00
Borrowings			—				110				40				—								150
Stockholders’ equity			217.3				339.1				168.4				702.3				(729.1	)			698
No. of branches			16				11				12				—				—				39

		(in thousands)
Three Months Ended September 30, 2012:
Net interest income (expense)		$	24,449			$	27,717			$	21,795			$	(2,015	)		$	—			$	71,946
Provision for credit losses			1,112				6,618				1,202				—				—				8,932

Net interest income (expense) after provision for credit losses			23,337				21,099				20,593				(2,015	)			—				63,014
Non-interest income			1,173				3,259				855				4,647				(2,952	)			6,982
Non-interest expense			(11,980	)			(16,467	)			(11,082	)			(10,966	)			2,952				(47,543	)

Income (loss) from continuing operations before income taxes			12,530				7,891				10,366				(8,334	)			—				22,453
Income tax expense (benefit)			3,768				2,055				3,958				(3,029	)			—				6,752

Income (loss) from continuing operations			8,762				5,836				6,408				(5,305	)			—				15,701
Loss from discontinued operations, net			—				—				—				(243	)			—				(243	)

Net income (loss)		$	8,762			$	5,836			$	6,408			$	(5,548	)		$	—			$	15,458


		(in thousands)
Nine Months Ended September 30, 2012:
Net interest income (expense)		$	71,564			$	83,054			$	64,406			$	(6,216	)		$	—			$	212,808
Provision for credit losses			1,215				28,846				5,282				—				—				35,343

Net interest income (expense) after provision for credit losses			70,349				54,208				59,124				(6,216	)			—				177,465
Non-interest income			5,021				11,132				3,111				8,539				(7,540	)			20,263
Noninterest expense			(35,986	)			(53,437	)			(33,492	)			(24,496	)			7,540				(139,871	)

Income (loss) from continuing operations before income taxes			39,384				11,903				28,743				(22,173	)			—				57,857
Income tax expense (benefit)			13,031				1,341				11,255				(9,175	)			—				16,452

Income (loss) from continuing operations			26,353				10,562				17,488				(12,998	)			—				41,405
Loss from discontinued operations, net			—				—				—				(686	)			—				(686	)

Net income (loss)		$	26,353			$	10,562			$	17,488			$	(13,684	)		$	—			$	40,719


*	Excludes discontinued operations.

Subsequent_Events

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	14. SUBSEQUENT EVENTS
	On October 1, 2013, the Company completed the sale of certain receivables related to its discontinued affinity credit card business, PartnersFirst. These receivables were classified as held for sale and totaled $25.4 million as of September 30, 2013. No significant gain or loss was recognized as a result of this transaction.
	Management has reviewed events occurring through the date the financial statements were available to be issued and other than the subsequent event disclosed above, no other subsequent events have occurred that would require accrual or disclosure.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Nature of Operations	'
	Nature of operations
	Western Alliance Bancorporation (“WAL” or “the Company”), incorporated under the laws of the state of Nevada, is a bank holding company providing full service banking and related services to locally owned businesses, professional firms, real estate developers and investors, local non-profit organizations, high net worth individuals and other consumers through its three wholly owned subsidiary banks: Bank of Nevada (“BON”), operating in Southern Nevada; Western Alliance Bank (“WAB”), operating in Arizona and Northern Nevada; and Torrey Pines Bank (“TPB”), operating in California. In addition, there are two non-bank subsidiaries, Western Alliance Equipment Finance (“WAEF”), which offers equipment finance services nationwide, and Las Vegas Sunset Properties (“LVSP”), which holds certain non-performing assets. These entities are collectively referred to herein as the Company.
Basis of Presentation	'
	Basis of presentation
	The accounting and reporting policies of the Company are in accordance with accounting principles generally accepted in the United States (“GAAP”) and conform to practices within the financial services industry. The accounts of the Company and its consolidated subsidiaries are included in these Consolidated Financial Statements. All intercompany balances and transactions have been eliminated.
Use of Estimates	'
	Use of estimates
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant changes in the near term relate to the determination of the allowance for credit losses; fair value determinations related to acquisitions, including loans acquired with deteriorated credit quality; fair value of other assets acquired through foreclosure; determination of the valuation allowance related to deferred tax assets; impairment of goodwill and other intangible assets and other than temporary impairment of securities. Although the Company’s management (“Management”) believes these estimates to be reasonably accurate, actual amounts may differ. In the opinion of Management, all adjustments considered necessary have been reflected in the Consolidated Financial Statements.
Principles of consolidation	'
	Principles of consolidation
	WAL has eleven wholly owned subsidiaries: BON, WAB, TPB, which are all banking subsidiaries; WAEF, which provides equipment finance services; LVSP, which holds certain non-performing assets; and six unconsolidated subsidiaries used as business trusts in connection with the issuance of trust-preferred securities. In addition, until October 31, 2012, WAL maintained an 80% interest in Shine Investment Advisory Services Inc. (“Shine”), a registered investment advisor. WAL divested its 80% interest in Shine as of October 31, 2012. On April 30, 2013, the Company completed its acquisition of Centennial Bank (“Centennial”) and merged Centennial into WAB effective as of the acquisition date. The assets and liabilities of Centennial are included in the Company’s Consolidated Financial Statements as of April 30, 2013. See Note 2, “Acquisitions and Dispositions” for further discussion.
	BON has three wholly owned subsidiaries: BW Real Estate, Inc., which operates as a real estate investment trust and holds certain of BON’s real estate loans and related securities; BON Investments, Inc., which holds certain investment securities, municipal loans and leases; and BW Nevada Holdings, LLC, which owns the Company’s 2700 West Sahara Avenue, Las Vegas, Nevada office building.
	WAB has one wholly owned subsidiary, WAB Investments, Inc., which holds certain investment securities, municipal loans and leases, and TPB has one wholly owned subsidiary, TPB Investments, Inc., which holds certain investment securities and leases.
	The Company does not have any other entities that should be considered for consolidation. All intercompany balances and transactions have been eliminated in consolidation.
Reclassifications	'
	Reclassifications
	Certain amounts in the Consolidated Financial Statements as of December 31, 2012 and for the three and nine months ended September 30, 2013 have been reclassified to conform to the current presentation. The reclassifications have no effect on net income or stockholders’ equity as previously reported.
Interim Financial Information	'
	Interim financial information
	The accompanying unaudited Consolidated Financial Statements as of September 30, 2013 and 2012 have been prepared in condensed format and, therefore, do not include all of the information and footnotes required by GAAP for complete financial statements. These statements have been prepared on a basis that is substantially consistent with the accounting principles applied to the Company’s Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

	The information furnished in these interim statements reflects all adjustments which are, in the opinion of Management, necessary for a fair statement of the results for each respective period presented. Such adjustments are of a normal, recurring nature. The results of operations in the interim statements are not necessarily indicative of the results that may be expected for any other quarter or for the full year. The interim financial information should be read in conjunction with the Company’s audited Consolidated Financial Statements.
Business Combinations	'
	Business combinations
	Acquisitions are accounted for in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations (“ASC 805”), which requires that all identified assets acquired and liabilities assumed are recorded at their estimated fair value as of the acquisition date. Any excess of the purchase price over amounts allocated to assets acquired, including identifiable intangible assets, and liabilities assumed, is recorded as goodwill. Where amounts allocated to assets acquired and liabilities assumed is greater than the purchase price, a bargain purchase gain is recognized. Acquisition-related costs are expensed as incurred.
	Fair values are determined in accordance with FASB ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). In many cases, the determination of these fair values required Management to make estimates about discount rates, future expected cash flows, market conditions and other future events that are subjective in nature and subject to change. Determining the fair value of the assets and liabilities, especially the loan portfolio and other real estate owned (“OREO”), is a complex process involving significant judgment regarding the methods and assumptions used to calculate estimated fair values. The fair value of loans acquired is estimated based on discounted cash flows, which take into consideration current portfolio interest rates and repricing characteristics as well as assumptions related to prepayment speeds and credit losses. Loans acquired with credit deterioration are considered to be impaired and are accounted for in accordance with GAAP (see the policy note, “Loans Acquired with Deteriorated Credit Quality,” for further discussion).
Investment Securities	'
	Investment securities
	Investment securities may be classified as held-to-maturity (“HTM”), available-for-sale (“AFS”) or trading. The appropriate classification is initially decided at the time of purchase. Securities classified as HTM are those debt securities that the Company has both the intent and ability to hold to maturity regardless of changes in market conditions, liquidity needs or general economic conditions. These securities are carried at amortized cost. The sale of a security within three months of its maturity date or after the majority of the principal outstanding has been collected is considered a maturity for purposes of classification and disclosure.
	Securities classified as AFS or trading are reported on the Consolidated Balance Sheets at their estimated fair value. As the fair value of AFS securities changes, the changes are reported net of income tax as an element of other comprehensive income (“OCI”), except for impaired securities. When AFS securities are sold, the unrealized gain or loss is reclassified from OCI to non-interest income. Changes in the fair values of trading securities are reported in non-interest income. Securities classified as AFS are securities that the Company intends to hold for an indefinite period of time, but not necessarily to maturity. Any decision to sell a security classified as AFS would be based on various factors, including significant movements in interest rates, changes in the maturity mix of the Company’s assets and liabilities, liquidity needs, decline in credit quality, and regulatory capital considerations.
	Interest income is recognized based on the coupon rate and increased by accretion of discounts earned or decreased by the amortization of premiums paid, over the contractual life of the security, using the interest method. For mortgage-backed securities, estimates of prepayments are considered in the constant yield calculations.
	In estimating whether there are any other than temporary impairment (“OTTI”) losses, Management considers (1) the length of time and the extent to which the fair value has been less than amortized cost, (2) the financial condition and near term prospects of the issuer, (3) the impact of changes in market interest rates, and (4) the intent and ability of the Company to retain its investment for a period of time sufficient to allow for any anticipated recovery in fair value and whether it is not more likely than not the Company would be required to sell the security prior to recovery.
	Declines in the fair value of individual debt securities classified as AFS that are deemed to be other than temporary are reflected in earnings when identified. The fair value of the security then becomes the new cost basis. For individual debt securities where the Company does not intend to sell the security and it is not more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis, the other than temporary decline in fair value of the debt security related to (1) credit loss is recognized in earnings, and (2) market or other factors is recognized in other comprehensive income or loss. Credit losses are recorded if the present value of cash flows is less than amortized cost.
	For individual debt securities where the Company intends to sell the security or more likely than not, will not recover all of its amortized cost, the OTTI is recognized in earnings equal to the entire difference between the securities cost basis and its fair value at the balance sheet date. For individual debt securities for which a credit loss has been recognized in earnings, interest accruals and amortization and accretion of premiums and discounts are suspended when the credit loss is recognized. Interest received after accruals have been suspended is recognized on a cash basis.
Allowance for Credit Losses	'
	Allowance for credit losses
	Credit risk is inherent in the business of extending loans and leases to borrowers. Like other financial institutions, the Company must maintain an adequate allowance for credit losses. The allowance for credit losses is established through a provision for credit losses charged to expense. Loans are charged against the allowance for credit losses when Management believes that the contractual principal or interest will not be collected. Subsequent recoveries, if any, are credited to the allowance. The allowance is an amount believed adequate to absorb probable losses on existing loans that may become uncollectable, based on evaluation of the collectability of loans and prior credit loss experience, together with other factors. The Company formally re-evaluates and establishes the appropriate level of the allowance for credit losses on a quarterly basis.
	The Company’s allowance for credit loss methodology incorporates several quantitative and qualitative risk factors used to establish the appropriate allowance for credit losses at each reporting date. Quantitative factors include the Company’s historical loss experience, delinquency and charge-off trends, collateral values, changes in the level of nonperforming loans and other factors. Qualitative factors include the economic condition of the Company’s operating markets and the state of certain industries. Specific changes in the risk factors are based on actual loss experience, as well as perceived risk of similar groups of loans classified by collateral type and loan grade. An internal one-year and five-year loss history are also incorporated into the allowance calculation model. Due to the credit concentration of the Company’s loan portfolio in real estate secured loans, the value of collateral is heavily dependent on real estate values in Nevada, Arizona and California. While Management uses the best information available to make its evaluation, future adjustments to the allowance may be necessary if there are significant changes in economic or other conditions. In addition, the Federal Deposit Insurance Corporation (“FDIC”) and state bank regulatory agencies, as an integral part of their examination processes, periodically review the Company’s subsidiary banks’ allowances for credit losses, and may require the subsidiary banks to make additions to the allowance based on their judgment about information available to them at the time of their examinations. Management regularly reviews the assumptions and formulas used in determining the allowance and makes adjustments if required to reflect the current risk profile of the portfolio.
	The allowance consists of specific and general components. The specific allowance relates to impaired loans. In general, impaired loans include non-accrual loans, loans 90 days past due and still accruing, and other criticized and classified loans. For such loans, an allowance is established when the discounted cash flows, collateral value or observable market price of the impaired loan are lower than the carrying value of that loan, pursuant to FASB ASC 310, Receivables (“ASC 310”). Loans not collateral dependent are evaluated based on the expected future cash flows discounted at the original contractual interest rate. The amount to which the present value falls short of the current loan obligation is recorded as a reserve or charge-off.
	The Company uses an appraised value method to determine the need for a reserve or charge-off on impaired, collateral dependent loans and further discounts the appraisal for disposition costs. The Company obtains an independent collateral valuation analysis for each impaired loan, at least annually.
Loans Acquired with Deteriorated Credit Quality	'
	Loans acquired with deteriorated credit quality
	FASB ASC 310-30, Accounting for Certain Loans or Debt Securities Acquired in a Transfer (“ASC 310-30”), applies to a loan with evidence of deterioration of credit quality since its origination, and for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. For these loans, accounted for under ASC 310-30, Management determines the value of the loan portfolio based, in part, on work provided by an appraiser. Factors considered in the valuation are projected cash flows for the loans, type of loan and related collateral, loan grade, delinquency and loan to value. Loans are grouped together according to similar characteristics and are treated in the aggregate when applying various valuation techniques. Loans are first evaluated individually to determine if there has been credit deterioration since origination. Once acquired loans are determined to have deteriorated credit quality, the Company evaluates such loans for common risk characteristics and aggregation into one or more pools. Common risk characteristics for pooling acquired loans may include credit ratings, loan type, collateral type, delinquency status, geographic location, loan to value, or combinations thereof. Management also estimates the amount of credit losses that are expected to be realized for individual loans by estimating the probability of default and the loss given default, which incorporates the liquidation value of collateral securing loans. These estimates are subjective. The accretion of the fair value adjustments attributable to interest rates on loans acquired with deteriorated credit quality is recorded in interest income in the Consolidated Income Statements over the estimated life of the pool. The fair value adjustment attributable to credit losses on these loans is non-accretable. When a loan is sold, paid off or transferred to OREO and liquidated, any remaining non-accretable yield is recorded in interest income.

	Adjustments to these loan values in future periods may occur based on Management’s expectation of future cash flows to be collected over the lives of the loans. Estimating cash flows is performed at a pool level and incorporates analysis of historical cash flows, delinquencies, and charge-offs as well as assumptions about future cash flows. Performance can vary from period to period, causing changes in estimates of the expected cash flows. If based on the review of a pool of loans, it is probable that a significant increase or improvement in cash flows previously expected to be collected, any valuation allowance established for the pool of loans is first reduced for the increase in the present value of cash flows expected to be collected, and any remaining increase in estimated cash flows increases the accretable yield and is recognized over the remaining estimated life of the loan pool. If based on the review of a pool of loans, it is probable that a decrease or impairment in cash flows previously expected to be collected or if actual cash flows are less than cash flows previously expected, the allowance for credit losses is increased for the decrease in the present value of the cash flows expected to be collected.
Other Assets Acquired through Foreclosure	'
	Other assets acquired through foreclosure
	Other assets acquired through foreclosure consist primarily of properties acquired as a result of, or in-lieu-of, foreclosure. Properties or other assets (primarily repossessed assets formerly leased) are classified as other real estate owned and other repossessed property and are initially reported at fair value of the asset less estimated selling costs. Subsequent adjustments are based on the lower of carrying value or fair value, less estimated costs to sell the property. Costs relating to the development or improvement of the assets are capitalized and costs relating to holding the assets are charged to non-interest expense. Property is evaluated regularly to ensure the recorded amount is supported by its current fair value and valuation allowances.
Derivative Financial Instruments	'
	Derivative financial instruments
	The Company uses interest-rate swaps to mitigate interest-rate risk associated with changes to (1) the fair value of certain fixed-rate financial instruments (fair value hedges) and (2) certain cash flows related to future interest payments on variable rate financial instruments (cash flow hedges).
	The Company recognizes derivatives as assets or liabilities in the Consolidated Balance Sheets at their fair value in accordance with FASB ASC 815, Derivatives and Hedging (“ASC 815”). The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. On the date the derivative contract is entered into, the Company designates the derivative as a fair value hedge or cash flow hedge. Derivative instruments designated in a hedge relationship to mitigate exposure to changes in the fair value of an asset or liability 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.
	For a fair value hedge, the change in the fair value of the derivative instrument is recognized in earnings. For a cash flow hedge, the effective portion of the change in the fair value of the derivative is recorded in accumulated other comprehensive income (loss) (“AOCI”) and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. Any ineffective portion of the change in fair value of a cash flow hedge is recognized immediately in non-interest income in the Consolidated Income Statement. Under both the fair value and cash flow hedge scenarios, changes in the fair value of derivatives not considered to be highly effective in hedging the change in fair value or the expected cash flows of the hedged item are recognized in earnings as non-interest income during the period of the change.

	The Company documents its hedge relationships, including identification of the hedging instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transaction at the time the derivative contract is executed. Both at inception and, at least quarterly, thereafter, the Company assesses whether the derivatives used in hedging transactions are highly effective (as defined in the guidance) in offsetting changes in either the fair value or cash flows of the hedged item. Retroactive effectiveness is assessed, as well as the continued expectation that the hedge will remain effective prospectively. The Company discontinues hedge accounting prospectively when it is determined that a hedge is no longer highly effective. When hedge accounting is discontinued on a fair value hedge that no longer qualifies as an effective hedge, the derivative continues to be reported at fair value on the Consolidated Balance Sheets, but the carrying amount of the hedged item is no longer adjusted for future changes in fair value. The adjustment to the carrying amount of the hedged item that existed at the date hedge accounting is discontinued is amortized over the remaining life of the hedged item into earnings.
	Derivative instruments that are not designated as hedges per the accounting guidance are reported in the Consolidated Balance Sheets at fair value and the changes in fair value are recognized in earnings as non-interest income during the period of change.
	The Company occasionally purchases a financial instrument or originates a loan that contains an embedded derivative instrument. Upon purchasing the instrument or originating the loan, the Company assesses whether the economic characteristics of the embedded derivative are clearly and closely related to the economic characteristics of the remaining component of the financial instrument (i.e., the host contract) and whether a separate instrument with the same terms as the embedded instrument would meet the definition of a derivative instrument. When it is determined that (1) the embedded derivative possesses economic characteristics that are not clearly and closely related to the economic characteristics of the host contract, and (2) a separate instrument with the same terms would qualify as a derivative instrument, the embedded derivative is separated from the host contract and carried at fair value. However, in cases where (1) the host contract is measured at fair value, with changes in fair value reported in current earnings, or (2) the Company is unable to reliably identify and measure an embedded derivative for separation from its host contract, the entire contract is carried on the Consolidated Balance Sheet at fair value and is not designated as a hedging instrument.
Commitments and Letters of Credit	'
	Commitments and letters of credit
	In the ordinary course of business, the Company enters into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the Consolidated Financial Statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for credit losses.
Income Taxes	'
	Income taxes
	The Company and its subsidiaries, other than BW Real Estate, Inc., file a consolidated federal tax return. Due to tax regulations, several items of income and expense are recognized in different periods for tax return purposes than for financial reporting purposes. These items represent “temporary differences.” Deferred taxes are provided on an asset and liability method, whereby deferred tax assets are recognized for deductible temporary differences and tax credit carry-forwards and deferred tax liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of Management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effect of changes in tax laws and rates on the date of enactment.
Fair Values of Financial Instruments	'
	Fair values of financial instruments
	The Company uses fair value measurements to record fair value adjustments to certain assets and liabilities. ASC 820 establishes a framework for measuring fair value, establishes a three-level valuation hierarchy for disclosure of fair value measurement and enhances disclosure requirements for fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The Company uses various valuation approaches, including market, income and/or cost approaches. ASC 820 establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability developed based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the factors market participants would consider in pricing the asset or liability developed based on the best information available in the circumstances. The hierarchy is broken down into three levels based on the reliability of inputs, as follows:

		•	Level 1 — Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

		•	Level 2 — Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, prepayment speeds, volatilities, etc.) or model-based valuation techniques where all significant assumptions are observable, either directly or indirectly, in the market.

		•	Level 3 — Valuation is generated from model-based techniques where one or more significant inputs are not observable, either directly or indirectly, in the market. These unobservable assumptions reflect the Company’s own estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques may include use of matrix pricing, discounted cash flow models and similar techniques.
	The availability of observable inputs varies based on the nature of the specific financial instrument. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety.
	Fair value is a market-based measure considered from the perspective of a market participant who holds the asset or owes the liability rather than an entity-specific measure. When market assumptions are available, ASC 820 requires the Company to make assumptions regarding the assumptions that market participants would use to estimate the fair value of the financial instrument at the measurement date.

	FASB ASC 825, Financial Instruments (“ASC 825”), requires disclosure of fair value information about financial instruments, whether or not recognized in the balance sheet, for which it is practicable to estimate that value.
	Management uses its best judgment in estimating the fair value of the Company’s financial instruments; however, there are inherent limitations in any estimation technique. Therefore, for substantially all financial instruments, the fair value estimates presented herein are not necessarily indicative of the amounts the Company could have realized in a sales transaction at September 30, 2013 or December 31, 2012. The estimated fair value amounts for September 30, 2013 and December 31, 2012 have been measured as of period-end, and have not been reevaluated or updated for purposes of these Consolidated Financial Statements subsequent to those dates. As such, the estimated fair values of these financial instruments subsequent to the reporting date may be different than the amounts reported at the period-end.
	The information in Note 11, “Fair Value Accounting,” should not be interpreted as an estimate of the fair value of the entire Company since a fair value calculation is only required for a limited portion of the Company’s assets and liabilities.
	Due to the wide range of valuation techniques and the degree of subjectivity used in making the estimate, comparisons between the Company’s disclosures and those of other companies or banks may not be meaningful.
	The following methods and assumptions were used by the Company in estimating the fair value of its financial instruments:
	Cash and cash equivalents
	The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks approximate their fair value.
	Money market and certificates of deposit investments
	The carrying amounts reported in the Consolidated Balance Sheets for money market investments approximate their fair value.
	Investment securities
	The fair values of U.S. Treasuries, corporate bonds, mutual funds, and exchange-listed preferred stock are based on quoted market prices and are categorized as Level 1 in the fair value hierarchy.
	The fair value of other investment securities were determined based on matrix pricing. Matrix pricing is a mathematical technique that utilizes observable market inputs including, for example, yield curves, credit ratings and prepayment speeds. Fair values determined using matrix pricing are generally categorized as Level 2 in the fair value hierarchy.
	The Company owns certain collateralized debt obligations (“CDOs”) for which quoted prices are not available. Quoted prices for similar assets are also not available for these investment securities. In order to determine the fair value of these securities, the Company has estimated the future cash flows and discount rate using observable market inputs adjusted based on assumptions regarding the adjustments a market participant would assume necessary for each specific security. As a result, the resulting fair values have been categorized as Level 3 in the fair value hierarchy.
	Restricted stock
	The Company’s subsidiary banks are members of the Federal Home Loan Bank (“FHLB”) system and maintain an investment in capital stock of the FHLB. The Company’s subsidiary banks also maintain an investment in their primary correspondent bank. These investments are carried at cost since no ready market exists for them, and they have no quoted market value. The Company conducts a periodic review and evaluation of its FHLB stock to determine if any impairment exists. The fair values have been categorized as Level 2 in the fair value hierarchy.
	Loans
	Fair value for loans is estimated based on discounted cash flows using interest rates currently being offered for loans with similar terms to borrowers with similar credit quality with adjustments that the Company believes a market participant would consider in determining fair value based on a third party independent valuation. As a result, the fair value for loans disclosed in Note 11, “Fair Value Accounting,” is categorized as Level 2 in the fair value hierarchy.
	Accrued interest receivable and payable
	The carrying amounts reported in the Consolidated Balance Sheets for accrued interest receivable and payable approximate their fair value. Accrued interest receivable and payable fair value measurements are classified as Level 3 in the fair value hierarchy.
	Derivative financial instruments
	All derivatives are recognized in the Consolidated Balance Sheet at their fair value. The fair value for derivatives is determined based on market prices, broker-dealer quotations on similar products or other related input parameters. As a result, the fair values have been categorized as Level 2 in the fair value hierarchy.

	Deposits
	The fair value disclosed for demand and savings deposits is by definition equal to the amount payable on demand at their reporting date (that is, their carrying amount), which the Company believes a market participant would consider in determining fair value. The carrying amount for variable-rate deposit accounts approximates their fair value. Fair values for 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 these deposits. The fair value measurement of the deposit liabilities disclosed in Note 11, “Fair Value Accounting,” is categorized as Level 2 in the fair value hierarchy.
	Federal Home Loan Bank advances and other borrowings
	The fair values of the Company’s borrowings are estimated using discounted cash flow analyses, based on the market rates for similar types of borrowing arrangements. The FHLB advances have been categorized as Level 2 in the fair value hierarchy due to their short durations. The other borrowings have been categorized as Level 3 in the fair value hierarchy.
	Junior subordinated debt
	Junior subordinated debt and subordinated debt are valued by comparing interest rates and spreads to benchmark indices offered to institutions with similar credit profiles to the Company and discounting the contractual cash flows on the Company’s debt using these market rates. The junior subordinated debt has been categorized as Level 3 in the fair value hierarchy.
	Off-balance sheet instruments
	Fair values for the Company’s off-balance sheet instruments (lending commitments and standby letters of credit) are based on quoted fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the counterparties’ credit standing.
Recent Accounting Pronouncements	'
	Recent accounting pronouncements
	In January 2013, the FASB issued guidance within Accounting Standards Update (“ASU”) 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities. The amendments in ASU 2013-01 to Topic 210, Balance Sheet, clarify that the scope of ASU 2011-11, Disclosures about Offsetting Assets and Liabilities, would apply to derivatives including bifurcated embedded derivatives, repurchase and reverse agreements, and securities borrowing and lending transactions that are either offset or subject to a master netting arrangement. The amendments are effective for fiscal years beginning on or after January 1, 2013, and interim periods within those annual periods. The adoption of this guidance did not have a material impact on the Company’s Consolidated Income Statement, Consolidated Balance Sheet, or Consolidated Cash Flows.

	In February 2013, the FASB issued guidance within ASU 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. The amendments in ASU 2013-02 to Topic 220, Comprehensive Income, update, supersede and replace the presentation requirements for reclassifications out of accumulated other comprehensive income in ASUs 2011-05 and 2011-12. The amendments require an entity to provide additional information about reclassifications out of accumulated other comprehensive income. The amendments are effective prospectively for reporting periods beginning after December 15, 2012. The adoption of this guidance did not have a material impact on the Company’s Consolidated Income Statement, its Consolidated Balance Sheet, or Consolidated Cash Flows and only impacted the presentation of other comprehensive income in the Consolidated Financial Statements.
	In February 2013, the FASB issued guidance within 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. The amendments in ASU 2013-04 to Topic 405, Liabilities, provide guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation within the scope of the Update is fixed at the reporting date, except for obligations addressed with existing GAAP. The guidance requires an entity to measure those obligations as the sum of the amount the reporting entity agreed to pay on behalf of its co-obligors. The guidance also requires an entity to disclose the nature and amount of the obligation, as well as other information about those obligations. The amendment is effective retrospectively for reporting periods beginning after December 15, 2013. Early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company’s Consolidated Income Statement, Consolidated Balance Sheet, or Consolidated Cash Flows.
	In July 2013, the FASB issued guidance within ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The amendments in ASU 2013-11 to Topic 740, Income Taxes, provide guidance on the financial statement presentation of unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendments are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this guidance is not expected to have a material impact on the Company’s Consolidated Financial Statements.

Acquisitions_and_Dispositions_

Acquisitions and Dispositions (Tables)	9 Months Ended
Acquisitions and Dispositions (Tables)	Sep. 30, 2013
Text Block [Abstract]	'
Schedule of Recognized Amounts of Identifiable Assets and Liabilities Assumed	'
	The recognized amounts of identifiable assets acquired and liabilities assumed are as follows:


			(in thousands)
	Assets:
	Cash and cash equivalents ⁽¹⁾		$	70,349
	Federal funds sold ⁽¹⁾			8,355
	Investment securities - avaialable-for-sale			26,014
	Loans			351,474
	Deferred tax assets, net			21,666
	Premises and equipment			44
	Other assets acquired through foreclosure, net			5,622
	Other assets			6,007

	Total assets acquired			489,531

	Liabilities:
	Deposits			338,811
	FHLB advances			79,943
	Other liabilities			3,233
	Total liabilities assumed		$	421,987

	Net assets acquired			67,544

	Consideration paid ⁽¹⁾			57,500

	Bargain purchase gain from acquisition		$	10,044


	-1	Cash acquired, net of cash consideration paid of $57.5 million represents the net cash and cash equivalents acquired of $21.2 million as part of the acquisition
Summary of Business Acquisition Pro-forma Information as Results of Operations	'
	The following table presents pro forma information as if the Centennial and Western Liberty acquisitions had occurred as of January 1, 2012. The pro forma information is not necessarily indicative of the results of operations as they would have been had the transactions been effected on the assumed dates.


			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands, except per share amounts)
	Net Interest income ⁽¹⁾		$	81,093		$	85,151		$	238,430		$	254,535
	Non Interest income ⁽²⁾			2,625			8,138			7,468			22,147
	Net income ⁽³⁾			25,820			13,549			69,435			36,012
	Earnings per share—basic		$	0.3		$	0.17		$	0.81		$	0.44
	Earnings per share—diluted		$	0.3		$	0.16		$	0.8		$	0.44

	-1	Excludes accretion (or amortization) of fair market value adjustments for loans, deposits and other borrowings advances of $3,466 for the three months ended September 30, 2013 and $10,285 for the nine months ended September 30, 2013.
	-2	Excludes bargain purchase gain of $10,044 related to the Centennial acquisition.
	-3	Excludes merger / restructure related costs incurred by the Company($181 for the three months ended September 30, 2013 and $2,660 for the nine months ended September 30, 2013) and Centennial ($0 for the three months ended September 30, 2013 and $1,000 for the nine months ended September 30, 2013) and footnotes 1 and 2 noted above as well as the related tax effects.
Summary of Operating Results of Discontinued Operations	'
	The following table summarizes the operating results of the discontinued operations for the periods indicated:


			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands)
	Operating revenue		$	1,105		$	315		$	3,376		$	947
	Non-interest expenses			(1,155	)		(734	)		(3,653	)		(2,130	)

	Loss before income taxes			(50	)		(419	)		(277	)		(1,183	)
	Income tax benefit			(21	)		(176	)		(117	)		(497	)

	Net loss		$	(29	)	$	(243	)	$	(160	)	$	(686	)

Investment_Securities_Tables

Investment Securities (Tables)	9 Months Ended
Investment Securities (Tables)	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Carrying Amounts and Fair Values of Securities Available-for-Sale	'
	Carrying amounts and fair values of investment securities at September 30, 2013 and December 31, 2012 are summarized as follows:

						OTTI
						Recognized
						in Other			Gross			Gross
			Amortized			Comprehensive			Unrealized			Unrealized			Fair
			Cost			Income			Gains			(Losses)			Value
			(in thousands)
	Available-for-sale
	U.S. government sponsored agency securities		$	28,694		$	—		$	—		$	(1,317	)	$	27,377
	Municipal obligations			110,081			—			302			(4,838	)		105,545
	Adjustable-rate preferred stock			66,093			—			864			(5,568	)		61,389
	Mutual funds			32,422			—			123			(222	)		32,323
	Direct U.S. obligations and GSE residential mortgage-backed securities			769,983			—			5,748			(7,253	)		768,478
	Private label residential mortgage-backed securities			27,683			—			8			(1,544	)		26,147
	Trust preferred securities			32,000			—			—			(8,166	)		23,834
	CRA investments			23,703			—			—			(403	)		23,300
	Collateralized mortgage-backed securities			5,283			—			210			—			5,493

			$	1,095,942		$	—		$	7,255		$	(29,311	)	$	1,073,886

	Measured at fair value
	Direct U.S. obligations and GSE residential mortgage-backed securities														$	3,621



						OTTI
						Recognized
						in Other			Gross			Gross
			Amortized			Comprehensive			Unrealized			Unrealized			Fair
			Cost			Income			Gains			(Losses)			Value
			(in thousands)
	Available-for-sale
	Municipal obligations		$	71,777		$	—		$	1,578		$	(184	)	$	73,171
	Adjustable-rate preferred stock			72,717			—			3,591			(753	)		75,555
	Mutual funds			36,314			—			1,647			—			37,961
	Direct U.S. obligations and GSE residential mortgage-backed securities			648,641			—			14,573			(10	)		663,204
	Private label residential mortgage-backed securities			35,868			(1,811	)		2,067			(517	)		35,607
	Private label commercial mortgage-backed securities			5,365			—			376			—			5,741
	Trust preferred securities			32,000			—			—			(7,865	)		24,135
	CRA investments			23,368			—			848			—			24,216

			$	926,050		$	(1,811	)	$	24,680		$	(9,329	)	$	939,590

	Measured at fair value
	Direct U.S. obligations and GSE residential mortgage-backed securities (3)														$	5,061
Carrying Amounts and Fair Values of Securities Held-to-Maturity	'
	Carrying amounts and fair values of investment securities at September 30, 2013 and December 31, 2012 are summarized as follows:


			September 30, 2013
						Gross			Gross
			Amortized			Unrealized			Unrealized			Fair
			Cost			Gains			(Losses)			Value
			(in thousands)
	Held-to-maturity
	Collateralized debt obligations		$	50		$	578		$	—		$	628
	Corporate bonds			97,778			647			(4,586	)		93,839
	Municipal obligations			189,680			3,531			(1,735	)		191,476
	Other			1,600			—			—			1,600

			$	289,108		$	4,756		$	(6,321	)	$	287,543




			December 31, 2012
						Gross			Gross
			Amortized			Unrealized			Unrealized			Fair
			Cost			Gains			(Losses)			Value
			(in thousands)
	Held-to-maturity
	Collateralized debt obligations		$	50		$	1,401		$	—		$	1,451
	Corporate bonds			97,781			984			(6,684	)		92,081
	Municipal obligations			191,902			5,887			(102	)		197,687
	CRA investments			1,600			—			—			1,600

			$	291,333		$	8,272		$	(6,786	)	$	292,819

Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position	'
	Information pertaining to securities with gross unrealized losses at September 30, 2013 and December 31, 2012, aggregated by investment category and length of time that individual securities have been in a continuous loss position follows:


			September 30, 2013
			Less Than Twelve Months						More Than Twelve Months						Total
			Gross						Gross						Gross
			Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
			Losses			Value			Losses			Value			Losses		Value
			(in thousands)
	Held-to-maturity
	Corporate bonds		$	—		$	—		$	4,586		$	80,414		$	4,586	$	80,414
	Municipal obligations			1,735			41,505			—			—			1,735		41,505

			$	1,735		$	41,505		$	4,586		$	80,414		$	6,321	$	121,919

	Available-for-sale
	U.S. Government-sponsored agency securities		$	1,317		$	17,377		$	—		$	—		$	1,317	$	17,377
	Adjustable-rate preferred stock			5,568			43,599			—			—			5,568		43,599
	Mutual funds			222			25,862			—			—			222		25,862
	Direct U.S obligations and GSE residential mortgage-backed securities			7,242			358,092			11			1,528			7,253		359,620
	Municipal obligations			4,838			79,308			—			—			4,838		79,308
	Private label residential mortgage-backed securities			1,500			20,322			44			3,460			1,544		23,782
	Trust preferred securities			—			—			8,166			23,834			8,166		23,834
	Other			403			23,299			—			—			403		23,299

			$	21,090		$	567,859		$	8,221		$	28,822		$	29,311	$	596,681



			December 31, 2012
			Less Than Twelve Months						More Than Twelve Months						Total
			Gross						Gross						Gross
			Unrealized			Fair			Unrealized			Fair			Unrealized		Fair
			Losses			Value			Losses			Value			Losses		Value
			(in thousands)
	Held-to-maturity
	Corporate bonds		$	206		$	14,794		$	6,478		$	63,522		$	6,684	$	78,316
	Municipal obligations			102			10,908			—			—			102		10,908

			$	308		$	25,702		$	6,478		$	63,522		$	6,786	$	89,224

	Available-for-sale
	Adjustable-rate preferred stock		$	110		$	7,811		$	643		$	8,723		$	753	$	16,534
	Mutual funds			—			—			—			—			—		—
	Corporate bonds			—			—			—			—			—		—
	Direct U.S obligations and GSE residential mortgage-backed securities			2			557			8			1,938			10		2,495
	Municipal obligations			184			15,713			—			—			184		15,713
	Private label residential mortgage-backed securities			120			16,901			397			6,986			517		23,887
	Trust preferred securities			—			—			7,865			24,135			7,865		24,135

			$	416		$	40,982		$	8,913		$	41,782		$	9,329	$	82,764

Amortized Cost and Fair Value of Investment Securities by Contractual Maturities	'
	The amortized cost and fair value of securities as of September 30, 2013 and December 31, 2012, by contractual maturities, are shown below. The actual maturities of the mortgage-backed securities may differ from their contractual maturities because the loans underlying the securities may be repaid without any penalties due to borrowers that have the right to call or prepay obligations with or without call or prepayment penalties. These securities are included in the after ten years category in the following table.


			September 30, 2013						December 31, 2012
			Amortized			Estimated			Amortized			Estimated
			Cost			Fair Value			Cost			Fair Value
			(in thousands)
	Held-to-maturity
	Due in one year or less		$	2,517		$	2,534		$	1,600		$	1,600
	After one year through five years			15,400			15,760			13,596			13,934
	After five years through ten years			147,897			144,898			121,238			116,020
	After ten years			123,294			124,351			154,899			161,265

			$	289,108		$	287,543		$	291,333		$	292,819

	Available-for-sale
	Due in one year or less		$	56,226		$	55,725		$	65,190		$	67,794
	After one year through five years			23,694			24,216			24,261			25,906
	After five years through ten years			34,019			32,661			8,165			8,000
	After ten years (1)			982,003			961,284			828,434			837,890

			$	1,095,942		$	1,073,886		$	926,050		$	939,590


	-1	Includes mortgage-backed securities.
Investment Securities by Credit Rating Type	'
	The following table summarizes the Company’s investment ratings position as of September 30, 2013:


			As of September 30, 2013
			AAA			Split-rated			AA+ to AA-			A+ to A-			BBB+ to BBB-		BB+ and below		Totals
			AAA			AAA/AA+			AA+ to AA-			A+ to A-			BBB+ to BBB-		BB+ and below		Totals
			(in thousands)
	Municipal obligations		$	8,006		$	—		$	130,149		$	149,477		$	7,323	$	270	$	295,225
	Direct U.S. obligations & GSE residential mortgage-backed securities			—			772,098			—			—			—		—		772,098
	Private label residential mortgage-backed securities			12,396			—			151			5,563			4,145		3,892		26,147
	Mutual funds (3)			—			—			—			—			32,323		—		32,323
	U.S. Government-sponsored agency securities			—			27,377			—			—			—		—		27,377
	Adjustable-rate preferred stock			—			—			—			—			45,970		13,371		59,341
	Trust preferred securities			—			—			—			—			23,834		—		23,834
	Collateralized debt obligations			—			—			—			—			—		50		50
	Corporate bonds			—			—			2,697			40,105			54,976		—		97,778
	Collarteralized mortgage-backed securities			5,493			—			—			—			—		—		5,493

	Total (1) (2)		$	25,895		$	799,475		$	132,997		$	195,145		$	168,571	$	17,583	$	1,339,666


	-1	The Company used the average credit rating of the combination of S&P, Moody’s and Fitch in the above table where ratings differed.
	-2	Securities values are shown at carrying value as of September 30, 2013. Unrated securities consist of CRA investments with a carrying value of $23.3 million, ARPS with a carrying value of $2.0 million and an other investment of $1.6 million.
	-3	At least 80% of mutual funds are investment grade corporate bonds.

	The following table summarizes the Company’s investment ratings position as of December 31, 2012:


			As of December 31, 2012
			AAA			Split-rated			AA+ to AA-			A+ to A-			BBB+ to BBB-		BB+ and below		Totals
			AAA			AAA/AA+			AA+ to AA-			A+ to A-			BBB+ to BBB-		BB+ and below		Totals
			(in thousands)
	Municipal obligations		$	8,120		$	—		$	149,352		$	92,401		$	14,922	$	278	$	265,073
	Direct U.S. obligations & GSE residential mortgage-backed securities			—			668,265			—			—			—		—		668,265
	Private label residential mortgage-backed securities			15,219			—			1,649			6,069			5,249		7,421		35,607
	Private label commercial mortgage-backed securities			5,741			—			—			—			—		—		5,741
	Mutual funds (3)			—			—			—			—			37,961		—		37,961
	U.S. Government-sponsored agency securities			—			—			—			—			—		—		—
	Adjustable-rate preferred stock			—			—			826			—			60,807		10,838		72,471
	Trust preferred securities			—			—			—			—			24,135		—		24,135
	Collateralized debt obligations			—			—			—			—			—		50		50
	Corporate bonds			—			—			2,696			40,116			54,969		—		97,781

	Total (1) (2)		$	29,080		$	668,265		$	154,523		$	138,586		$	198,043	$	18,587	$	1,207,084


	-1	The Company used the average credit rating of the combination of S&P, Moody’s and Fitch in the above table where ratings differed.
	-2	Securities values are shown at carrying value as of December 31, 2012. Unrated securities consist of CRA investments with a carrying value of $24.2 million, one ARPS security with a carrying value of $3.1 million and an other investment of $1.6 million.
	-3	At least 80% of mutual funds are investment grade corporate bonds.
Gross Gains and (Losses) on Sales of Investment Securities	'
	The following table presents gross gains and (losses) on sales of investment securities:


			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(in thousands)
	Gross gains		$	602		$	1,073		$	870		$	2,786
	Gross (losses)			(2,281	)		(42	)		(2,407	)		(284	)

			$	(1,679	)	$	1,031		$	(1,537	)	$	2,502

Loans_Leases_and_Allowance_For1

Loans, Leases and Allowance For Credit Losses (Tables)	9 Months Ended
Loans, Leases and Allowance For Credit Losses (Tables)	Sep. 30, 2013
Receivables [Abstract]	'
Schedule of Held for Investment Loan Portfolio Composition of Loans, Leases and Allowance for Credit Losses	'
	The composition of the Company’s loans held for investment portfolio is as follows:


			September 30,				December 31,
			2013				2012
			(in thousands)
	Commercial and industrial		$	1,990,568			$	1,659,003
	Commercial real estate—non-owner occupied			1,864,333				1,505,600
	Commercial real estate—owner occupied			1,551,187				1,396,797
	Construction and land development			459,764				394,319
	Residential real estate			358,962				407,937
	Commercial leases			244,312				288,747
	Consumer			29,850				31,836
	Deferred fees and unearned income, net			(8,106	)			(6,045	)

				6,490,870				5,678,194
	Allowance for credit losses			(97,851	)			(95,427	)

	Total		$	6,393,019			$	5,582,767

Contractual Aging of Loan Portfolio by Class of Loans Including Loans Held for Sale and Excluding Deferred Fees/Costs	'
	The following table presents the contractual aging of the recorded investment in past due loans by class of loans including loans held for sale and excluding deferred fees:


			September 30, 2013
							30-59 Days				60-89 Days				Over 90 days				Total
			Current				Past Due				Past Due				Past Due				Past Due				Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,538,589			$	2,123			$	—			$	10,475			$	12,598			$	1,551,187
	Non-owner occupied			1,629,045				1,475				12,607				7,294				21,376				1,650,421
	Multi-family			213,912				—				—				—				—				213,912
	Commercial and industrial
	Commercial			1,986,782				1,094				817				1,875				3,786				1,990,568
	Leases			243,959				—				—				353				353				244,312
	Construction and land development
	Construction			264,145				—				—				—				—				264,145
	Land			194,218				56				—				1,345				1,401				195,619
	Residential real estate			342,382				560				127				15,893				16,580				358,962
	Consumer			54,195				309				248				511				1,068				55,263

	Total loans		$	6,467,227			$	5,617			$	13,799			$	37,746			$	57,162			$	6,524,389



			December 31, 2012
							30-59 Days				60-89 Days				Over 90 days				Total
			Current				Past Due				Past Due				Past Due				Past Due				Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,372,550			$	13,153			$	1,757			$	9,337			$	24,247			$	1,396,797
	Non-owner occupied			1,327,481				917				4,416				8,573				13,906				1,341,387
	Multi-family			164,213				—				—				—				—				164,213
	Commercial and industrial
	Commercial			1,654,787				3,109				121				986				4,216				1,659,003
	Leases			287,768				515				—				464				979				288,747
	Construction and land development
	Construction			215,597				—				—				—				—				215,597
	Land			171,919				826				571				5,406				6,803				178,722
	Residential real estate			387,641				3,525				1,837				14,934				20,296				407,937
	Consumer			62,271				524				—				165				689				62,960

	Total loans		$	5,644,227			$	22,569			$	8,702			$	39,865			$	71,136			$	5,715,363

Summary of Recorded Investment in Nonaccrual Loans and Loans Past Due 90 Days Still Accruing Interest by Loan Class	'
	The following table presents the recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing interest by class of loans:


			September 30, 2013																December 31, 2012
															Loans past															Loans past
			Non-accrual loans												due 90 days				Non-accrual loans											due 90 days
							Past Due/				Total				or more and								Past Due/				Total			or more and
			Current				Delinquent				Non-accrual				still accruing				Current				Delinquent				Non-accrual			still accruing
			(in thousands)
	Commercial real estate
	Owner occupied		$	10,222			$	10,391			$	20,613			$	388			$	14,392			$	18,394			$	32,786		$	1,272
	Non-owner occupied			12,761				12,885				25,646				4,553				18,299				8,572				26,871			—
	Multi-family			—				—				—				—				318				—				318			—
	Commercial and industrial
	Commercial			1,909				2,092				4,001				4				2,549				3,194				5,743			15
	Leases			114				353				467				—				—				979				979			—
	Construction and land development
	Construction			—				—				—				—				—				—				—			—
	Land			5,241				1,401				6,642				—				4,375				6,718				11,093			—
	Residential real estate			3,350				15,894				19,244				—				11,561				15,161				26,722			101
	Consumer			28				—				28				511				39				165				204			—

	Total		$	33,625			$	43,016			$	76,641			$	5,456			$	51,533			$	53,183			$	104,716		$	1,388

Recorded Investment and Delinquency Status by Class of Loans Including Loans Held For Sale and Excluding Deferred Fees by Risk Rating	'
	The following tables present the recorded investment and delinquency status by class of loans including loans held for sale and excluding deferred fees by risk rating:


			September 30, 2013
			Pass				Special				Substandard				Doubtful				Loss				Total
			Pass				Mention				Substandard				Doubtful				Loss				Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,465,697			$	35,217			$	49,293			$	980			$	—			$	1,551,187
	Non-owner occupied			1,490,250				64,405				95,766				—				—				1,650,421
	Multi-family			206,586				5,618				1,708				—				—				213,912
	Commercial and industrial
	Commercial			1,964,491				9,661				14,904				1,512				—				1,990,568
	Leases			239,002				4,843				467				—				—				244,312
	Construction and land development
	Construction			256,037				8,108				—				—				—				264,145
	Land			167,523				4,676				23,420				—				—				195,619
	Residential real estate			324,254				3,865				30,843				—				—				358,962
	Consumer			53,518				853				892				—				—				55,263

	Total		$	6,167,358			$	137,246			$	217,293			$	2,492			$	—			$	6,524,389



			September 30, 2013
			Pass				Special				Substandard				Doubtful				Loss				Total
			Pass				Mention				Substandard				Doubtful				Loss				Total
			(in thousands)
	Current (up to 29 days past due)		$	6,164,416			$	136,297			$	165,836			$	678			$	—			$	6,467,227
	Past due 30—59 days			2,622				378				2,617				—				—				5,617
	Past due 60—89 days			320				571				12,908				—				—				13,799
	Past due 90 days or more			—				—				35,932				1,814				—				37,746

	Total		$	6,167,358			$	137,246			$	217,293			$	2,492			$	—			$	6,524,389



			December 31, 2012
			Pass				Special				Substandard				Doubtful				Loss				Total
			Pass				Mention				Substandard				Doubtful				Loss				Total
			(in thousands)
	Commercial real estate
	Owner occupied		$	1,280,337			$	50,552			$	65,908			$	—			$	—			$	1,396,797
	Non-owner occupied			1,257,011				21,065				63,311				—				—				1,341,387
	Multi-family			163,895				—				318				—				—				164,213
	Commercial and industrial
	Commercial			1,630,166				12,370				15,499				968				—				1,659,003
	Leases			282,075				5,693				979				—				—				288,747
	Construction and land development
	Construction			215,395				202				—				—				—				215,597
	Land			141,436				5,641				31,645				—				—				178,722
	Residential real estate			365,042				7,559				32,446				2,890				—				407,937
	Consumer			61,469				469				1,022				—				—				62,960

	Total		$	5,396,826			$	103,551			$	211,128			$	3,858			$	—			$	5,715,363


			31-Dec-12
			Pass				Special				Substandard				Doubtful				Loss				Total
			Pass				Mention				Substandard				Doubtful				Loss				Total
			(in thousands)
	Current (up to 29 days past due)		$	5,387,543			$	100,549			$	152,827			$	3,308			$	—			$	5,644,227
	Past due 30—59 days			4,410				1,310				16,849				—				—				22,569
Past due 60—89 days			4,450				1,692				2,560				—				—				8,702
Past due 90 days or more			423				—				38,892				550				—				39,865

Total		$	5,396,826			$	103,551			$	211,128			$	3,858			$	—			$	5,715,363

Recorded Investment in Loans Classified as Impaired	'
	The table below reflects recorded investment in loans classified as impaired:


			September 30,				December 31,
			2013				2012
			(in thousands)
	Impaired loans with a specific valuation allowance under ASC 310		$	20,717			$	51,538
	Impaired loans without a specific valuation allowance under ASC 310			153,514				146,617

	Total impaired loans		$	174,231			$	198,155

	Valuation allowance related to impaired loans		$	(5,909	)		$	(12,866	)

Impaired Loans by Loan Class	'
	The following table presents the impaired loans by class:


			September 30,				December 31,
			2013				2012
			(in thousands)
	Commercial real estate
	Owner occupied		$	45,516			$	58,074
	Non-owner occupied			54,052				52,146
	Multi-family			—				318
	Commercial and industrial
	Commercial			14,106				15,531
	Leases			467				979
	Construction and land development
	Construction			—				—
	Land			26,748				32,492
	Residential real estate			32,811				37,851
	Consumer			531				764

	Total		$	174,231			$	198,155

Average Investment in Impaired Loans by Loan Class	'
	The following table presents average investment in impaired loans by loan class:


			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(in thousands)
	Commercial real estate
	Owner occupied		$	46,108			$	61,223			$	52,030			$	55,881
	Non-owner occupied			54,211				60,207				54,553				57,433
	Multi-family			—				882				118				983
	Commercial and industrial
	Commercial			13,786				25,616				14,558				26,097
	Leases			565				1,030				817				839
	Construction and land development
	Construction			—				—				—				1,315
	Land			27,418				35,215				28,268				37,440
	Residential real estate			34,616				37,814				34,972				34,567
	Consumer			564				794				629				1,256

	Total		$	177,268			$	222,781			$	185,945			$	215,811

Interest Income on Impaired Loans by Loan Class	'
	The following table presents interest income on impaired loans by class:


			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(in thousands)
	Commercial real estate
	Owner occupied		$	426			$	841			$	1,182			$	1,696
	Non-owner occupied			458				649				1,283				1,661
	Multi-family			—				—				—				—
	Commercial and industrial
	Commercial			185				406				454				920
	Leases			—				—				—				—
	Construction and land development
	Construction			—				—				—				—
	Land			328				171				874				867
	Residential real estate			21				78				45				199
	Consumer			7				13				22				31

	Total		$	1,425			$	2,158			$	3,860			$	5,374

Tabular Disclosure of Nonperforming Assets	'
	The following table summarizes nonperforming assets:


			September 30,				December 31,
			2013				2012
			(in thousands)
	Nonaccrual loans		$	76,641			$	104,716
	Loans past due 90 days or more on accrual status			5,456				1,388
	Troubled debt restructured loans			87,387				84,609

	Total nonperforming loans			169,484				190,713
	Other assets acquired through foreclosure, net			76,475				77,247

	Total nonperforming assets		$	245,959			$	267,960

Schedule of Contractually Required Payments Receivable, Cash Flow Expected to be Collected and Estimated Fair Value of Loans Acquired	'
	The following table presents information regarding the contractually required payments receivable, cash flows expected to be collected and the estimated fair value of loans acquired in the Centennial acquisition, as of April 30, 2013, the closing date of the transaction:


			April 30, 2013
			Commercial				Residential				Total
			Real Estate				Real Estate				Total
			(in thousands)
	Contractually required payments :
	Loans with credit deterioration since origination		$	253,419			$	—			$	253,419
	Purchased non-credit impaired loans			368,040				2,136				370,176

	Total loans acquired		$	621,459			$	2,136			$	623,595

	Cash flows expected to be collected:
	Loans with credit deterioration since origination		$	145,346			$	—			$	145,346
	Purchased non-credit impaired loans			304,818				1,352				306,170

	Total loans acquired		$	450,164			$	1,352			$	451,516

	Fair value of loans acquired:
	Loans with credit deterioration since origination		$	108,863			$	—			$	108,863
	Purchased non-credit impaired loans			241,541				1,070				242,611

	Total loans acquired		$	350,404			$	1,070			$	351,474

Changes in Accretable Yield for Loans Acquired With Deteriorated Credit Quality	'
	Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows:


			September 30, 2013
			Three Months				Nine Months
			Ended				Ended
			(in thousands)
	Balance, at beginning of period		$	26,073			$	7,072
	Addition due to acquisition			—				22,318
	Reclassification from nonaccretable difference			4,804				5,851
	Accretion to interest income			(2,044	)			(6,408	)

	Balance, at end of period		$	28,833			$	28,833

Allowances for Credit Losses	'
	The following table summarizes the changes in the allowance for credit losses by portfolio type:


			For the Three Months Ended September 30,
			Construction and				Commercial				Residential				Commercial				Consumer				Total
			Land Development				Real Estate				Real Estate				and Industrial				Consumer				Total
			(in thousands)
	2013
	Beginning Balance		$	9,614			$	34,583			$	13,847			$	37,383			$	896			$	96,323
	Charge-offs			—				(864	)			(1,138	)			(544	)			(712	)			(3,258	)
	Recoveries			966				422				430				2,242				726				4,786
	Provision			(533	)			(278	)			(247	)			354				704				—

	Ending balance		$	10,047			$	33,863			$	12,892			$	39,435			$	1,614			$	97,851

	2012
	Beginning Balance		$	13,378			$	36,733			$	16,957			$	26,132			$	4,312			$	97,512
	Charge-offs			(2,315	)			(1,470	)			(2,242	)			(4,100	)			(799	)			(10,926	)
	Recoveries			567				633				153				501				38				1,892
	Provision			18				2,324				(82	)			5,611				1,061				8,932

	Ending balance		$	11,648			$	38,220			$	14,786			$	28,144			$	4,612			$	97,410


			For the Nine Months Ended September 30,
			Construction and				Commercial				Residential				Commercial				Consumer				Total
			Land Development				Real Estate				Real Estate				and Industrial				Consumer				Total
			(in thousands)
	2013
	Beginning Balance		$	10,554			$	34,982			$	15,237			$	32,860			$	1,794			$	95,427
	Charge-offs			(852	)			(6,142	)			(5,641	)			(3,379	)			(1,005	)			(17,019	)
	Recoveries			1,787				1,997				1,548				4,440				751				10,523
	Provision			(1,442	)			3,026				1,748				5,514				74				8,920

	Ending balance		$	10,047			$	33,863			$	12,892			$	39,435			$	1,614			$	97,851

	2012
	Beginning Balance		$	14,195			$	35,031			$	19,134			$	25,535			$	5,275			$	99,170
	Charge-offs			(10,587	)			(12,023	)			(5,756	)			(12,687	)			(3,571	)			(44,624	)
	Recoveries			870				2,897				765				2,695				294				7,521
	Provision			7,170				12,315				643				12,601				2,614				35,343

	Ending balance		$	11,648			$	38,220			$	14,786			$	28,144			$	4,612			$	97,410

Summary of Impairment Method Information Related to Loans and Allowance for Credit Losses	'
	The following table presents impairment method information related to loans and allowance for credit losses by loan portfolio segment:


			Commercial				Commercial				Commercial				Residential				Construction				Commercial				Consumer			Total
			Real Estate-				Real Estate-				and				Real				and Land				Leases							Loans
			Owner				Non-Owner				Industrial				Estate				Development
			Occupied				Occupied
			(in thousands)
	Loans Held for Investment as of September 30, 2013:
	Recorded Investment:
	Impaired loans with an allowance recorded		$	2,440			$	7,654			$	2,285			$	6,018			$	2,178			$	114			$	28		$	20,717
	Impaired loans with no allowance recorded			43,076				46,398				11,821				26,793				24,570				353				503			153,514

	Total loans individually evaluated for impairment			45,516				54,052				14,106				32,811				26,748				467				531			174,231
	Loans collectively evaluated for impairment			1,482,207				1,709,255				1,976,080				323,942				432,521				243,845				29,319			6,197,169
	Loans acquired with deteriorated credit quality			23,464				101,026				382				2,209				495				—				—			127,576

	Total loans held for investment		$	1,551,187			$	1,864,333			$	1,990,568			$	358,962			$	459,764			$	244,312			$	29,850		$	6,498,976

	Unpaid Principal Balance
	Impaired loans with an allowance recorded		$	2,933			$	8,169			$	2,498			$	6,082			$	2,178			$	114			$	28			22,002
	Impaired loans with no allowance recorded			49,720				48,656				12,325				33,706				25,223				505				515			170,650

	Total loans individually evaluated for impairment			52,653				56,825				14,823				39,788				27,401				619				543			192,652
	Loans collectively evaluated for impairment			1,482,207				1,709,255				1,976,080				323,942				432,521				243,845				29,319			6,197,169
	Loans acquired with deteriorated credit quality			33,112				145,235				1,513				3,750				827				—				—			184,437

	Total loans held for investment		$	1,567,972			$	1,911,315			$	1,992,416			$	367,480			$	460,749			$	244,464			$	29,862		$	6,574,258

	Related Allowance for Credit Losses
	Impaired loans with an allowance recorded		$	580			$	810			$	1,004			$	2,594			$	831			$	86			$	4			5,909
	Impaired loans with no allowance recorded			—				—				—				—				—				—				—			—

	Total loans individually evaluated for impairment			580				810				1,004				2,594				831				86				4			5,909
	Loans collectively evaluated for impairment			14,255				16,845				35,482				10,298				9,216				2,863				1,610			90,569
	Loans acquired with deteriorated credit quality			—				1,373				—				—				—				—				—			1,373

	Total loans held for investment		$	14,835			$	19,028			$	36,486			$	12,892			$	10,047			$	2,949			$	1,614		$	97,851


			Commercial				Commercial				Commercial				Residential				Construction				Commercial				Consumer			Total
			Real Estate-				Real Estate-				and				Real				and Land				Leases							Loans
			Owner				Non-Owner				Industrial				Estate				Development
			Occupied				Occupied
			(in thousands)
	Loans Held for Investment as of December 31, 2012:
	Recorded Investment:
	Impaired loans with an allowance recorded		$	13,615			$	15,217			$	4,700			$	16,482			$	844			$	515			$	165		$	51,538
	Impaired loans with no allowance recorded			44,459				37,247				10,831				21,369				31,648				464				599			146,617

	Total loans individually evaluated for impairment			58,074				52,464				15,531				37,851				32,492				979				764			198,155
	Loans collectively evaluated for impairment			1,332,185				1,440,214				1,642,313				368,034				361,074				287,768				31,072			5,462,660
	Loans acquired with deteriorated credit quality			6,538				12,922				1,159				2,052				753				—				—			23,424

	Total loans held for investment		$	1,396,797			$	1,505,600			$	1,659,003			$	407,937			$	394,319			$	288,747			$	31,836		$	5,684,239

	Unpaid Principal Balance
	Impaired loans with an allowance recorded		$	13,634			$	18,746			$	9,877			$	17,837			$	848			$	515			$	540		$	61,997
	Impaired loans with no allowance recorded			54,947				43,208				11,248				27,098				35,669				464				612			173,246

	Total loans individually evaluated for impairment			68,581				61,954				21,125				44,935				36,517				979				1,152			235,243
	Loans collectively evaluated for impairment			1,332,185				1,440,214				1,642,313				368,034				361,074				287,768				31,072			5,462,660
	Loans acquired with deteriorated credit quality			11,893				18,397				3,730				3,811				1,170				—				—			39,001

Total loans held for investment		$	1,412,659			$	1,520,565			$	1,667,168			$	416,780			$	398,761			$	288,747			$	32,224		$	5,736,904

Related Allowance for Credit Losses
Impaired loans with an allowance recorded		$	2,815			$	1,602			$	2,314			$	5,448			$	284			$	238			$	165		$	12,866
Impaired loans with no allowance recorded			—				—				—				—				—				—				—			—

Total loans individually evaluated for impairment			2,815				1,602				2,314				5,448				284				238				165			12,866
Loans collectively evaluated for impairment			15,118				15,447				27,546				9,789				10,270				2,762				1,629			82,561
Loans acquired with deteriorated credit quality			—				—				—				—				—				—				—			—

Total loans held for investment		$	17,933			$	17,049			$	29,860			$	15,237			$	10,554			$	3,000			$	1,794		$	95,427

Troubled Debt Restructured Loans by Loan Class	'
	The following table presents information on the financial effects of troubled debt restructured loans by class for the periods presented:


			Three Months Ended
			September 30, 2013
			Number				Pre-Modification				Forgiven				Lost				Post-Modification				Waived Fees
			of Loans				Outstanding				Principal				Interest				Outstanding				and Other
							Recorded Investment				Balance				Income (1)				Recorded Investment				Expenses
			(dollars in thousands)
	Commercial real estate
	Owner occupied			—			$	—			$	—			$	—			$	—			$	—
	Non-owner occupied			—				—				—				—				—				—
	Multi-family			—				—				—				—				—				—
	Commercial and industrial
	Commercial			3				1,253				—				10				1,243				—
	Leases			—				—				—				—				—				—
	Construction and land development
	Construction			—				—				—				—				—				—
	Land			—				—				—				—				—				—
	Residential real estate			3				2,304				267				613				1,424				9
	Consumer			—				—				—				—				—				—

	Total			6			$	3,557			$	267			$	623			$	2,667			$	9


	-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


			Nine Months Ended
			September 30, 2013
			Number				Pre-Modification				Forgiven				Lost				Post-Modification				Waived Fees
			of Loans				Outstanding				Principal				Interest				Outstanding				and Other
							Recorded Investment				Balance				Income (1)				Recorded Investment				Expenses
			(dollars in thousands)
	Commercial real estate
	Owner occupied			7			$	3,506			$	—			$	54			$	3,452			$	28
	Non-owner occupied			5				10,735				1,030				63				9,642				14
	Multi-family			—				—				—				—				—				—
	Commercial and industrial
	Commercial			11				3,611				—				19				3,592				11
	Leases			—				—				—				—				—				—
	Construction and land development
	Construction			—				—				—				—				—				—
	Land			2				286				—				—				286				1
	Residential real estate			12				5,308				267				887				4,154				24
	Consumer			2				74				—				5				69				3

	Total			39			$	23,520			$	1,297			$	1,028			$	21,195			$	81


	-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


			Three Months Ended
			30-Sep-12
			Number				Pre-Modification				Forgiven				Lost				Post-Modification				Waived Fees
			of Loans				Outstanding				Principal				Interest				Outstanding				and Other
							Recorded Investment				Balance				Income (1)				Recorded Investment				Expenses
			(dollars in thousands)
	Commercial real estate
	Owner occupied			2			$	3,111			$	—			$	28			$	3,083			$	11
	Non-owner occupied			10				19,773				10				194				19,569				5
	Multi-family			—				—				—				—				—				—
Commercial and industrial
Commercial			—				—				—				—				—				—
Leases			—				—				—				—				—				—
Construction and land development
Construction			—				—				—				—				—				—
Land			1				2,581				—				26				2,555				—
Residential real estate			4				4,113				—				163				3,950				1
Consumer			1				46				—				3				43				2

Total			18			$	29,624			$	10			$	414			$	29,200			$	19


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.


		Nine Months Ended
		30-Sep-12
		Number				Pre-Modification				Forgiven				Lost				Post-Modification				Waived Fees
		of Loans				Outstanding				Principal				Interest				Outstanding				and Other
						Recorded Investment				Balance				Income (1)				Recorded Investment				Expenses
		(dollars in thousands)
Commercial real estate
Owner occupied			14			$	21,740			$	750			$	493			$	20,497			$	71
Non-owner occupied			15				33,629				440				321				32,868				16
Multi-family			—				—				—				—				—				—
Commercial and industrial
Commercial			14				7,707				—				26				7,681				37
Leases			—				—				—				—				—				—
Construction and land development
Construction			—				—				—				—				—				—
Land			6				6,460				—				259				6,201				12
Residential real estate			19				10,306				40				1,148				9,118				8
Consumer			3				114				—				3				111				2

Total			71			$	79,956			$	1,230			$	2,250			$	76,476			$	146


-1	Lost interest income is processed as a charge-off to loan principal in the Company’s Consolidated Financial Statements.
Troubled Debt Restructured Loans by Class for Which There was a Payment Default	'
	The following table presents TDR loans by class for which there was a payment default during the period:


			Three Months Ended																Nine Months Ended
			September 30,																September 30,
			2013								2012								2013								2012
			Number				Recorded				Number				Recorded				Number				Recorded				Number			Recorded
			of Loans				Investment				of Loans				Investment				of Loans				Investment				of Loans			Investment
			(dollars in thousands)
	Commercial real estate
	Owner occupied			—			$	—				5			$	4,263				3			$	2,506				10		$	10,611
	Non-owner occupied			2				1,330				1				1,049				3				1,490				3			4,442
	Multi-family			—				—				—				—				—				—				1			193
	Commercial and industrial
	Commercial			1				307				3				1,794				3				1,089				7			6,700
	Leases			—				—				—				—				—				—				—			—
	Construction and land development
	Construction			—				—				—				—				—				—				—			—
	Land			—				—				1				347				2				330				5			4,013
	Residential real estate			—				—				3				3,823				2				655				5			4,143
	Consumer			—				—				—				—				—				—				1			375

	Total			3			$	1,637				13			$	11,276				13			$	6,070				32		$	30,477

Other_Assets_Acquired_through_1

Other Assets Acquired through Foreclosure (Tables)	9 Months Ended
Other Assets Acquired through Foreclosure (Tables)	Sep. 30, 2013
Text Block [Abstract]	'
Changes in Other Assets Acquired through Foreclosure	'
	The following table presents the changes in other assets acquired through foreclosure:


			For the Three Months Ended September 30,
			2013									2012
			Gross Balance			Valuation			Net Balance			Gross Balance			Valuation			Net Balance
			Gross Balance			Allowance			Net Balance			Gross Balance			Allowance			Net Balance
			(in thousands)
	Balance, beginning of the period		$	102,923		$	(26,424	)	$	76,499		$	120,391		$	(43,397	)	$	76,994
	Transfers to other assets acquired through foreclosure, net			2,737			—			2,737			10,807			—			10,807
	Proceeds from sale of other real estate owned and repossessed assets, net			(3,411	)		1,055			(2,356	)		(13,733	)		4,335			(9,398	)
	Valuation adjustments, net			—			(697	)		(697	)		—			(781	)		(781	)
	Gains (losses), net ⁽¹⁾			292			—			292			611			—			611

	Balance, end of period		$	102,541		$	(26,066	)	$	76,475		$	118,076		$	(39,843	)	$	78,233


	-1	Included in gains (losses), net are gains related to transfers to other assets of $62 thousand during the quarter ended September 30, 2013 and $249 thousand during the quarter ended September 30, 2012 pursuant to accounting guidance.


			For the Nine Months Ended September 30,
			2013									2012
			Gross Balance			Valuation			Net Balance			Gross Balance			Valuation			Net Balance
			Gross Balance			Allowance			Net Balance			Gross Balance			Allowance			Net Balance
			(in thousands)
	Balance, beginning of the period		$	113,474		$	(36,227	)	$	77,247		$	135,148		$	(46,044	)	$	89,104
	Transfers to other assets acquired through foreclosure, net			14,010			—			14,010			19,522			—			19,522
	Additions from acquisition of Centennial			5,622			—			5,622			—			—			—
	Proceeds from sale of other real estate owned and repossessed assets, net			(32,953	)		12,440			(20,513	)		(36,911	)		10,261			(26,650	)
	Valuation adjustments, net			—			(2,279	)		(2,279	)		—			(4,060	)		(4,060	)
	Gains (losses), net ⁽¹⁾			2,388			—			2,388			317			—			317

	Balance, end of period		$	102,541		$	(26,066	)	$	76,475		$	118,076		$	(39,843	)	$	78,233


	-1	Included in gains (losses), net are gains related to transfers to other assets of $407 thousand during the nine month period ended September 30, 2013 and $291 thousand during the nine month period ended September 30, 2012 pursuant to accounting guidance.

Other_Borrowings_and_Other_Lia1

Other Borrowings and Other Liabilities (Tables)	9 Months Ended
Other Borrowings and Other Liabilities (Tables)	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Summary of Borrowings	'
	The following table summarizes the Company’s borrowings as of September 30, 2013 and December 31, 2012:


		September 30,		December 31,
		2013		2012
		(in thousands)
	Short Term:
	Federal funds purchased	$	13,285	$	—
	Revolving line of credit		32,500		—
	FHLB advances		—		120,000

	Total short term debt	$	45,785	$	120,000

	Long Term:
	FHLB advances	$	274,277	$	—
	Other long term debt		74,043		73,717

		$	348,320	$	73,717

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit	'
	A summary of the contractual amounts for unfunded commitments and letters of credit are as follows:


		September 30		December 31,
		2013		2012
		(in thousands)
	Commitments to extend credit, including unsecured loan commitments of $266,189 at September 30, 2013 and $172,002 at December 31, 2012	$	1,692,150	$	1,096,264
	Credit card commitments and financial guarantees		287,186		295,506
	Standby letters of credit, including unsecured letters of credit of $4,032 at September 30, 2013 and $3,915 at December 31, 2012		28,105		32,757

	Total	$	2,007,441	$	1,424,527

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
Accumulated Other Comprehensive Income (Tables)	Sep. 30, 2013
Equity [Abstract]	'
Summary of Changes in Accumulated Other Comprehensive Income	'
	The following table summarizes the changes in accumulated other comprehensive income by component, net of tax for the period indicated:


		Three Months Ended September 30,
		2013									2012
		Unrealized			Unrealized gain			Total			Unrealized			Unrealized gain			Total
		holding gains			on cash flow						holding gains			on cash flow
		(losses) on AFS			hedge						(losses) on AFS			hedge
		(in thousands)
	Beginning balance	$	(10,780	)	$	30		$	(10,750	)	$	4,283		$	8		$	4,291
	Other comprehensive income before reclassifications		(4,770	)		(30	)		(4,800	)		8,478			9			8,487
	Amounts reclassified from accumulated other comprehensive income		1,046			—			1,046			(668	)		—			(668	)

	Net current-period other comprehensive income		(3,724	)		(30	)		(3,754	)		7,810			9			7,819

	Ending balance	$	(14,504	)	$	—		$	(14,504	)	$	12,093		$	17		$	12,110



		Nine Months Ended September 30,
		2013									2012
		Unrealized			Unrealized gain						Unrealized			Unrealized gain
		holding gains			on cash flow						holding gains			on cash flow
		(losses) on AFS			hedge			Total			(losses) on AFS			hedge			Total
		(in thousands)
	Beginning balance	$	8,209		$	17		$	8,226		$	(5,112	)	$	519		$	(4,593	)
	Other comprehensive income before reclassifications		(23,670	)		(17	)		(23,687	)		18,803			17			18,820
	Amounts reclassified from accumulated other comprehensive income		957			—			957			(1,598	)		(519	)		(2,117	)

	Net current-period other comprehensive income		(22,713	)		(17	)		(22,730	)		17,205			(502	)		16,703

	Ending balance	$	(14,504	)	$	—		$	(14,504	)	$	12,093		$	17		$	12,110
Schedule of Reclassifications Out of Accumulated Other Comprehensive Income	'
	The following table presents reclassifications out of accumulated other comprehensive income:


		Amount reclassified from accumulated
		other comprehensive income
	Details about accumulated other	Three Months Ended						Affected line item in the statement
	Details about accumulated other	September 30,						Affected line item in the statement
	comprehensive income components	2013			2012			where net income is presented
		(in thousands)
	Unrealized gains and losses on AFS
		$	(1,679	)	$	1,031		Realized gain on sale of Investment securities
			633			(363	)	Income tax expense

		$	(1,046	)	$	668		Net of tax


		Amount reclassified from accumulated
		other comprehensive income
	Details about accumulated other	Nine Months Ended						Affected line item in the statement
	Details about accumulated other	September 30,						Affected line item in the statement
	comprehensive income components	2013			2012			where net income is presented
		(in thousands)
	Unrealized gains and losses on AFS
		$	(1,537	)	$	2,502		Realized gain on sale of Investment securities
			580			(904	)	Income tax expense

		$	(957	)	$	1,598		Net of tax

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
Earnings Per Share (Tables)	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Basic and Diluted Earnings Per Share, Based on Weighted Average Outstanding Shares	'
	Basic and diluted earnings per share, based on the weighted average outstanding shares, are summarized as follows:


		Three Months Ended				Nine Months Ended
		September 30,				September 30,
		2013		2012		2013		2012
		(in thousands,except per share amounts)
	Weighted average shares—basic		85,799		81,758		85,596		81,570
	Dilutive effect of stock awards		970		536		832		589

	Weighted average shares—diluted		86,769		82,294		86,428		82,159

	Net income available to common shareholders	$	27,840	$	15,106	$	82,114	$	37,279
	Earnings per share—basic		0.32		0.18		0.96		0.46
	Earnings per share—diluted		0.32		0.18		0.95		0.45

Fair_Value_Accounting_Tables

Fair Value Accounting (Tables)	9 Months Ended
Fair Value Accounting (Tables)	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations	'
	For the three and nine months ended September 30, 2013 and 2012, gains and losses from fair value changes included in the Consolidated Income Statements were as follows:


			Changes in Fair Values for Items Measured at Fair
			Value Pursuant to Election of the FVO
			Unrealized												Total
			Gain/(Loss) on								Interest				Changes
			Assets and								Expense on				Included in
			Liabilities				Interest				Junior				Current-
			Measured at				Income on				Subordinated				Period
	Description		Fair Value, Net				Securities				Debt				Earnings
			(in thousands)
	Three Months Ended September 30, 2013
	Securities measured at fair value		$	(142	)		$	1			$	—			$	(141	)
	Junior subordinated debt			478				—				329				149

			$	336			$	1			$	329			$	8

	Nine Months Ended September 30, 2013
	Securities measured at fair value		$	(196	)		$	7			$	—			$	(189	)
	Junior subordinated debt			(3,229	)			—				1,012				(4,241	)

			$	(3,425	)		$	7			$	1,012			$	(4,430	)


			Changes in Fair Values for Items Measured at Fair
			Value Pursuant to Election of the FVO
			Unrealized												Total
			Gain/(Loss) on								Interest				Changes
			Assets and								Expense on				Included in
			Liabilities				Interest				Junior				Current-
			Measured at				Income on				Subordinated				Period
	Description		Fair Value, Net				Securities				Debt				Earnings
			(in thousands)
	Three Months Ended September 30, 2012
	Securities measured at fair value		$	—			$	3			$	—			$	3
	Junior subordinated debt			469				—				329				140

			$	469			$	3			$	329			$	143

	Nine Months Ended September 30, 2012
	Securities measured at fair value		$	(66	)		$	10			$	—			$	(56	)
	Junior subordinated debt			767				—				981				(214	)

			$	701			$	10			$	981			$	(270	)

Gains and Losses from Fair Value Changes on Securities Measured at Fair Value	'
	The following table presents gains and losses from fair value changes on securities measured at fair value:


			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(in thousands)
	Net losses for the period on trading securities included in earnings		$	(142	)		$	—			$	(196	)		$	(66	)
	Less: net gains and (losses) recognized during the period on trading securities sold during the period			—				—				—				—

	Change in unrealized gains or (losses) for the period included in earnings for trading securities held at the end of the reporting period		$	(142	)		$	—			$	(196	)		$	(66	)

Fair Value of Assets and Liabilities	'
	The fair value of these assets and liabilities were determined using the following inputs at the periods presented:


			Fair Value Measurements at the End of the Reporting Period Using:
			Quoted Prices
			in Active				Significant
			Markets for				Other				Significant
			Identical				Observable				Unobservable
			Assets				Inputs				Inputs				Fair
	September 30, 2013		(Level 1)				(Level 2)				(Level 3)				Value
			(in thousands)
	Assets:
	Measured at fair value
	Direct U.S. obligations and GSE residential mortgage- backed securities		$	—			$	3,621			$	—			$	3,621

	Available-for-sale
	U.S. Government-sponsored agency securities		$	—			$	27,377			$	—			$	27,377
	Municipal obligations			—				105,545				—				105,545
	Direct U.S. obligations and GSE residential mortgage-backed securities			—				768,478				—				768,478
	Mutual funds			32,323				—				—				32,323
	Private label residential mortgage-backed securities			—				26,147				—				26,147
	Adjustable-rate preferred stock			61,389				—				—				61,389
	Trust preferred			—				23,834				—				23,834
	Collateralized mortgage-backed securities			—				5,493				—				5,493
	Other			23,300				—				—				23,300

			$	117,012			$	956,874			$	—			$	1,073,886

	Interest rate swaps		$	—			$	39			$	—			$	39

	Liabilities:
	Securities sold short		$	126,664			$	—			$	—			$	126,664

	Junior subordinated debt		$	—			$	—			$	39,447			$	39,447

	Interest rate swaps		$	—			$	2,188			$	—			$	2,188



			Fair Value Measurements at the End of the Reporting Period Using:
	December 31, 2012		Quoted Prices				Significant				Significant				Fair
			in Active				Other				Unobservable				Value
			Markets for				Observable				Inputs
			Identical				Inputs				(Level 3)
			Assets				(Level 2)
			(Level 1)
			(in thousands)
	Assets:
	Measured at fair value
	Direct U.S. obligations and GSE residential mortgage- backed securities		$	—			$	5,061			$	—			$	5,061

	Available-for-sale
	Municipal obligations		$	—			$	73,171			$	—			$	73,171
	Direct U.S. obligations and GSE residential mortgage-backed securities			—				663,204				—				663,204
	Mutual funds			37,961				—				—				37,961
	Private label residential mortgage-backed securities			—				35,607				—				35,607
	Private label commercial mortgage-backed securities			—				5,741								5,741
	Adjustable-rate preferred stock			75,555				—				—				75,555
	Trust preferred			24,135				—				—				24,135
	Other			24,216				—				—				24,216

			$	161,867			$	777,723			$	—			$	939,590

Interest rate swaps		$	—			$	777			$	—			$	777

Liabilities:
Junior subordinated debt		$	—			$	—			$	36,218			$	36,218

Interest rate swaps		$	—			$	751			$	—			$	751

Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis	'
	For the three and nine months ended September 30, 2013, the change in Level 3 liabilities measured at fair value on a recurring basis was as follows:


	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
			Junior Subordinated Debt
			Three Months Ended
			September 30,
			2013				2012
			(in thousands)
	Opening balance		$	(39,925	)		$	(36,687	)
	Transfers into Level 3			—				—
	Transfers out of Level 3			—				—
	Total gains or losses for the period
	Included in earnings (or changes in net assets) (1)			478				469
	Included in other comprehensive income			—				—
	Purchases, sales, and settlements
	Purchases			—				—
	Sales			—				—
	Settlements			—				—

	Closing balance		$	(39,447	)		$	(36,218	)

	Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.		$	478			$	469


	-1	Total gains (losses) for the period are included in the non-interest income line, mark to market (losses) gains, net.


			Junior Subordinated Debt
			Nine Months Ended
			September 30,
			2013				2012
			(in thousands)
	Opening balance		$	(36,218	)		$	(36,985	)
	Transfers into Level 3			—				—
	Transfers out of Level 3			—				—
	Total gains or losses for the period
	Included in earnings (or changes in net assets) (1)			(3,229	)			767
	Included in other comprehensive income			—				—
	Purchases, sales, and settlements
	Purchases			—				—
	Sales			—				—
	Settlements			—				—

	Closing balance		$	(39,447	)		$	(36,218	)

	Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.		$	(3,229	)		$	767


	-1	Total gains (losses) for the period are included in the non-interest income line, mark to market (losses) gains, net.
	For Level 3 liabilities measured at fair value on a recurring basis, the significant unobservable inputs used in the fair value measurements as of the periods presented, were as follows:


			Fair Value at
			September 30,				Valuation		Significant		Input Value
			2013				Technique		Unobservable Inputs		Input Value
			(dollars in thousands)
	Junior subordinated debt		$	39,447			Discounted cash flow		BB Corporate Bond over Treasury Index			6.28	%
	Junior subordinated debt		$	39,447			Discounted cash flow		with comparable credit spread			6.28	%

			Fair Value at
			December 31,				Valuation		Significant		Input Value
			2012				Technique		Unobservable Inputs		Input Value
		(dollars in thousands)
Junior subordinated debt		$	36,218			Discounted cash flow		Median market spreads on publicly issued trust preferreds with comparable credit risk			6.846	%
Assets Measured at Fair Value on Nonrecurring Basis	'
	The following table presents such assets carried on the Consolidated Balance Sheet by caption and by level within the ASC 825 hierarchy:


			Fair Value Measurements at the End of the Reporting Period Using
			Total				Quoted Prices				Active				Unobservable
							in Active				Markets for				Inputs
							Markets for				Similar Assets				(Level 3)
							Identical Assets				(Level 2)
							(Level 1)
			(in thousands)
	As of September 30, 2013:
	Impaired loans with specific valuation allowance		$	14,808			$	—			$	—			$	14,808
	Impaired loans without specific valuation allowance			95,843				—				—				95,843
	Other assets acquired through foreclosure, net			76,475				—				—				76,475
	As of December 31, 2012:
	Impaired loans with specific valuation allowance		$	38,672			$	—			$	—			$	38,672
	Impaired loans without specific valuation allowance			67,207				—				—				67,207
	Other assets acquired through foreclosure, net			77,247				—				—				77,247
Debt Security Credit Losses Recognized in Other Comprehensive Income/Earnings	'
	For the three and nine months ended September 30, 2013 and 2012, the Company determined that no securities contained credit losses.


			Private Label
			Mortgage-Backed
			Securities
			Nine Months Ended
			September 30,
			2013				2012
			(in thousands)
	Beginning balance of impairment losses held in other comprehensive income		$	(1,811	)		$	(1,811	)
	Current period other-than temporary impairment credit losses recognized through earnings			—				—
	Reductions for securities sold during the period			1,811				—
	Additions or reductions in credit losses due to change of intent to sell			—				—
	Reductions for increases in cash flows to be collected on impaired securities			—				—

	Ending balance of net unrealized gains and (losses) held in other comprehensive income		$	—			$	(1,811	)

Estimated Fair Value of Financial Instruments	'
	The estimated fair value of the Company’s financial instruments is as follows:


			September 30, 2013
			Carrying				Fair Value
			Amount				Level 1				Level 2				Level 3			Total
			(in thousands)
	Financial assets:
	Investment securities		$	1,366,615			$	176,570			$	1,188,472			$	8		$	1,365,050
	Derivatives (1)			39				—				39				—			39
	Loans, net			6,418,432				—				5,876,917				110,651			5,987,568
	Financial liabilities:
	Deposits			7,275,311				—				7,349,886				—			7,349,886
	Customer repurchases			55,524				—				55,524				—			55,524
	Securities sold short			126,664				126,664				—				—			126,664
	Other borrowings			394,105				45,785				274,277				82,500			402,562
	Junior subordinated debt			39,447				—				—				39,447			39,447
	Derivatives (2)			2,188				—				2,188				—			2,188

	-1	Included in other assets.
	-2	Included in other liabilities.


			31-Dec-12
			Carrying				Fair Value
			Amount				Level 1				Level 2				Level 3			Total
			(in thousands)
	Financial assets:
	Investment securities		$	1,235,984			$	216,337			$	1,021,133			$	—		$	1,237,470
	Derivatives (1)			777				—				777				—			777
	Loans, net			5,613,891				—				5,156,776				105,879			5,262,655
	Financial liabilities:
	Deposits			6,455,177				—				6,458,100				—			6,458,100
	Customer repurchases			79,034				—				79,034				—			79,034
	Other borrowings			193,717				—				120,000				85,125			205,125
	Junior subordinated debt			36,218				—				—				36,218			36,218
	Derivatives (2)			751				—				751				—			751

	-1	Included in other assets.
	-2	Included in other liabilities.

Segments_Tables

Segments (Tables)	9 Months Ended
Segments (Tables)	Sep. 30, 2013
Segment Reporting [Abstract]	'
Operating Segment Information	'
	The following is a summary of selected operating segment information as of and for the three and nine month periods ended September 30, 2013 and 2012:

	Western Alliance Bancorporation and Subsidiaries
	Operating Segment Results
	Unaudited


																			Inter-
																			segment				Consoli-
			Western				Bank				Torrey								elimi-				dated
			Alliance Bank				of Nevada				Pines Bank*				Other				nations				Company
			(dollars in millions)
	At September 30, 2013
	Assets		$	3,346.70			$	3,288.10			$	2,076.20			$	1,127.80			$	(917.4	)		$	8,921.40
	Held for sale loans			—				—				25.4				—				—				25.4
	Gross loans and deferred fees, net			2,589.20				2,387.10				1,498.70				58.9				(43.0	)			6,490.90
	Less: Allowance for credit losses			(28.0	)			(51.0	)			(18.3	)			(0.6	)			—				(97.9	)

	Loans, net			2,561.20				2,336.10				1,480.40				58.3				(43.0	)			6,393.00

	Goodwill and intangible assets			2.8				25.1				—				—				—				27.9
	Deposits			2,832.00				2,613.50				1,844.70				—				(14.9	)			7,275.30
	Borrowings			81.4				203				3.2				106.5				—				394.1
	Stockholders’ equity			291.5				373.7				171.8				844.7				(855.4	)			826.3
	No. of branches			18				12				12				—				—				42

			(in thousands)
	Three Months Ended September 30, 2013:
	Net interest income (expense)		$	33,755			$	31,888			$	21,055			$	(2,139	)		$	—			$	84,559
	Provision for (recovery of) credit losses			6,277				(6,918	)			2,387				(1,746	)			—				—

	Net interest income (expense) after provision for credit losses			27,478				38,806				18,668				(393	)			—				84,559
	Non-interest income			1,816				2,314				108				2,914				(4,527	)			2,625
	Non-interest expense			(15,520	)			(18,799	)			(11,949	)			(7,934	)			4,527				(49,675	)

	Income (loss) from continuing operations before income taxes			13,774				22,321				6,827				(5,413	)			—				37,509
	Income tax expense (benefit)			3,977				6,027				2,230				(2,946	)			—				9,288

	Income (loss) from continuing operations			9,797				16,294				4,597				(2,467	)			—				28,221
	Loss from discontinued operations, net			—				—				—				(29	)			—				(29	)

	Net income (loss)		$	9,797			$	16,294			$	4,597			$	(2,496	)		$	—			$	28,192


			(in thousands)
	Nine Months Ended September 30, 2013:
	Net interest income (expense)		$	92,920			$	91,821			$	62,435			$	(4,262	)		$	—			$	242,914
	Provision for (recovery of) credit losses			9,921				(5,514	)			3,219				1,294				—				8,920

	Net interest income (expense) after provision for credit losses			82,999				97,335				59,216				(5,556	)			—				233,994
	Non-interest income			14,520				9,383				1,312				4,325				(12,154	)			17,386
	Non-interest expense			(45,688	)			(52,724	)			(35,876	)			(23,001	)			12,154				(145,135	)

	Income (loss) from continuing operations before income taxes			51,831				53,994				24,652				(24,232	)			—				106,245
	Income tax expense (benefit)			13,066				14,292				7,898				(12,343	)			—				22,913

	Income (loss) from continuing operations			38,765				39,702				16,754				(11,889	)			—				83,332
	Loss from discontinued operations, net			—				—				—				(160	)			—				(160	)

	Net income (loss)		$	38,765			$	39,702			$	16,754			$	(12,049	)		$	—			$	83,172


	*	Excludes discontinued operations.

Western Alliance Bancorporation and Subsidiaries
Operating Segment Results
Unaudited


																		Inter-
																		segment				Consoli-
		Western				Bank				Torrey								elimi-				dated
		Alliance Bank				of Nevada				Pines Bank*				Other				nations				Company
		(dollars in millions)
At September 30, 2012
Assets		$	2,429.80			$	2,918.00			$	1,888.70			$	961.3			$	(794.2	)		$	7,403.60
Gross loans and deferred fees, net			1,871.40				2,061.00				1,430.60				12.8				(42.9	)			5,332.90
Less: Allowance for credit losses			(20.4	)			(59.5	)			(17.5	)			—				—				(97.4	)

Loans, net			1,851.00				2,001.50				1,413.10				12.8				(42.9	)			5,235.50

Goodwill and intangible assets			—				23.2				—				—				—				23.2
Deposits			2,150.50				2,408.50				1,613.80				—				(10.8	)			6,162.00
Borrowings			—				110				40				—								150
Stockholders’ equity			217.3				339.1				168.4				702.3				(729.1	)			698
No. of branches			16				11				12				—				—				39

		(in thousands)
Three Months Ended September 30, 2012:
Net interest income (expense)		$	24,449			$	27,717			$	21,795			$	(2,015	)		$	—			$	71,946
Provision for credit losses			1,112				6,618				1,202				—				—				8,932

Net interest income (expense) after provision for credit losses			23,337				21,099				20,593				(2,015	)			—				63,014
Non-interest income			1,173				3,259				855				4,647				(2,952	)			6,982
Non-interest expense			(11,980	)			(16,467	)			(11,082	)			(10,966	)			2,952				(47,543	)

Income (loss) from continuing operations before income taxes			12,530				7,891				10,366				(8,334	)			—				22,453
Income tax expense (benefit)			3,768				2,055				3,958				(3,029	)			—				6,752

Income (loss) from continuing operations			8,762				5,836				6,408				(5,305	)			—				15,701
Loss from discontinued operations, net			—				—				—				(243	)			—				(243	)

Net income (loss)		$	8,762			$	5,836			$	6,408			$	(5,548	)		$	—			$	15,458


		(in thousands)
Nine Months Ended September 30, 2012:
Net interest income (expense)		$	71,564			$	83,054			$	64,406			$	(6,216	)		$	—			$	212,808
Provision for credit losses			1,215				28,846				5,282				—				—				35,343

Net interest income (expense) after provision for credit losses			70,349				54,208				59,124				(6,216	)			—				177,465
Non-interest income			5,021				11,132				3,111				8,539				(7,540	)			20,263
Noninterest expense			(35,986	)			(53,437	)			(33,492	)			(24,496	)			7,540				(139,871	)

Income (loss) from continuing operations before income taxes			39,384				11,903				28,743				(22,173	)			—				57,857
Income tax expense (benefit)			13,031				1,341				11,255				(9,175	)			—				16,452

Income (loss) from continuing operations			26,353				10,562				17,488				(12,998	)			—				41,405
Loss from discontinued operations, net			—				—				—				(686	)			—				(686	)

Net income (loss)		$	26,353			$	10,562			$	17,488			$	(13,684	)		$	—			$	40,719


*	Excludes discontinued operations.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 17, 2012	Sep. 30, 2013
	Oct. 31, 2012	Subsidiary	Subsidiary
Significant Of Accounting Policies [Line Items]	'	'	'
Number of unconsolidated subsidiaries	'	'	6
Percentage of interest held by Company in Shine Investment Advisory Services Inc.	80.00%	'	'
Business acquisition date	'	'	30-Apr-13
Number of wholly-owned subsidiaries	'	2	11
Minimum period of internal loss allowance calculation model	'	'	'1 year
Maximum period of internal loss allowance calculation model	'	'	'5 years
Western Alliance Bank [Member]	'	'	'
Significant Of Accounting Policies [Line Items]	'	'	'
Number of wholly-owned subsidiaries	'	'	1
Torrey Pines Bank [Member]	'	'	'
Significant Of Accounting Policies [Line Items]	'	'	'
Number of wholly-owned subsidiaries	'	'	1
Bank of Nevada [Member]	'	'	'
Significant Of Accounting Policies [Line Items]	'	'	'
Number of wholly-owned subsidiaries	'	'	3
Minimum [Member]	'	'	'
Significant Of Accounting Policies [Line Items]	'	'	'
Period of collateral valuation analysis	'	'	'6 months
Maximum [Member]	'	'	'
Significant Of Accounting Policies [Line Items]	'	'	'
Period of collateral valuation analysis	'	'	'12 months

Acquisitions_and_Dispositions_1

Acquisitions and Dispositions - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	9 Months Ended
	Apr. 30, 2013	Oct. 17, 2012	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
	Apr. 30, 2013	Subsidiary	Sep. 30, 2013	Subsidiary	Dec. 31, 2012
Business Acquisition [Line Items]	'	'	'	'	'
Payment for equity interests	$57,500,000	'	'	'	'
Acquisition related expenses	'	'	181,000	2,660,000	'
Bargain purchase gain	10,044,000	'	0	10,044,000	'
Loans receivable not acquired by the company	'	'	6,393,019,000	6,393,019,000	5,582,767,000
Number of wholly owned subsidiaries	'	2	'	11	'
Outstanding credit card loans	'	'	25,413,000	25,413,000	31,124,000
Centennial [Member]	'	'	'	'	'
Business Acquisition [Line Items]	'	'	'	'	'
Combined assets	3,160,000,000	'	'	'	'
Combined deposits	2,760,000,000	'	'	'	'
Acquisition related costs	'	'	0	1,000,000	'
Loans receivable not acquired by the company	$12,700,000	'	'	'	'

Acquisitions_and_Dispositions_2

Acquisitions and Dispositions - Schedule of Recognized Amounts of Identifiable Assets and Liabilities Assumed (Detail) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
Assets:	'	'	'
Cash and cash equivalents	$70,349,000	'	'
Federal funds sold	8,355,000	'	'
Investment securities-available-for-sale	26,014,000	'	'
Loans	351,474,000	'	'
Deferred tax assets	21,666,000	'	'
Premises and equipment	44,000	'	'
Other assets acquired through foreclosure, net	5,622,000	'	'
Other assets	6,007,000	'	'
Total assets acquired	489,531,000	'	'
Liabilities:	'	'	'
Deposits	338,811,000	'	'
FHLB advances	79,943,000	'	'
Other liabilities	3,233,000	'	'
Total liabilities assumed	421,987,000	'	'
Net assets acquired	67,544,000	'	'
Consideration paid	57,500,000	'	'
Bargain purchase gain from acquisition	$10,044,000	$0	$10,044,000

Acquisitions_and_Dispositions_3

Acquisitions and Dispositions - Schedule of Recognized Amounts of Identifiable Assets and Liabilities Assumed (Parenthetical) (Detail) (USD $)	1 Months Ended	9 Months Ended
	Apr. 30, 2013	Sep. 30, 2013
Business Acquisition [Line Items]	'	'
Net cash consideration paid	$57,500,000	'
Total assets acquired	'	21,204,000
Cash and Cash Equivalents [Member]	'	'
Business Acquisition [Line Items]	'	'
Total assets acquired	$21,200,000	'

Acquisitions_and_Dispositions_4

Acquisitions and Dispositions - Summary of Business Acquisition Pro-forma Information as Results of Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Business Combinations [Abstract]	'	'	'	'
Net Interest income	$81,093	$85,151	$238,430	$254,535
Non Interest income	2,625	8,138	7,468	22,147
Net income	$25,820	$13,549	$69,435	$36,012
Earnings per share-basic	$0.30	$0.17	$0.81	$0.44
Earnings per share-diluted	$0.30	$0.16	$0.80	$0.44

Acquisitions_and_Dispositions_5

Acquisitions and Dispositions - Summary of Business Acquisition Pro-forma Information as Results of Operations (Parenthetical) (Detail) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Apr. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'	'	'
Accretion (or amortization) of fair market value adjustments	'	$3,466	$10,285
Bargain purchase gain	10,044	0	10,044
Merger/restructure related costs	'	181	2,660
Centennial [Member]	'	'	'
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]	'	'	'
Merger/restructure related costs	'	$0	$1,000

Acquisitions_and_Dispositions_6

Acquisitions and Dispositions - Summary of Operating Results of Discontinued Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations And Disposal Groups [Abstract]	'	'	'	'
Operating revenue	$1,105	$315	$3,376	$947
Non-interest expenses	-1,155	-734	-3,653	-2,130
Loss before income taxes	-50	-419	-277	-1,183
Income tax benefit	-21	-176	-117	-497
Net loss	($29)	($243)	($160)	($686)

Investment_Securities_Carrying

Investment Securities - Carrying Amounts and Fair Values of Securities Held-to-Maturity (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	$289,108	$291,333
Held-to-maturity, Gross Unrealized Gains	4,756	8,272
Held-to-maturity, Gross Unrealized (Losses)	-6,321	-6,786
Held-to-maturity, Fair Value	287,543	292,819
Collateralized Debt Obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	50	50
Held-to-maturity, Gross Unrealized Gains	578	1,401
Held-to-maturity, Gross Unrealized (Losses)	'	'
Held-to-maturity, Fair Value	628	1,451
Corporate Bonds [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	97,778	97,781
Held-to-maturity, Gross Unrealized Gains	647	984
Held-to-maturity, Gross Unrealized (Losses)	-4,586	-6,684
Held-to-maturity, Fair Value	93,839	92,081
Municipal Obligations [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	189,680	191,902
Held-to-maturity, Gross Unrealized Gains	3,531	5,887
Held-to-maturity, Gross Unrealized (Losses)	-1,735	-102
Held-to-maturity, Fair Value	191,476	197,687
Other [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	1,600	'
Held-to-maturity, Gross Unrealized Gains	'	'
Held-to-maturity, Gross Unrealized (Losses)	'	'
Held-to-maturity, Fair Value	1,600	'
CRA Investments [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Held-to-maturity, Amortized Cost	'	1,600
Held-to-maturity, Gross Unrealized Gains	'	'
Held-to-maturity, Gross Unrealized (Losses)	'	'
Held-to-maturity, Fair Value	'	$1,600

Investment_Securities_Carrying1

Investment Securities - Carrying Amounts and Fair Values of Securities Available-for-Sale (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	$1,095,942	$926,050	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	-1,811	-1,811	-1,811
Available-for-sale, Gross Unrealized Gains	7,255	24,680	'	'
Available-for-sale, Gross Unrealized (Losses)	-29,311	-9,329	'	'
Available for sale Total, Estimated Fair Value	1,073,886	939,590	'	'
Securities measured at fair value	3,621	5,061	'	'
Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	769,983	648,641	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	5,748	14,573	'	'
Available-for-sale, Gross Unrealized (Losses)	-7,253	-10	'	'
Available for sale Total, Estimated Fair Value	768,478	663,204	'	'
Securities measured at fair value	3,621	5,061	'	'
U.S. Government-sponsored Agency Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	28,694	'	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	'	'	'	'
Available-for-sale, Gross Unrealized (Losses)	-1,317	'	'	'
Available for sale Total, Estimated Fair Value	27,377	'	'	'
Municipal Obligations [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	110,081	71,777	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	302	1,578	'	'
Available-for-sale, Gross Unrealized (Losses)	-4,838	-184	'	'
Available for sale Total, Estimated Fair Value	105,545	73,171	'	'
Adjustable-Rate Preferred Stock [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	66,093	72,717	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	864	3,591	'	'
Available-for-sale, Gross Unrealized (Losses)	-5,568	-753	'	'
Available for sale Total, Estimated Fair Value	61,389	75,555	'	'
Mutual Funds [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	32,422	'	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	123	'	'	'
Available-for-sale, Gross Unrealized (Losses)	-222	'	'	'
Available for sale Total, Estimated Fair Value	32,323	'	'	'
Private Label Residential Mortgage-backed Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	27,683	35,868	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	-1,811	'	'
Available-for-sale, Gross Unrealized Gains	8	2,067	'	'
Available-for-sale, Gross Unrealized (Losses)	-1,544	-517	'	'
Available for sale Total, Estimated Fair Value	26,147	35,607	'	'
Trust Preferred Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	32,000	32,000	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	'	'	'	'
Available-for-sale, Gross Unrealized (Losses)	-8,166	-7,865	'	'
Available for sale Total, Estimated Fair Value	23,834	24,135	'	'
CRA Investments [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	23,703	23,368	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	'	848	'	'
Available-for-sale, Gross Unrealized (Losses)	-403	'	'	'
Available for sale Total, Estimated Fair Value	23,300	24,216	'	'
Collateralized Mortgage Backed Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	5,283	'	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	210	'	'	'
Available-for-sale, Gross Unrealized (Losses)	'	'	'	'
Available for sale Total, Estimated Fair Value	5,493	'	'	'
Private Label Commercial Mortgage-backed Securities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Available-for-sale, Amortized Cost	'	5,365	'	'
Available-for-sale, OTTI Recognized in Other Comprehensive Income	'	'	'	'
Available-for-sale, Gross Unrealized Gains	'	376	'	'
Available-for-sale, Gross Unrealized (Losses)	'	'	'	'
Available for sale Total, Estimated Fair Value	'	$5,741	'	'

Investment_Securities_Addition

Investment Securities - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Jun. 30, 2013

Trust Preferred Securities [Member]

Corporate Bond [Member]

Private Label Residential Mortgage-backed Securities [Member]

Investment Identifier [Line Items]

OTTI balance recognized in other comprehensive income sold

($1,811,000)

$1,800,000

OTTI balance recognized in other comprehensive income

Securities impairment charges

Total number of securities in an unrealized loss position

202

Net unrealized loss on trust preferred securities

29,311,000

9,329,000

8,166,000

7,865,000

Held-to-maturity, Gross Unrealized Losses

6,321,000

6,786,000

4,586,000

6,684,000

Securities with carrying amounts were pledged

$638,500,000

$711,700,000

Investment_Securities_Unrealiz

Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Held-to-maturity , Less Than Twelve Months, Gross Unrealized Losses	$1,735	$308
Held-to-maturity, Less Than Twelve Months, Fair Value	41,505	25,702
Held-to-maturity , More Than Twelve Months, Gross Unrealized Losses	4,586	6,478
Held-to-maturity , More Than Twelve Months, Fair Value	80,414	63,522
Held-to-maturity, Gross Unrealized Losses	6,321	6,786
Held-to-maturity, Fair Value	121,919	89,224
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	21,090	416
Available-for-sale, Less Than Twelve Months, Fair Value	567,859	40,982
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	8,221	8,913
Available-for-sale, More Than Twelve Months, Fair Value	28,822	41,782
Available-for-sale, Gross Unrealized Losses	29,311	9,329
Available-for-sale, Fair Value	596,681	82,764
Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Held-to-maturity , Less Than Twelve Months, Gross Unrealized Losses	'	206
Held-to-maturity, Less Than Twelve Months, Fair Value	'	14,794
Held-to-maturity , More Than Twelve Months, Gross Unrealized Losses	4,586	6,478
Held-to-maturity , More Than Twelve Months, Fair Value	80,414	63,522
Held-to-maturity, Gross Unrealized Losses	4,586	6,684
Held-to-maturity, Fair Value	80,414	78,316
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, Less Than Twelve Months, Fair Value	'	'
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, More Than Twelve Months, Fair Value	'	'
Available-for-sale, Gross Unrealized Losses	'	'
Available-for-sale, Fair Value	'	'
Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Held-to-maturity , Less Than Twelve Months, Gross Unrealized Losses	1,735	102
Held-to-maturity, Less Than Twelve Months, Fair Value	41,505	10,908
Held-to-maturity , More Than Twelve Months, Gross Unrealized Losses	'	'
Held-to-maturity , More Than Twelve Months, Fair Value	'	'
Held-to-maturity, Gross Unrealized Losses	1,735	102
Held-to-maturity, Fair Value	41,505	10,908
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	4,838	184
Available-for-sale, Less Than Twelve Months, Fair Value	79,308	15,713
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, More Than Twelve Months, Fair Value	'	'
Available-for-sale, Gross Unrealized Losses	4,838	184
Available-for-sale, Fair Value	79,308	15,713
U.S. Government-Sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	1,317	'
Available-for-sale, Less Than Twelve Months, Fair Value	17,377	'
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, More Than Twelve Months, Fair Value	'	'
Available-for-sale, Gross Unrealized Losses	1,317	'
Available-for-sale, Fair Value	17,377	'
Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	5,568	110
Available-for-sale, Less Than Twelve Months, Fair Value	43,599	7,811
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	643
Available-for-sale, More Than Twelve Months, Fair Value	'	8,723
Available-for-sale, Gross Unrealized Losses	5,568	753
Available-for-sale, Fair Value	43,599	16,534
Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	222	'
Available-for-sale, Less Than Twelve Months, Fair Value	25,862	'
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, More Than Twelve Months, Fair Value	'	'
Available-for-sale, Gross Unrealized Losses	222	'
Available-for-sale, Fair Value	25,862	'
Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	7,242	2
Available-for-sale, Less Than Twelve Months, Fair Value	358,092	557
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	11	8
Available-for-sale, More Than Twelve Months, Fair Value	1,528	1,938
Available-for-sale, Gross Unrealized Losses	7,253	10
Available-for-sale, Fair Value	359,620	2,495
Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	1,500	120
Available-for-sale, Less Than Twelve Months, Fair Value	20,322	16,901
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	44	397
Available-for-sale, More Than Twelve Months, Fair Value	3,460	6,986
Available-for-sale, Gross Unrealized Losses	1,544	517
Available-for-sale, Fair Value	23,782	23,887
Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, Less Than Twelve Months, Fair Value	'	'
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	8,166	7,865
Available-for-sale, More Than Twelve Months, Fair Value	23,834	24,135
Available-for-sale, Gross Unrealized Losses	8,166	7,865
Available-for-sale, Fair Value	23,834	24,135
Other [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Available-for-sale, Less Than Twelve Months, Gross Unrealized Losses	403	'
Available-for-sale, Less Than Twelve Months, Fair Value	23,299	'
Available-for-sale, More Than Twelve Months, Gross Unrealized Losses	'	'
Available-for-sale, More Than Twelve Months, Fair Value	'	'
Available-for-sale, Gross Unrealized Losses	403	'
Available-for-sale, Fair Value	$23,299	'

Investment_Securities_Amortize

Investment Securities - Amortized Cost and Fair Value of Investment Securities by Contractual Maturities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investments Debt And Equity Securities [Abstract]	'	'
Held to maturity, Due in one year or less, Amortized Cost	$2,517	$1,600
Held to maturity, After one year through five years, Amortized Cost	15,400	13,596
Held to maturity, After five years through ten years, Amortized Cost	147,897	121,238
Held to maturity, After ten years, Amortized Cost	123,294	154,899
Held to maturity Total, Amortized Cost	289,108	291,333
Available for sale, Due in one year or less, Amortized Cost	56,226	65,190
Available for sale, After one year through five years, Amortized Cost	23,694	24,261
Available for sale, After five years through ten years, Amortized Cost	34,019	8,165
Available for sale, After ten years, Amortized Cost	982,003	828,434
Available for sale Total, Amortized Cost	1,095,942	926,050
Held to maturity, Due in one year or less, Estimated Fair Value	2,534	1,600
Held to maturity, After one year through five years, Estimated Fair Value	15,760	13,934
Held to maturity, After five years through ten years, Estimated Fair Value	144,898	116,020
Held to maturity, After ten years, Estimated Fair Value	124,351	161,265
Held-to-maturity, Fair Value	287,543	292,819
Available for sale, Due in one year or less, Estimated Fair Value	55,725	67,794
Available for sale, After one year through five years, Estimated Fair Value	24,216	25,906
Available for sale, After five years through ten years, Estimated Fair Value	32,661	8,000
Available for sale, After ten years, Estimated Fair Value	961,284	837,890
Available for sale Total, Estimated Fair Value	$1,073,886	$939,590

Investment_Securities_Investme

Investment Securities - Investment Securities by Credit Rating Type (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	$1,339,666	$1,207,084
Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	295,225	265,073
Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	772,098	668,265
Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	26,147	35,607
Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	5,741
Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	32,323	37,961
U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	27,377	'
Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	59,341	72,471
Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	23,834	24,135
Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	50	50
Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	97,778	97,781
Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	5,493	'
AAA [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	25,895	29,080
AAA [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	8,006	8,120
AAA [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	12,396	15,219
AAA [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	5,741
AAA [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AAA [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	5,493	'
Split-rated AAA/AA+ [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	799,475	668,265
Split-rated AAA/AA+ [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	772,098	668,265
Split-rated AAA/AA+ [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	27,377	'
Split-rated AAA/AA+ [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
Split-rated AAA/AA+ [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	132,997	154,523
AA+ to AA- [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	130,149	149,352
AA+ to AA- [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	151	1,649
AA+ to AA- [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	826
AA+ to AA- [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
AA+ to AA- [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	2,697	2,696
AA+ to AA- [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	195,145	138,586
A+ to A- [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	149,477	92,401
A+ to A- [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	5,563	6,069
A+ to A- [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
A+ to A- [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	40,105	40,116
A+ to A- [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BBB+ to BBB- [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	168,571	198,043
BBB+ to BBB- [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	7,323	14,922
BBB+ to BBB- [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BBB+ to BBB- [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	4,145	5,249
BBB+ to BBB- [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BBB+ to BBB- [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	32,323	37,961
BBB+ to BBB- [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BBB+ to BBB- [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	45,970	60,807
BBB+ to BBB- [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	23,834	24,135
BBB+ to BBB- [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BBB+ to BBB- [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	54,976	54,969
BBB+ to BBB- [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	17,583	18,587
BB+ and Below [Member] \| Municipal Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	270	278
BB+ and Below [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| Private Label Residential Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	3,892	7,421
BB+ and Below [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| Mutual Funds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| U.S. Government-sponsored Agency Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	13,371	10,838
BB+ and Below [Member] \| Trust Preferred Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| Collateralized Debt Obligations [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	50	50
BB+ and Below [Member] \| Corporate Bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'
BB+ and Below [Member] \| Collateralized Mortgage Backed Securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Investment ratings position	'	'

Investment_Securities_Investme1

Investment Securities - Investment Securities by Credit Rating Type (Parenthetical) (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Amortized Cost And Fair Value Debt Securities [Abstract]	'	'
CRA investments with a carrying value	$23.30	$24.20
ARPS with a carrying value	2	3.1
An other investment	$1.60	$1.60
Minimum percentage of investment grade mutual funds	80.00%	80.00%

Investment_Securities_Gross_Ga

Investment Securities - Gross Gains and (Losses) on Sales of Investment Securities (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Amortized Cost And Fair Value Debt Securities [Abstract]	'	'	'	'
Gross gains	$602	$1,073	$870	$2,786
Gross (losses)	-2,281	-42	-2,407	-284
Gain (Loss) on Sales of Investments, Total	($1,679)	$1,031	($1,537)	$2,502

Recovered_Sheet1

Loans, Leases and Allowance for Credit Losses - Schedule of Held for Investment Loan Portfolio Composition of Loans, Leases and Allowance for Credit Losses (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	$6,498,976	$5,684,239
Deferred fees and unearned income, net	-8,106	-6,045
Held for investment, net of deferred fees	6,490,870	5,678,194
Allowance for credit losses	-97,851	-95,427
Net loans	6,393,019	5,582,767
Construction and Land Development [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	459,764	394,319
Residential Real Estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	358,962	407,937
Consumer [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	29,850	31,836
Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	1,990,568	1,659,003
Non Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	1,864,333	1,505,600
Owner Occupied [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	1,551,187	1,396,797
Allowance for credit losses	-14,835	-17,933
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	1,551,187	1,396,797
Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Held for investment, without deferred fees	$244,312	$288,747

LoansLeases_and_Allowance_for_

Loans,Leases and Allowance for Credit Losses - Contractual Aging of Loan Portfolio by Class of Loans Including Loans Held for Sale and Excluding Deferred Fees/Costs (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	$6,467,227	$5,644,227
30-59 Days Past Due	5,617	22,569
60-89 Days Past Due	13,799	8,702
Over 90 days Past Due	37,746	39,865
Total Past Due	57,162	71,136
Total	6,524,389	5,715,363
Commercial Real Estate [Member] \| Owner Occupied [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,538,589	1,372,550
30-59 Days Past Due	2,123	13,153
60-89 Days Past Due	'	1,757
Over 90 days Past Due	10,475	9,337
Total Past Due	12,598	24,247
Total	1,551,187	1,396,797
Commercial Real Estate [Member] \| Non-owner Occupied [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,629,045	1,327,481
30-59 Days Past Due	1,475	917
60-89 Days Past Due	12,607	4,416
Over 90 days Past Due	7,294	8,573
Total Past Due	21,376	13,906
Total	1,650,421	1,341,387
Commercial Real Estate [Member] \| Multi-Family [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	213,912	164,213
30-59 Days Past Due	'	'
60-89 Days Past Due	'	'
Over 90 days Past Due	'	'
Total Past Due	'	'
Total	213,912	164,213
Commercial and Industrial [Member] \| Commercial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,986,782	1,654,787
30-59 Days Past Due	1,094	3,109
60-89 Days Past Due	817	121
Over 90 days Past Due	1,875	986
Total Past Due	3,786	4,216
Total	1,990,568	1,659,003
Commercial and Industrial [Member] \| Leases [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	243,959	287,768
30-59 Days Past Due	'	515
60-89 Days Past Due	'	'
Over 90 days Past Due	353	464
Total Past Due	353	979
Total	244,312	288,747
Construction and Land Development [Member] \| Construction [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	264,145	215,597
30-59 Days Past Due	'	'
60-89 Days Past Due	'	'
Over 90 days Past Due	'	'
Total Past Due	'	'
Total	264,145	215,597
Construction and Land Development [Member] \| Land [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	194,218	171,919
30-59 Days Past Due	56	826
60-89 Days Past Due	'	571
Over 90 days Past Due	1,345	5,406
Total Past Due	1,401	6,803
Total	195,619	178,722
Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	342,382	387,641
30-59 Days Past Due	560	3,525
60-89 Days Past Due	127	1,837
Over 90 days Past Due	15,893	14,934
Total Past Due	16,580	20,296
Total	358,962	407,937
Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	54,195	62,271
30-59 Days Past Due	309	524
60-89 Days Past Due	248	'
Over 90 days Past Due	511	165
Total Past Due	1,068	689
Total	$55,263	$62,960

Recovered_Sheet2

Loans, Leases and Allowance for Credit Losses - Summary of Recorded Investment in Nonaccrual Loans and Loans Past Due 90 Days Still Accruing Interest by Loan Class (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	$6,467,227	$5,644,227
Past Due/ Delinquent	57,162	71,136
Total Non-accrual	76,641	104,716
Loans past due 90 days or more and still accruing	5,456	1,388
Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	342,382	387,641
Past Due/ Delinquent	16,580	20,296
Loans past due 90 days or more and still accruing	'	101
Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	54,195	62,271
Past Due/ Delinquent	1,068	689
Loans past due 90 days or more and still accruing	511	'
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,538,589	1,372,550
Past Due/ Delinquent	12,598	24,247
Loans past due 90 days or more and still accruing	388	1,272
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,629,045	1,327,481
Past Due/ Delinquent	21,376	13,906
Loans past due 90 days or more and still accruing	4,553	'
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	213,912	164,213
Past Due/ Delinquent	'	'
Loans past due 90 days or more and still accruing	'	'
Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,986,782	1,654,787
Past Due/ Delinquent	3,786	4,216
Loans past due 90 days or more and still accruing	4	15
Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	243,959	287,768
Past Due/ Delinquent	353	979
Loans past due 90 days or more and still accruing	'	'
Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	264,145	215,597
Past Due/ Delinquent	'	'
Loans past due 90 days or more and still accruing	'	'
Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	194,218	171,919
Past Due/ Delinquent	1,401	6,803
Loans past due 90 days or more and still accruing	'	'
Non-accrual Loans [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	33,625	51,533
Past Due/ Delinquent	43,016	53,183
Total Non-accrual	76,641	104,716
Non-accrual Loans [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	3,350	11,561
Past Due/ Delinquent	15,894	15,161
Total Non-accrual	19,244	26,722
Non-accrual Loans [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	28	39
Past Due/ Delinquent	'	165
Total Non-accrual	28	204
Non-accrual Loans [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	10,222	14,392
Past Due/ Delinquent	10,391	18,394
Total Non-accrual	20,613	32,786
Non-accrual Loans [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	12,761	18,299
Past Due/ Delinquent	12,885	8,572
Total Non-accrual	25,646	26,871
Non-accrual Loans [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	'	318
Past Due/ Delinquent	'	'
Total Non-accrual	'	318
Non-accrual Loans [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	1,909	2,549
Past Due/ Delinquent	2,092	3,194
Total Non-accrual	4,001	5,743
Non-accrual Loans [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	114	'
Past Due/ Delinquent	353	979
Total Non-accrual	467	979
Non-accrual Loans [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	'	'
Past Due/ Delinquent	'	'
Total Non-accrual	'	'
Non-accrual Loans [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Current	5,241	4,375
Past Due/ Delinquent	1,401	6,718
Total Non-accrual	$6,642	$11,093

Loans_Leases_and_Allowance_for2

Loans, Leases and Allowance for Credit Losses - Additional Information (Detail) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Reduction in interest income due to nonaccrual loans	$1,300,000	'	$1,300,000	'	$3,800,000	$4,100,000	'
Allowance for credit losses	97,851,000	'	'	'	97,851,000	'	95,427,000
Increase (decrease) in provision and allowance for credit losses	'	7,200,000	'	2,600,000	'	'	'
Loan commitments outstanding	0	'	'	'	0	'	200,000
Loan purchases	87,300,000	'	'	'	217,800,000	132,300,000	'
Transfer of affinity credit card portfolio to loans held for sale	25,400,000	'	'	'	25,400,000	'	31,100,000
Commercial Leases [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Allowance for credit losses	2,949,000	'	'	'	2,949,000	'	3,000,000
Loan purchases	'	'	'	'	'	66,100,000	'
Loans Acquired with Deteriorated Credit Quality [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Allowance for credit losses	1,400,000	'	'	'	1,400,000	'	0
Commercial Real Estate [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Increase (decrease) in provision and allowance for credit losses	'	'	'	1,500,000	'	'	'
Loan purchases	'	'	'	'	4,500,000	1,000,000	'
Commercial and Industrial [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Increase (decrease) in provision and allowance for credit losses	'	'	'	800,000	'	'	'
Loan purchases	'	'	'	'	213,400,000	65,200,000	'
Consumer [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Increase (decrease) in provision and allowance for credit losses	'	'	'	200,000	'	'	'
Residential Real Estate [Member]	'	'	'	'	'	'	'
Accounts, Notes, Loans and Financing Receivable [Line Items]	'	'	'	'	'	'	'
Increase (decrease) in provision and allowance for credit losses	'	'	'	$41,000	'	'	'

Loans_Leases_and_Allowance_for3

Loans, Leases and Allowance for Credit Losses - Recorded Investment and Delinquency Status by Class of Loans Including Loans Held For Sale and Excluding Deferred Fees by Risk Rating (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	$6,524,389	$5,715,363
Current (up to 29 days past due)	6,467,227	5,644,227
Past due 30-59 days	5,617	22,569
Past due 60-89 days	13,799	8,702
Past due 90 days or more	37,746	39,865
Total	6,524,389	5,715,363
Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	358,962	407,937
Current (up to 29 days past due)	342,382	387,641
Past due 30-59 days	560	3,525
Past due 60-89 days	127	1,837
Past due 90 days or more	15,893	14,934
Total	358,962	407,937
Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	55,263	62,960
Current (up to 29 days past due)	54,195	62,271
Past due 30-59 days	309	524
Past due 60-89 days	248	'
Past due 90 days or more	511	165
Total	55,263	62,960
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,551,187	1,396,797
Current (up to 29 days past due)	1,538,589	1,372,550
Past due 30-59 days	2,123	13,153
Past due 60-89 days	'	1,757
Past due 90 days or more	10,475	9,337
Total	1,551,187	1,396,797
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,650,421	1,341,387
Current (up to 29 days past due)	1,629,045	1,327,481
Past due 30-59 days	1,475	917
Past due 60-89 days	12,607	4,416
Past due 90 days or more	7,294	8,573
Total	1,650,421	1,341,387
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	213,912	164,213
Current (up to 29 days past due)	213,912	164,213
Past due 30-59 days	'	'
Past due 60-89 days	'	'
Past due 90 days or more	'	'
Total	213,912	164,213
Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,990,568	1,659,003
Current (up to 29 days past due)	1,986,782	1,654,787
Past due 30-59 days	1,094	3,109
Past due 60-89 days	817	121
Past due 90 days or more	1,875	986
Total	1,990,568	1,659,003
Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	244,312	288,747
Current (up to 29 days past due)	243,959	287,768
Past due 30-59 days	'	515
Past due 60-89 days	'	'
Past due 90 days or more	353	464
Total	244,312	288,747
Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	264,145	215,597
Current (up to 29 days past due)	264,145	215,597
Past due 30-59 days	'	'
Past due 60-89 days	'	'
Past due 90 days or more	'	'
Total	264,145	215,597
Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	195,619	178,722
Current (up to 29 days past due)	194,218	171,919
Past due 30-59 days	56	826
Past due 60-89 days	'	571
Past due 90 days or more	1,345	5,406
Total	195,619	178,722
Pass [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	6,167,358	5,396,826
Current (up to 29 days past due)	6,164,416	5,387,543
Past due 30-59 days	2,622	4,410
Past due 60-89 days	320	4,450
Past due 90 days or more	'	423
Total	6,167,358	5,396,826
Pass [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	324,254	365,042
Total	324,254	365,042
Pass [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	53,518	61,469
Total	53,518	61,469
Pass [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,465,697	1,280,337
Total	1,465,697	1,280,337
Pass [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,490,250	1,257,011
Total	1,490,250	1,257,011
Pass [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	206,586	163,895
Total	206,586	163,895
Pass [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,964,491	1,630,166
Total	1,964,491	1,630,166
Pass [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	239,002	282,075
Total	239,002	282,075
Pass [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	256,037	215,395
Total	256,037	215,395
Pass [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	167,523	141,436
Total	167,523	141,436
Special Mention [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	137,246	103,551
Current (up to 29 days past due)	136,297	100,549
Past due 30-59 days	378	1,310
Past due 60-89 days	571	1,692
Past due 90 days or more	'	'
Total	137,246	103,551
Special Mention [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	3,865	7,559
Total	3,865	7,559
Special Mention [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	853	469
Total	853	469
Special Mention [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	35,217	50,552
Total	35,217	50,552
Special Mention [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	64,405	21,065
Total	64,405	21,065
Special Mention [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	5,618	'
Total	5,618	'
Special Mention [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	9,661	12,370
Total	9,661	12,370
Special Mention [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	4,843	5,693
Total	4,843	5,693
Special Mention [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	8,108	202
Total	8,108	202
Special Mention [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	4,676	5,641
Total	4,676	5,641
Substandard [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	217,293	211,128
Current (up to 29 days past due)	165,836	152,827
Past due 30-59 days	2,617	16,849
Past due 60-89 days	12,908	2,560
Past due 90 days or more	35,932	38,892
Total	217,293	211,128
Substandard [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	30,843	32,446
Total	30,843	32,446
Substandard [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	892	1,022
Total	892	1,022
Substandard [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	49,293	65,908
Total	49,293	65,908
Substandard [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	95,766	63,311
Total	95,766	63,311
Substandard [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,708	318
Total	1,708	318
Substandard [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	14,904	15,499
Total	14,904	15,499
Substandard [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	467	979
Total	467	979
Substandard [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Substandard [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	23,420	31,645
Total	23,420	31,645
Doubtful [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	2,492	3,858
Current (up to 29 days past due)	678	3,308
Past due 30-59 days	'	'
Past due 60-89 days	'	'
Past due 90 days or more	1,814	550
Total	2,492	3,858
Doubtful [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	2,890
Total	'	2,890
Doubtful [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Doubtful [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	980	'
Total	980	'
Doubtful [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Doubtful [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Doubtful [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	1,512	968
Total	1,512	968
Doubtful [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Doubtful [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Doubtful [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Current (up to 29 days past due)	'	'
Past due 30-59 days	'	'
Past due 60-89 days	'	'
Past due 90 days or more	'	'
Total	'	'
Loss [Member] \| Residential Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Consumer [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'
Loss [Member] \| Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Recorded Investment, Past Due [Line Items]	'	'
Total	'	'
Total	'	'

Loans_Leases_and_Allowance_for4

Loans, Leases and Allowance for Credit Losses - Recorded Investment in Loans Classified as Impaired (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Receivables [Abstract]	'	'
Impaired loans with a specific valuation allowance under ASC 310	$20,717	$51,538
Impaired loans without a specific valuation allowance under ASC 310	153,514	146,617
Total impaired loans	174,231	198,155
Valuation allowance related to impaired loans	($5,909)	($12,866)

Loans_Leases_and_Allowance_for5

Loans, Leases and Allowance for Credit Losses - Impaired Loans by Loan Class (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	$174,231	$198,155
Residential Real Estate [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	32,811	37,851
Consumer [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	531	764
Owner Occupied [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	45,516	58,074
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	45,516	58,074
Non-owner Occupied [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	54,052	52,464
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	54,052	52,146
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	'	318
Commercial [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	14,106	15,531
Leases [Member] \| Commercial and Industrial [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	467	979
Construction [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	'	'
Land [Member] \| Construction and Land Development [Member]	'	'
Financing Receivable, Impaired [Line Items]	'	'
Total impaired loans by class	$26,748	$32,492

Loans_Leases_and_Allowance_for6

Loans, Leases and Allowance for Credit Losses - Average Investment in Impaired Loans by Loan Class (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	$177,268	$222,781	$185,945	$215,811
Residential Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	34,616	37,814	34,972	34,567
Consumer [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	564	794	629	1,256
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	46,108	61,223	52,030	55,881
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	54,211	60,207	54,553	57,433
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	'	882	118	983
Commercial [Member] \| Commercial and Industrial [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	13,786	25,616	14,558	26,097
Leases [Member] \| Commercial and Industrial [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	565	1,030	817	839
Construction [Member] \| Construction and Land Development [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	'	'	'	1,315
Land [Member] \| Construction and Land Development [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total average investment in impaired loans by loan class	$27,418	$35,215	$28,268	$37,440

Loans_Leases_and_Allowance_for7

Loans, Leases and Allowance for Credit Losses - Interest Income on Impaired Loans by Loan Class (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	$1,425	$2,158	$3,860	$5,374
Residential Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	21	78	45	199
Consumer [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	7	13	22	31
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	426	841	1,182	1,696
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	458	649	1,283	1,661
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	'	'	'	'
Commercial [Member] \| Commercial and Industrial [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	185	406	454	920
Leases [Member] \| Commercial and Industrial [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	'	'	'	'
Construction [Member] \| Construction and Land Development [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	'	'	'	'
Land [Member] \| Construction and Land Development [Member]	'	'	'	'
Financing Receivable, Impaired [Line Items]	'	'	'	'
Total interest income on impaired loans by class	$328	$171	$874	$867

Loans_Leases_and_Allowance_for8

Loans, Leases and Allowance for Credit Losses - Tabular Disclosure of Nonperforming Assets (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Receivables [Abstract]	'	'
Nonaccrual loans	$76,641	$104,716
Loans past due 90 days or more on accrual status	5,456	1,388
Troubled debt restructured loans	87,387	84,609
Total nonperforming loans	169,484	190,713
Other assets acquired through foreclosure, net	76,475	77,247
Total nonperforming assets	$245,959	$267,960

Loans_Leases_and_Allowance_for9

Loans, Leases and Allowance for Credit Losses - Schedule of Contractually Required Payments Receivable, Cash Flow Expected to be Collected and Estimated Fair Value of Loans Acquired (Detail) (USD $)	Apr. 30, 2013
In Thousands, unless otherwise specified	Apr. 30, 2013
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	$623,595
Cash flows expected to be collected	451,516
Fair value of loans acquired	351,474
Loans Acquired with Deteriorated Credit Quality [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Loans with credit deterioration since origination	253,419
Loans with credit deterioration since origination	145,346
Fair value of loans acquired	108,863
Purchased Noncredit Impaired Loans [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	370,176
Cash flows expected to be collected	306,170
Fair value of loans acquired	242,611
Commercial Real Estate [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	621,459
Cash flows expected to be collected	450,164
Fair value of loans acquired	350,404
Commercial Real Estate [Member] \| Loans Acquired with Deteriorated Credit Quality [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Loans with credit deterioration since origination	253,419
Loans with credit deterioration since origination	145,346
Fair value of loans acquired	108,863
Commercial Real Estate [Member] \| Purchased Noncredit Impaired Loans [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	368,040
Cash flows expected to be collected	304,818
Fair value of loans acquired	241,541
Residential Real Estate [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	2,136
Cash flows expected to be collected	1,352
Fair value of loans acquired	1,070
Residential Real Estate [Member] \| Loans Acquired with Deteriorated Credit Quality [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Loans with credit deterioration since origination	'
Loans with credit deterioration since origination	'
Fair value of loans acquired	'
Residential Real Estate [Member] \| Purchased Noncredit Impaired Loans [Member]	'
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]	'
Contractually required payments	2,136
Cash flows expected to be collected	1,352
Fair value of loans acquired	$1,070

Recovered_Sheet3

Loans, Leases and Allowance for Credit Losses - Changes in Accretable Yield for Loans Acquired With Deteriorated Credit Quality (Detail) (USD $)	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013
Receivables [Abstract]	'	'
Balance at beginning of period	$26,073	$7,072
Addition due to acquisitions	'	22,318
Reclassification from nonaccretable difference	4,804	5,851
Accretion to interest income	-2,044	-6,408
Balance at end of period	$28,833	$28,833

Recovered_Sheet4

Loans, Leases and Allowance for Credit Losses - Allowances for Credit Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	$96,323	$97,512	$95,427	$99,170
Charge-offs	-3,258	-10,926	-17,019	-44,624
Recoveries	4,786	1,892	10,523	7,521
Provision	'	8,932	8,920	35,343
Ending balance	97,851	97,410	97,851	97,410
Construction and Land Development [Member]	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	9,614	13,378	10,554	14,195
Charge-offs	'	-2,315	-852	-10,587
Recoveries	966	567	1,787	870
Provision	-533	18	-1,442	7,170
Ending balance	10,047	11,648	10,047	11,648
Commercial Real Estate [Member]	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	34,583	36,733	34,982	35,031
Charge-offs	-864	-1,470	-6,142	-12,023
Recoveries	422	633	1,997	2,897
Provision	-278	2,324	3,026	12,315
Ending balance	33,863	38,220	33,863	38,220
Residential Real Estate [Member]	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	13,847	16,957	15,237	19,134
Charge-offs	-1,138	-2,242	-5,641	-5,756
Recoveries	430	153	1,548	765
Provision	-247	-82	1,748	643
Ending balance	12,892	14,786	12,892	14,786
Commercial and Industrial [Member]	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	37,383	26,132	32,860	25,535
Charge-offs	-544	-4,100	-3,379	-12,687
Recoveries	2,242	501	4,440	2,695
Provision	354	5,611	5,514	12,601
Ending balance	39,435	28,144	39,435	28,144
Consumer [Member]	'	'	'	'
Valuation Allowance [Line Items]	'	'	'	'
Beginning Balance	896	4,312	1,794	5,275
Charge-offs	-712	-799	-1,005	-3,571
Recoveries	726	38	751	294
Provision	704	1,061	74	2,614
Ending balance	$1,614	$4,612	$1,614	$4,612

Recovered_Sheet5

Loans, Leases and Allowance for Credit Losses - Summary of Impairment Method Information Related to Loans and Allowance for Credit Losses (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	$20,717	$51,538
Impaired loans with no allowance recorded	153,514	146,617
Total impaired loans	174,231	198,155
Loans collectively evaluated for impairment	6,197,169	5,462,660
Loans acquired with deteriorated credit quality	127,576	23,424
Total loans held for investment	6,498,976	5,684,239
Impaired loans with an allowance recorded	22,002	61,997
Impaired loans with no allowance recorded	170,650	173,246
Total loans individually evaluated for impairment	192,652	235,243
Loans collectively evaluated for impairment	6,197,169	5,462,660
Loans acquired with deteriorated credit quality	184,437	39,001
Total loans held for investment	6,574,258	5,736,904
Impaired loans with an allowance recorded	5,909	12,866
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	5,909	12,866
Loans collectively evaluated for impairment	90,569	82,561
Loans acquired with deteriorated credit quality	1,373	'
Total loans held for investment	97,851	95,427
Owner Occupied [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	2,440	13,615
Impaired loans with no allowance recorded	43,076	44,459
Total impaired loans	45,516	58,074
Loans collectively evaluated for impairment	1,482,207	1,332,185
Loans acquired with deteriorated credit quality	23,464	6,538
Total loans held for investment	1,551,187	1,396,797
Impaired loans with an allowance recorded	2,933	13,634
Impaired loans with no allowance recorded	49,720	54,947
Total loans individually evaluated for impairment	52,653	68,581
Loans collectively evaluated for impairment	1,482,207	1,332,185
Loans acquired with deteriorated credit quality	33,112	11,893
Total loans held for investment	1,567,972	1,412,659
Impaired loans with an allowance recorded	580	2,815
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	580	2,815
Loans collectively evaluated for impairment	14,255	15,118
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	14,835	17,933
Non-owner Occupied [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	7,654	15,217
Impaired loans with no allowance recorded	46,398	37,247
Total impaired loans	54,052	52,464
Loans collectively evaluated for impairment	1,709,255	1,440,214
Loans acquired with deteriorated credit quality	101,026	12,922
Total loans held for investment	1,864,333	1,505,600
Impaired loans with an allowance recorded	8,169	18,746
Impaired loans with no allowance recorded	48,656	43,208
Total loans individually evaluated for impairment	56,825	61,954
Loans collectively evaluated for impairment	1,709,255	1,440,214
Loans acquired with deteriorated credit quality	145,235	18,397
Total loans held for investment	1,911,315	1,520,565
Impaired loans with an allowance recorded	810	1,602
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	810	1,602
Loans collectively evaluated for impairment	16,845	15,447
Loans acquired with deteriorated credit quality	1,373	'
Total loans held for investment	19,028	17,049
Commercial and Industrial [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	2,285	4,700
Impaired loans with no allowance recorded	11,821	10,831
Total impaired loans	14,106	15,531
Loans collectively evaluated for impairment	1,976,080	1,642,313
Loans acquired with deteriorated credit quality	382	1,159
Total loans held for investment	1,990,568	1,659,003
Impaired loans with an allowance recorded	2,498	9,877
Impaired loans with no allowance recorded	12,325	11,248
Total loans individually evaluated for impairment	14,823	21,125
Loans collectively evaluated for impairment	1,976,080	1,642,313
Loans acquired with deteriorated credit quality	1,513	3,730
Total loans held for investment	1,992,416	1,667,168
Impaired loans with an allowance recorded	1,004	2,314
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	1,004	2,314
Loans collectively evaluated for impairment	35,482	27,546
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	36,486	29,860
Residential Real Estate [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	6,018	16,482
Impaired loans with no allowance recorded	26,793	21,369
Total impaired loans	32,811	37,851
Loans collectively evaluated for impairment	323,942	368,034
Loans acquired with deteriorated credit quality	2,209	2,052
Total loans held for investment	358,962	407,937
Impaired loans with an allowance recorded	6,082	17,837
Impaired loans with no allowance recorded	33,706	27,098
Total loans individually evaluated for impairment	39,788	44,935
Loans collectively evaluated for impairment	323,942	368,034
Loans acquired with deteriorated credit quality	3,750	3,811
Total loans held for investment	367,480	416,780
Impaired loans with an allowance recorded	2,594	5,448
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	2,594	5,448
Loans collectively evaluated for impairment	10,298	9,789
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	12,892	15,237
Construction and Land Development [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	2,178	844
Impaired loans with no allowance recorded	24,570	31,648
Total impaired loans	26,748	32,492
Loans collectively evaluated for impairment	432,521	361,074
Loans acquired with deteriorated credit quality	495	753
Total loans held for investment	459,764	394,319
Impaired loans with an allowance recorded	2,178	848
Impaired loans with no allowance recorded	25,223	35,669
Total loans individually evaluated for impairment	27,401	36,517
Loans collectively evaluated for impairment	432,521	361,074
Loans acquired with deteriorated credit quality	827	1,170
Total loans held for investment	460,749	398,761
Impaired loans with an allowance recorded	831	284
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	831	284
Loans collectively evaluated for impairment	9,216	10,270
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	10,047	10,554
Commercial Leases [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	114	515
Impaired loans with no allowance recorded	353	464
Total impaired loans	467	979
Loans collectively evaluated for impairment	243,845	287,768
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	244,312	288,747
Impaired loans with an allowance recorded	114	515
Impaired loans with no allowance recorded	505	464
Total loans individually evaluated for impairment	619	979
Loans collectively evaluated for impairment	243,845	287,768
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	244,464	288,747
Impaired loans with an allowance recorded	86	238
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	86	238
Loans collectively evaluated for impairment	2,863	2,762
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	2,949	3,000
Consumer [Member]	'	'
Loans And Leases [Line Items]	'	'
Impaired loans with an allowance recorded	28	165
Impaired loans with no allowance recorded	503	599
Total impaired loans	531	764
Loans collectively evaluated for impairment	29,319	31,072
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	29,850	31,836
Impaired loans with an allowance recorded	28	540
Impaired loans with no allowance recorded	515	612
Total loans individually evaluated for impairment	543	1,152
Loans collectively evaluated for impairment	29,319	31,072
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	29,862	32,224
Impaired loans with an allowance recorded	4	165
Impaired loans with no allowance recorded	'	'
Total loans individually evaluated for impairment	4	165
Loans collectively evaluated for impairment	1,610	1,629
Loans acquired with deteriorated credit quality	'	'
Total loans held for investment	$1,614	$1,794

Recovered_Sheet6

Loans, Leases and Allowance for Credit Losses - Troubled Debt Restructured Loans by Loan Class (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	Contract	Contract	Contract	Contract
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	6	18	39	71
Pre-Modification Outstanding Recorded Investment	$3,557	$29,624	$23,520	$79,956
Forgiven Principal Balance	267	18	1,297	1,230
Lost Interest Income	623	414	1,028	2,250
Post-Modification Outstanding Recorded Investment	2,667	29,200	21,195	76,476
Waived Fees and Other Expenses	9	19	81	146
Residential Real Estate [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	3	4	12	19
Pre-Modification Outstanding Recorded Investment	2,304	4,113	5,308	10,306
Forgiven Principal Balance	267	4	267	40
Lost Interest Income	613	163	887	1,148
Post-Modification Outstanding Recorded Investment	1,424	3,950	4,154	9,118
Waived Fees and Other Expenses	9	1	24	8
Consumer [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	1	2	3
Pre-Modification Outstanding Recorded Investment	'	46	74	114
Forgiven Principal Balance	'	1	'	'
Lost Interest Income	'	3	5	3
Post-Modification Outstanding Recorded Investment	'	43	69	111
Waived Fees and Other Expenses	'	2	3	2
Owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	2	7	14
Pre-Modification Outstanding Recorded Investment	'	3,111	3,506	21,740
Forgiven Principal Balance	'	2	'	750
Lost Interest Income	'	28	54	493
Post-Modification Outstanding Recorded Investment	'	3,083	3,452	20,497
Waived Fees and Other Expenses	'	11	28	71
Non-owner Occupied [Member] \| Commercial Real Estate [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	10	5	15
Pre-Modification Outstanding Recorded Investment	'	19,773	10,735	33,629
Forgiven Principal Balance	'	10	1,030	440
Lost Interest Income	'	194	63	321
Post-Modification Outstanding Recorded Investment	'	19,569	9,642	32,868
Waived Fees and Other Expenses	'	5	14	16
Multi-Family [Member] \| Commercial Real Estate [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	'	'	'
Pre-Modification Outstanding Recorded Investment	'	'	'	'
Forgiven Principal Balance	'	'	'	'
Lost Interest Income	'	'	'	'
Post-Modification Outstanding Recorded Investment	'	'	'	'
Waived Fees and Other Expenses	'	'	'	'
Commercial [Member] \| Commercial and Industrial [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	3	'	11	14
Pre-Modification Outstanding Recorded Investment	1,253	'	3,611	7,707
Forgiven Principal Balance	'	'	'	'
Lost Interest Income	10	'	19	26
Post-Modification Outstanding Recorded Investment	1,243	'	3,592	7,681
Waived Fees and Other Expenses	'	'	11	37
Leases [Member] \| Commercial and Industrial [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	'	'	'
Pre-Modification Outstanding Recorded Investment	'	'	'	'
Forgiven Principal Balance	'	'	'	'
Lost Interest Income	'	'	'	'
Post-Modification Outstanding Recorded Investment	'	'	'	'
Waived Fees and Other Expenses	'	'	'	'
Construction [Member] \| Construction and Land Development [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	'	'	'
Pre-Modification Outstanding Recorded Investment	'	'	'	'
Forgiven Principal Balance	'	'	'	'
Lost Interest Income	'	'	'	'
Post-Modification Outstanding Recorded Investment	'	'	'	'
Waived Fees and Other Expenses	'	'	'	'
Land [Member] \| Construction and Land Development [Member]	'	'	'	'
Troubled Debt Restructured Loan Modifications by Class [Line Items]	'	'	'	'
Number of Loans	'	1	2	6
Pre-Modification Outstanding Recorded Investment	'	2,581	286	6,460
Forgiven Principal Balance	'	1	'	'
Lost Interest Income	'	26	'	259
Post-Modification Outstanding Recorded Investment	'	2,555	286	6,201
Waived Fees and Other Expenses	'	'	$1	$12

Recovered_Sheet7

Loans, Leases and Allowance for Credit Losses - Troubled Debt Restructured Loans by Class for Which There was Payment Default (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	Contract	Contract	Contract	Contract
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	3	13	13	32
Recorded Investment	$1,637	$11,276	$6,070	$30,477
Commercial Real Estate [Member] \| Owner Occupied [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	5	3	10
Recorded Investment	'	4,263	2,506	10,611
Commercial Real Estate [Member] \| Non-owner Occupied [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	2	1	3	3
Recorded Investment	1,330	1,049	1,490	4,442
Commercial Real Estate [Member] \| Multi-Family [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	'	'	1
Recorded Investment	'	'	'	193
Commercial and Industrial [Member] \| Commercial [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	1	3	3	7
Recorded Investment	307	1,794	1,089	6,700
Commercial and Industrial [Member] \| Leases [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	'	'	'
Recorded Investment	'	'	'	'
Construction and Land Development [Member] \| Construction [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	'	'	'
Recorded Investment	'	'	'	'
Construction and Land Development [Member] \| Land [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	1	2	5
Recorded Investment	'	347	330	4,013
Residential Real Estate [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	3	2	5
Recorded Investment	'	3,823	655	4,143
Consumer [Member]	'	'	'	'
Trouble Debt Restructured Loans [Line Items]	'	'	'	'
Number of Loans	'	'	'	1
Recorded Investment	'	'	'	$375

Other_Assets_Acquired_through_2

Other Assets Acquired through Foreclosure - Changes in Other Assets Acquired through Foreclosure (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Real Estate And Foreclosed Assets [Abstract]	'	'	'	'
Balance, beginning of the period, Gross Balance	$102,923	$120,391	$113,474	$135,148
Transfers to other assets acquired through foreclosure, net, Gross Balance	2,737	10,807	14,010	19,522
Additions from acquisition of Centennial, Gross Balance	'	'	5,622	'
Proceeds from sale of other real estate owned and repossessed assets, net, Gross Balance	-3,411	-13,733	-32,953	-36,911
Valuation adjustments, net, Gross Balance	'	'	'	'
Gains (losses), net, Gross Balance	292	611	2,388	317
Balance, end of period, Gross Balance	102,541	118,076	102,541	118,076
Balance, beginning of the period, Valuation Allowance	-26,424	-43,397	-36,227	-46,044
Transfers to other assets acquired through foreclosure, net, Valuation Allowance	'	'	'	'
Additions from acquisition of Centennial, Valuation Allowance	'	'	'	'
Proceeds from sale of other real estate owned and repossessed assets, net, Valuation Allowance	1,055	4,335	12,440	10,261
Valuation adjustments, net, Valuation Allowance	-697	-781	-2,279	-4,060
Gains (losses), net, Valuation Allowance	'	'	'	'
Balance, end of period, Valuation Allowance	-26,066	-39,843	-26,066	-39,843
Balance, beginning of the period, Net Balance	76,499	76,994	77,247	89,104
Transfers to other assets acquired through foreclosure, net, Net Balance	2,737	10,807	14,010	19,522
Additions from acquisition of Centennial, Net Balance	'	'	5,622	'
Proceeds from sale of other real estate owned and repossessed assets, net, Net Balance	-2,356	-9,398	-20,513	-26,650
Valuation adjustments, net, Net Balance	-697	-781	-2,279	-4,060
Gains (losses), net, Net Balance	292	611	2,388	317
Balance, end of period, Net Balance	$76,475	$78,233	$76,475	$78,233

Other_Assets_Acquired_through_3

Other Assets Acquired through Foreclosure - Changes in Other Assets Acquired through Foreclosure (Parenthetical) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Real Estate And Foreclosed Assets [Abstract]	'	'	'	'
Gains (losses), net, Net Balance	$62	$249	$407	$291

Other_Borrowings_and_Other_Lia2

Other Borrowings and Other Liabilities - Summary of Borrowings (Detail) (USD $)	Sep. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Short Term:	'	'	'
Federal Funds Purchased	$13,285	'	'
Revolving line of credit	32,500	'	'
FHLB advances	0	'	120,000
Total short term debt	45,785	'	120,000
Long Term:	'	'	'
FHLB advances	274,277	200,000	'
Other long term debt	74,043	'	73,717
Long-term Debt, Total	$348,320	'	$73,717

Other_Borrowings_and_Other_Lia3

Other Borrowings and Other Liabilities - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

6 Months Ended

9 Months Ended

Sep. 30, 2013

Mar. 31, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Dec. 31, 2010

Jun. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Centennial [Member]

Minimum [Member]

Maximum [Member]

Weighted Average [Member]

FHLB [Member]

FRB [Member]

Line of Credit Facility [Line Items]

Federal Funds Purchased

$13,285,000

Short Term FHLB Advances

120,000,000

Revolving Line of Credit outstanding advance

32,500,000

Weighted Average Interest Rate

1.75%

4.70%

2.43%

Public offering

75,000,000

Interest bearing on public offering

10.00%

Long-term federal home loan bank advance

274,277,000

200,000,000

274,277,000

77,200,000

Bearing interest rate

1.04%

Federal home loan bank maturity date

2-Jan-18

Repayment of long-term federal home loan bank advance

5,000,000

Federal Home loan bank premium

2,500,000

Bearing interest rate

1.56%

Bearing interest rate

3.05%

Weighted average cost on all long term debt

3.30%

10.80%

3.30%

10.81%

Weighted Average Interest Rate

2.67%

Additional available credit with the entity

1,050,000,000

952,800,000

598,300,000

600,600,000

Securities sold short

$126,664,000

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]	'	'	'	'	'
Letters of credit expiration period	'	'	'1 year	'	'
Unfunded commitments on credit cards loans held for sale	$2.80	'	$2.80	'	$262.60
Loss contingency for unfunded loan commitments	2	'	2	'	1.3
Percent of commercial real estate related loans	59.00%	'	59.00%	'	58.00%
Percent of commercial real estate related loans secured by undeveloped land	1.00%	'	1.00%	'	3.00%
Percentage of first liens initial loan to value ratio	'	'	75.00%	'	75.00%
Percent of commercial real estate loans owner occupied	40.00%	'	40.00%	'	48.00%
Total loans unsecured	3.00%	'	3.00%	'	4.00%
Total rent expense	$1.80	$1.50	$5.50	$4.40	'

Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Commitments [Line Items]	'	'
Total amount	$2,007,441	$1,424,527
Commitments to Extend Credit [Member]	'	'
Commitments [Line Items]	'	'
Total amount	1,692,150	1,096,264
Credit Card Commitments and Financial Guarantees [Member]	'	'
Commitments [Line Items]	'	'
Total amount	287,186	295,506
Standby Letters of Credit [Member]	'	'
Commitments [Line Items]	'	'
Total amount	$28,105	$32,757

Commitments_and_Contingencies_3

Commitments and Contingencies - Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit (Parenthetical) (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Commitments to Extend Credit [Member]	'	'
Commitments [Line Items]	'	'
Unsecured loan commitments	$266,189	$172,002
Standby Letters of Credit [Member]	'	'
Commitments [Line Items]	'	'
Unsecured letters of credit	$4,032	$3,915

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Restricted Stock Awards [Member]	Restricted Stock Awards [Member]	Restricted Stock Awards [Member]	Restricted Stock Awards [Member]	Stock Options [Member]	Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'
Stock options granted to certain key employees and directors	17,600	537,125	'	0	'	56,311	'	'	'
Amount of weighted average grant date fair value of stock options granted	$0.30	$6.70	'	'	'	'	'	'	'
Restricted stock grants vesting period	'	'	'	'	'	'3 years	'	'	'
Restricted shares outstanding	1,255,640	1,255,640	1,469,285	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	$1.30	$1.10	$2.80	$3.40	'	'
Options outstanding	'	'	'	'	'	'	'	1,200,000	1,700,000

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	($10,750)	$4,291	$8,226	($4,593)
Other comprehensive income before reclassifications	-4,800	8,487	-23,687	18,820
Amounts reclassified from accumulated other comprehensive income	1,046	-668	957	-2,117
Net current-period other comprehensive income	-3,754	7,819	-22,730	16,703
Ending balance	-14,504	12,110	-14,504	12,110
Unrealized Holding Gains (Losses) on AFS [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	-10,780	4,283	8,209	-5,112
Other comprehensive income before reclassifications	-4,770	8,478	-23,670	18,803
Amounts reclassified from accumulated other comprehensive income	1,046	-668	957	-1,598
Net current-period other comprehensive income	-3,724	7,810	-22,713	17,205
Ending balance	-14,504	12,093	-14,504	12,093
Unrealized Gain on Cash Flow Hedge [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	30	8	17	519
Other comprehensive income before reclassifications	-30	9	-17	17
Amounts reclassified from accumulated other comprehensive income	'	'	'	-519
Net current-period other comprehensive income	-30	9	-17	-502
Ending balance	'	$17	'	$17

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Amount reclassified from accumulated other comprehensive income	$633	($363)	$580	($904)
Amount reclassified from accumulated other comprehensive income	-1,046	668	-957	2,117
Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Amount reclassified from accumulated other comprehensive income	-1,046	668	-957	1,598
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Realized Gain on Sale of Investment Securities [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Amount reclassified from accumulated other comprehensive income	-1,679	1,031	-1,537	2,502
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Income Tax Expense [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Amount reclassified from accumulated other comprehensive income	$633	($363)	$580	($904)

Earnings_Per_Share_Basic_and_D

Earnings Per Share - Basic and Diluted Earnings Per Share, Based on Weighted Average Outstanding Shares (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Weighted average shares-basic	85,799	81,758	85,596	81,570
Dilutive effect of stock awards	970	536	832	589
Weighted average shares-diluted	86,769	82,294	86,428	82,159
Net income available to common shareholders	$27,840	$15,106	$82,114	$37,279
Earnings per share-basic	$0.32	$0.18	$0.96	$0.46
Earnings per share-diluted	$0.32	$0.18	$0.95	$0.45

Earnings_Per_Share_Additional_

Earnings Per Share - Additional Information (Detail)	9 Months Ended	12 Months Ended
Earnings Per Share - Additional Information (Detail)	Sep. 30, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]	'	'
Anti-dilutive stock options outstanding that were not included in computation of diluted earnings per common share	216,310	1,053,045

Fair_Value_Accounting_Gains_an

Fair Value Accounting - Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]	'	'	'	'
Unrealized Gain/(Loss) on Assets and Liabilities Measured at Fair Value, Net	$336	$469	($3,425)	$701
Interest Income on Securities	1	3	7	10
Interest Expense on Junior Subordinated Debt	329	329	1,012	981
Total Changes Included in Current-Period Earnings	8	143	-4,430	-270
Securities Measured at Fair Value [Member]	'	'	'	'
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]	'	'	'	'
Unrealized Gain/(Loss) on Assets and Liabilities Measured at Fair Value, Net	-142	'	-196	-66
Interest Income on Securities	1	3	7	10
Interest Expense on Junior Subordinated Debt	'	'	'	'
Total Changes Included in Current-Period Earnings	-141	3	-189	-56
Junior Subordinated Debt [Member]	'	'	'	'
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]	'	'	'	'
Unrealized Gain/(Loss) on Assets and Liabilities Measured at Fair Value, Net	478	469	-3,229	767
Interest Income on Securities	'	'	'	'
Interest Expense on Junior Subordinated Debt	329	329	1,012	981
Total Changes Included in Current-Period Earnings	$149	$140	($4,241)	($214)

Fair_Value_Accounting_Gains_an1

Fair Value Accounting - Gains and Losses from Fair Value Changes on Securities Measured at Fair Value (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Amortized Cost And Fair Value Debt Securities [Abstract]	'	'	'	'
Net losses for the period on trading securities included in earnings	($142)	'	($196)	($66)
Less: net gains and (losses) recognized during the period on trading securities sold during the period	'	'	'	'
Change in unrealized gains or (losses) for the period included in earnings for trading securities held at the end of the reporting period	($142)	'	($196)	($66)

Fair_Value_Accounting_Addition

Fair Value Accounting - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
	Sep. 30, 2013	Dec. 31, 2012	Collateralized Debt Obligations [Member]	Collateralized Debt Obligations [Member]	Collateralized Debt Obligations [Member]	Collateralized Debt Obligations [Member]	Level 3 [Member]	Level 3 [Member]	Junior Subordinated Debt [Member]	Junior Subordinated Debt [Member]	Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Aggregate fair value of junior subordinated debt	$39,447,000	$36,218,000	'	'	'	'	$39,447,000	$36,218,000	$39,400,000	'	$36,200,000
Aggregate unpaid principal balance	'	'	'	'	'	'	'	'	66,500,000	'	66,500,000
Aggregate changes in fair value of junior subordinated debt	'	'	'	'	'	'	'	'	27,100,000	'	30,300,000
Debt instrument, discount rate	'	'	'	'	'	'	'	'	6.28%	6.53%	6.85%
Debt instrument, basis point spread	'	'	'	'	'	'	'	'	0.06%	6.17%	6.54%
Period of basis point spread	'	'	'	'	'	'	'	'	'3 months	'3 months	'3 months
Percentage of LIBOR	'	'	'	'	'	'	'	'	0.25%	0.36%	0.31%
Aggregate carrying amount of impaired loans	20,717,000	51,538,000	'	'	'	'	20,700,000	51,500,000	'	'	'
Specific reserves in allowance in loan losses	5,909,000	12,866,000	'	'	'	'	5,900,000	12,900,000	'	'	'
Other assets acquired through foreclosure	'	'	'	'	'	'	$76,500,000	$77,200,000	'	'	'
Securities containing credit losses	'	'	0	0	0	0	'	'	'	'	'

Fair_Value_Accounting_Fair_Val

Fair Value Accounting - Fair Value of Assets and Liabilities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities measured at fair value	$3,621	$5,061
Securities available for sale	1,073,886	939,590
Interest rate swaps	39	777
Securities sold short	126,664	'
Junior subordinated debt	39,447	36,218
Interest rate swaps	2,188	751
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate swaps	'	'
Junior subordinated debt	'	'
Interest rate swaps	'	'
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate swaps	39	777
Junior subordinated debt	'	'
Interest rate swaps	2,188	751
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate swaps	'	'
Junior subordinated debt	39,447	36,218
Interest rate swaps	'	'
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	1,073,886	939,590
Interest rate swaps	39	777
Securities sold short	126,664	'
Junior subordinated debt	39,447	36,218
Interest rate swaps	2,188	751
Fair Value, Measurements, Recurring [Member] \| Collateralized Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	5,493	'
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	117,012	161,867
Interest rate swaps	'	'
Securities sold short	126,664	'
Junior subordinated debt	'	'
Interest rate swaps	'	'
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Collateralized Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	956,874	777,723
Interest rate swaps	39	777
Securities sold short	'	'
Junior subordinated debt	'	'
Interest rate swaps	2,188	751
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Collateralized Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	5,493	'
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Interest rate swaps	'	'
Securities sold short	'	'
Junior subordinated debt	39,447	36,218
Interest rate swaps	'	'
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Collateralized Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities measured at fair value	3,621	5,061
Securities available for sale	768,478	663,204
Fair Value, Measurements, Recurring [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-Backed Securities [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities measured at fair value	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-Backed Securities [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities measured at fair value	3,621	5,061
Securities available for sale	768,478	663,204
Fair Value, Measurements, Recurring [Member] \| Direct U.S. Obligations and GSE Residential Mortgage-Backed Securities [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities measured at fair value	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| U.S. Government-Sponsored Agency Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	27,377	'
Fair Value, Measurements, Recurring [Member] \| U.S. Government-Sponsored Agency Securities [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| U.S. Government-Sponsored Agency Securities [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	27,377	'
Fair Value, Measurements, Recurring [Member] \| U.S. Government-Sponsored Agency Securities [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Municipal Obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	105,545	73,171
Fair Value, Measurements, Recurring [Member] \| Municipal Obligations [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Municipal Obligations [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	105,545	73,171
Fair Value, Measurements, Recurring [Member] \| Municipal Obligations [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Mutual Funds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	32,323	37,961
Fair Value, Measurements, Recurring [Member] \| Mutual Funds [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	32,323	37,961
Fair Value, Measurements, Recurring [Member] \| Mutual Funds [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Mutual Funds [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Private Label Residential Mortgage-Backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	26,147	35,607
Fair Value, Measurements, Recurring [Member] \| Private Label Residential Mortgage-Backed Securities [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Private Label Residential Mortgage-Backed Securities [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	26,147	35,607
Fair Value, Measurements, Recurring [Member] \| Private Label Residential Mortgage-Backed Securities [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Adjustable-Rate Preferred Stock [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	61,389	75,555
Fair Value, Measurements, Recurring [Member] \| Adjustable-Rate Preferred Stock [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	61,389	75,555
Fair Value, Measurements, Recurring [Member] \| Adjustable-Rate Preferred Stock [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Adjustable-Rate Preferred Stock [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Trust Preferred Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	23,834	24,135
Fair Value, Measurements, Recurring [Member] \| Trust Preferred Securities [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	24,135
Fair Value, Measurements, Recurring [Member] \| Trust Preferred Securities [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	23,834	'
Fair Value, Measurements, Recurring [Member] \| Trust Preferred Securities [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Other [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	23,300	24,216
Fair Value, Measurements, Recurring [Member] \| Other [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	23,300	24,216
Fair Value, Measurements, Recurring [Member] \| Other [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Other [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Private Label Commercial Mortgage-backed Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	5,741
Fair Value, Measurements, Recurring [Member] \| Private Label Commercial Mortgage-backed Securities [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'
Fair Value, Measurements, Recurring [Member] \| Private Label Commercial Mortgage-backed Securities [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	5,741
Fair Value, Measurements, Recurring [Member] \| Private Label Commercial Mortgage-backed Securities [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale	'	'

Fair_Value_Accounting_Change_i

Fair Value Accounting - Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Purchases, sales, and settlements	'	'	'	'	'
Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.	$336	$469	($3,425)	$701	'
Junior subordinated debt, Fair Value	39,447	'	39,447	'	36,218
Junior subordinated debt, Valuation Technique	'	'	'Discounted cash flow	'	'Discounted cash flow
Junior subordinated debt, Input Value	'	'	6.28%	'	6.85%
Level 3 [Member]	'	'	'	'	'
Purchases, sales, and settlements	'	'	'	'	'
Junior subordinated debt, Fair Value	39,447	'	39,447	'	36,218
Junior subordinated debt, Significant Unobservable Inputs	'	'	'BB Corporate Bond over Treasury Index with comparable credit spread	'	'Median market spreads on publicly issued trust preferreds with comparable credit risk
Junior Subordinated Debt [Member]	'	'	'	'	'
Purchases, sales, and settlements	'	'	'	'	'
Junior subordinated debt, Fair Value	39,400	'	39,400	'	36,200
Fair Value, Measurements, Recurring [Member]	'	'	'	'	'
Purchases, sales, and settlements	'	'	'	'	'
Junior subordinated debt, Fair Value	39,447	'	39,447	'	36,218
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]	'	'	'	'	'
Purchases, sales, and settlements	'	'	'	'	'
Junior subordinated debt, Fair Value	39,447	'	39,447	'	36,218
Fair Value, Measurements, Recurring [Member] \| Junior Subordinated Debt [Member]	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'
Opening balance	-39,925	-36,687	-36,218	-36,985	-36,985
Transfers into Level 3	'	'	'	'	'
Transfers out of Level 3	'	'	'	'	'
Total gains or losses for the period	'	'	'	'	'
Included in earnings (or changes in net assets)	478	469	-3,229	767	'
Included in other comprehensive income	'	'	'	'	'
Purchases, sales, and settlements	'	'	'	'	'
Purchases	'	'	'	'	'
Sales	'	'	'	'	'
Settlements	'	'	'	'	'
Closing balance	-39,447	-36,218	-39,447	-36,218	'
Change in unrealized gains (losses) for the period included in earnings (or changes in net assets) held at the end of the reporting period.	$478	$469	($3,229)	$767	'

Fair_Value_Accounting_Assets_M

Fair Value Accounting - Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	$20,717	$51,538
Impaired loans without specific valuation allowance	153,514	146,617
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	20,700	51,500
Other assets acquired through foreclosure, net	76,500	77,200
Fair Value, Measurements, Nonrecurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	14,808	38,672
Impaired loans without specific valuation allowance	95,843	67,207
Other assets acquired through foreclosure, net	76,475	77,247
Fair Value, Measurements, Nonrecurring [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	'	'
Impaired loans without specific valuation allowance	'	'
Other assets acquired through foreclosure, net	'	'
Fair Value, Measurements, Nonrecurring [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	'	'
Impaired loans without specific valuation allowance	'	'
Other assets acquired through foreclosure, net	'	'
Fair Value, Measurements, Nonrecurring [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Impaired loans with specific valuation allowance	14,808	38,672
Impaired loans without specific valuation allowance	95,843	67,207
Other assets acquired through foreclosure, net	$76,475	$77,247

Fair_Value_Accounting_Debt_Sec

Fair Value Accounting - Debt Security Credit Losses Recognized in Other Comprehensive Income/Earnings (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Fair Value Disclosures [Abstract]	'	'
Beginning balance of impairment losses held in other comprehensive income	($1,811)	($1,811)
Current period other-than temporary impairment credit losses recognized through earnings	'	'
Reductions for securities sold during the period	1,811	'
Additions or reductions in credit losses due to change of intent to sell	'	'
Reductions for increases in cash flows to be collected on impaired securities	'	'
Ending balance of net unrealized gains and (losses) held in other comprehensive income	'	($1,811)

Fair_Value_Accounting_Estimate

Fair Value Accounting - Estimated Fair Value of Financial Instruments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Investment securities, Fair Value	$1,365,050	$1,237,470
Investment securities, Carrying Amount	1,366,615	1,235,984
Derivatives, Fair Value	39	777
Loans, net, Carrying Amount	6,418,432	5,613,891
Loans, net, Fair Value	5,987,568	5,262,655
Deposits, Carrying Amount	7,275,311	6,455,177
Deposits, Fair Value	7,349,886	6,458,100
Customer repurchases, Carrying Amount	55,524	79,034
Customer repurchases, Fair Value	55,524	79,034
Securities sold short, Carrying Amount	126,664	'
Other borrowings, Fair Value	402,562	205,125
Other borrowings, Carrying Amount	394,105	193,717
Junior subordinated debt, Fair Value	39,447	36,218
Junior subordinated debt, Carrying Amount	39,447	36,218
Derivatives, Fair Value	2,188	751
Carrying Amount [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Derivatives, Fair Value	39	777
Derivatives, Fair Value	2,188	751
Level 1 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Investment securities, Fair Value	176,570	216,337
Derivatives, Fair Value	'	'
Loans, net, Fair Value	'	'
Deposits, Fair Value	'	'
Customer repurchases, Fair Value	'	'
Securities sold short, Carrying Amount	126,664	'
Other borrowings, Fair Value	45,785	'
Junior subordinated debt, Fair Value	'	'
Derivatives, Fair Value	'	'
Level 2 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Investment securities, Fair Value	1,188,472	1,021,133
Derivatives, Fair Value	39	777
Loans, net, Fair Value	5,876,917	5,156,776
Deposits, Fair Value	7,349,886	6,458,100
Customer repurchases, Fair Value	55,524	79,034
Securities sold short, Carrying Amount	'	'
Other borrowings, Fair Value	274,277	120,000
Junior subordinated debt, Fair Value	'	'
Derivatives, Fair Value	2,188	751
Level 3 [Member]	'	'
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]	'	'
Investment securities, Fair Value	8	'
Derivatives, Fair Value	'	'
Loans, net, Fair Value	110,651	105,879
Deposits, Fair Value	'	'
Customer repurchases, Fair Value	'	'
Securities sold short, Carrying Amount	'	'
Other borrowings, Fair Value	82,500	85,125
Junior subordinated debt, Fair Value	39,447	36,218
Derivatives, Fair Value	'	'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]	'	'	'	'	'
Realization of the recognized net deferred tax asset	$79,570,000	'	$79,570,000	'	$51,757,000
Effective tax rate	24.80%	30.10%	21.60%	28.40%	'
Deferred tax valuation	5,200,000	'	5,200,000	'	8,000,000
Amount recognized on interest or penalties	0	0	0	0	'
Arizona [Member]	'	'	'	'	'
Operating Loss Carryforwards [Line Items]	'	'	'	'	'
Tax benefits from state net operating loss carry forwards	'	'	$1,900,000	'	'
Arizona [Member] \| State [Member]	'	'	'	'	'
Operating Loss Carryforwards [Line Items]	'	'	'	'	'
Operating loss carryforwards expiration year	'	'	'2013	'	'

Segments_Operating_Segment_Inf

Segments - Operating Segment Information (Detail) (USD $)	3 Months Ended		9 Months Ended
Segments - Operating Segment Information (Detail) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Operating Statistics [Line Items]	'	'	'	'	'
Assets	$8,921,429,000	'	$8,921,429,000	'	$7,622,637,000
Held for sale loans	25,413,000	'	25,413,000	'	31,124,000
Gross loans and deferred fees, net	6,490,870,000	'	6,490,870,000	'	5,678,194,000
Less: allowance for credit losses	-97,851,000	'	-97,851,000	'	-95,427,000
Loans, net	6,393,019,000	'	6,393,019,000	'	5,582,767,000
Deposits	7,275,311,000	'	7,275,311,000	'	6,455,177,000
Borrowings	394,105,000	'	394,105,000	'	193,717,000
Stockholders' equity	826,288,000	'	826,288,000	'	759,616,000
Net interest income (expense)	84,559,000	71,946,000	242,914,000	212,808,000	'
Provision for (recovery of) credit losses	'	8,932,000	8,920,000	35,343,000	'
Net interest income (expense) after provision for credit losses	84,559,000	63,014,000	233,994,000	177,465,000	'
Non-interest income	2,625,000	6,982,000	17,386,000	20,263,000	'
Non-interest expense	-49,675,000	-47,543,000	-145,135,000	-139,871,000	'
Income (loss) from continuing operations before income taxes	37,509,000	22,453,000	106,245,000	57,857,000	'
Income tax expense (benefit)	9,288,000	6,752,000	22,913,000	16,452,000	'
Income (loss) from continuing operations	28,221,000	15,701,000	83,332,000	41,405,000	'
Loss from discontinued operations, net	-29,000	-243,000	-160,000	-686,000	'
Net income (loss)	28,192,000	15,458,000	83,172,000	40,719,000	'
Operating Segments [Member] \| Western Alliance Bank [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	3,346,700,000	2,429,800,000	3,346,700,000	2,429,800,000	'
Gross loans and deferred fees, net	2,589,200,000	1,871,400,000	2,589,200,000	1,871,400,000	'
Less: allowance for credit losses	-28,000,000	-20,400,000	-28,000,000	-20,400,000	'
Loans, net	2,561,200,000	1,851,000,000	2,561,200,000	1,851,000,000	'
Goodwill and intangible assets	2,800,000	'	2,800,000	'	'
Deposits	2,832,000,000	2,150,500,000	2,832,000,000	2,150,500,000	'
Borrowings	81,400,000	'	81,400,000	'	'
Stockholders' equity	291,500,000	217,300,000	291,500,000	217,300,000	'
No. of branches	18	16	18	16	'
Net interest income (expense)	33,755,000	24,449,000	92,920,000	71,564,000	'
Provision for (recovery of) credit losses	6,277,000	1,112,000	9,921,000	1,215,000	'
Net interest income (expense) after provision for credit losses	27,478,000	23,337,000	82,999,000	70,349,000	'
Non-interest income	1,816,000	1,173,000	14,520,000	5,021,000	'
Non-interest expense	-15,520,000	-11,980,000	-45,688,000	-35,986,000	'
Income (loss) from continuing operations before income taxes	13,774,000	12,530,000	51,831,000	39,384,000	'
Income tax expense (benefit)	3,977,000	3,768,000	13,066,000	13,031,000	'
Income (loss) from continuing operations	9,797,000	8,762,000	38,765,000	26,353,000	'
Net income (loss)	9,797,000	8,762,000	38,765,000	26,353,000	'
Operating Segments [Member] \| Bank of Nevada [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	3,288,100,000	2,918,000,000	3,288,100,000	2,918,000,000	'
Gross loans and deferred fees, net	2,387,100,000	2,061,000,000	2,387,100,000	2,061,000,000	'
Less: allowance for credit losses	-51,000,000	-59,500,000	-51,000,000	-59,500,000	'
Loans, net	2,336,100,000	2,001,500,000	2,336,100,000	2,001,500,000	'
Goodwill and intangible assets	25,100,000	23,200,000	25,100,000	23,200,000	'
Deposits	2,613,500,000	2,408,500,000	2,613,500,000	2,408,500,000	'
Borrowings	203,000,000	110,000,000	203,000,000	110,000,000	'
Stockholders' equity	373,700,000	339,100,000	373,700,000	339,100,000	'
No. of branches	12	11	12	11	'
Net interest income (expense)	31,888,000	27,717,000	91,821,000	83,054,000	'
Provision for (recovery of) credit losses	-6,918,000	6,618,000	-5,514,000	28,846,000	'
Net interest income (expense) after provision for credit losses	38,806,000	21,099,000	97,335,000	54,208,000	'
Non-interest income	2,314,000	3,259,000	9,383,000	11,132,000	'
Non-interest expense	-18,799,000	-16,467,000	-52,724,000	-53,437,000	'
Income (loss) from continuing operations before income taxes	22,321,000	7,891,000	53,994,000	11,903,000	'
Income tax expense (benefit)	6,027,000	2,055,000	14,292,000	1,341,000	'
Income (loss) from continuing operations	16,294,000	5,836,000	39,702,000	10,562,000	'
Net income (loss)	16,294,000	5,836,000	39,702,000	10,562,000	'
Operating Segments [Member] \| Torrey Pines Bank [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	2,076,200,000	1,888,700,000	2,076,200,000	1,888,700,000	'
Held for sale loans	25,413,000	'	25,413,000	'	'
Gross loans and deferred fees, net	1,498,700,000	1,430,600,000	1,498,700,000	1,430,600,000	'
Less: allowance for credit losses	-18,300,000	-17,500,000	-18,300,000	-17,500,000	'
Loans, net	1,480,400,000	1,413,100,000	1,480,400,000	1,413,100,000	'
Deposits	1,844,700,000	1,613,800,000	1,844,700,000	1,613,800,000	'
Borrowings	3,200,000	40,000,000	3,200,000	40,000,000	'
Stockholders' equity	171,800,000	168,400,000	171,800,000	168,400,000	'
No. of branches	12	12	12	12	'
Net interest income (expense)	21,055,000	21,795,000	62,435,000	64,406,000	'
Provision for (recovery of) credit losses	2,387,000	1,202,000	3,219,000	5,282,000	'
Net interest income (expense) after provision for credit losses	18,668,000	20,593,000	59,216,000	59,124,000	'
Non-interest income	108,000	855,000	1,312,000	3,111,000	'
Non-interest expense	-11,949,000	-11,082,000	-35,876,000	-33,492,000	'
Income (loss) from continuing operations before income taxes	6,827,000	10,366,000	24,652,000	28,743,000	'
Income tax expense (benefit)	2,230,000	3,958,000	7,898,000	11,255,000	'
Income (loss) from continuing operations	4,597,000	6,408,000	16,754,000	17,488,000	'
Net income (loss)	4,597,000	6,408,000	16,754,000	17,488,000	'
Operating Segments [Member] \| Other [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	1,127,800,000	961,300,000	1,127,800,000	961,300,000	'
Gross loans and deferred fees, net	58,900,000	12,800,000	58,900,000	12,800,000	'
Less: allowance for credit losses	-600,000	'	-600,000	'	'
Loans, net	58,300,000	12,800,000	58,300,000	12,800,000	'
Borrowings	106,500,000	'	106,500,000	'	'
Stockholders' equity	844,700,000	702,300,000	844,700,000	702,300,000	'
Net interest income (expense)	-2,139,000	-2,015,000	-4,262,000	-6,216,000	'
Provision for (recovery of) credit losses	-1,746,000	'	1,294,000	'	'
Net interest income (expense) after provision for credit losses	-393,000	-2,015,000	-5,556,000	-6,216,000	'
Non-interest income	2,914,000	4,647,000	4,325,000	8,539,000	'
Non-interest expense	-7,934,000	-10,966,000	-23,001,000	-24,496,000	'
Income (loss) from continuing operations before income taxes	-5,413,000	-8,334,000	-24,232,000	-22,173,000	'
Income tax expense (benefit)	-2,946,000	-3,029,000	-12,343,000	-9,175,000	'
Income (loss) from continuing operations	-2,467,000	-5,305,000	-11,889,000	-12,998,000	'
Loss from discontinued operations, net	-29,000	-243,000	-160,000	-686,000	'
Net income (loss)	-2,496,000	-5,548,000	-12,049,000	-13,684,000	'
Inter-segment Eliminations [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	-917,400,000	-794,200,000	-917,400,000	-794,200,000	'
Gross loans and deferred fees, net	-43,000,000	-42,900,000	-43,000,000	-42,900,000	'
Loans, net	-43,000,000	-42,900,000	-43,000,000	-42,900,000	'
Deposits	-14,900,000	-10,800,000	-14,900,000	-10,800,000	'
Stockholders' equity	-855,400,000	-729,100,000	-855,400,000	-729,100,000	'
Non-interest income	-4,527,000	-2,952,000	-12,154,000	-7,540,000	'
Non-interest expense	4,527,000	2,952,000	12,154,000	7,540,000	'
Consolidated Company [Member]	'	'	'	'	'
Operating Statistics [Line Items]	'	'	'	'	'
Assets	8,921,400,000	7,403,600,000	8,921,400,000	7,403,600,000	'
Held for sale loans	25,413,000	'	25,413,000	'	'
Gross loans and deferred fees, net	6,490,900,000	5,332,900,000	6,490,900,000	5,332,900,000	'
Less: allowance for credit losses	-97,900,000	-97,400,000	-97,900,000	-97,400,000	'
Loans, net	6,393,000,000	5,235,500,000	6,393,000,000	5,235,500,000	'
Goodwill and intangible assets	27,900,000	23,200,000	27,900,000	23,200,000	'
Deposits	7,275,300,000	6,162,000,000	7,275,300,000	6,162,000,000	'
Borrowings	394,100,000	150,000,000	394,100,000	150,000,000	'
Stockholders' equity	826,300,000	698,000,000	826,300,000	698,000,000	'
No. of branches	42	39	42	39	'
Net interest income (expense)	84,559,000	71,946,000	242,914,000	212,808,000	'
Provision for (recovery of) credit losses	'	8,932,000	8,920,000	35,343,000	'
Net interest income (expense) after provision for credit losses	84,559,000	63,014,000	233,994,000	177,465,000	'
Non-interest income	2,625,000	6,982,000	17,386,000	20,263,000	'
Non-interest expense	-49,675,000	-47,543,000	-145,135,000	-139,871,000	'
Income (loss) from continuing operations before income taxes	37,509,000	22,453,000	106,245,000	57,857,000	'
Income tax expense (benefit)	9,288,000	6,752,000	22,913,000	16,452,000	'
Income (loss) from continuing operations	28,221,000	15,701,000	83,332,000	41,405,000	'
Loss from discontinued operations, net	-29,000	-243,000	-160,000	-686,000	'
Net income (loss)	$28,192,000	$15,458,000	$83,172,000	$40,719,000	'

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Subsequent Event [Line Items]	'	'
Held for sale totaled	$25,413	$31,124
Subsequent Event [Member]	'	'
Subsequent Event [Line Items]	'	'
Held for sale totaled	$25,413	'