Western Alliance Bancorporation (WAL) 10-Q 27 Apr 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 21, 2017
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	WAL
Entity Registrant Name	WESTERN ALLIANCE BANCORPORATION
Entity Central Index Key	1,212,545
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		105,428,718

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash and due from banks	$ 135,379	$ 168,066
Interest-bearing deposits in other financial institutions	511,655	116,425
Cash and cash equivalents	647,034	284,491
Money Market Funds, at Carrying Value	90	0
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	1,019	1,053
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011	2,609,380
Held-to-maturity Securities	102,590	92,079
Investments in restricted stock, at cost	65,404	65,249
Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group	17,865	18,909
Loans:
Loans, net of deferred loan fees and costs	13,644,883	13,189,527
Less: Allowance for credit losses	(127,649)	(124,704)
Net loans held for investment	13,517,234	13,064,823
Premises and equipment, net	120,038	119,833
Other assets acquired through foreclosure, net	45,200	47,815
Bank owned life insurance	165,458	164,510
Goodwill	289,895	289,967
Other intangible assets, net	12,238	12,927
Deferred tax assets, net	88,083	95,194
Other assets	350,347	334,612
Total assets	18,122,506	17,200,842
Deposits:
Non-interest-bearing demand	6,114,148	5,632,926
Interest-bearing	9,241,822	8,916,937
Total deposits	15,355,970	14,549,863
Customer repurchase agreements	35,711	41,728
Other borrowings	0	80,000
Qualifying debt	366,885	367,937
Other liabilities	394,948	269,785
Total liabilities	16,153,514	15,309,313
Commitments and Contingencies
Stockholders’ equity:
Common stock - par value $0.0001; 200,000,000 authorized; 106,929,801 shares issued at March 31, 2017 and 106,371,093 at December 31, 2016	10	10
Treasury stock, at cost (1,501,538 shares at March 31, 2017 and 1,300,232 shares at December 31, 2016)	(36,605)	(26,362)
Additional paid in capital	1,406,943	1,400,140
Accumulated other comprehensive income (loss)	2,851	(4,695)
Retained earnings	595,793	522,436
Total stockholders’ equity	1,968,992	1,891,529
Total liabilities and stockholders’ equity	$ 18,122,506	$ 17,200,842

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized cost of investment securities available for sale	$ 2,709,686	$ 2,633,298
Preferred stock, par value	$ 0	$ 0.0001
Preferred stock, liquidation value	$ 0	$ 1,000
Preferred stock, shares authorized	0	20,000,000
Preferred Stock, Shares Issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	106,929,801	106,371,093
Common stock, shares outstanding	105,428,263	105,070,861

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest income:
Loans, including fees	$ 172,553	$ 139,786
Investment securities	16,571	12,026
Dividends	2,229	2,013
Other	912	431
Total interest income	192,265	154,256
Interest expense:
Deposits	8,412	6,243
Qualifying debt	4,338	2,184
Qualifying debt	190	102
Other	16	16
Total interest expense	12,956	8,545
Net interest income	179,309	145,711
Provision for credit losses	4,250	2,500
Net interest income after provision for credit losses	175,059	143,211
Non-interest income:
Service charges and fees	4,738	4,466
Card income	1,218	1,013
Income from bank owned life insurance	948	930
Gain (Loss) on Sale of Securities, Net	635	1,001
Small Business Administration and Warrant Income	516	1,006
Lending related fees	492	2,935
Other income	1,997	1,782
Total non-interest income	10,544	13,133
Non-interest expense:
Salaries and employee benefits	51,620	44,855
Legal, professional, and directors' fees	8,803	5,572
Occupancy	6,894	6,257
Data processing	5,271	4,561
Insurance	3,228	3,323
Loan and repossessed asset expenses	1,278	902
Marketing Expense	721	657
Intangible amortization	689	697
Card expense	654	887
Net (gain) loss on sales / valuations of repossessed and other assets (1)	(543)	(302)
Other expense	9,142	8,084
Total non-interest expense	87,757	75,493
Income before provision for income taxes	97,846	80,851
Income tax expense	24,489	19,519
Net income available to common stockholders	$ 73,357	$ 61,332
Earnings per share available to common stockholders:
Basic	$ 0.71	$ 0.60
Diluted	$ 0.70	$ 0.60
Weighted average number of common shares outstanding:
Basic	103,987	101,895
Diluted	104,836	102,538

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 73,357	$ 61,332
Other comprehensive income, net:
Unrealized gain (loss) on AFS securities, net of tax effect of $(5,670) and $(4,501), respectively	9,169	11,019
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(1)	6
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Subordinated Debt	(1,229)	759
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	(1,229)	759
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(1,987)	1,207
Realized (gain) loss on sale of AFS securities included in income, net of tax effect of $242 and $290, respectively	(393)	(711)
Net other comprehensive income (loss)	7,546	11,073
Comprehensive income	$ 80,903	$ 72,405

CONSOLIDATED STATEMENTS OF COM6

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	$ 0	$ 0
Unrealized gain on securities available-for-sale securities, tax	5,670	4,501
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	1	(2)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Debt Carried at Fair Value, Tax	757	(453)
Realized gain on sale of securities, tax	$ 242	$ 290

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated (Deficit) [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2015	$ 1,591,502	$ 10	$ 1,323,473	$ 22,260	$ 262,638	$ (16,879)
Beginning balance, shares at Dec. 31, 2015		103,087,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	61,332				61,332
Exercise of stock options, shares		39,000
Exercise of stock options	305		305
Restricted stock grants, net, shares		678,000
Restricted stock grants, net	$ 4,900		4,900
Treasury Stock, Shares, Acquired	290,432	(290,000)
Restricted Stock Award, Forfeitures	$ (8,949)					(8,949)
Other comprehensive (loss) income, net	11,073			11,073
Ending balance at Mar. 31, 2016	1,660,163	$ 10	1,328,678	33,333	323,970	(25,828)
Ending balance, shares at Mar. 31, 2016		103,514,000
Retained earnings	522,436
Beginning balance at Dec. 31, 2016	1,891,529	$ 10	1,400,140	(4,695)	522,436	(26,362)
Beginning balance, shares at Dec. 31, 2016		105,071,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	73,357				73,357
Exercise of stock options, shares		9,000
Exercise of stock options	184		184
Restricted stock grants, net, shares		549,000
Restricted stock grants, net	$ 6,619		6,619
Treasury Stock, Shares, Acquired	201,306	(201,000)
Restricted Stock Award, Forfeitures	$ (10,243)					(10,243)
Other comprehensive (loss) income, net	7,546			7,546
Ending balance at Mar. 31, 2017	1,968,992	$ 10	$ 1,406,943	$ 2,851	$ 595,793	$ (36,605)
Ending balance, shares at Mar. 31, 2017		105,428,000
Retained earnings	$ 595,793

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 73,357	$ 61,332
Adjustments to reconcile net income to cash provided by operating activities:
Provision for credit losses	4,250	2,500
Depreciation and amortization	3,211	2,606
Stock-based compensation	6,342	5,394
Excess tax benefit of stock-based compensation	(4,593)	(3,871)
Deferred income taxes	2,401	4,887
Amortization of net premiums for investment securities	4,007	2,766
Accretion And Amortization Fair Market Value Adjustments Relating To Acquisitions of Loans	(6,393)	(5,315)
Accretion and Amortization Fair Market Value Adjustments Relating to Acquisitions of Other Assets and Liabilities	767	774
Income from bank owned life insurance	(948)	(930)
(Gains) / Losses on:
Sales of investment securities	(635)	(1,001)
Gain (Loss) on Sales of Loans, Net	52	(2,671)
Other assets acquired through foreclosure, net	106	(160)
Valuation adjustments of other repossessed assets, net	(380)	(177)
Sale of premises, equipment, and other assets, net	47	35
Changes in, net of acquisitions:
Other assets	10,779	21,271
Other liabilities	(4,398)	(16,125)
Net cash provided by operating activities	87,972	71,315
Investment securities - measured at fair value
Principal pay downs and maturities	33	95
Investment securities - AFS
Purchases	(185,199)	(128,101)
Principal pay downs and maturities	90,585	78,751
Proceeds from sales	15,170	34,304
Payments to Acquire Held-to-maturity Securities	10,533	21,514
Purchase of investment tax credits	(3,516)	(6,782)
Proceeds from Sale (Payments to Purchase) Investment In Money Market	(90)	(5,798)
(Purchase) liquidation of restricted stock	(154)	(124)
Payments for (Proceeds from) Loans and Leases	(342,069)	(105,402)
Purchase of premises, equipment, and other assets, net	(2,575)	(3,086)
Proceeds from sale of other real estate owned and repossessed assets, net	2,889	2,141
Net cash used in investing activities	(435,459)	(155,516)
Cash flows from financing activities:
Net increase (decrease) in deposits	806,106	1,051,031
Net (decrease) increase in borrowings	(86,017)	(151,849)
Proceeds from exercise of common stock options	184	305
Restricted stock surrendered	(10,243)	(8,949)
Net cash provided by financing activities	710,030	890,538
Net increase (decrease) in cash and cash equivalents	362,543	806,337
Cash and cash equivalents at beginning of period	284,491	224,640
Cash and cash equivalents at end of period	647,034	1,030,977
Cash paid (returned) during the period for:
Interest	17,851	13,892
Income taxes	(23)	(6,278)
Non-cash investing and financing activities:
Transfers to other assets acquired through foreclosure, net	0	10,638
Change in unfunded LIHTC and SBIC commitments	30,869	26,961
Change in unrealized gain (loss) on AFS securities, net of tax	8,775	10,308
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	(1,229)	759
Change in unfunded obligations	$ (114,716)	$ 19,930

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of operation WAL is a bank holding company headquartered in Phoenix, Arizona, incorporated under the laws of the state of Delaware. WAL provides a full spectrum of deposit, lending, treasury management, international banking, and online banking products and services through its wholly-owned banking subsidiary, WAB. WAB operates the following full-service banking divisions: ABA, BON, FIB, Bridge, and TPB. The Company also serves business customers through a national platform of specialized financial services including AAB, Corporate Finance, Equity Fund Resources, HFF, Life Sciences Group, Mortgage Warehouse Lending, Public and Nonprofit Finance, Renewable Resource Group, Resort Finance, and Technology Finance. In addition, the Company has one non-bank subsidiary, LVSP, which holds and manages certain non-performing loans and OREO. Basis of presentation The accounting and reporting policies of the Company are in accordance with GAAP and conform to practices within the financial services industry. The accounts of the Company and its consolidated subsidiaries are included in the Consolidated Financial Statements. 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. Management's estimates and judgments are ongoing and are based on experience, current and expected future conditions, third-party evaluations and various other assumptions that management believes are reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities, as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from those estimates and assumptions used in the Consolidated Financial Statements and related notes. Material estimates that are particularly susceptible to significant changes in the near term relate to the determination of the allowance for credit losses; estimated cash flows related to PCI loans; fair value determinations related to acquisitions and certain assets and liabilities carried at fair value; and accounting for income taxes. Principles of consolidation As of March 31, 2017 , WAL has ten wholly-owned subsidiaries: WAB, LVSP, and eight unconsolidated subsidiaries used as business trusts in connection with the issuance of trust-preferred securities. The Bank has the following significant wholly-owned subsidiaries: WABT, which holds certain investment securities, municipal and nonprofit loans, and leases; WA PWI, LLC, which holds certain limited partnerships invested primarily in low income housing tax credits and small business investment corporations; and BW Real Estate, Inc., which operates as a real estate investment trust and holds certain of WAB's real estate loans and related securities. The Company does not have any other significant entities that should be considered for consolidation. All significant intercompany balances and transactions have been eliminated in consolidation. Reclassifications Certain amounts in the Consolidated Financial Statements as of December 31, 2016 and for the three months ended March 31, 2016 may 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 and for the three months ended March 31, 2017 and 2016 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 audited Consolidated Financial Statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 . 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 are accounted for under the acquisition method of accounting in accordance with ASC 805, Business Combinations. Under the acquisition method, the acquiring entity in a business combination recognizes all of the acquired assets and assumed liabilities at their estimated fair values as of the date of acquisition. Any excess of the purchase price over the fair value of net assets and other identifiable intangible assets acquired is recorded as goodwill. To the extent the fair value of net assets acquired, including identified intangible assets, exceeds the purchase price, a bargain purchase gain is recognized. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill during the measurement period and are recognized in the proper reporting period in which the adjustment amounts are determined. Results of operations of an acquired business are included in the Consolidated Income Statement from the date of acquisition. Acquisition-related costs, including conversion and restructuring charges, are expensed as incurred. Investment securities Investment securities may be classified as HTM, AFS, or measured at fair value. 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 securities measured at fair value are reported as an asset in the Consolidated Balance Sheet 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 OCI, except for other-than-temporarily-impaired securities. When AFS securities are sold, the unrealized gain or loss is reclassified from OCI to non-interest income. The changes in the fair values of trading securities are reported in non-interest income. Securities classified as AFS are both equity and debt 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, adjusted for prepayment estimates, using the interest method. In estimating whether there are any OTTI losses, management considers the 1) length of time and the extent to which the fair value has been less than amortized cost; 2) financial condition and near term prospects of the issuer; 3) impact of changes in market interest rates; and 4) 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. Declines in the fair value of individual AFS debt securities that are deemed to be other-than-temporary are reflected in earnings when identified. The fair value of the debt 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) interest rate, market, or other factors is recognized in other comprehensive income or loss. For individual debt securities where the Company either 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 security's 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. Restricted stock WAB is a member of the Federal Reserve System and, as part of its membership, is required to maintain stock in the FRB in a specified ratio to its capital. In addition, WAB is a member of the FHLB system and, accordingly, maintains an investment in capital stock of the FHLB based on the borrowing capacity used. The Bank also maintains an investment in its primary correspondent bank. All of these investments are considered equity securities with no actively traded market. Therefore, the shares are considered restricted investment securities. These investments are carried at cost, which is equal to the value at which they may be redeemed. The dividend income received from the stock is reported in interest income. The Company conducts a periodic review and evaluation of its restricted stock to determine if any impairment exists. No impairment has been recorded to date. Loans, held for sale Loans, held for sale consist of SBA loans that the Company originates (or acquires) and intends to sell. These loans are carried at the lower of aggregate cost or fair value. Fair value is determined based on available market data for similar assets, expected cash flows, and appraisals of underlying collateral or the credit quality of the borrower. Gains and losses on the sale of loans are recognized pursuant to ASC 860, Transfers and Servicing . Interest income of these loans is accrued daily and loan origination fees and costs are deferred and included in the cost basis of the loan. The Company issues various representations and warranties associated with these loan sales. The Company has not experienced any losses as a result of these representations and warranties. Loans, held for investment The Company generally holds loans for investment and has the intent and ability to hold loans until their maturity. Therefore, they are reported at book value. Net loans are stated at the amount of unpaid principal, adjusted for net deferred fees and costs, purchase accounting fair value adjustments, and an allowance for credit losses. In addition, the book value of loans that are subject to a fair value hedge is adjusted for changes in value attributable to the effective portion of the hedged benchmark interest rate risk. The Company may also acquire loans through a business combination. These acquired loans are recorded at estimated fair value on the date of purchase, which is comprised of unpaid principal adjusted for estimated credit losses and interest rate fair value adjustments. Loans are evaluated individually at the acquisition date to determine if there has been credit deterioration since origination. Such loans may then be aggregated and accounted for as a pool of loans based on common characteristics. When the Company acquires such loans, the yield that may be accreted (accretable yield) is limited to the excess of the Company’s estimate of undiscounted cash flows expected to be collected over the Company’s initial investment in the loan. The excess of contractual cash flows over the cash flows expected to be collected may not be recognized as an adjustment to yield, loss, or a valuation allowance. Subsequent increases in cash flows expected to be collected generally are recognized prospectively through adjustment of the loan’s yield over the remaining life. Subsequent decreases to cash flows expected to be collected are recognized as impairment. The Company may not carry over or create a valuation allowance in the initial accounting for loans acquired under these circumstances. For purchased loans that are not deemed impaired at the acquisition date, fair value adjustments attributable to both credit and interest rates are accreted (or amortized) over the contractual life of the individual loan. For additional information, see " Note 3. Loans, Leases and Allowance for Credit Losses " of these Notes to Unaudited Consolidated Financial Statements. Loan fees collected for the origination of loans less direct loan origination costs (net deferred loan fees) are amortized over the contractual life of the loan through interest income. If the loan has scheduled payments, the amortization of the net deferred loan fee is calculated using the interest method over the contractual life of the loan. If the loan does not have scheduled payments, such as a line of credit, the net deferred loan fee is recognized as interest income on a straight-line basis over the contractual life of the loan commitment. Commitment fees based on a percentage of a customer’s unused line of credit and fees related to standby letters of credit are recognized over the commitment period. When loans are repaid, any remaining unamortized balances of premiums, discounts, or net deferred fees are recognized as interest income. Non-accrual loans: When a borrower discontinues making payments as contractually required by the note, the Company must determine whether it is appropriate to continue to accrue interest. The Company ceases accruing interest income when the loan has become delinquent by more than 90 days or when management determines that the full repayment of principal and collection of interest according to contractual terms is no longer likely. The Company may decide to continue to accrue interest on certain loans more than 90 days delinquent if the loans are well secured by collateral and in the process of collection. For all loan types, when a loan is placed on non-accrual status, all interest accrued but uncollected is reversed against interest income in the period in which the status is changed and, the Company makes a loan-level decision to apply either the cash basis or cost recovery method. The Company recognizes income on a cash basis only for those non-accrual loans for which the collection of the remaining principal balance is not in doubt. Under the cost recovery method, subsequent payments received from the customer are applied to principal and generally no further interest income is recognized until the principal has been paid in full or until circumstances have changed such that payments are again consistently received as contractually required. Impaired loans: A loan is identified as impaired when it is no longer probable that interest and principal will be collected according to the contractual terms of the original loan agreement. Generally, impaired loans are classified as non-accrual. However, in certain instances, impaired loans may continue on an accrual basis, if full repayment of all principal and interest is expected and the loan is both well secured and in the process of collection. Impaired loans are measured for reserve requirements in accordance with ASC 310, Receivables, based on the present value of expected future cash flows discounted at the loan's effective interest rate or, as a practical expedient, at the loan's observable market price or the fair value of the collateral less applicable disposition costs if the loan is collateral dependent. The amount of an impairment reserve, if any, and any subsequent changes are recorded as a provision for credit losses. Losses are recorded as a charge-off when losses are confirmed. In addition to management's internal loan review process, regulators may from time to time direct the Company to modify loan grades, loan impairment calculations, or loan impairment methodology. Troubled Debt Restructured Loans : A TDR 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, or deferral of interest payments. A TDR loan is also considered impaired. A TDR loan may be returned to accrual status when the loan is brought current, has performed in accordance with the contractual restructured terms for a reasonable period of time (generally six months) and the ultimate collectability of the total contractual restructured principal and interest is no longer in doubt. However, such loans continue to be considered impaired. Consistent with regulatory guidance, a TDR loan that is subsequently modified in another restructuring agreement but has shown sustained performance and classification as a TDR, will be removed from TDR status provided that the modified terms were market-based at the time of modification. Allowance for credit losses Credit risk is inherent in the business of extending loans and leases to borrowers, for which the Company must maintain an adequate allowance for credit losses. The allowance for credit losses is established through a provision for credit losses recorded 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 estimated 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 allowance consists of specific and general components. The specific allowance applies to impaired loans. For impaired collateral dependent loans, the reserve is calculated based on the collateral value, net of estimated disposition costs. Generally, the Company obtains independent collateral valuation analysis for each loan every twelve months. Loans not collateral dependent are evaluated based on the expected future cash flows discounted at the original contractual interest rate. The general allowance covers all non-impaired loans and incorporates several quantitative and qualitative factors. Quantitative factors include company-specific, ten-year historical net charge-offs stratified by loans with similar characteristics. Qualitative factors include: 1) levels of and trends in delinquencies and impaired loans; 2) levels of and trends in charge-offs and recoveries; 3) trends in volume and terms of loans; 4) changes in underwriting standards or lending policies; 5) experience, ability, depth of lending staff; 6) national and local economic trends and conditions; 7) changes in credit concentrations; 8) out-of-market exposures; 9) changes in quality of loan review system; and 10) changes in the value of underlying collateral. 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 Arizona, Nevada, 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, regulators, as an integral part of their examination processes, periodically review the Bank's allowance for credit losses, and may require the Bank to make additions to the allowance based on their judgment about information available to them at the time of their examination. Management regularly reviews the assumptions and formulae used in determining the allowance and makes adjustments if required to reflect the current risk profile of the portfolio. Goodwill and other intangible assets The Company records as goodwill the excess of the purchase price over the fair value of the identifiable net assets acquired in accordance with applicable guidance. The Company performs its annual goodwill and intangibles impairment tests as of October 1 each year, or more often if events or circumstances indicate that the carrying value may not be recoverable. The Company can first elect to assess, through qualitative factors, whether it is more likely than not that goodwill is impaired. If the qualitative assessment indicates potential impairment, the Company will proceed with a two-step process. The first step tests for impairment, while the second step, if necessary, measures the impairment. The resulting impairment amount, if any, is charged to current period earnings as non-interest expense. The Company’s intangible assets consist primarily of core deposit intangible assets that are amortized over periods ranging from 5 to 10 years. The Company considers the remaining useful lives of its core deposit intangible assets each reporting period, as required by ASC 350, Intangibles—Goodwill and Other, to determine whether events and circumstances warrant a revision to the remaining period of amortization. If the estimate of an intangible asset’s remaining useful life has changed, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. The Company has not revised its estimates of the useful lives of its core deposit intangibles during the three months ended March 31, 2017 and 2016 . 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 OREO 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 related to the development or improvement of the assets are capitalized and costs related 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. Treasury Shares Effective January 1, 2016, the Company separately presents treasury shares, which represent shares surrendered to the Company equal in value to the statutory payroll tax withholding obligations arising from the vesting of employee restricted stock awards. Prior period amounts have been adjusted to reflect this new presentation, with no change to total stockholders' equity. Treasury shares are carried at cost. 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 Sheet at their fair value in accordance with ASC 815, Derivatives and Hedging . 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. Changes in the fair value of a derivative that is designated and qualifies as a fair value hedge, along with changes in the fair value of the hedged asset or liability that are attributable to the hedged risk are recorded in current-period earnings. For a cash flow hedge, the effective portion of the change in the fair value of the derivative is recorded in 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 in the Consolidated Balance Sheet, 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, so called free-standing derivatives, are reported in the Consolidated Balance Sheet at fair value and the changes in fair value are recognized in earnings as non-interest income during the period of change. The Company may in the normal course of business purchase a financial instrument or originate 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 the embedded derivative possesses economic characteristics that are not clearly and closely related to the economic characteristics of the host contract and 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 the host contract is measured at fair value, with changes in fair value reported in current earnings, or the Company is unable to reliably identify and measure an embedded derivative for separation from its host contract, the entire contract is carried in the Consolidated Balance Sheet at fair value and is not designated as a hedging instrument. Income taxes The Company is subject to income taxes in the United States and files a consolidated federal income tax return with all of its subsidiaries, with the exception of BW Real Estate, Inc. Deferred income taxes are recorded to reflect the effects of temporary differences between the financial reporting carrying amounts of assets and liabilities and their income tax bases using enacted tax rates that are expected to be in effect when the taxes are actually paid or recovered. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Net deferred tax assets are recorded to the extent that these assets will more-likely-than-not be realized. In making these determinations, all available positive and negative evidence is considered, including scheduled reversals of deferred tax liabilities, tax planning strategies, projected future taxable income, and recent operating results. If it is determined that deferred income tax assets to be realized in the future are in excess of their net recorded amount, an adjustment to the valuation allowance will be recorded, which will reduce the Company's provision for income taxes. A tax benefit from an unrecognized tax benefit may be recognized when it is more-likely-than-not that the position will be sustained upon examination, including related appeals or litigation, based on technical merits. Income tax benefits must meet a more-likely-than-not recognition threshold at the effective date to be recognized. Interest and penalties related to unrecognized tax benefits are recognized as part of the provision for income taxes in the Consolidated Income Statement. Accrued interest and penalties are included in the related tax liability line with other liabilities in the Consolidated Balance Sheet. See " Note 11. Income Taxes " of these Notes to Unaudited Consolidated Financial Statements for further discussion on income taxes. Off-balance sheet instruments In the ordinary course of business, the Company has entered into off-balance sheet financial instrument arrangements consisting of commitments to extend credit and standby letters of credit. Such financial instruments are recorded in the Consolidated Financial Statements when they are funded. They involve, to varying degrees, elements of credit risk in excess of amounts recognized in the Consolidated Balance Sheet. Losses would be experienced when the Company is contractually obligated to make a payment under these instruments and must seek repayment from the borrower, which may not be as financially sound in the current period as they were when the commitment was originally made. 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. As with outstanding loans, the Company applies qualitative factors and utilization rates to its

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investment Securities	2. INVESTMENT SECURITIES The carrying amounts and fair values of investment securities at March 31, 2017 and December 31, 2016 are summarized as follows: March 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity Tax-exempt $ 102,590 $ 1,388 $ (312 ) $ 103,666 Available-for-sale Collateralized debt obligations $ 50 $ 19,973 $ — $ 20,023 Commercial MBS issued by GSEs 119,646 15 (3,961 ) 115,700 Corporate debt securities 69,643 370 (1,618 ) 68,395 CRA investments 47,722 — (514 ) 47,208 Preferred stock 96,030 2,819 (247 ) 98,602 Private label residential MBS 504,213 419 (7,566 ) 497,066 Residential MBS issued by GSEs 1,375,584 3,349 (16,133 ) 1,362,800 Tax-exempt 403,302 9,760 (8,947 ) 404,115 Trust preferred securities 32,000 — (4,320 ) 27,680 U.S. government sponsored agency securities 59,000 — (3,080 ) 55,920 U.S. treasury securities 2,496 6 — 2,502 Total AFS securities $ 2,709,686 $ 36,711 $ (46,386 ) $ 2,700,011 Securities measured at fair value Residential MBS issued by GSEs $ 1,019 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity Tax-exempt $ 92,079 $ 433 $ (546 ) $ 91,966 Available-for-sale Collateralized debt obligations $ 50 $ 13,440 $ — $ 13,490 Commercial MBS issued by GSEs 121,742 — (3,950 ) 117,792 Corporate debt securities 65,058 371 (1,285 ) 64,144 CRA investments 37,627 — (514 ) 37,113 Preferred stock 96,071 833 (2,242 ) 94,662 Private label residential MBS 440,272 182 (6,769 ) 433,685 Residential MBS issued by GSEs 1,369,289 3,046 (17,130 ) 1,355,205 Tax-exempt 409,693 8,477 (9,937 ) 408,233 Trust preferred securities 32,000 — (5,468 ) 26,532 U.S. government sponsored agency securities 59,000 — (2,978 ) 56,022 U.S. treasury securities 2,496 6 — 2,502 Total AFS securities $ 2,633,298 $ 26,355 $ (50,273 ) $ 2,609,380 Securities measured at fair value Residential MBS issued by GSEs $ 1,053 For additional information on the fair value changes of securities measured at fair value, see the trading securities table in " Note 13. Fair Value Accounting " of these Notes to Unaudited Consolidated Financial Statements. 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 taking into account 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, for the purpose of an OTTI analysis, the Company also considers the cause of the price decline (general level of interest rates, credit spreads, 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, as well as the issuer’s ability to service debt, and any change in agencies’ ratings at the evaluation date from the acquisition date and any likely imminent action. The Company has reviewed securities for which there is an unrealized loss in accordance with its accounting policy for OTTI described above and determined that there are no impairment charges for the three months ended March 31, 2017 and 2016 . The Company does not consider any securities to be other-than-temporarily impaired as of March 31, 2017 and December 31, 2016 . No assurance can be made that OTTI will not occur in future periods. Information pertaining to securities with gross unrealized losses at March 31, 2017 and December 31, 2016 , aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: March 31, 2017 Less Than Twelve Months More Than Twelve Months Total Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (in thousands) Held-to-maturity Tax-exempt $ 312 $ 30,542 $ — $ — $ 312 $ 30,542 Available-for-sale Commercial MBS issued by GSEs $ 3,961 $ 113,795 $ — $ — $ 3,961 $ 113,795 Corporate debt securities 1,618 62,971 — — 1,618 62,971 CRA investments 514 47,208 — — 514 47,208 Preferred stock 247 11,946 — — 247 11,946 Private label residential MBS 7,566 391,073 — — 7,566 391,073 Residential MBS issued by GSEs 15,699 868,033 434 33,662 16,133 901,695 Tax-exempt 8,947 142,516 — — 8,947 142,516 Trust preferred securities — — 4,320 27,680 4,320 27,680 U.S. government sponsored agency securities 3,080 55,920 — — 3,080 55,920 Total AFS securities $ 41,632 $ 1,693,462 $ 4,754 $ 61,342 $ 46,386 $ 1,754,804 December 31, 2016 Less Than Twelve Months More Than Twelve Months Total Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (in thousands) Held-to-maturity Tax-exempt $ 546 $ 30,364 $ — $ — $ 546 $ 30,364 Available-for-sale Commercial MBS issued by GSEs $ 3,950 $ 117,792 $ — $ — $ 3,950 $ 117,792 Corporate debt securities 1,285 38,716 — — 1,285 38,716 CRA investments 514 37,113 — — 514 37,113 Preferred stock 2,188 63,151 54 1,471 2,242 64,622 Private label residential MBS 6,170 377,638 599 16,969 6,769 394,607 Residential MBS issued by GSEs 16,990 950,480 140 5,326 17,130 955,806 Tax-exempt 9,937 148,780 — — 9,937 148,780 Trust preferred securities — — 5,468 26,532 5,468 26,532 U.S. government sponsored agency securities 2,978 56,022 — — 2,978 56,022 Total AFS securities $ 44,012 $ 1,789,692 $ 6,261 $ 50,298 $ 50,273 $ 1,839,990 At March 31, 2017 and December 31, 2016 , the Company’s unrealized losses relate primarily to interest rate fluctuations and credit spread widening in applicable markets. The total number of securities in an unrealized loss position at March 31, 2017 is 204 , compared to 244 at December 31, 2016 . 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 in an unrealized loss position in the foreseeable future, none of the securities described in the above table or in this paragraph are deemed to be OTTI. The trust preferred securities have yields based on floating rate LIBOR, which are highly correlated to the federal funds rate and have been negatively affected by the low rate environment. This has resulted in unrealized losses for these securities. The amortized cost and fair value of securities as of March 31, 2017 , by contractual maturities, are shown below. MBS are shown separately as individual MBS are comprised of pools of loans with varying maturities. Therefore, these securities are listed separately in the maturity summary. March 31, 2017 Amortized Cost Estimated Fair Value (in thousands) Held-to-maturity After ten years $ 102,590 $ 103,666 Available-for-sale Due in one year or less $ 50,000 $ 49,549 After one year through five years 52,331 53,380 After five years through ten years 214,862 214,145 After ten years 393,050 407,371 Mortgage-backed securities 1,999,443 1,975,566 Total AFS securities $ 2,709,686 $ 2,700,011 The following tables summarize the carrying amount of the Company’s investment ratings position as of March 31, 2017 and December 31, 2016 : March 31, 2017 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity Tax-exempt $ — $ — $ — $ — $ — $ — $ 102,590 $ 102,590 Available-for-sale Collateralized debt obligations $ — $ — $ — $ — $ — $ 20,023 $ — $ 20,023 Commercial MBS issued by GSEs — 115,700 — — — — — 115,700 Corporate debt securities — — — 44,561 19,300 — 4,534 68,395 CRA investments — 24,940 — — — — 22,268 47,208 Preferred stock — — — 10,550 64,715 7,311 16,026 98,602 Private label residential MBS 464,029 — 27,457 1,896 3,684 — — 497,066 Residential MBS issued by GSEs — 1,362,800 — — — — — 1,362,800 Tax-exempt 36,121 24,985 222,352 120,657 — — — 404,115 Trust preferred securities — — — — 27,680 — — 27,680 U.S. government sponsored agency securities — 55,920 — — — — — 55,920 U.S. treasury securities — 2,502 — — — — — 2,502 Total AFS securities (1) $ 500,150 $ 1,586,847 $ 249,809 $ 177,664 $ 115,379 $ 27,334 $ 42,828 $ 2,700,011 Securities measured at fair value Residential MBS issued by GSEs $ — $ 1,019 $ — $ — $ — $ — $ — $ 1,019 (1) Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch. December 31, 2016 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity Tax-exempt $ — $ — $ — $ — $ — $ — $ 92,079 $ 92,079 Available-for-sale Collateralized debt obligations $ — $ — $ — $ — $ — $ 13,490 $ — $ 13,490 Commercial MBS issued by GSEs — 117,792 — — — — — 117,792 Corporate debt securities — — 5,429 38,715 20,000 — — 64,144 CRA investments — — — — — — 37,113 37,113 Preferred stock — — — — 64,486 14,658 15,518 94,662 Private label residential MBS 399,013 — 29,921 2,117 2,634 — — 433,685 Residential MBS issued by GSEs — 1,355,205 — — — — — 1,355,205 Tax-exempt 80,862 — 268,249 59,122 — — — 408,233 Trust preferred securities — — — — 26,532 — — 26,532 U.S. government sponsored agency securities — 56,022 — — — — — 56,022 U.S. treasury securities — 2,502 — — — — — 2,502 Total AFS securities (1) $ 479,875 $ 1,531,521 $ 303,599 $ 99,954 $ 113,652 $ 28,148 $ 52,631 $ 2,609,380 Securities measured at fair value Residential MBS issued by GSEs $ — $ 1,053 $ — $ — $ — $ — $ — $ 1,053 (1) Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch. Securities with carrying amounts of approximately $902.6 million and $763.0 million at March 31, 2017 and December 31, 2016 , 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 March 31, 2017 2016 (in thousands) Gross gains $ 636 $ 2,057 Gross losses (1 ) (1,056 ) Net gains on sales of investment securities $ 635 $ 1,001

Loans, Leases and Allowance for

Loans, Leases and Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Loans, Leases and Allowance for Credit Losses	3. LOANS, LEASES AND ALLOWANCE FOR CREDIT LOSSES The composition of the Company’s held for investment loan portfolio is as follows: March 31, 2017 December 31, 2016 (in thousands) Commercial and industrial $ 5,948,307 $ 5,755,021 Commercial real estate - non-owner occupied 3,607,783 3,543,956 Commercial real estate - owner occupied 2,043,431 2,013,276 Construction and land development 1,601,721 1,478,114 Residential real estate 309,870 259,432 Commercial leases 90,722 100,765 Consumer 43,049 38,963 Loans, net of deferred loan fees and costs 13,644,883 13,189,527 Allowance for credit losses (127,649 ) (124,704 ) Total loans HFI $ 13,517,234 $ 13,064,823 Net deferred loan fees and costs as of March 31, 2017 and December 31, 2016 total $21.5 million and $22.3 million , respectively, which is a reduction in the carrying value of loans. Net unamortized purchase discounts on loans total $7.3 million and $5.2 million as of March 31, 2017 and December 31, 2016 , respectively. Total loans held for investment are also net of interest rate and credit marks on acquired loans totaling $65.1 million and $69.5 million as of March 31, 2017 and December 31, 2016 , respectively, which is a net reduction in the carrying value of loans. As of March 31, 2017 and December 31, 2016 , the Company also has $17.9 million and $ 18.9 million of HFS loans, respectively. The following table presents the contractual aging of the recorded investment in past due loans held for investment by class of loans: March 31, 2017 Current 30-59 Days 60-89 Days Over 90 Days Total Total (in thousands) Commercial real estate Owner occupied $ 2,037,324 $ 302 $ 1,947 $ 3,858 $ 6,107 $ 2,043,431 Non-owner occupied 3,388,556 308 — 3 311 3,388,867 Multi-family 218,916 — — — — 218,916 Commercial and industrial Commercial 5,936,803 3,692 4,322 3,490 11,504 5,948,307 Leases 90,581 14 24 103 141 90,722 Construction and land development Construction 1,053,336 — — — — 1,053,336 Land 547,039 56 6 1,284 1,346 548,385 Residential real estate 301,868 328 319 7,355 8,002 309,870 Consumer 42,874 10 — 165 175 43,049 Total loans $ 13,617,297 $ 4,710 $ 6,618 $ 16,258 $ 27,586 $ 13,644,883 December 31, 2016 Current 30-59 Days 60-89 Days Over 90 Days Total Total (in thousands) Commercial real estate Owner occupied $ 2,009,728 $ 71 $ — $ 3,477 $ 3,548 $ 2,013,276 Non-owner occupied 3,339,121 672 2 — 674 3,339,795 Multi-family 204,161 — — — — 204,161 Commercial and industrial Commercial 5,747,368 549 584 6,520 7,653 5,755,021 Leases 100,761 — — 4 4 100,765 Construction and land development Construction 973,242 — — — — 973,242 Land 503,588 — — 1,284 1,284 504,872 Residential real estate 249,726 4,333 281 5,092 9,706 259,432 Consumer 38,765 26 2 170 198 38,963 Total loans $ 13,166,460 $ 5,651 $ 869 $ 16,547 $ 23,067 $ 13,189,527 The following table presents the recorded investment in non-accrual loans and loans past due ninety days or more and still accruing interest by class of loans: March 31, 2017 December 31, 2016 Non-accrual loans Loans past due 90 days or more and still accruing Non-accrual loans Loans past due 90 days or more and still accruing Current Past Due/ Total Current Past Due/ Total (in thousands) Commercial real estate Owner occupied $ 4,210 $ 4,499 $ 8,709 $ — $ 5,084 $ 3,264 $ 8,348 $ 285 Non-owner occupied 2,524 3 2,527 — 8,317 1 8,318 — Multi-family — — — — — — — — Commercial and industrial Commercial 12,528 3,839 16,367 51 10,893 6,043 16,936 775 Leases 24 54 78 49 28 3 31 — Construction and land development Construction — — — — — — — — Land — 1,284 1,284 — — 1,284 1,284 — Residential real estate 1,214 4,115 5,329 3,559 99 5,093 5,192 — Consumer — 164 164 — — 163 163 7 Total $ 20,500 $ 13,958 $ 34,458 $ 3,659 $ 24,421 $ 15,851 $ 40,272 $ 1,067 The reduction in interest income associated with loans on non-accrual status was approximately $0.6 million and $0.4 million for the three months ended March 31, 2017 and 2016 , 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, or risk rated nine, have all the weaknesses inherent in those classified as 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 warrant management’s close attention, are deemed to be Special Mention. Risk ratings are updated, at a minimum, quarterly. The following tables present gross loans by risk rating: March 31, 2017 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial real estate Owner occupied $ 1,971,261 $ 49,568 $ 20,325 $ 2,277 $ — $ 2,043,431 Non-owner occupied 3,336,170 13,775 38,922 — — 3,388,867 Multi-family 218,723 193 — — — 218,916 Commercial and industrial Commercial 5,773,313 92,556 82,434 — — 5,948,303 Leases 87,012 3,640 74 — — 90,726 Construction and land development Construction 1,041,338 — 11,998 — — 1,053,336 Land 531,195 14,366 2,824 — — 548,385 Residential real estate 299,302 928 9,640 — — 309,870 Consumer 42,803 54 192 — — 43,049 Total $ 13,301,117 $ 175,080 $ 166,409 $ 2,277 $ — $ 13,644,883 March 31, 2017 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 13,296,590 $ 171,409 $ 147,764 $ 1,534 $ — $ 13,617,297 Past due 30 - 59 days 2,993 1,058 659 — — 4,710 Past due 60 - 89 days 1,342 2,613 2,663 — — 6,618 Past due 90 days or more 192 — 15,323 743 — 16,258 Total $ 13,301,117 $ 175,080 $ 166,409 $ 2,277 $ — $ 13,644,883 December 31, 2016 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial real estate Owner occupied $ 1,935,322 $ 53,634 $ 22,090 $ 2,230 $ — $ 2,013,276 Non-owner occupied 3,278,090 22,972 38,733 — — 3,339,795 Multi-family 203,964 197 — — — 204,161 Commercial and industrial Commercial 5,621,448 70,011 58,562 5,000 — 5,755,021 Leases 100,737 — 28 — — 100,765 Construction and land development Construction 961,290 — 11,952 — — 973,242 Land 501,569 337 2,966 — — 504,872 Residential real estate 252,304 929 6,199 — — 259,432 Consumer 38,698 64 201 — — 38,963 Total $ 12,893,422 $ 148,144 $ 140,731 $ 7,230 $ — $ 13,189,527 December 31, 2016 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 12,887,308 $ 147,838 $ 124,084 $ 7,230 $ — $ 13,166,460 Past due 30 - 59 days 5,433 96 122 — — 5,651 Past due 60 - 89 days 410 210 249 — — 869 Past due 90 days or more 271 — 16,276 — — 16,547 Total $ 12,893,422 $ 148,144 $ 140,731 $ 7,230 $ — $ 13,189,527 The table below reflects the recorded investment in loans classified as impaired: March 31, 2017 December 31, 2016 (in thousands) Impaired loans with a specific valuation allowance under ASC 310 (1) $ 10,919 $ 10,909 Impaired loans without a specific valuation allowance under ASC 310 (2) 102,787 88,300 Total impaired loans $ 113,706 $ 99,209 Valuation allowance related to impaired loans (3) $ (3,965 ) $ (4,239 ) (1) Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016 , respectively. (2) Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016 , respectively. (3) Includes valuation allowance related to TDR loans of $2.6 million and $0.6 million at March 31, 2017 and December 31, 2016 , respectively. The following table presents impaired loans by class: March 31, 2017 December 31, 2016 (in thousands) Commercial real estate Owner occupied $ 21,321 $ 20,748 Non-owner occupied 22,565 25,524 Multi-family — — Commercial and industrial Commercial 36,283 21,107 Leases 400 355 Construction and land development Construction — — Land 14,117 14,838 Residential real estate 18,806 16,391 Consumer 214 246 Total $ 113,706 $ 99,209 A valuation allowance 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 a specific valuation allowance under ASC 310.” However, before concluding that an impaired loan needs no associated valuation allowance, an assessment is made to consider all available and relevant information for the method used to evaluate impairment and the type of loan being assessed. The valuation allowance disclosed above is included in the allowance for credit losses reported in the Consolidated Balance Sheets as of March 31, 2017 and December 31, 2016 . The following table presents the average investment in impaired loans and income recognized on impaired loans: Three Months Ended March 31, 2017 2016 (in thousands) Average balance on impaired loans $ 103,387 $ 122,545 Interest income recognized on impaired loans 921 1,113 Interest recognized on non-accrual loans, cash basis 332 172 The following table presents average investment in impaired loans by loan class: Three Months Ended March 31, 2017 2016 (in thousands) Commercial real estate Owner occupied $ 21,128 $ 21,737 Non-owner occupied 24,399 33,033 Multi-family — — Commercial and industrial Commercial 25,734 31,733 Leases 367 2,049 Construction and land development Construction — — Land 14,432 17,900 Residential real estate 17,103 15,764 Consumer 224 329 Total $ 103,387 $ 122,545 The average investment in TDR loans included in the average investment in impaired loans table above for the three months ended March 31, 2017 and 2016 was $60.4 million and $78.0 million , respectively. The following table presents interest income on impaired loans by class: Three Months Ended March 31, 2017 2016 (in thousands) Commercial real estate Owner occupied $ 177 $ 295 Non-owner occupied 239 338 Multi-family — — Commercial and industrial Commercial 140 108 Leases 4 32 Construction and land development Construction — — Land 221 207 Residential real estate 139 131 Consumer 1 2 Total $ 921 $ 1,113 The Company is not committed to lend significant additional funds on these impaired loans. The following table summarizes nonperforming assets: March 31, 2017 December 31, 2016 (in thousands) Non-accrual loans (1) $ 34,458 $ 40,272 Loans past due 90 days or more on accrual status (2) 3,659 1,067 Accruing troubled debt restructured loans 49,292 53,637 Total nonperforming loans 87,409 94,976 Other assets acquired through foreclosure, net 45,200 47,815 Total nonperforming assets $ 132,609 $ 142,791 (1) Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016 , respectively. (2) Includes $0.1 million from loans acquired with deteriorated credit quality at each of the periods ended March 31, 2017 and December 31, 2016 . Loans Acquired with Deteriorated Credit Quality Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows: Three Months Ended March 31, 2017 2016 (in thousands) Balance, at beginning of period $ 15,177 $ 15,925 Reclassifications from non-accretable to accretable yield (1) — — Accretion to interest income (907 ) (782 ) Reversal of fair value adjustments upon disposition of loans (458 ) (1,602 ) Balance, at end of period $ 13,812 $ 13,541 (1) The primary drivers of reclassification from non-accretable 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: Three Months Ended March 31, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2017 Beginning Balance $ 21,175 $ 25,673 $ 3,851 $ 73,333 $ 672 $ 124,704 Charge-offs — — 115 2,594 34 2,743 Recoveries (277 ) (533 ) (251 ) (328 ) (49 ) (1,438 ) Provision (355 ) 1,798 425 2,362 20 4,250 Ending balance $ 21,097 $ 28,004 $ 4,412 $ 73,429 $ 707 $ 127,649 2016 Beginning Balance $ 18,976 $ 23,160 $ 5,278 $ 71,181 $ 473 $ 119,068 Charge-offs — 410 26 7,491 74 8,001 Recoveries (95 ) (3,665 ) (257 ) (1,576 ) (67 ) (5,660 ) Provision 354 (3,311 ) (571 ) 5,890 138 2,500 Ending balance $ 19,425 $ 23,104 $ 4,938 $ 71,156 $ 604 $ 119,227 The following table presents impairment method information related to loans and allowance for credit losses by loan portfolio segment: Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Commercial Leases Consumer Total Loans (in thousands) Loans as of March 31, 2017: Recorded Investment: Impaired loans with an allowance recorded $ 3,088 $ — $ 7,831 $ — $ — $ — $ — $ 10,919 Impaired loans with no allowance recorded 18,233 22,565 28,452 18,806 14,117 400 214 102,787 Total loans individually evaluated for impairment 21,321 22,565 36,283 18,806 14,117 400 214 113,706 Loans collectively evaluated for impairment 2,010,916 3,435,971 5,912,024 290,446 1,587,604 90,322 42,835 13,370,118 Loans acquired with deteriorated credit quality 11,194 149,247 — 618 — — — 161,059 Total recorded investment $ 2,043,431 $ 3,607,783 $ 5,948,307 $ 309,870 $ 1,601,721 $ 90,722 $ 43,049 $ 13,644,883 Unpaid Principal Balance Impaired loans with an allowance recorded $ 3,088 $ — $ 7,831 $ — $ — $ — $ — $ 10,919 Impaired loans with no allowance recorded 26,599 30,204 57,433 28,275 32,767 551 10,813 186,642 Total loans individually evaluated for impairment 29,687 30,204 65,264 28,275 32,767 551 10,813 197,561 Loans collectively evaluated for impairment 2,010,916 3,435,971 5,912,024 290,446 1,587,604 90,322 42,835 13,370,118 Loans acquired with deteriorated credit quality 14,962 180,747 4,949 733 — — — 201,391 Total unpaid principal balance $ 2,055,565 $ 3,646,922 $ 5,982,237 $ 319,454 $ 1,620,371 $ 90,873 $ 53,648 $ 13,769,070 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 932 $ — $ 3,033 $ — $ — $ — $ — $ 3,965 Impaired loans with no allowance recorded — — — — — — — — Total loans individually evaluated for impairment 932 — 3,033 — — — — 3,965 Loans collectively evaluated for impairment 12,067 13,124 70,396 4,412 21,097 — 707 121,803 Loans acquired with deteriorated credit quality — 1,881 — — — — — 1,881 Total allowance for credit losses $ 12,999 $ 15,005 $ 73,429 $ 4,412 $ 21,097 $ — $ 707 $ 127,649 Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Commercial Leases Consumer Total Loans (in thousands) Loans as of December 31, 2016: Recorded Investment: Impaired loans with an allowance recorded $ 3,125 $ — $ 7,766 $ — $ — $ — $ 18 $ 10,909 Impaired loans with no allowance recorded 17,624 25,524 13,340 16,391 14,838 355 228 88,300 Total loans individually evaluated for impairment 20,749 25,524 21,106 16,391 14,838 355 246 99,209 Loans collectively evaluated for impairment 1,981,176 3,383,585 5,733,915 242,409 1,443,952 100,410 38,717 12,924,164 Loans acquired with deteriorated credit quality 11,351 134,847 — 632 19,324 — — 166,154 Total recorded investment $ 2,013,276 $ 3,543,956 $ 5,755,021 $ 259,432 $ 1,478,114 $ 100,765 $ 38,963 $ 13,189,527 Unpaid Principal Balance Impaired loans with an allowance recorded $ 3,125 $ — $ 8,019 $ — $ — $ — $ 18 $ 11,162 Impaired loans with no allowance recorded 26,336 33,632 43,176 26,225 33,487 507 1,358 164,721 Total loans individually evaluated for impairment 29,461 33,632 51,195 26,225 33,487 507 1,376 175,883 Loans collectively evaluated for impairment 1,981,176 3,383,585 5,733,915 242,409 1,443,952 100,410 38,717 12,924,164 Loans acquired with deteriorated credit quality 14,878 165,275 925 738 19,858 — — 201,674 Total unpaid principal balance $ 2,025,515 $ 3,582,492 $ 5,786,035 $ 269,372 $ 1,497,297 $ 100,917 $ 40,093 $ 13,301,721 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 937 $ — $ 3,301 $ — $ — $ — $ 1 $ 4,239 Impaired loans with no allowance recorded — — — — — — — — Total loans individually evaluated for impairment 937 — 3,301 — — — 1 4,239 Loans collectively evaluated for impairment 11,403 12,646 69,673 3,851 20,398 — 671 118,642 Loans acquired with deteriorated credit quality — 687 359 — 777 — — 1,823 Total allowance for credit losses $ 12,340 $ 13,333 $ 73,333 $ 3,851 $ 21,175 $ — $ 672 $ 124,704 Troubled Debt Restructurings A TDR 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, or deferral of interest payments. 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 TDR loan is also considered impaired. Consistent with regulatory guidance, a TDR loan that is subsequently modified in another restructuring agreement but has shown sustained performance and classification as a TDR, will be removed from TDR status provided that the modified terms were market-based at the time of modification. During the three months ended March 31, 2017 , the Company had one new TDR loan with a recorded investment of $4.9 million . No principal amounts were forgiven and there were no waived fees or other expenses resulting from the TDR. The Company did not have any new TDR loans during the three months ended March 31, 2016. During the three months ended March 31, 2017 , there was one commercial and industrial TDR loan with a recorded investment of $0.1 million for which there was a payment default. During the three months ended March 31, 2016 , there was one CRE, non-owner occupied TDR loan with a recorded investment of $5.4 million for which there was a payment default. A TDR loan is deemed to have a payment default when it becomes past due 90 days, goes on non-accrual, or is restructured again. Payment defaults, along with other qualitative indicators, are considered by management in the determination of the allowance for credit losses. At March 31, 2017 and December 31, 2016 , there were no loan commitments outstanding on TDR loans. Loan Purchases and Sales For the three months ended March 31, 2017 and 2016 , secondary market loan purchases totaled $253.3 million and $33.8 million , respectively. For 2017 , these purchased loans consisted of $200.3 million of commercial and industrial loans and $53.0 million of residential real estate loans. For 2016 , these purchased loans consisted of commercial and industrial loans. During the three months ended March 31, 2017 , the Company sold CRE loans with a carrying value of $9.2 million and recognized a loss of less than $0.1 million on the sales. During the three months ended March 31, 2016 , the Company sold loans, which consisted primarily of CRE and commercial and industrial loans, with a carrying value of $ 23.8 million and recognized a gain of $ 2.5 million on the sales.

Other Assets Acquired Through F

Other Assets Acquired Through Foreclosure	3 Months Ended
	Mar. 31, 2017
Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]
Other Assets Acquired Through Foreclosure	4. OTHER ASSETS ACQUIRED THROUGH FORECLOSURE The following table represents the changes in other assets acquired through foreclosure: Three Months Ended March 31, 2017 Gross Balance Valuation Allowance Net Balance (in thousands) Balance, beginning of period $ 54,138 $ (6,323 ) $ 47,815 Transfers to other assets acquired through foreclosure, net — — — Proceeds from sale of other real estate owned and repossessed assets, net (3,113 ) 224 (2,889 ) Valuation adjustments, net — 380 380 (Losses) gains, net (1) (106 ) — (106 ) Balance, end of period $ 50,919 $ (5,719 ) $ 45,200 Three Months Ended March 31, 2016 Balance, beginning of period $ 52,984 $ (9,042 ) $ 43,942 Transfers to other assets acquired through foreclosure, net 10,638 — 10,638 Proceeds from sale of other real estate owned and repossessed assets, net (2,436 ) 295 (2,141 ) Valuation adjustments, net — 177 177 Gains (losses), net (1) 160 — 160 Balance, end of period $ 61,346 $ (8,570 ) $ 52,776 (1) There were no net gains related to initial transfers to other assets during the three months ended March 31, 2017 and 2016 . At March 31, 2017 and 2016 , the majority of the Company’s repossessed assets consisted of properties located in Nevada. The Company held 25 properties at March 31, 2017 , compared to 31 at December 31, 2016 and 37 at March 31, 2016.

Other Borrowings

Other Borrowings	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Other Borrowings	5. OTHER BORROWINGS The following table summarizes the Company’s borrowings as of March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 (in thousands) Short-Term: FHLB advances $ — $ 80,000 Total short-term borrowings $ — $ 80,000 The Company maintains other lines of credit with correspondent banks totaling $168.3 million , of which $23.3 million is secured by pledged securities and has a floating interest rate of one-month or three-month LIBOR plus 1.50%. The remaining $145.0 million is unsecured and has a floating interest rate of one-month LIBOR plus 3.25%. As of March 31, 2017 and December 31, 2016 , there were no outstanding balances on the Company's lines of credit. The Company maintains lines of credit with the FHLB and the 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. At March 31, 2017 , the Company had no short-term borrowings. At December 31, 2016 , short-term FHLB advances of $80.0 million had a weighted average interest rate of 0.55% . As of March 31, 2017 and December 31, 2016 , the Company had additional available credit with the FHLB of approximately $2.29 billion and $2.15 billion , respectively, and with the FRB of approximately $1.03 billion and $997.0 million , respectively.

Qualifying Debt Qualifying Debt

Qualifying Debt Qualifying Debt (Notes)	3 Months Ended
	Mar. 31, 2017
Qualifying Debt Disclosure [Abstract]
Subordinated Borrowings Disclosure [Text Block]	6. QUALIFYING DEBT Subordinated Debt The Company has $175.0 million of subordinated debentures with a maturity date of July 1, 2056. Beginning on or after July 1, 2021, the Company may redeem the debentures, in whole or in part, at their principal amount plus any accrued and unpaid interest. The subordinated debt was recorded net of issuance costs of $5.5 million . The debentures have a fixed interest rate of 6.25% per annum. WAB has $150.0 million of subordinated debt, which was recorded net of debt issuance costs of $1.8 million , and matures July 15, 2025. The subordinated debt has a fixed interest rate of 5.00% through June 30, 2020 and then converts to a variable rate of 3.20% plus three-month LIBOR through maturity. To hedge the interest rate risk on the Company's subordinated debt issuances, the Company entered into fair value interest rate hedges with pay variable/receive fixed swaps. The carrying value of all subordinated debt, which includes the effective portion of related hedges, totals $302.7 million and $305.8 million at March 31, 2017 and December 31, 2016 , respectively. Junior Subordinated Debt The Company has formed or acquired through acquisition eight statutory business trusts, which exist for the exclusive purpose of issuing Cumulative Trust Preferred Securities. With the exception of debt issued by Bridge Capital Trust I and Bridge Capital Trust II, junior subordinated debt is recorded at fair value at each reporting date due to the FVO election made by the Company under ASC 825. The Company did not make the FVO election for the junior subordinated debt acquired as part of the Bridge acquisition. Accordingly, the carrying value of these trusts does not reflect the current fair value of the debt and includes a fair market value adjustment established at acquisition that is being accreted over the remaining life of the trusts. The carrying value of junior subordinated debt was $64.2 million and $62.2 million at March 31, 2017 and December 31, 2016 , respectively. The weighted average interest rate of all junior subordinated debt as of March 31, 2017 was 3.49% , which is three-month LIBOR plus the contractual spread of 2.34%, compared to a weighted average interest rate of 3.34% at December 31, 2016 .

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholder's Equity	7. STOCKHOLDERS' EQUITY Stock-Based Compensation Stock Awards and Stock Options Restricted stock awards granted to employees in 2017 and 2016 generally vest over a three -year period. Stock grants made to non-employee WAL directors during 2017 will be fully vested at June 30, 2017. The Company estimates the compensation cost for stock grants based upon the grant date fair value. Stock compensation cost is recognized on a straight-line basis over the requisite service period for the entire award. The aggregate grant date fair value for the restricted stock awards granted in 2017 was $15.9 million . For the three months ended March 31, 2017 , the Company recognized $4.5 million in stock-based compensation expense related to all restricted stock award grants, including those assumed as part of the Bridge acquisition, compared to $3.8 million for the same period in 2016 . In addition, the Company grants shares of restricted stock to certain members of executive management that have both performance and service conditions that affect vesting. During the three months ended March 31, 2017 , the Company granted 40,451 shares of these restricted stock awards. The performance condition is based on achieving an EPS target for fiscal year 2017. The grant date fair value of the awards was $2.0 million . For the three months ended March 31, 2017 , the Company recognized $0.4 million in stock-based compensation expense related to all performance-based restricted stock grants, compared to $0.3 million in 2016 . Performance Stock Units The Company grants members of its executive management committee performance stock units that do not vest unless the Company achieves a specified cumulative EPS target over a three-year performance period. The number of shares issued will vary based on the cumulative EPS target that is achieved. The Company estimates the cost of performance stock units based upon the grant date fair value and expected vesting percentage over the three-year performance period. For the three months ended March 31, 2017 and 2016 , the Company recognized $1.3 million and $1.2 million , respectively, in stock-based compensation expense related to these performance stock units. The three-year performance period for the 2014 grant ended on December 31, 2016, and the Company's cumulative EPS for the performance period exceeded the level required for a maximum award under the terms of the grant. As a result, executive management committee members were entitled to the maximum award, which was 206,050 shares. Stock Options The Company's stock option awards consist of those awards assumed as part of the Bridge acquisition. During each of the three months ended March 31, 2017 and 2016 , the Company recognized $0.2 million in compensation expense related to these awards. Treasury Shares The Company purchased 201,306 treasury shares at a weighted average price of $50.88 per share and 290,432 treasury shares at a weighted average price of $30.81 per share during the three months ended March 31, 2017 and 2016 , respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income	8. ACCUMULATED OTHER COMPREHENSIVE INCOME The following table summarizes the changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods indicated: Unrealized holding gains (losses) on AFS Unrealized holding gains (losses) on SERP Unrealized holding gains (losses) on junior subordinated debt Impairment loss on securities Total (in thousands) Balance, December 31, 2016 $ (14,916 ) $ 121 $ 9,956 $ 144 $ (4,695 ) Other comprehensive income before reclassifications 9,169 (1 ) (1,229 ) — 7,939 Amounts reclassified from accumulated other comprehensive income (393 ) — — — (393 ) Net current-period other comprehensive income (loss) 8,776 (1 ) (1,229 ) — 7,546 Balance, March 31, 2017 $ (6,140 ) $ 120 $ 8,727 $ 144 $ 2,851 Balance, December 31, 2015 $ 9,993 $ 90 $ 12,033 $ 144 $ 22,260 Other comprehensive income before reclassifications 11,019 6 759 — 11,784 Amounts reclassified from accumulated other comprehensive income (711 ) — — — (711 ) Net current-period other comprehensive income (loss) 10,308 6 759 — 11,073 Balance, March 31, 2016 $ 20,301 $ 96 $ 12,792 $ 144 $ 33,333 The following table presents reclassifications out of accumulated other comprehensive income: Three Months Ended March 31, Income Statement Classification 2017 2016 (in thousands) Gain (loss) on sales of investment securities, net $ 635 $ 1,001 Income tax (expense) benefit (242 ) (290 ) Net of tax $ 393 $ 711

Derivatives and Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	9. DERIVATIVES AND HEDGING ACTIVITIES The Company is a party to various derivative instruments. Derivative instruments are contracts between two or more parties that have a notional amount and an underlying variable, require a small or no initial investment, and allow for the net settlement of positions. A derivative’s notional amount serves as the basis for the payment provision of the contract and takes the form of units, such as shares or dollars. A derivative’s underlying variable is a specified interest rate, security price, commodity price, foreign exchange rate, index, or other variable. The interaction between the notional amount and the underlying variable determines the number of units to be exchanged between the parties and influences the fair value of the derivative contract. The primary type of derivatives that the Company uses are interest rate swaps. Generally, these instruments are used to help manage the Company's exposure to interest rate risk and meet client financing and hedging needs. Derivatives are recorded at fair value in the Consolidated Balance Sheets, after taking into account the effects of bilateral collateral and master netting agreements. These agreements allow the Company to settle all derivative contracts held with the same counterparty on a net basis, and to offset net derivative positions with related cash collateral, where applicable. As of March 31, 2017 , December 31, 2016 , and March 31, 2016 , the Company does not have any significant outstanding cash flow hedges or free-standing derivatives. Derivatives Designated in Hedge Relationships The Company utilizes derivatives that have been designated as part of a hedge relationship in accordance with the applicable accounting guidance to minimize the exposure to changes in benchmark interest rates and volatility of net interest income and EVE to interest rate fluctuations. The primary derivative instruments used to manage interest rate risk are interest rate swaps, which convert the contractual interest rate index of agreed-upon amounts of assets and liabilities (i.e., notional amounts) to another interest rate index. The Company has entered into pay fixed/receive variable interest rate swaps designated as fair value hedges of certain fixed rate loans. As a result, the Company receives variable-rate interest payments in exchange for making fixed-rate payments over the lives of the contracts without exchanging the notional amounts. The Company has also entered into pay variable/receive fixed interest rate swaps, designated as fair value hedges on its fixed rate subordinated debt offerings. As a result, the Company is paying a floating rate of three month LIBOR plus 3.16% and is receiving semi-annual fixed payments of 5.00% to match the payments on the $150.0 million subordinated debt. For the fair value hedge on the Company's $175.0 million subordinated debentures issued on June 16, 2016, the Company is paying a floating rate of three month LIBOR plus 3.25% and is receiving quarterly fixed payments of 6.25% to match the payments on the debt. Fair Values, Volume of Activity, and Gain/Loss Information Related to Derivative Instruments The following table summarizes the fair values of the Company's derivative instruments on a gross and net basis as of March 31, 2017 , December 31, 2016 , and March 31, 2016 . The change in the notional amounts of these derivatives from March 31, 2016 to March 31, 2017 indicates the volume of the Company's derivative transaction activity during these periods. The derivative asset and liability balances are presented on a gross basis, prior to the application of bilateral collateral and master netting agreements. Total derivative assets and liabilities are adjusted to take into account the impact of legally enforceable master netting agreements that allow the Company to settle all derivative contracts with the same counterparty on a net basis and to offset the net derivative position with the related collateral. Where master netting agreements are not in effect or are not enforceable under bankruptcy laws, the Company does not adjust those derivative amounts with counterparties. The fair value of derivative contracts, after taking into account the effects of master netting agreements, is included in other assets or other liabilities in the Consolidated Balance Sheets, as indicated in the following table: March 31, 2017 December 31, 2016 March 31, 2016 Fair Value Fair Value Fair Value Notional Derivative Assets Derivative Liabilities Notional Derivative Assets Derivative Liabilities Notional Derivative Assets Derivative Liabilities (in thousands) Derivatives designated as hedging instruments: Fair value hedges Interest rate swaps $ 1,035,151 $ 1,985 $ 59,136 $ 993,485 $ 4,220 $ 65,749 $ 797,304 $ 4,733 $ 88,981 Total 1,035,151 1,985 59,136 993,485 4,220 65,749 797,304 4,733 88,981 Netting adjustments (1) — 1,947 1,947 — 1,869 1,869 — — — Net derivatives in the balance sheet $ 1,035,151 $ 38 $ 57,189 $ 993,485 $ 2,351 $ 63,880 $ 797,304 $ 4,733 $ 88,981 (1) Netting adjustments represent the amounts recorded to convert the Company's derivative balances from a gross basis to a net basis in accordance with the applicable accounting guidance. Fair value hedges An assessment of effectiveness is performed at initiation of a hedge and on a quarterly basis thereafter. All of the Company's fair value hedges remained “highly effective” as of March 31, 2017 , December 31, 2016 , and March 31, 2016 . The following table summarizes the gains (losses) on fair value hedges for the three months ended March 31, 2017 and 2016 , all of which are recorded in non-interest income. Three Months Ended March 31, 2017 2016 (in thousands) Hedge of Fixed Rate Loans (1) Gain (loss) on "pay fixed" swap $ 7,568 $ (24,197 ) Gain (loss) on receive fixed rate loans (7,553 ) 24,197 Net ineffectiveness $ 15 $ — Hedge of Fixed Rate Subordinated Debt Issuances (1) Gain (loss) on "receive fixed" swap $ (3,191 ) $ 1,164 Gain (loss) on subordinated debt 3,191 (1,164 ) Net ineffectiveness $ — $ — (1) The fair value of derivatives contracts are carried as other assets and other liabilities in the Consolidated Balance Sheets. The effective portion of hedging gains (losses) is recorded as basis adjustments to the underlying hedged asset or liability. Gains and losses on both the hedging derivative and hedged item are recorded through non-interest income with a resulting net income impact for the amount of ineffectiveness. Counterparty Credit Risk Like other financial instruments, derivatives contain an element of credit risk. This risk is measured as the expected positive replacement value of the contracts. Management generally enters into bilateral collateral and master netting agreements that provide for the net settlement of all contracts with the same counterparty. Additionally, management monitors counterparty credit risk exposure on each contract to determine appropriate limits on the Company's total credit exposure across all product types. In general, the Company has a zero credit threshold with regard to derivative exposure with counterparties. Management reviews the Company's collateral positions on a daily basis and exchanges collateral with counterparties in accordance with standard ISDA documentation and other related agreements. The Company generally holds collateral in the form of highly rated securities issued by the U.S. Treasury or government-sponsored enterprises, such as GNMA, FNMA, and FHLMC. The total collateral netted against net derivative liabilities totaled $59.1 million at March 31, 2017 , $65.7 million at December 31, 2016 , and $85.0 million at March 31, 2016 . The following table summarizes the Company's largest exposure to an individual counterparty at the dates indicated: March 31, 2017 December 31, 2016 March 31, 2016 (in thousands) Largest gross exposure (derivative asset) to an individual counterparty $ 1,150 $ 2,351 $ 4,733 Collateral posted by this counterparty — 1,691 4,292 Derivative liability with this counterparty 41,220 — — Collateral pledged to this counterparty 50,165 — — Net exposure after netting adjustments and collateral $ — $ 660 $ 441 Credit Risk Contingent Features Management has entered into certain derivative contracts that require the Company to post collateral to the counterparties when these contracts are in a net liability position. Conversely, the counterparties may be required to post collateral when these contracts are in a net asset position. The amount of collateral to be posted is based on the amount of the net liability and exposure thresholds. As of March 31, 2017 , December 31, 2016 , and March 31, 2016 the aggregate fair value of all derivative contracts with credit risk contingent features (i.e., those containing collateral posting provisions) held by the Company that were in a net liability position totaled $57.2 million , $63.9 million , and $89.0 million , respectively. As of March 31, 2017 , the Company was in an over-collateralized net position of $11.7 million after considering $70.8 million of collateral held in the form of cash and securities. As of December 31, 2016 and March 31, 2016 , the Company was in an over-collateralized position of $24.3 million and $9.2 million , respectively.

Earnings per Share (Notes)

Earnings per Share (Notes)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	10. EARNINGS PER SHARE Diluted EPS is based on the weighted average outstanding common shares during each period, including common stock equivalents. Basic EPS is based on the weighted average outstanding common shares during the period. The following table presents the calculation of basic and diluted EPS: Three Months Ended March 31, 2017 2016 (in thousands, except per share amounts) Weighted average shares - basic 103,987 101,895 Dilutive effect of stock awards 849 643 Weighted average shares - diluted 104,836 102,538 Net income available to common stockholders $ 73,357 $ 61,332 Earnings per share - basic 0.71 0.60 Earnings per share - diluted 0.70 0.60 The Company had no anti-dilutive stock options outstanding at each of the periods ended March 31, 2017 and 2016 .

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	The effective tax rate for the three months ended March 31, 2017 was 25.03% , compared to 24.14% for the three months ended March 31, 2016 . The increase in the effective tax rate for the three months ended March 31, 2017 compared to the three months ended March 31, 2016 is due primarily to an increase in pre-tax book income without proportional increases to favorable tax rate items. As of March 31, 2017 , the net deferred tax assets was $88.1 million , a decrease of $7.1 million from December 31, 2016 . This overall decrease in the net deferred tax asset was primarily the result of increases in the fair market value of AFS securities and stock compensation vesting. Although realization is not assured, the Company believes that the realization of the recognized deferred tax asset of $88.1 million at March 31, 2017 is more-likely-than-not based on expectations as to future taxable income and based on available tax planning strategies within the meaning of ASC 740, Income Taxes , that could be implemented if necessary to prevent a carryover from expiring. At each of the periods ended March 31, 2017 and December 31, 2016 , the Company had no deferred tax valuation allowance. The deferred tax asset related to federal and state NOL carryovers outstanding at each of the periods ended March 31, 2017 and December 31, 2016 available to reduce the tax liability in future years totaled $9.0 million . The $9.0 million of tax benefits relate entirely to federal NOL carryovers (subject to an annual limitation imposed by IRC Section 382). The Company’s ability to use federal NOL carryovers, as well as its ability to use certain future tax deductions called NUBILs associated with the Company's acquisitions is subject to annual limitations. In management’s opinion, it is more-likely-than-not that the results of future operations will generate sufficient taxable income to realize all of the deferred tax benefits related to these NOL carryovers and NUBILs. Investments in LIHTC The Company invests in LIHTC funds that are designed to generate a return primarily through the realization of federal tax credits. Investments in LIHTC and unfunded LIHTC obligations are included as part of other assets and other liabilities, respectively, in the Consolidated Balance Sheets and total $206.5 million and $105.8 million , respectively, as of March 31, 2017 , compared to $187.4 million and $84.4 million as of December 31, 2016 . For the three months ended March 31, 2017 and 2016 , $5.8 million and $4.4 million , respectively, of amortization related to LIHTC investments was recognized as a component of income tax expense.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12. 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 potential 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: March 31, 2017 December 31, 2016 (in thousands) Commitments to extend credit, including unsecured loan commitments of $357,462 at March 31, 2017 and $360,840 at December 31, 2016 $ 4,951,254 $ 4,428,495 Credit card commitments and financial guarantees 122,969 115,536 Standby letters of credit, including unsecured letters of credit of $9,396 at March 31, 2017 and $6,431 at December 31, 2016 98,674 78,576 Total $ 5,172,897 $ 4,622,607 Commitments to extend credit are agreements to lend to a customer provided that 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 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 included in other liabilities as a separate loss contingency and are not included in the allowance for credit losses reported in " Note 3. Loans, Leases and Allowance for Credit Losses " of these Consolidated Financial Statements. This loss contingency for unfunded loan commitments and letters of credit was $6.4 million and $7.0 million as of March 31, 2017 and December 31, 2016 , respectively. Changes to this liability are adjusted through non-interest expense. Concentrations of Lending Activities The Company’s lending activities are driven in large part by the customers served in the market areas where the Company has branch offices in the states of Arizona, Nevada, and California. Despite the geographic concentration of lending activities, the Company does not have a single external customer from which it derives 10% or more of its revenues. The Company monitors concentrations within four broad categories: geography, industry, product, and collateral. The Company's loan portfolio includes significant credit exposure to the CRE market. As of each of the periods ended March 31, 2017 and December 31, 2016 , CRE related loans accounted for approximately 53% of total loans. Substantially all of these loans are secured by first liens with an initial loan to value ratio of generally not more than 75% . Approximately 36% of these CRE loans, excluding construction and land loans, were owner-occupied at each of the periods ended March 31, 2017 and December 31, 2016 . 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 these lawsuits, but in the opinion of management, based in part on consultation with outside 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 $2.6 million and $2.5 million for three months ended March 31, 2017 and 2016 , respectively, was included in occupancy expense.

Fair Value Accounting

Fair Value Accounting	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Accounting	13. 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 825 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 " of these Notes to Unaudited Consolidated Financial Statements. 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. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. Transfers between levels in the fair value hierarchy are recognized as of the end of the month following the event or change in circumstances that caused the transfer. Under ASC 825, the Company elected the FVO treatment for junior subordinated debt issued by WAL. This election is irrevocable and results in the recognition of unrealized gains and losses on these items at each reporting date. Due to the Company's election to early adopt an element of ASU 2016-01, effective January 1, 2015, these unrealized gains and losses are recognized as part of other comprehensive income rather than earnings. The Company did not elect FVO treatment for assumed Bridge junior subordinated debt. All securities for which the fair value measurement option had been elected are included in a separate line item in the Consolidated Balance Sheets as securities measured at fair value. For the three months ended March 31, 2017 and 2016 , gains and losses from fair value changes on securities and junior subordinated debt were as follows: Changes in Fair Values for Items Measured at Fair Value Unrealized Gain/(Loss) on Assets and Liabilities Measured at Fair Value, Net Interest Income on Securities Interest Expense on Junior Subordinated Debt Total Changes Included in Current-Period Earnings Total Changes Included in OCI (in thousands) Three Months Ended March 31, 2017 Securities measured at fair value $ (1 ) $ 7 $ — $ 6 $ — Junior subordinated debt (1,986 ) — (749 ) (749 ) (1,229 ) Total $ (1,987 ) $ 7 $ (749 ) $ (743 ) $ (1,229 ) Three Months Ended March 31, 2016 Securities measured at fair value $ (5 ) $ 11 $ — $ 6 $ — Junior subordinated debt 1,212 — (680 ) (680 ) 759 Total $ 1,207 $ 11 $ (680 ) $ (674 ) $ 759 There were no net gains or losses recognized during the three months ended March 31, 2017 and 2016 on sales of securities measured at fair value. Interest income on securities measured at fair value is accounted for similarly to those classified as AFS. Any premiums or discounts are recognized in interest income over the term of the securities. For MBS, estimates of prepayments are considered in the constant yield calculations. 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: Securities measured at fair value: All of the Company’s securities measured at fair value, which consist of MBS, are reported at fair value utilizing Level 2 inputs in the same manner as described below for AFS securities. AFS securities: Preferred stock, CRA investments, and certain corporate debt securities 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. Historically, the Company has estimated the fair value of its CDO securities utilizing Level 3 inputs, which include pricing indications from comparable securities. During the year ended December 31, 2016, these securities were transferred from Level 3 to Level 2 as a result of an increase in the availability and reliability of the observable inputs utilized in the securities' fair value measurement. Independent pricing service: The Company's independent pricing service provides pricing information on the majority of the Company's Level 1 and 2 securities. Management independently evaluates the fair value measurements received from the Company's third party pricing service through multiple review steps. First, management reviews what has transpired in the marketplace with respect to interest rates, credit spreads, volatility, and mortgage rates, among other things, and develops an expectation of changes to the securities' valuations from the previous quarter. Then, management obtains market values from additional sources. 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 between management’s review and the prices provided by the vendor are discussed with the vendor and the Company’s other valuation advisors. Lastly, management selects a sample of investment securities and compares the values provided by its primary third party pricing service to the market values obtained from secondary sources and evaluates those with notable variances. Annually, the Company receives an SSAE 16 report from its independent pricing service attesting to the controls placed on the operations of the service from its auditor. Interest rate swaps: 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 are based on contractual cash flows as the Company anticipates that it will pay the debt according to its contractual terms. As of March 31, 2017 , the Company estimates the discount rate at 5.54% , which represents an implied credit spread of 4.39% plus three-month LIBOR ( 1.15% ). As of December 31, 2016 , the Company estimated the discount rate at 5.66% , which was a 4.66% credit spread plus three-month LIBOR ( 1.00% ). The fair value of assets and liabilities measured at fair value on a recurring basis was determined using the following inputs as of the periods presented: Fair Value Measurements at the End of the Reporting Period Using: Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Fair Value (in thousands) March 31, 2017 Assets: Measured at fair value Residential MBS issued by GSEs $ — $ 1,019 $ — $ 1,019 Available-for-sale Collateralized debt obligations $ — $ 20,023 $ — $ 20,023 Commercial MBS issued by GSEs — 115,700 — 115,700 Corporate debt securities — 68,395 — 68,395 CRA investments 47,208 — — 47,208 Preferred stock 98,602 — — 98,602 Private label residential MBS — 497,066 — 497,066 Residential MBS issued by GSEs — 1,362,800 — 1,362,800 Tax-exempt — 404,115 — 404,115 Trust preferred securities — 27,680 — 27,680 U.S. government sponsored agency securities — 55,920 — 55,920 U.S. treasury securities — 2,502 — 2,502 Total AFS securities $ 145,810 $ 2,554,201 $ — $ 2,700,011 Loans - HFS $ — $ 17,865 $ — $ 17,865 Derivative assets (1) — 1,985 — 1,985 Liabilities: Junior subordinated debt (2) $ — $ — $ 52,396 $ 52,396 Derivative liabilities (1) — 59,136 — 59,136 (1) Derivative assets and liabilities relate to interest rate swaps, see " Note 9. Derivatives and Hedging Activities ." In addition, the carrying value of loans is increased by $40,886 and the net carrying value of subordinated debt is decreased by $15,517 as of March 31, 2017 , which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates. (2) Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment. Fair Value Measurements at the End of the Reporting Period Using: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value (in thousands) December 31, 2016 Assets: Measured at fair value Residential MBS issued by GSEs $ — $ 1,053 $ — $ 1,053 Available-for-sale Collateralized debt obligations — 13,490 — 13,490 Commercial MBS issued by GSEs — 117,792 — 117,792 Corporate debt securities 20,000 44,144 — 64,144 CRA investments 37,113 — — 37,113 Preferred stock 94,662 — — 94,662 Private label residential MBS — 433,685 — 433,685 Residential MBS issued by GSEs — 1,355,205 — 1,355,205 Tax-exempt — 408,233 — 408,233 Trust preferred securities — 26,532 — 26,532 U.S. government sponsored agency securities 56,022 56,022 U.S. treasury securities — 2,502 — 2,502 Total AFS securities $ 151,775 $ 2,457,605 $ — $ 2,609,380 Loans - HFS $ — $ 18,909 $ — $ 18,909 Derivative assets (1) — 4,220 — 4,220 Liabilities: Junior subordinated debt $ — $ — $ 50,410 $ 50,410 Derivative liabilities (1) — 65,749 $ — 65,749 (1) Derivative assets and liabilities relate to interest rate swaps, see " Note 9. Derivatives and Hedging Activities ." In addition, the carrying value of loans is increased by $ 48,161 and the net carrying value of subordinated debt is decreased by $12,325 as of December 31, 2016 , which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates. For the three months ended March 31, 2017 and 2016 , the change in Level 3 assets and liabilities measured at fair value on a recurring basis was as follows: Junior Subordinated Debt Three Months Ended March 31, 2017 2016 (in thousands) Beginning balance $ (50,410 ) $ (46,928 ) Transfers into Level 3 — — Total gains (losses) for the period Included in other comprehensive income (1,986 ) 1,212 Ending balance $ (52,396 ) $ (45,716 ) CDO Securities Three Months Ended March 31, 2017 2016 (in thousands) Beginning balance $ — $ 10,060 Transfers into Level 3 — — Total gains (losses) for the period Included in other comprehensive income — (984 ) Ending balance $ — $ 9,076 The Company transferred all CDO securities from Level 3 to Level 2 during the year ended December 31, 2016 as a result of an increase in the availability and reliability of the observable inputs utilized in the securities' fair value measurement. The Company recognized this transfer between levels on October 31, 2016, in accordance with its policy to recognize transfers between levels in the fair value hierarchy as of the end of the month following the event or change in circumstance that caused the transfer. For Level 3 assets and liabilities measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 , the significant unobservable inputs used in the fair value measurements were as follows: March 31, 2017 Valuation Technique Significant Unobservable Inputs Input Value (in thousands) Junior subordinated debt $ 52,396 Discounted cash flow Implied credit rating of the Company 5.54 % December 31, 2016 Valuation Technique Significant Unobservable Inputs Input Value (in thousands) Junior subordinated debt $ 50,410 Discounted cash flow Implied credit rating of the Company 5.66 % The significant unobservable inputs used in the fair value measurement of the Company’s junior subordinated debt as of March 31, 2017 and December 31, 2016 was the implied credit risk for the Company, calculated as the difference between the 20-year 'BB' rated financial index over the corresponding swap index. Fair value on a nonrecurring basis Certain assets are measured at fair value on a nonrecurring basis. That is, the assets 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 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 in Active Markets for Identical Assets (Level 1) Active Markets for Similar Assets (Level 2) Unobservable Inputs (Level 3) (in thousands) As of March 31, 2017: Impaired loans with specific valuation allowance $ 6,954 $ — $ — $ 6,954 Impaired loans without specific valuation allowance (1) 79,351 — — 79,351 Other assets acquired through foreclosure 45,200 — — 45,200 As of December 31, 2016: Impaired loans with specific valuation allowance $ 6,670 $ — $ — $ 6,670 Impaired loans without specific valuation allowance (1) 60,738 — — 60,738 Other assets acquired through foreclosure 47,815 — — 47,815 (1) Net of loan balances with charge-offs of $23.4 million and $27.6 million as of March 31, 2017 and December 31, 2016 , respectively. For Level 3 assets measured at fair value on a nonrecurring basis as of March 31, 2017 and December 31, 2016 , the significant unobservable inputs used in the fair value measurements were as follows: March 31, 2017 Valuation Technique(s) Significant Unobservable Inputs Range (in thousands) Impaired loans $ 86,305 Collateral method Third party appraisal Costs to sell 4.0% to 10.0% Discounted cash flow method Discount rate Contractual loan rate 4.0% to 7.0% Scheduled cash collections Probability of default 0% to 20.0% Proceeds from non-real estate collateral Loss given default 0% to 70.0% Other assets acquired through foreclosure 45,200 Collateral method Third party appraisal Costs to sell 4.0% to 10.0% December 31, 2016 Valuation Technique(s) Significant Unobservable Inputs Range (in thousands) Impaired loans $ 67,408 Collateral method Third party appraisal Costs to sell 4.0% to 10.0% Discounted cash flow method Discount rate Contractual loan rate 4.0% to 7.0% Scheduled cash collections Probability of default 0% to 20.0% Proceeds from non-real estate collateral Loss given default 0% to 70.0% Other assets acquired through foreclosure 47,815 Collateral method Third party appraisal Costs to sell 4.0% to 10.0% Impaired loans: The specific reserves for collateral dependent impaired loans are based on collateral value, net of estimated disposition costs and other identified quantitative inputs. Collateral value is determined based on independent third-party appraisals or internally-developed discounted cash flow analyses. 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 addition, when adjustments are made to an appraised value to reflect various factors such as the age of the appraisal or known changes in the market or the collateral, such valuation inputs are considered unobservable and the fair value measurement is categorized as a Level 3 measurement. Internal discounted cash flow analyses are also utilized to estimate the fair value of impaired loans, which considers internally-developed, unobservable inputs such as discount rates, default rates, and loss severity. Total Level 3 impaired loans had an estimated fair value of $86.3 million and $67.4 million at March 31, 2017 and December 31, 2016 , respectively. Impaired loans with a specific valuation allowance had a gross estimated fair value of $10.9 million at each of the periods ended March 31, 2017 and December 31, 2016 , which was reduced by a specific valuation allowance of $4.0 million and $4.2 million , respectively. Other assets acquired through foreclosure: Other assets acquired through foreclosure consist of properties acquired as a result of, or in-lieu-of, foreclosure. These assets are initially reported at the fair value determined by independent appraisals using appraised value less estimated 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. 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 the appraised value and there is no observable market price, the resulting fair value measurement has been categorized as a Level 3 measurement. The Company had $45.2 million and $47.8 million of such assets at March 31, 2017 and December 31, 2016 , respectively. Credit vs. non-credit losses Under the provisions of ASC 320, Investments-Debt and Equity Securities , OTTI is separated into the amount of total impairment related to the credit loss and the amount of the total impairment related to all other factors. The amount of the total OTTI related to the credit loss is recognized in earnings. The amount of the total impairment related to all other factors is recognized in OCI. For the three months ended March 31, 2017 and 2016 , the Company determined that no securities experienced credit losses. There is no OTTI balance recognized in comprehensive income as of March 31, 2017 and 2016 . FAIR VALUE OF FINANCIAL INSTRUMENTS The estimated fair value of the Company’s financial instruments is as follows: March 31, 2017 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 102,590 $ — $ 103,666 $ — $ 103,666 AFS 2,700,011 145,810 2,554,201 — 2,700,011 Trading 1,019 — 1,019 — 1,019 Derivative assets 1,985 — 1,985 — 1,985 Loans, net 13,535,099 — 13,365,680 86,305 13,451,985 Accrued interest receivable 66,453 — 66,453 — 66,453 Financial liabilities: Deposits $ 15,355,970 $ — $ 15,361,363 $ — $ 15,361,363 Customer repurchase agreements 35,711 — 35,711 — 35,711 Qualifying debt 366,885 — — 390,689 390,689 Derivative liabilities 59,136 — 59,136 — 59,136 Accrued interest payable 10,459 — 10,459 — 10,459 December 31, 2016 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 92,079 $ — $ 91,966 $ — $ 91,966 AFS 2,609,380 151,775 2,457,605 — 2,609,380 Trading 1,053 — 1,053 — 1,053 Derivative assets 4,220 — 4,220 — 4,220 Loans, net 13,083,732 — 12,736,336 67,408 12,803,744 Accrued interest receivable 70,320 — 70,320 — 70,320 Financial liabilities: Deposits $ 14,549,863 $ — $ 14,553,931 $ — $ 14,553,931 Customer repurchase agreements 41,728 — 41,728 — 41,728 FHLB advances 80,000 — 80,000 — 80,000 Qualifying debt 367,937 — — 375,626 375,626 Derivative liabilities 65,749 — 65,749 — 65,749 Accrued interest payable 15,354 — 15,354 — 15,354 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 Company's change in EVE and net interest income resulting from hypothetical changes in interest rates. If potential changes to EVE and net interest income resulting from hypothetical interest rate changes are not within the limits established by the BOD, the BOD may direct management to adjust the asset and liability mix to bring interest rate risk within BOD-approved limits. As of March 31, 2017 , the Company’s interest rate risk profile was within BOD-approved limits. WAB has an ALCO charged with managing interest rate risk within the BOD-approved limits. Limits are structured to prohibit an interest rate risk profile that does not conform to both management and BOD risk tolerances. There is also ALCO reporting at the Parent company level for reviewing interest rate risk for the Company, which gets reported to the BOD and its Finance and Investment Committee. Fair value of commitments The estimated fair value of standby letters of credit outstanding at March 31, 2017 and December 31, 2016 is insignificant. Loan commitments on which the committed interest rates are less than the current market rate are also insignificant at March 31, 2017 and December 31, 2016 .

Segments

Segments	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segments	14. SEGMENTS The Company's reportable segments are aggregated based primarily on geographic location, services offered, and markets served. The Company's regional segments, which include Arizona, Nevada, Southern California, and Northern California, provide full service banking and related services to their respective markets. The operations from the regional segments correspond to the following banking divisions: ABA in Arizona, BON and FIB in Nevada, TPB in Southern California, and Bridge in Northern California. The Company's NBL segments provide specialized banking services to niche markets. The Company's NBL reportable segments include HOA Services, Public & Nonprofit Finance, Technology & Innovation, HFF, and Other NBLs. These NBLs are managed centrally and are broader in geographic scope than the Company's other segments, though still predominately located within the Company's core market areas. The HOA Services NBL corresponds to the AAB division. The operations of Public and Nonprofit Finance are combined into one reportable segment. The Technology & Innovation NBL includes the operations of Equity Fund Resources, Life Sciences Group, Renewable Resource Group, and Technology Finance. The HFF NBL includes the hotel franchise loan portfolio acquired from GE on April 20, 2016. The Other NBLs segment consists of Corporate Finance, Mortgage Warehouse Lending, and Resort Finance. The Corporate & Other segment consists of corporate-related items, income and expense items not allocated to the Company's other reportable segments, and inter-segment eliminations. The Company's segment reporting process begins with the assignment of all loan and deposit accounts directly to the segments where these products are originated and/or serviced. Equity capital is assigned to each segment based on the risk profile of their assets and liabilities. With the exception of goodwill, which is assigned a 100% weighting, equity capital allocations ranged from 0% to 12% during the year, with a funds credit provided for the use of this equity as a funding source. Any excess or deficient equity not allocated to segments based on risk is assigned to the Corporate & Other segment. Net interest income, provision for credit losses, and non-interest expense amounts are recorded in their respective segment to the extent that the amounts are directly attributable to those segments. Net interest income is recorded in each segment on a TEB with a corresponding increase in income tax expense, which is eliminated in the Corporate & Other segment. Further, net interest income of a reportable segment includes a funds transfer pricing process that matches assets and liabilities with similar interest rate sensitivity and maturity characteristics. Using this funds transfer pricing methodology, liquidity is transferred between users and providers. A net user of funds has lending/investing in excess of deposits/borrowings and a net provider of funds has deposits/borrowings in excess of lending/investing. A segment that is a user of funds is charged for the use of funds, while a provider of funds is credited through funds transfer pricing, which is determined based on the average life of the assets or liabilities in the portfolio. The net income amount for each reportable segment is further derived by the use of expense allocations. Certain expenses not directly attributable to a specific segment are allocated across all segments based on key metrics, such as number of employees, average loan balances, and average deposit balances. These types of expenses include information technology, operations, human resources, finance, risk management, credit administration, legal, and marketing. Income taxes are applied to each segment based on the effective tax rate for the geographic location of the segment. Any difference in the corporate tax rate and the aggregate effective tax rates in the segments are adjusted in the Corporate & Other segment. The following is a summary of operating segment balance sheet information for the periods indicated: Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At March 31, 2017 (in millions) Assets: Cash, cash equivalents, and investment securities $ 3,516.1 $ 1.8 $ 8.9 $ 1.9 $ 1.7 Loans, net of deferred loan fees and costs 13,662.7 3,039.7 1,769.3 1,806.7 1,130.1 Less: allowance for credit losses (127.6 ) (30.3 ) (18.7 ) (20.1 ) (9.4 ) Total loans 13,535.1 3,009.4 1,750.6 1,786.6 1,120.7 Other assets acquired through foreclosure, net 45.2 5.0 17.1 — 0.2 Goodwill and other intangible assets, net 302.1 — 23.4 — 157.2 Other assets 724.0 42.3 58.9 13.9 13.5 Total assets $ 18,122.5 $ 3,058.5 $ 1,858.9 $ 1,802.4 $ 1,293.3 Liabilities: Deposits $ 15,356.0 $ 4,255.0 $ 3,896.1 $ 2,397.2 $ 1,461.3 Borrowings and qualifying debt 366.9 — — — — Other liabilities 430.6 13.4 27.4 4.5 13.6 Total liabilities 16,153.5 4,268.4 3,923.5 2,401.7 1,474.9 Allocated equity: 1,969.0 365.7 259.0 205.2 284.6 Total liabilities and stockholders' equity $ 18,122.5 $ 4,634.1 $ 4,182.5 $ 2,606.9 $ 1,759.5 Excess funds provided (used) — 1,575.6 2,323.6 804.5 466.2 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 3,501.8 Loans, net of deferred loan fees and costs 132.7 1,528.7 1,011.2 1,279.6 1,955.1 9.6 Less: allowance for credit losses (1.4 ) (16.0 ) (9.7 ) (1.3 ) (20.0 ) (0.7 ) Total loans 131.3 1,512.7 1,001.5 1,278.3 1,935.1 8.9 Other assets acquired through foreclosure, net — — — — — 22.9 Goodwill and other intangible assets, net — — 121.4 0.1 — — Other assets 0.4 11.9 5.7 5.4 2.8 569.2 Total assets $ 131.7 $ 1,524.6 $ 1,128.6 $ 1,283.8 $ 1,937.9 $ 4,102.8 Liabilities: Deposits $ 2,112.8 $ — $ 1,142.2 $ — $ — $ 91.4 Borrowings and qualifying debt — — — — — 366.9 Other liabilities 1.8 43.1 0.8 0.6 132.6 192.8 Total liabilities 2,114.6 43.1 1,143.0 0.6 132.6 651.1 Allocated equity: 72.9 122.3 225.5 105.5 162.2 166.1 Total liabilities and stockholders' equity $ 2,187.5 $ 165.4 $ 1,368.5 $ 106.1 $ 294.8 $ 817.2 Excess funds provided (used) 2,055.8 (1,359.2 ) 239.9 (1,177.7 ) (1,643.1 ) (3,285.6 ) Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At December 31, 2016 (in millions) Assets: Cash, cash equivalents, and investment securities $ 3,052.3 $ 1.9 $ 10.1 $ 2.1 $ 1.9 Loans, net of deferred loan fees and costs 13,208.5 2,955.9 1,725.5 1,766.8 1,095.4 Less: allowance for credit losses (124.7 ) (30.1 ) (18.5 ) (19.4 ) (8.8 ) Total loans 13,083.8 2,925.8 1,707.0 1,747.4 1,086.6 Other assets acquired through foreclosure, net 47.8 6.2 18.0 — 0.3 Goodwill and other intangible assets, net 302.9 — 23.7 — 157.5 Other assets 714.0 42.9 58.8 14.5 14.3 Total assets $ 17,200.8 $ 2,976.8 $ 1,817.6 $ 1,764.0 $ 1,260.6 Liabilities: Deposits $ 14,549.8 $ 3,843.4 $ 3,731.5 $ 2,382.6 $ 1,543.6 Borrowings and qualifying debt 447.9 — — — — Other liabilities 311.6 12.8 28.3 12.9 12.4 Total liabilities 15,309.3 3,856.2 3,759.8 2,395.5 1,556.0 Allocated equity: 1,891.5 346.6 250.7 201.6 283.7 Total liabilities and stockholders' equity $ 17,200.8 $ 4,202.8 $ 4,010.5 $ 2,597.1 $ 1,839.7 Excess funds provided (used) — 1,226.0 2,192.9 833.1 579.1 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 3,036.3 Loans, net of deferred loan fees and costs 116.8 1,454.3 1,011.4 1,292.1 1,776.9 13.4 Less: allowance for credit losses (1.3 ) (15.6 ) (10.6 ) (0.8 ) (19.0 ) (0.6 ) Total loans 115.5 1,438.7 1,000.8 1,291.3 1,757.9 12.8 Other assets acquired through foreclosure, net — — — — — 23.3 Goodwill and other intangible assets, net — — 121.5 0.2 — — Other assets 0.3 15.6 7.2 5.3 11.1 544.0 Total assets $ 115.8 $ 1,454.3 $ 1,129.5 $ 1,296.8 $ 1,769.0 $ 3,616.4 Liabilities: Deposits $ 1,890.3 $ — $ 1,038.2 $ — $ — $ 120.2 Borrowings and qualifying debt — — — — — 447.9 Other liabilities 0.7 50.5 2.0 1.4 17.5 173.1 Total liabilities 1,891.0 50.5 1,040.2 1.4 17.5 741.2 Allocated equity: 65.6 117.1 224.1 107.1 145.5 149.5 Total liabilities and stockholders' equity $ 1,956.6 $ 167.6 $ 1,264.3 $ 108.5 $ 163.0 $ 890.7 Excess funds provided (used) 1,840.8 (1,286.7 ) 134.8 (1,188.3 ) (1,606.0 ) (2,725.7 ) The following is a summary of operating segment income statement information for the periods indicated: Regional Segments Consolidated Company Arizona Nevada Southern California Northern California Three Months Ended March 31, 2017: (in thousands) Net interest income (expense) $ 179,309 $ 43,907 $ 35,296 $ 25,218 $ 22,035 Provision for (recovery of) credit losses 4,250 14 (211 ) 91 396 Net interest income (expense) after provision for credit losses 175,059 43,893 35,507 25,127 21,639 Non-interest income 10,544 1,113 2,133 743 2,113 Non-interest expense (87,757 ) (18,622 ) (15,870 ) (12,703 ) (12,709 ) Income (loss) before income taxes 97,846 26,384 21,770 13,167 11,043 Income tax expense (benefit) 24,489 10,350 7,620 5,537 4,643 Net income (loss) $ 73,357 $ 16,034 $ 14,150 $ 7,630 $ 6,400 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other (in thousands) Net interest income (expense) $ 12,748 $ 6,485 $ 18,166 $ 13,581 $ 14,143 $ (12,270 ) Provision for (recovery of) credit losses 127 509 296 — 3,527 (499 ) Net interest income (expense) after provision for credit losses 12,621 5,976 17,870 13,581 10,616 (11,771 ) Non-interest income 141 15 1,873 — 721 1,692 Non-interest expense (7,147 ) (2,253 ) (8,779 ) (2,988 ) (4,721 ) (1,965 ) Income (loss) before income taxes 5,615 3,738 10,964 10,593 6,616 (12,044 ) Income tax expense (benefit) 2,106 1,402 4,111 3,972 2,481 (17,733 ) Net income (loss) $ 3,509 $ 2,336 $ 6,853 $ 6,621 $ 4,135 $ 5,689 Regional Segments Consolidated Company Arizona Nevada Southern California Northern California Three Months Ended March 31, 2016: (in thousands) Net interest income (expense) $ 145,711 $ 38,456 $ 32,575 $ 24,428 $ 23,195 Provision for (recovery of) credit losses 2,500 6,773 (813 ) 30 1,042 Net interest income (expense) after provision for credit losses 143,211 31,683 33,388 24,398 22,153 Non-interest income 13,133 3,681 2,059 660 2,426 Non-interest expense (75,493 ) (14,456 ) (14,746 ) (11,234 ) (13,967 ) Income (loss) before income taxes 80,851 20,908 20,701 13,824 10,612 Income tax expense (benefit) 19,519 8,202 7,245 5,813 4,463 Net income (loss) $ 61,332 $ 12,706 $ 13,456 $ 8,011 $ 6,149 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Other NBLs Corporate & Other (in thousands) Net interest income (expense) $ 8,632 $ 5,221 $ 16,309 $ 10,637 $ (13,742 ) Provision for (recovery of) credit losses 78 (369 ) (1,165 ) 238 (3,314 ) Net interest income (expense) after provision for credit losses 8,554 5,590 17,474 10,399 (10,428 ) Non-interest income 105 (4 ) 1,637 635 1,934 Non-interest expense (5,541 ) (2,024 ) (6,906 ) (3,437 ) (3,182 ) Income (loss) before income taxes 3,118 3,562 12,205 7,597 (11,676 ) Income tax expense (benefit) 1,169 1,336 4,577 2,849 (16,135 ) Net income (loss) $ 1,949 $ 2,226 $ 7,628 $ 4,748 $ 4,459

Mergers, Acquisitions and Dispo

Mergers, Acquisitions and Dispositions	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Acquisition of GE Capital US Holdings, Inc. Loan Portfolio On April 20, 2016, WAB completed its acquisition of GE Capital US Holdings, Inc.'s domestic select-service hotel franchise finance loan portfolio, paying cash of $1.27 billion . The acquisition was undertaken, in part, to expand the Company's national reach and diversify the Company's loan portfolio. Effective April 20, 2016, the results of the acquired loan portfolio are reflected in the Company's HFF NBL operating segment. There were no acquisition / restructure expenses related to the acquisition recognized during the three months ended March 31, 2017 . The transaction was accounted for under the acquisition method of accounting in accordance with ASC 805. Assets purchased and liabilities assumed were recorded at their respective acquisition date estimated fair values. 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. During the three months ended March 31, 2017 , the Company recognized measurement period adjustments totaling $0.1 million for tax related items. The measurement period for the HFF acquisition ended on April 20, 2017. Therefore, the fair values of these assets acquired and liabilities assumed were considered final effective April 20, 2017. The recognized amounts of identifiable assets acquired and liabilities assumed, at their as adjusted acquisition date fair values, are as follows: April 20, 2016 (in thousands) Assets: Loans $ 1,280,997 Other assets 3,632 Total assets $ 1,284,629 Liabilities: Other liabilities $ 12,559 Total liabilities 12,559 Net assets acquired $ 1,272,070 Consideration paid Cash $ 1,272,187 Goodwill $ 117 The following table presents pro forma information as if the acquisition was completed on January 1, 2015. The pro forma information includes adjustments for interest income on loans acquired and excludes acquisition / restructure expense. 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 March 31, 2016 (in thousands, except per share amounts) Interest income $ 170,885 Non-interest income 13,133 Net income available to common stockholders 68,491 Earnings per share - basic 0.67 Earnings per share - diluted 0.67

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Nature of Operation	Nature of operation WAL is a bank holding company headquartered in Phoenix, Arizona, incorporated under the laws of the state of Delaware. WAL provides a full spectrum of deposit, lending, treasury management, international banking, and online banking products and services through its wholly-owned banking subsidiary, WAB. WAB operates the following full-service banking divisions: ABA, BON, FIB, Bridge, and TPB. The Company also serves business customers through a national platform of specialized financial services including AAB, Corporate Finance, Equity Fund Resources, HFF, Life Sciences Group, Mortgage Warehouse Lending, Public and Nonprofit Finance, Renewable Resource Group, Resort Finance, and Technology Finance. In addition, the Company has one non-bank subsidiary, LVSP, which holds and manages certain non-performing loans and OREO.
Basis of Presentation	Basis of presentation The accounting and reporting policies of the Company are in accordance with GAAP and conform to practices within the financial services industry. The accounts of the Company and its consolidated subsidiaries are included in the Consolidated Financial Statements.
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. Management's estimates and judgments are ongoing and are based on experience, current and expected future conditions, third-party evaluations and various other assumptions that management believes are reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities, as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from those estimates and assumptions used in the Consolidated Financial Statements and related notes. Material estimates that are particularly susceptible to significant changes in the near term relate to the determination of the allowance for credit losses; estimated cash flows related to PCI loans; fair value determinations related to acquisitions and certain assets and liabilities carried at fair value; and accounting for income taxes.
Principles of Consolidation	Principles of consolidation As of March 31, 2017 , WAL has ten wholly-owned subsidiaries: WAB, LVSP, and eight unconsolidated subsidiaries used as business trusts in connection with the issuance of trust-preferred securities. The Bank has the following significant wholly-owned subsidiaries: WABT, which holds certain investment securities, municipal and nonprofit loans, and leases; WA PWI, LLC, which holds certain limited partnerships invested primarily in low income housing tax credits and small business investment corporations; and BW Real Estate, Inc., which operates as a real estate investment trust and holds certain of WAB's real estate loans and related securities. The Company does not have any other significant entities that should be considered for consolidation. All significant intercompany balances and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications Certain amounts in the Consolidated Financial Statements as of December 31, 2016 and for the three months ended March 31, 2016 may have been reclassified to conform to the current presentation. The reclassifications have no effect on net income or stockholders’ equity as previously reported.
Business Combinations	Business combinations Business combinations are accounted for under the acquisition method of accounting in accordance with ASC 805, Business Combinations. Under the acquisition method, the acquiring entity in a business combination recognizes all of the acquired assets and assumed liabilities at their estimated fair values as of the date of acquisition. Any excess of the purchase price over the fair value of net assets and other identifiable intangible assets acquired is recorded as goodwill. To the extent the fair value of net assets acquired, including identified intangible assets, exceeds the purchase price, a bargain purchase gain is recognized. Changes to estimated fair values from a business combination are recognized as an adjustment to goodwill during the measurement period and are recognized in the proper reporting period in which the adjustment amounts are determined. Results of operations of an acquired business are included in the Consolidated Income Statement from the date of acquisition. Acquisition-related costs, including conversion and restructuring charges, are expensed as incurred.
Investment Securities	Investment securities Investment securities may be classified as HTM, AFS, or measured at fair value. 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 securities measured at fair value are reported as an asset in the Consolidated Balance Sheet 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 OCI, except for other-than-temporarily-impaired securities. When AFS securities are sold, the unrealized gain or loss is reclassified from OCI to non-interest income. The changes in the fair values of trading securities are reported in non-interest income. Securities classified as AFS are both equity and debt 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, adjusted for prepayment estimates, using the interest method. In estimating whether there are any OTTI losses, management considers the 1) length of time and the extent to which the fair value has been less than amortized cost; 2) financial condition and near term prospects of the issuer; 3) impact of changes in market interest rates; and 4) 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. Declines in the fair value of individual AFS debt securities that are deemed to be other-than-temporary are reflected in earnings when identified. The fair value of the debt 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) interest rate, market, or other factors is recognized in other comprehensive income or loss. For individual debt securities where the Company either 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 security's 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.
Restricted Stock	Restricted stock WAB is a member of the Federal Reserve System and, as part of its membership, is required to maintain stock in the FRB in a specified ratio to its capital. In addition, WAB is a member of the FHLB system and, accordingly, maintains an investment in capital stock of the FHLB based on the borrowing capacity used. The Bank also maintains an investment in its primary correspondent bank. All of these investments are considered equity securities with no actively traded market. Therefore, the shares are considered restricted investment securities. These investments are carried at cost, which is equal to the value at which they may be redeemed. The dividend income received from the stock is reported in interest income. The Company conducts a periodic review and evaluation of its restricted stock to determine if any impairment exists.
Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]	Loans, held for sale Loans, held for sale consist of SBA loans that the Company originates (or acquires) and intends to sell. These loans are carried at the lower of aggregate cost or fair value. Fair value is determined based on available market data for similar assets, expected cash flows, and appraisals of underlying collateral or the credit quality of the borrower. Gains and losses on the sale of loans are recognized pursuant to ASC 860, Transfers and Servicing . Interest income of these loans is accrued daily and loan origination fees and costs are deferred and included in the cost basis of the loan. The Company issues various representations and warranties associated with these loan sales. The Company has not experienced any losses as a result of these representations and warranties.
Loans, Interest and Fees from Loans	Loans, held for investment The Company generally holds loans for investment and has the intent and ability to hold loans until their maturity. Therefore, they are reported at book value. Net loans are stated at the amount of unpaid principal, adjusted for net deferred fees and costs, purchase accounting fair value adjustments, and an allowance for credit losses. In addition, the book value of loans that are subject to a fair value hedge is adjusted for changes in value attributable to the effective portion of the hedged benchmark interest rate risk. The Company may also acquire loans through a business combination. These acquired loans are recorded at estimated fair value on the date of purchase, which is comprised of unpaid principal adjusted for estimated credit losses and interest rate fair value adjustments. Loans are evaluated individually at the acquisition date to determine if there has been credit deterioration since origination. Such loans may then be aggregated and accounted for as a pool of loans based on common characteristics. When the Company acquires such loans, the yield that may be accreted (accretable yield) is limited to the excess of the Company’s estimate of undiscounted cash flows expected to be collected over the Company’s initial investment in the loan. The excess of contractual cash flows over the cash flows expected to be collected may not be recognized as an adjustment to yield, loss, or a valuation allowance. Subsequent increases in cash flows expected to be collected generally are recognized prospectively through adjustment of the loan’s yield over the remaining life. Subsequent decreases to cash flows expected to be collected are recognized as impairment. The Company may not carry over or create a valuation allowance in the initial accounting for loans acquired under these circumstances. For purchased loans that are not deemed impaired at the acquisition date, fair value adjustments attributable to both credit and interest rates are accreted (or amortized) over the contractual life of the individual loan. For additional information, see " Note 3. Loans, Leases and Allowance for Credit Losses " of these Notes to Unaudited Consolidated Financial Statements. Loan fees collected for the origination of loans less direct loan origination costs (net deferred loan fees) are amortized over the contractual life of the loan through interest income. If the loan has scheduled payments, the amortization of the net deferred loan fee is calculated using the interest method over the contractual life of the loan. If the loan does not have scheduled payments, such as a line of credit, the net deferred loan fee is recognized as interest income on a straight-line basis over the contractual life of the loan commitment. Commitment fees based on a percentage of a customer’s unused line of credit and fees related to standby letters of credit are recognized over the commitment period. When loans are repaid, any remaining unamortized balances of premiums, discounts, or net deferred fees are recognized as interest income. Non-accrual loans: When a borrower discontinues making payments as contractually required by the note, the Company must determine whether it is appropriate to continue to accrue interest. The Company ceases accruing interest income when the loan has become delinquent by more than 90 days or when management determines that the full repayment of principal and collection of interest according to contractual terms is no longer likely. The Company may decide to continue to accrue interest on certain loans more than 90 days delinquent if the loans are well secured by collateral and in the process of collection. For all loan types, when a loan is placed on non-accrual status, all interest accrued but uncollected is reversed against interest income in the period in which the status is changed and, the Company makes a loan-level decision to apply either the cash basis or cost recovery method. The Company recognizes income on a cash basis only for those non-accrual loans for which the collection of the remaining principal balance is not in doubt. Under the cost recovery method, subsequent payments received from the customer are applied to principal and generally no further interest income is recognized until the principal has been paid in full or until circumstances have changed such that payments are again consistently received as contractually required. Impaired loans: A loan is identified as impaired when it is no longer probable that interest and principal will be collected according to the contractual terms of the original loan agreement. Generally, impaired loans are classified as non-accrual. However, in certain instances, impaired loans may continue on an accrual basis, if full repayment of all principal and interest is expected and the loan is both well secured and in the process of collection. Impaired loans are measured for reserve requirements in accordance with ASC 310, Receivables, based on the present value of expected future cash flows discounted at the loan's effective interest rate or, as a practical expedient, at the loan's observable market price or the fair value of the collateral less applicable disposition costs if the loan is collateral dependent. The amount of an impairment reserve, if any, and any subsequent changes are recorded as a provision for credit losses. Losses are recorded as a charge-off when losses are confirmed. In addition to management's internal loan review process, regulators may from time to time direct the Company to modify loan grades, loan impairment calculations, or loan impairment methodology. Troubled Debt Restructured Loans : A TDR 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, or deferral of interest payments. A TDR loan is also considered impaired. A TDR loan may be returned to accrual status when the loan is brought current, has performed in accordance with the contractual restructured terms for a reasonable period of time (generally six months) and the ultimate collectability of the total contractual restructured principal and interest is no longer in doubt. However, such loans continue to be considered impaired. Consistent with regulatory guidance, a TDR loan that is subsequently modified in another restructuring agreement but has shown sustained performance and classification as a TDR, will be removed from TDR status provided that the modified terms were market-based at the time of modification.
Allowance for Credit Losses	Allowance for credit losses Credit risk is inherent in the business of extending loans and leases to borrowers, for which the Company must maintain an adequate allowance for credit losses. The allowance for credit losses is established through a provision for credit losses recorded 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 estimated 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 allowance consists of specific and general components. The specific allowance applies to impaired loans. For impaired collateral dependent loans, the reserve is calculated based on the collateral value, net of estimated disposition costs. Generally, the Company obtains independent collateral valuation analysis for each loan every twelve months. Loans not collateral dependent are evaluated based on the expected future cash flows discounted at the original contractual interest rate. The general allowance covers all non-impaired loans and incorporates several quantitative and qualitative factors. Quantitative factors include company-specific, ten-year historical net charge-offs stratified by loans with similar characteristics. Qualitative factors include: 1) levels of and trends in delinquencies and impaired loans; 2) levels of and trends in charge-offs and recoveries; 3) trends in volume and terms of loans; 4) changes in underwriting standards or lending policies; 5) experience, ability, depth of lending staff; 6) national and local economic trends and conditions; 7) changes in credit concentrations; 8) out-of-market exposures; 9) changes in quality of loan review system; and 10) changes in the value of underlying collateral. 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 Arizona, Nevada, 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, regulators, as an integral part of their examination processes, periodically review the Bank's allowance for credit losses, and may require the Bank to make additions to the allowance based on their judgment about information available to them at the time of their examination. Management regularly reviews the assumptions and formulae used in determining the allowance and makes adjustments if required to reflect the current risk profile of the portfolio.
Goodwill and Intangible Assets, Policy [Policy Text Block]	Goodwill and other intangible assets The Company records as goodwill the excess of the purchase price over the fair value of the identifiable net assets acquired in accordance with applicable guidance. The Company performs its annual goodwill and intangibles impairment tests as of October 1 each year, or more often if events or circumstances indicate that the carrying value may not be recoverable. The Company can first elect to assess, through qualitative factors, whether it is more likely than not that goodwill is impaired. If the qualitative assessment indicates potential impairment, the Company will proceed with a two-step process. The first step tests for impairment, while the second step, if necessary, measures the impairment. The resulting impairment amount, if any, is charged to current period earnings as non-interest expense. The Company’s intangible assets consist primarily of core deposit intangible assets that are amortized over periods ranging from 5 to 10 years. The Company considers the remaining useful lives of its core deposit intangible assets each reporting period, as required by ASC 350, Intangibles—Goodwill and Other, to determine whether events and circumstances warrant a revision to the remaining period of amortization. If the estimate of an intangible asset’s remaining useful life has changed, the remaining carrying amount of the intangible asset is amortized prospectively over the revised remaining useful life. The Company has not revised its estimates of the useful lives of its core deposit intangibles during the three months ended March 31, 2017 and 2016 .
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 OREO 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 related to the development or improvement of the assets are capitalized and costs related 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.
Treasury Stock [Text Block]	Treasury Shares Effective January 1, 2016, the Company separately presents treasury shares, which represent shares surrendered to the Company equal in value to the statutory payroll tax withholding obligations arising from the vesting of employee restricted stock awards. Prior period amounts have been adjusted to reflect this new presentation, with no change to total stockholders' equity. Treasury shares are carried at cost.
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 Sheet at their fair value in accordance with ASC 815, Derivatives and Hedging . 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. Changes in the fair value of a derivative that is designated and qualifies as a fair value hedge, along with changes in the fair value of the hedged asset or liability that are attributable to the hedged risk are recorded in current-period earnings. For a cash flow hedge, the effective portion of the change in the fair value of the derivative is recorded in 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 in the Consolidated Balance Sheet, 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, so called free-standing derivatives, are reported in the Consolidated Balance Sheet at fair value and the changes in fair value are recognized in earnings as non-interest income during the period of change. The Company may in the normal course of business purchase a financial instrument or originate 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 the embedded derivative possesses economic characteristics that are not clearly and closely related to the economic characteristics of the host contract and 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 the host contract is measured at fair value, with changes in fair value reported in current earnings, or the Company is unable to reliably identify and measure an embedded derivative for separation from its host contract, the entire contract is carried in the Consolidated Balance Sheet at fair value and is not designated as a hedging instrument.
Income Taxes	Income taxes The Company is subject to income taxes in the United States and files a consolidated federal income tax return with all of its subsidiaries, with the exception of BW Real Estate, Inc. Deferred income taxes are recorded to reflect the effects of temporary differences between the financial reporting carrying amounts of assets and liabilities and their income tax bases using enacted tax rates that are expected to be in effect when the taxes are actually paid or recovered. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Net deferred tax assets are recorded to the extent that these assets will more-likely-than-not be realized. In making these determinations, all available positive and negative evidence is considered, including scheduled reversals of deferred tax liabilities, tax planning strategies, projected future taxable income, and recent operating results. If it is determined that deferred income tax assets to be realized in the future are in excess of their net recorded amount, an adjustment to the valuation allowance will be recorded, which will reduce the Company's provision for income taxes. A tax benefit from an unrecognized tax benefit may be recognized when it is more-likely-than-not that the position will be sustained upon examination, including related appeals or litigation, based on technical merits. Income tax benefits must meet a more-likely-than-not recognition threshold at the effective date to be recognized. Interest and penalties related to unrecognized tax benefits are recognized as part of the provision for income taxes in the Consolidated Income Statement. Accrued interest and penalties are included in the related tax liability line with other liabilities in the Consolidated Balance Sheet. See " Note 11. Income Taxes " of these Notes to Unaudited Consolidated Financial Statements for further discussion on income taxes.
Off-Balance Sheet Instruments	Off-balance sheet instruments In the ordinary course of business, the Company has entered into off-balance sheet financial instrument arrangements consisting of commitments to extend credit and standby letters of credit. Such financial instruments are recorded in the Consolidated Financial Statements when they are funded. They involve, to varying degrees, elements of credit risk in excess of amounts recognized in the Consolidated Balance Sheet. Losses would be experienced when the Company is contractually obligated to make a payment under these instruments and must seek repayment from the borrower, which may not be as financially sound in the current period as they were when the commitment was originally made. 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. As with outstanding loans, the Company applies qualitative factors and utilization rates to its off-balance sheet obligations in determining an estimate of losses inherent in these contractual obligations. The estimate for credit losses on off-balance sheet instruments is included in other liabilities and the charge to income that establishes this liability is included in non-interest expense. The Company also has off-balance sheet arrangements related to its derivative instruments. Derivative instruments are recognized in the Consolidated Financial Statements at fair value and their notional values are carried off-balance sheet. See " Note 9. Derivatives and Hedging Activities " of these Notes to Unaudited Consolidated Financial Statements for further discussion.
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, Fair Value Measurement , establishes a framework for measuring fair value and a three-level valuation hierarchy for disclosure of fair value measurement, as well as 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 may purchase the asset or assume 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. ASC 825, Financial Instruments , 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 March 31, 2017 and 2016 . The estimated fair value amounts for March 31, 2017 and 2016 have been measured as of period-end, and have not been re-evaluated 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 period-end. The information in " Note 13. Fair Value Accounting " in these Notes to Unaudited Consolidated Financial Statements 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 investments The carrying amounts reported in the Consolidated Balance Sheets for money market investments approximate their fair value. Investment securities The fair values of CRA investments, exchange-listed preferred stock, and certain corporate debt securities are based on quoted market prices and are categorized as Level 1 in the fair value hierarchy. The fair values 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. During the year ended December 31, 2016, the Company's CDO securities were transferred from Level 3 to Level 2 as a result of an increase in the availability and reliability of the observable inputs utilized in the securities' fair value measurement. Previously, quoted prices and quoted prices for similar assets were not available. Therefore, the Company would engage a third party to estimate the future cash flows and discount rate using third party quotes adjusted based on assumptions a market participant would assume necessary for each specific security, which resulted in fair values for these securities being categorized as Level 3 in the fair value hierarchy. Restricted stock WAB is a member of the Federal Reserve System and the FHLB and, accordingly, maintains investments in the capital stock of the FRB and the FHLB. WAB also maintains an investment in its 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 restricted stock to determine if any impairment exists. The fair values of these investments have been categorized as Level 2 in the fair value hierarchy. Loans The fair value of 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 and 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 is categorized as Level 2 in the fair value hierarchy, excluding impaired loans which are categorized as Level 3. Accrued interest receivable and payable The carrying amounts reported in the Consolidated Balance Sheets for accrued interest receivable and payable approximate their fair value. Derivative financial instruments All derivatives are recognized in the Consolidated Balance Sheets 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 is categorized as Level 2 in the fair value hierarchy. FHLB advances and customer repurchase agreements 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 and customer repurchase agreements have been categorized as Level 2 in the fair value hierarchy due to their short durations. Subordinated debt The fair value of subordinated debt is based on the market rate for the respective subordinated debt security. Subordinated debt has been categorized as Level 3 in the fair value hierarchy. Junior subordinated debt Junior subordinated debt is valued based on a discounted cash flow model which uses as inputs Treasury Bond rates and the 'BB' rated financial index. Junior subordinated debt has been categorized as Level 3 in the fair value hierarchy. Off-balance sheet instruments The fair value of the Company’s off-balance sheet instruments (lending commitments and standby letters of credit) is 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 May 2014, the FASB issued guidance within ASU 2014-09, Revenue from Contracts with Customers . The amendments in ASU 2014-09 to Topic 606, Revenue from Contracts with Customers, creates a common revenue standard and clarifies the principles for recognizing revenue that can be applied consistently across various transactions, industries, and capital markets. The amendments in the ASU clarify that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. As part of that principle, the entity should identify the contract(s) with the customer, identify the performance obligation(s) of the contract, determine the transaction price, allocate that transaction price to the performance obligation(s) of the contract, and then recognize revenue when or as the entity satisfies the performance obligation(s). In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date , which deferred the original effective date of ASU No. 2014-09 by one year. Accordingly, the amendments in ASU No. 2014-09 will be effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that annual reporting period. The amendments will be applied through the election of one of two retrospective methods. The Company is currently assessing the effect, but does not expect the adoption will have a significant impact on the Company’s Consolidated Financial Statements. In January 2016, the FASB issued guidance within ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in ASU 2016-01 to Subtopic 825-10, Financial Instruments, contain the following elements: 1) requires equity investments to be measured at fair value with changes in fair value recognized in net income; 2) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3) eliminates the requirement for public entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; 4) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; 5) requires an entity to present separately in OCI the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 6) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or accompanying notes to the financial statements; 7) clarifies that the entity should evaluate the need for a valuation allowance on a deferred tax asset related to AFS securities in combination with the entity's other deferred tax assets. The amendments are effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. Except for the early application of the amendment noted in item 5) above, which the Company elected to early adopt effective January 1, 2015 as discussed in the Company's Annual Report on Form 10-K for the year ended December 31, 2015, early adoption of the amendments in this Update is not permitted. The adoption of the other amendments in this guidance is not expected to have a material impact on the Company's Consolidated Financial Statements. In February 2016, the FASB issued guidance within ASU 2016-02, Leases . The amendments in ASU 2016-02 to Topic 842, Leases, require lessees to recognize the lease assets and lease liabilities arising from operating leases in the statement of financial position. The accounting applied by a lessor is largely unchanged from that applied under previous GAAP. The amendments in this Update are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. Management is in the process of evaluating the effects that the standard is expected to have on the Company's Consolidated Financial Statements and related disclosures. In June 2016, the FASB issued guidance within ASU 2016-13, Measurement of Credit Losses on Financial Instruments . The amendments in ASU 2016-13 to Topic 326, Financial Instruments - Credit Losses, require that an organization measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. The ASU also requires enhanced disclosures, including qualitative and quantitative disclosures that provide additional information about the amounts recorded in the financial statements. Additionally, the ASU amends the accounting for credit losses on AFS debt securities and purchased financial assets with credit deterioration. The amendments in this Update are effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Management is in the process of evaluating the effects that the standard is expected to have on the Company's Consolidated Financial Statements and related disclosures. In August 2016, the FASB issued guidance within ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments. The amendments in ASU 2016-15 to Topic 230, Statement of Cash Flows, provide guidance on eight specific cash flow classification issues: 1) debt prepayment or debt extinguishment costs; 2) settlement of zero-coupon debt instruments; 3) contingent consideration payments made after a business combination; 4) proceeds from the settlement of insurance claims; 5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; 6) distributions received from equity method investments; 7) beneficial interest in securitization transactions; and 8) separately identifiable cash flows and the application of the predominance principle. The amendments in this Update are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. However, an entity is required to adopt all of the amendments in the same period. The amendments in this Update should be applied using a retrospective transition method to each period presented. The adoption of this guidance is not expected to have a significant impact on the Company's Consolidated Statement of Cash Flows. In January 2017, the FASB issued guidance within ASU 2017-01, Clarifying the Definition of a Business . The amendments in ASU 2017-01 to Topic 805, Business Combinations, clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this Update should be applied prospectively and are effective for annual periods beginning after December 31, 2017, including interim periods within those periods. The adoption of this guidance is not expected to have a material impact on the Company's Consolidated Financial Statements. In January 2017, the FASB issued guidance within ASU 2017-04, Simplifying the Test for Goodwill Impairment . The amendments in ASU 2017-04 to Topic 350, Intangibles - Goodwill and Other, modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. Accordingly, the amendments eliminate Step 2 from the goodwill impairment test because goodwill impairment will no longer be determined by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. The amendments in this Update should be applied on a prospective basis and are effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed after January 1, 2017. The adoption of this guidance is not expected to have a material impact on the Company's Consolidated Financial Statements. In February 2017, the FASB issued guidance within ASU 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets . The amendments in ASU 2017-05 to Subtopic 610-20, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets, clarify the scope of Subtopic 610-20 and add guidance for partial sales of nonfinancial assets, including partial sales of real estate. Under current GAAP, there are several different accounting models to evaluate whether the transfer of certain assets qualify for sale treatment. The new standard reduces the number of potential accounting models that might apply and clarifies which model does apply in various circumstances. An entity may elect to apply the amendments in this Update either retrospectively to each period presented in the financial statements or, retrospectively with a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The amendments in this Update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Early adoption is permitted for annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The adoption of this guidance is not expected to have a material impact on the Company's Consolidated Financial Statements. In March 2017, the FASB issued guidance within ASU 2017-08, Premium Amortization on Purchased Callable Debt Securities . The amendments in ASU 2017-08 to Subtopic 310-20, Receivables-Nonrefundable Fees and Other Costs, shorten the amortization period for certain purchased callable debt securities held at a premium to the earliest call date, which more closely align the amortization period of premiums and discounts to expectations incorporated in market pricing on the underlying securities. Under current GAAP, entities generally amortize the premium as an adjustment of yield over the contractual life of the instrument. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments in this Update should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The amendments in this Update are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. The adoption of this guidance is not expected to have a material impact on the Company's Consolidated Financial Statements. Recently adopted accounting guidance In November 2015, the FASB issued guidance within ASU 2015-17, Income Taxes . The amendments in ASU 2015-17 to Topic 740, Income Taxes, changes the presentation of deferred income tax liabilities and assets, from previously bifurcated current and noncurrent, to a single noncurrent amount on the classified statement of financial position. The amendment is effective for the annual period ending after December 15, 2016, and for and interim periods within those annual periods. The adoption of this guidance did not have a material impact on the Company's Consolidated Financial Statements. In March 2016, the FASB issued guidance within ASU 2016-05, Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships . The amendments in ASU 2016-05 to Topic 815, Derivatives and Hedging, clarify that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The amendments in this Update are effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The adoption of this guidance did not have a material impact on the Company's Consolidated Financial Statements.

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Carrying Amounts and Fair Values of Investment Securities	The carrying amounts and fair values of investment securities at March 31, 2017 and December 31, 2016 are summarized as follows: March 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity Tax-exempt $ 102,590 $ 1,388 $ (312 ) $ 103,666 Available-for-sale Collateralized debt obligations $ 50 $ 19,973 $ — $ 20,023 Commercial MBS issued by GSEs 119,646 15 (3,961 ) 115,700 Corporate debt securities 69,643 370 (1,618 ) 68,395 CRA investments 47,722 — (514 ) 47,208 Preferred stock 96,030 2,819 (247 ) 98,602 Private label residential MBS 504,213 419 (7,566 ) 497,066 Residential MBS issued by GSEs 1,375,584 3,349 (16,133 ) 1,362,800 Tax-exempt 403,302 9,760 (8,947 ) 404,115 Trust preferred securities 32,000 — (4,320 ) 27,680 U.S. government sponsored agency securities 59,000 — (3,080 ) 55,920 U.S. treasury securities 2,496 6 — 2,502 Total AFS securities $ 2,709,686 $ 36,711 $ (46,386 ) $ 2,700,011 Securities measured at fair value Residential MBS issued by GSEs $ 1,019 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity Tax-exempt $ 92,079 $ 433 $ (546 ) $ 91,966 Available-for-sale Collateralized debt obligations $ 50 $ 13,440 $ — $ 13,490 Commercial MBS issued by GSEs 121,742 — (3,950 ) 117,792 Corporate debt securities 65,058 371 (1,285 ) 64,144 CRA investments 37,627 — (514 ) 37,113 Preferred stock 96,071 833 (2,242 ) 94,662 Private label residential MBS 440,272 182 (6,769 ) 433,685 Residential MBS issued by GSEs 1,369,289 3,046 (17,130 ) 1,355,205 Tax-exempt 409,693 8,477 (9,937 ) 408,233 Trust preferred securities 32,000 — (5,468 ) 26,532 U.S. government sponsored agency securities 59,000 — (2,978 ) 56,022 U.S. treasury securities 2,496 6 — 2,502 Total AFS securities $ 2,633,298 $ 26,355 $ (50,273 ) $ 2,609,380 Securities measured at fair value Residential MBS issued by GSEs $ 1,053
Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position	Information pertaining to securities with gross unrealized losses at March 31, 2017 and December 31, 2016 , aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: March 31, 2017 Less Than Twelve Months More Than Twelve Months Total Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (in thousands) Held-to-maturity Tax-exempt $ 312 $ 30,542 $ — $ — $ 312 $ 30,542 Available-for-sale Commercial MBS issued by GSEs $ 3,961 $ 113,795 $ — $ — $ 3,961 $ 113,795 Corporate debt securities 1,618 62,971 — — 1,618 62,971 CRA investments 514 47,208 — — 514 47,208 Preferred stock 247 11,946 — — 247 11,946 Private label residential MBS 7,566 391,073 — — 7,566 391,073 Residential MBS issued by GSEs 15,699 868,033 434 33,662 16,133 901,695 Tax-exempt 8,947 142,516 — — 8,947 142,516 Trust preferred securities — — 4,320 27,680 4,320 27,680 U.S. government sponsored agency securities 3,080 55,920 — — 3,080 55,920 Total AFS securities $ 41,632 $ 1,693,462 $ 4,754 $ 61,342 $ 46,386 $ 1,754,804 December 31, 2016 Less Than Twelve Months More Than Twelve Months Total Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value (in thousands) Held-to-maturity Tax-exempt $ 546 $ 30,364 $ — $ — $ 546 $ 30,364 Available-for-sale Commercial MBS issued by GSEs $ 3,950 $ 117,792 $ — $ — $ 3,950 $ 117,792 Corporate debt securities 1,285 38,716 — — 1,285 38,716 CRA investments 514 37,113 — — 514 37,113 Preferred stock 2,188 63,151 54 1,471 2,242 64,622 Private label residential MBS 6,170 377,638 599 16,969 6,769 394,607 Residential MBS issued by GSEs 16,990 950,480 140 5,326 17,130 955,806 Tax-exempt 9,937 148,780 — — 9,937 148,780 Trust preferred securities — — 5,468 26,532 5,468 26,532 U.S. government sponsored agency securities 2,978 56,022 — — 2,978 56,022 Total AFS securities $ 44,012 $ 1,789,692 $ 6,261 $ 50,298 $ 50,273 $ 1,839,990
Amortized Cost and Fair Value of Investment Securities by Contractual Maturities	The amortized cost and fair value of securities as of March 31, 2017 , by contractual maturities, are shown below. MBS are shown separately as individual MBS are comprised of pools of loans with varying maturities. Therefore, these securities are listed separately in the maturity summary. March 31, 2017 Amortized Cost Estimated Fair Value (in thousands) Held-to-maturity After ten years $ 102,590 $ 103,666 Available-for-sale Due in one year or less $ 50,000 $ 49,549 After one year through five years 52,331 53,380 After five years through ten years 214,862 214,145 After ten years 393,050 407,371 Mortgage-backed securities 1,999,443 1,975,566 Total AFS securities $ 2,709,686 $ 2,700,011
Investment Securities by Credit Rating Type	The following tables summarize the carrying amount of the Company’s investment ratings position as of March 31, 2017 and December 31, 2016 : March 31, 2017 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity Tax-exempt $ — $ — $ — $ — $ — $ — $ 102,590 $ 102,590 Available-for-sale Collateralized debt obligations $ — $ — $ — $ — $ — $ 20,023 $ — $ 20,023 Commercial MBS issued by GSEs — 115,700 — — — — — 115,700 Corporate debt securities — — — 44,561 19,300 — 4,534 68,395 CRA investments — 24,940 — — — — 22,268 47,208 Preferred stock — — — 10,550 64,715 7,311 16,026 98,602 Private label residential MBS 464,029 — 27,457 1,896 3,684 — — 497,066 Residential MBS issued by GSEs — 1,362,800 — — — — — 1,362,800 Tax-exempt 36,121 24,985 222,352 120,657 — — — 404,115 Trust preferred securities — — — — 27,680 — — 27,680 U.S. government sponsored agency securities — 55,920 — — — — — 55,920 U.S. treasury securities — 2,502 — — — — — 2,502 Total AFS securities (1) $ 500,150 $ 1,586,847 $ 249,809 $ 177,664 $ 115,379 $ 27,334 $ 42,828 $ 2,700,011 Securities measured at fair value Residential MBS issued by GSEs $ — $ 1,019 $ — $ — $ — $ — $ — $ 1,019 (1) Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch. December 31, 2016 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity Tax-exempt $ — $ — $ — $ — $ — $ — $ 92,079 $ 92,079 Available-for-sale Collateralized debt obligations $ — $ — $ — $ — $ — $ 13,490 $ — $ 13,490 Commercial MBS issued by GSEs — 117,792 — — — — — 117,792 Corporate debt securities — — 5,429 38,715 20,000 — — 64,144 CRA investments — — — — — — 37,113 37,113 Preferred stock — — — — 64,486 14,658 15,518 94,662 Private label residential MBS 399,013 — 29,921 2,117 2,634 — — 433,685 Residential MBS issued by GSEs — 1,355,205 — — — — — 1,355,205 Tax-exempt 80,862 — 268,249 59,122 — — — 408,233 Trust preferred securities — — — — 26,532 — — 26,532 U.S. government sponsored agency securities — 56,022 — — — — — 56,022 U.S. treasury securities — 2,502 — — — — — 2,502 Total AFS securities (1) $ 479,875 $ 1,531,521 $ 303,599 $ 99,954 $ 113,652 $ 28,148 $ 52,631 $ 2,609,380 Securities measured at fair value Residential MBS issued by GSEs $ — $ 1,053 $ — $ — $ — $ — $ — $ 1,053 (1) Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch.
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 March 31, 2017 2016 (in thousands) Gross gains $ 636 $ 2,057 Gross losses (1 ) (1,056 ) Net gains on sales of investment securities $ 635 $ 1,001

Loans, Leases and Allowance f26

Loans, Leases and Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Schedule of Held for Investment Loan Portfolio Composition of Loans, Leases and Allowance for Credit Losses	The composition of the Company’s held for investment loan portfolio is as follows: March 31, 2017 December 31, 2016 (in thousands) Commercial and industrial $ 5,948,307 $ 5,755,021 Commercial real estate - non-owner occupied 3,607,783 3,543,956 Commercial real estate - owner occupied 2,043,431 2,013,276 Construction and land development 1,601,721 1,478,114 Residential real estate 309,870 259,432 Commercial leases 90,722 100,765 Consumer 43,049 38,963 Loans, net of deferred loan fees and costs 13,644,883 13,189,527 Allowance for credit losses (127,649 ) (124,704 ) Total loans HFI $ 13,517,234 $ 13,064,823
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 held for investment by class of loans: March 31, 2017 Current 30-59 Days 60-89 Days Over 90 Days Total Total (in thousands) Commercial real estate Owner occupied $ 2,037,324 $ 302 $ 1,947 $ 3,858 $ 6,107 $ 2,043,431 Non-owner occupied 3,388,556 308 — 3 311 3,388,867 Multi-family 218,916 — — — — 218,916 Commercial and industrial Commercial 5,936,803 3,692 4,322 3,490 11,504 5,948,307 Leases 90,581 14 24 103 141 90,722 Construction and land development Construction 1,053,336 — — — — 1,053,336 Land 547,039 56 6 1,284 1,346 548,385 Residential real estate 301,868 328 319 7,355 8,002 309,870 Consumer 42,874 10 — 165 175 43,049 Total loans $ 13,617,297 $ 4,710 $ 6,618 $ 16,258 $ 27,586 $ 13,644,883 December 31, 2016 Current 30-59 Days 60-89 Days Over 90 Days Total Total (in thousands) Commercial real estate Owner occupied $ 2,009,728 $ 71 $ — $ 3,477 $ 3,548 $ 2,013,276 Non-owner occupied 3,339,121 672 2 — 674 3,339,795 Multi-family 204,161 — — — — 204,161 Commercial and industrial Commercial 5,747,368 549 584 6,520 7,653 5,755,021 Leases 100,761 — — 4 4 100,765 Construction and land development Construction 973,242 — — — — 973,242 Land 503,588 — — 1,284 1,284 504,872 Residential real estate 249,726 4,333 281 5,092 9,706 259,432 Consumer 38,765 26 2 170 198 38,963 Total loans $ 13,166,460 $ 5,651 $ 869 $ 16,547 $ 23,067 $ 13,189,527
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 non-accrual loans and loans past due ninety days or more and still accruing interest by class of loans: March 31, 2017 December 31, 2016 Non-accrual loans Loans past due 90 days or more and still accruing Non-accrual loans Loans past due 90 days or more and still accruing Current Past Due/ Total Current Past Due/ Total (in thousands) Commercial real estate Owner occupied $ 4,210 $ 4,499 $ 8,709 $ — $ 5,084 $ 3,264 $ 8,348 $ 285 Non-owner occupied 2,524 3 2,527 — 8,317 1 8,318 — Multi-family — — — — — — — — Commercial and industrial Commercial 12,528 3,839 16,367 51 10,893 6,043 16,936 775 Leases 24 54 78 49 28 3 31 — Construction and land development Construction — — — — — — — — Land — 1,284 1,284 — — 1,284 1,284 — Residential real estate 1,214 4,115 5,329 3,559 99 5,093 5,192 — Consumer — 164 164 — — 163 163 7 Total $ 20,500 $ 13,958 $ 34,458 $ 3,659 $ 24,421 $ 15,851 $ 40,272 $ 1,067
Loans by Risk Rating	The following tables present gross loans by risk rating: March 31, 2017 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial real estate Owner occupied $ 1,971,261 $ 49,568 $ 20,325 $ 2,277 $ — $ 2,043,431 Non-owner occupied 3,336,170 13,775 38,922 — — 3,388,867 Multi-family 218,723 193 — — — 218,916 Commercial and industrial Commercial 5,773,313 92,556 82,434 — — 5,948,303 Leases 87,012 3,640 74 — — 90,726 Construction and land development Construction 1,041,338 — 11,998 — — 1,053,336 Land 531,195 14,366 2,824 — — 548,385 Residential real estate 299,302 928 9,640 — — 309,870 Consumer 42,803 54 192 — — 43,049 Total $ 13,301,117 $ 175,080 $ 166,409 $ 2,277 $ — $ 13,644,883 March 31, 2017 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 13,296,590 $ 171,409 $ 147,764 $ 1,534 $ — $ 13,617,297 Past due 30 - 59 days 2,993 1,058 659 — — 4,710 Past due 60 - 89 days 1,342 2,613 2,663 — — 6,618 Past due 90 days or more 192 — 15,323 743 — 16,258 Total $ 13,301,117 $ 175,080 $ 166,409 $ 2,277 $ — $ 13,644,883 December 31, 2016 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial real estate Owner occupied $ 1,935,322 $ 53,634 $ 22,090 $ 2,230 $ — $ 2,013,276 Non-owner occupied 3,278,090 22,972 38,733 — — 3,339,795 Multi-family 203,964 197 — — — 204,161 Commercial and industrial Commercial 5,621,448 70,011 58,562 5,000 — 5,755,021 Leases 100,737 — 28 — — 100,765 Construction and land development Construction 961,290 — 11,952 — — 973,242 Land 501,569 337 2,966 — — 504,872 Residential real estate 252,304 929 6,199 — — 259,432 Consumer 38,698 64 201 — — 38,963 Total $ 12,893,422 $ 148,144 $ 140,731 $ 7,230 $ — $ 13,189,527 December 31, 2016 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 12,887,308 $ 147,838 $ 124,084 $ 7,230 $ — $ 13,166,460 Past due 30 - 59 days 5,433 96 122 — — 5,651 Past due 60 - 89 days 410 210 249 — — 869 Past due 90 days or more 271 — 16,276 — — 16,547 Total $ 12,893,422 $ 148,144 $ 140,731 $ 7,230 $ — $ 13,189,527
Impaired Loans by Loan Class	The following table presents impaired loans by class: March 31, 2017 December 31, 2016 (in thousands) Commercial real estate Owner occupied $ 21,321 $ 20,748 Non-owner occupied 22,565 25,524 Multi-family — — Commercial and industrial Commercial 36,283 21,107 Leases 400 355 Construction and land development Construction — — Land 14,117 14,838 Residential real estate 18,806 16,391 Consumer 214 246 Total $ 113,706 $ 99,209
Recorded Investment in Loans Classified as Impaired	The following table presents the average investment in impaired loans and income recognized on impaired loans: Three Months Ended March 31, 2017 2016 (in thousands) Average balance on impaired loans $ 103,387 $ 122,545 Interest income recognized on impaired loans 921 1,113 Interest recognized on non-accrual loans, cash basis 332 172 The table below reflects the recorded investment in loans classified as impaired: March 31, 2017 December 31, 2016 (in thousands) Impaired loans with a specific valuation allowance under ASC 310 (1) $ 10,919 $ 10,909 Impaired loans without a specific valuation allowance under ASC 310 (2) 102,787 88,300 Total impaired loans $ 113,706 $ 99,209 Valuation allowance related to impaired loans (3) $ (3,965 ) $ (4,239 ) (1) Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016 , respectively. (2) Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016 , respectively. (3) Includes valuation allowance related to TDR loans of $2.6 million and $0.6 million at March 31, 2017 and December 31, 2016 , respectively.
Average Investment in Impaired Loans by Loan Class	The following table presents average investment in impaired loans by loan class: Three Months Ended March 31, 2017 2016 (in thousands) Commercial real estate Owner occupied $ 21,128 $ 21,737 Non-owner occupied 24,399 33,033 Multi-family — — Commercial and industrial Commercial 25,734 31,733 Leases 367 2,049 Construction and land development Construction — — Land 14,432 17,900 Residential real estate 17,103 15,764 Consumer 224 329 Total $ 103,387 $ 122,545
Interest Income on Impaired Loans by Loan Class	The following table presents interest income on impaired loans by class: Three Months Ended March 31, 2017 2016 (in thousands) Commercial real estate Owner occupied $ 177 $ 295 Non-owner occupied 239 338 Multi-family — — Commercial and industrial Commercial 140 108 Leases 4 32 Construction and land development Construction — — Land 221 207 Residential real estate 139 131 Consumer 1 2 Total $ 921 $ 1,113
Tabular Disclosure of Nonperforming Assets	The following table summarizes nonperforming assets: March 31, 2017 December 31, 2016 (in thousands) Non-accrual loans (1) $ 34,458 $ 40,272 Loans past due 90 days or more on accrual status (2) 3,659 1,067 Accruing troubled debt restructured loans 49,292 53,637 Total nonperforming loans 87,409 94,976 Other assets acquired through foreclosure, net 45,200 47,815 Total nonperforming assets $ 132,609 $ 142,791 (1) Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016 , respectively. (2)
Accretable Yield Table	Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows: Three Months Ended March 31, 2017 2016 (in thousands) Balance, at beginning of period $ 15,177 $ 15,925 Reclassifications from non-accretable to accretable yield (1) — — Accretion to interest income (907 ) (782 ) Reversal of fair value adjustments upon disposition of loans (458 ) (1,602 ) Balance, at end of period $ 13,812 $ 13,541 (1) The primary drivers of reclassification from non-accretable to accretable yield resulted from changes in estimated cash flows.
Allowances for Credit Losses	The following table presents impairment method information related to loans and allowance for credit losses by loan portfolio segment: Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Commercial Leases Consumer Total Loans (in thousands) Loans as of March 31, 2017: Recorded Investment: Impaired loans with an allowance recorded $ 3,088 $ — $ 7,831 $ — $ — $ — $ — $ 10,919 Impaired loans with no allowance recorded 18,233 22,565 28,452 18,806 14,117 400 214 102,787 Total loans individually evaluated for impairment 21,321 22,565 36,283 18,806 14,117 400 214 113,706 Loans collectively evaluated for impairment 2,010,916 3,435,971 5,912,024 290,446 1,587,604 90,322 42,835 13,370,118 Loans acquired with deteriorated credit quality 11,194 149,247 — 618 — — — 161,059 Total recorded investment $ 2,043,431 $ 3,607,783 $ 5,948,307 $ 309,870 $ 1,601,721 $ 90,722 $ 43,049 $ 13,644,883 Unpaid Principal Balance Impaired loans with an allowance recorded $ 3,088 $ — $ 7,831 $ — $ — $ — $ — $ 10,919 Impaired loans with no allowance recorded 26,599 30,204 57,433 28,275 32,767 551 10,813 186,642 Total loans individually evaluated for impairment 29,687 30,204 65,264 28,275 32,767 551 10,813 197,561 Loans collectively evaluated for impairment 2,010,916 3,435,971 5,912,024 290,446 1,587,604 90,322 42,835 13,370,118 Loans acquired with deteriorated credit quality 14,962 180,747 4,949 733 — — — 201,391 Total unpaid principal balance $ 2,055,565 $ 3,646,922 $ 5,982,237 $ 319,454 $ 1,620,371 $ 90,873 $ 53,648 $ 13,769,070 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 932 $ — $ 3,033 $ — $ — $ — $ — $ 3,965 Impaired loans with no allowance recorded — — — — — — — — Total loans individually evaluated for impairment 932 — 3,033 — — — — 3,965 Loans collectively evaluated for impairment 12,067 13,124 70,396 4,412 21,097 — 707 121,803 Loans acquired with deteriorated credit quality — 1,881 — — — — — 1,881 Total allowance for credit losses $ 12,999 $ 15,005 $ 73,429 $ 4,412 $ 21,097 $ — $ 707 $ 127,649 Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Commercial Leases Consumer Total Loans (in thousands) Loans as of December 31, 2016: Recorded Investment: Impaired loans with an allowance recorded $ 3,125 $ — $ 7,766 $ — $ — $ — $ 18 $ 10,909 Impaired loans with no allowance recorded 17,624 25,524 13,340 16,391 14,838 355 228 88,300 Total loans individually evaluated for impairment 20,749 25,524 21,106 16,391 14,838 355 246 99,209 Loans collectively evaluated for impairment 1,981,176 3,383,585 5,733,915 242,409 1,443,952 100,410 38,717 12,924,164 Loans acquired with deteriorated credit quality 11,351 134,847 — 632 19,324 — — 166,154 Total recorded investment $ 2,013,276 $ 3,543,956 $ 5,755,021 $ 259,432 $ 1,478,114 $ 100,765 $ 38,963 $ 13,189,527 Unpaid Principal Balance Impaired loans with an allowance recorded $ 3,125 $ — $ 8,019 $ — $ — $ — $ 18 $ 11,162 Impaired loans with no allowance recorded 26,336 33,632 43,176 26,225 33,487 507 1,358 164,721 Total loans individually evaluated for impairment 29,461 33,632 51,195 26,225 33,487 507 1,376 175,883 Loans collectively evaluated for impairment 1,981,176 3,383,585 5,733,915 242,409 1,443,952 100,410 38,717 12,924,164 Loans acquired with deteriorated credit quality 14,878 165,275 925 738 19,858 — — 201,674 Total unpaid principal balance $ 2,025,515 $ 3,582,492 $ 5,786,035 $ 269,372 $ 1,497,297 $ 100,917 $ 40,093 $ 13,301,721 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 937 $ — $ 3,301 $ — $ — $ — $ 1 $ 4,239 Impaired loans with no allowance recorded — — — — — — — — Total loans individually evaluated for impairment 937 — 3,301 — — — 1 4,239 Loans collectively evaluated for impairment 11,403 12,646 69,673 3,851 20,398 — 671 118,642 Loans acquired with deteriorated credit quality — 687 359 — 777 — — 1,823 Total allowance for credit losses $ 12,340 $ 13,333 $ 73,333 $ 3,851 $ 21,175 $ — $ 672 $ 124,704 The following table summarizes the changes in the allowance for credit losses by portfolio type: Three Months Ended March 31, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2017 Beginning Balance $ 21,175 $ 25,673 $ 3,851 $ 73,333 $ 672 $ 124,704 Charge-offs — — 115 2,594 34 2,743 Recoveries (277 ) (533 ) (251 ) (328 ) (49 ) (1,438 ) Provision (355 ) 1,798 425 2,362 20 4,250 Ending balance $ 21,097 $ 28,004 $ 4,412 $ 73,429 $ 707 $ 127,649 2016 Beginning Balance $ 18,976 $ 23,160 $ 5,278 $ 71,181 $ 473 $ 119,068 Charge-offs — 410 26 7,491 74 8,001 Recoveries (95 ) (3,665 ) (257 ) (1,576 ) (67 ) (5,660 ) Provision 354 (3,311 ) (571 ) 5,890 138 2,500 Ending balance $ 19,425 $ 23,104 $ 4,938 $ 71,156 $ 604 $ 119,227

Other Assets Acquired Through27

Other Assets Acquired Through Foreclosure (Tables)	3 Months Ended
	Mar. 31, 2017
Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]
Changes in Other Assets Acquired Through Foreclosure	The following table represents the changes in other assets acquired through foreclosure: Three Months Ended March 31, 2017 Gross Balance Valuation Allowance Net Balance (in thousands) Balance, beginning of period $ 54,138 $ (6,323 ) $ 47,815 Transfers to other assets acquired through foreclosure, net — — — Proceeds from sale of other real estate owned and repossessed assets, net (3,113 ) 224 (2,889 ) Valuation adjustments, net — 380 380 (Losses) gains, net (1) (106 ) — (106 ) Balance, end of period $ 50,919 $ (5,719 ) $ 45,200 Three Months Ended March 31, 2016 Balance, beginning of period $ 52,984 $ (9,042 ) $ 43,942 Transfers to other assets acquired through foreclosure, net 10,638 — 10,638 Proceeds from sale of other real estate owned and repossessed assets, net (2,436 ) 295 (2,141 ) Valuation adjustments, net — 177 177 Gains (losses), net (1) 160 — 160 Balance, end of period $ 61,346 $ (8,570 ) $ 52,776 (1) There were no net gains related to initial transfers to other assets during the three months ended March 31, 2017 and 2016 .

Other Borrowings (Tables)

Other Borrowings (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Company's Borrowings	The following table summarizes the Company’s borrowings as of March 31, 2017 and December 31, 2016 : March 31, 2017 December 31, 2016 (in thousands) Short-Term: FHLB advances $ — $ 80,000 Total short-term borrowings $ — $ 80,000

Accumulated Other Comprehensi29

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income	The following table summarizes the changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods indicated: Unrealized holding gains (losses) on AFS Unrealized holding gains (losses) on SERP Unrealized holding gains (losses) on junior subordinated debt Impairment loss on securities Total (in thousands) Balance, December 31, 2016 $ (14,916 ) $ 121 $ 9,956 $ 144 $ (4,695 ) Other comprehensive income before reclassifications 9,169 (1 ) (1,229 ) — 7,939 Amounts reclassified from accumulated other comprehensive income (393 ) — — — (393 ) Net current-period other comprehensive income (loss) 8,776 (1 ) (1,229 ) — 7,546 Balance, March 31, 2017 $ (6,140 ) $ 120 $ 8,727 $ 144 $ 2,851 Balance, December 31, 2015 $ 9,993 $ 90 $ 12,033 $ 144 $ 22,260 Other comprehensive income before reclassifications 11,019 6 759 — 11,784 Amounts reclassified from accumulated other comprehensive income (711 ) — — — (711 ) Net current-period other comprehensive income (loss) 10,308 6 759 — 11,073 Balance, March 31, 2016 $ 20,301 $ 96 $ 12,792 $ 144 $ 33,333
Schedule of Reclassifications Out of Accumulated Other Comprehensive Income	The following table presents reclassifications out of accumulated other comprehensive income: Three Months Ended March 31, Income Statement Classification 2017 2016 (in thousands) Gain (loss) on sales of investment securities, net $ 635 $ 1,001 Income tax (expense) benefit (242 ) (290 ) Net of tax $ 393 $ 711

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position	The fair value of derivative contracts, after taking into account the effects of master netting agreements, is included in other assets or other liabilities in the Consolidated Balance Sheets, as indicated in the following table: March 31, 2017 December 31, 2016 March 31, 2016 Fair Value Fair Value Fair Value Notional Derivative Assets Derivative Liabilities Notional Derivative Assets Derivative Liabilities Notional Derivative Assets Derivative Liabilities (in thousands) Derivatives designated as hedging instruments: Fair value hedges Interest rate swaps $ 1,035,151 $ 1,985 $ 59,136 $ 993,485 $ 4,220 $ 65,749 $ 797,304 $ 4,733 $ 88,981 Total 1,035,151 1,985 59,136 993,485 4,220 65,749 797,304 4,733 88,981 Netting adjustments (1) — 1,947 1,947 — 1,869 1,869 — — — Net derivatives in the balance sheet $ 1,035,151 $ 38 $ 57,189 $ 993,485 $ 2,351 $ 63,880 $ 797,304 $ 4,733 $ 88,981 (1) Netting adjustments represent the amounts recorded to convert the Company's derivative balances from a gross basis to a net basis in accordance with the applicable accounting guidance.
Gain (Loss) on Derivative Instruments	The following table summarizes the gains (losses) on fair value hedges for the three months ended March 31, 2017 and 2016 , all of which are recorded in non-interest income. Three Months Ended March 31, 2017 2016 (in thousands) Hedge of Fixed Rate Loans (1) Gain (loss) on "pay fixed" swap $ 7,568 $ (24,197 ) Gain (loss) on receive fixed rate loans (7,553 ) 24,197 Net ineffectiveness $ 15 $ — Hedge of Fixed Rate Subordinated Debt Issuances (1) Gain (loss) on "receive fixed" swap $ (3,191 ) $ 1,164 Gain (loss) on subordinated debt 3,191 (1,164 ) Net ineffectiveness $ — $ — (1) The fair value of derivatives contracts are carried as other assets and other liabilities in the Consolidated Balance Sheets. The effective portion of hedging gains (losses) is recorded as basis adjustments to the underlying hedged asset or liability. Gains and losses on both the hedging derivative and hedged item are recorded through non-interest income with a resulting net income impact for the amount of ineffectiveness.
Largest Exposure To Individual Counterparty	The following table summarizes the Company's largest exposure to an individual counterparty at the dates indicated: March 31, 2017 December 31, 2016 March 31, 2016 (in thousands) Largest gross exposure (derivative asset) to an individual counterparty $ 1,150 $ 2,351 $ 4,733 Collateral posted by this counterparty — 1,691 4,292 Derivative liability with this counterparty 41,220 — — Collateral pledged to this counterparty 50,165 — — Net exposure after netting adjustments and collateral $ — $ 660 $ 441

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the calculation of basic and diluted EPS: Three Months Ended March 31, 2017 2016 (in thousands, except per share amounts) Weighted average shares - basic 103,987 101,895 Dilutive effect of stock awards 849 643 Weighted average shares - diluted 104,836 102,538 Net income available to common stockholders $ 73,357 $ 61,332 Earnings per share - basic 0.71 0.60 Earnings per share - diluted 0.70 0.60

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
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: March 31, 2017 December 31, 2016 (in thousands) Commitments to extend credit, including unsecured loan commitments of $357,462 at March 31, 2017 and $360,840 at December 31, 2016 $ 4,951,254 $ 4,428,495 Credit card commitments and financial guarantees 122,969 115,536 Standby letters of credit, including unsecured letters of credit of $9,396 at March 31, 2017 and $6,431 at December 31, 2016 98,674 78,576 Total $ 5,172,897 $ 4,622,607

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations	For the three months ended March 31, 2017 and 2016 , gains and losses from fair value changes on securities and junior subordinated debt were as follows: Changes in Fair Values for Items Measured at Fair Value Unrealized Gain/(Loss) on Assets and Liabilities Measured at Fair Value, Net Interest Income on Securities Interest Expense on Junior Subordinated Debt Total Changes Included in Current-Period Earnings Total Changes Included in OCI (in thousands) Three Months Ended March 31, 2017 Securities measured at fair value $ (1 ) $ 7 $ — $ 6 $ — Junior subordinated debt (1,986 ) — (749 ) (749 ) (1,229 ) Total $ (1,987 ) $ 7 $ (749 ) $ (743 ) $ (1,229 ) Three Months Ended March 31, 2016 Securities measured at fair value $ (5 ) $ 11 $ — $ 6 $ — Junior subordinated debt 1,212 — (680 ) (680 ) 759 Total $ 1,207 $ 11 $ (680 ) $ (674 ) $ 759
Fair Value of Assets and Liabilities	The fair value of assets and liabilities measured at fair value on a recurring basis was determined using the following inputs as of the periods presented: Fair Value Measurements at the End of the Reporting Period Using: Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Fair Value (in thousands) March 31, 2017 Assets: Measured at fair value Residential MBS issued by GSEs $ — $ 1,019 $ — $ 1,019 Available-for-sale Collateralized debt obligations $ — $ 20,023 $ — $ 20,023 Commercial MBS issued by GSEs — 115,700 — 115,700 Corporate debt securities — 68,395 — 68,395 CRA investments 47,208 — — 47,208 Preferred stock 98,602 — — 98,602 Private label residential MBS — 497,066 — 497,066 Residential MBS issued by GSEs — 1,362,800 — 1,362,800 Tax-exempt — 404,115 — 404,115 Trust preferred securities — 27,680 — 27,680 U.S. government sponsored agency securities — 55,920 — 55,920 U.S. treasury securities — 2,502 — 2,502 Total AFS securities $ 145,810 $ 2,554,201 $ — $ 2,700,011 Loans - HFS $ — $ 17,865 $ — $ 17,865 Derivative assets (1) — 1,985 — 1,985 Liabilities: Junior subordinated debt (2) $ — $ — $ 52,396 $ 52,396 Derivative liabilities (1) — 59,136 — 59,136 (1) Derivative assets and liabilities relate to interest rate swaps, see " Note 9. Derivatives and Hedging Activities ." In addition, the carrying value of loans is increased by $40,886 and the net carrying value of subordinated debt is decreased by $15,517 as of March 31, 2017 , which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates. (2) Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment. Fair Value Measurements at the End of the Reporting Period Using: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value (in thousands) December 31, 2016 Assets: Measured at fair value Residential MBS issued by GSEs $ — $ 1,053 $ — $ 1,053 Available-for-sale Collateralized debt obligations — 13,490 — 13,490 Commercial MBS issued by GSEs — 117,792 — 117,792 Corporate debt securities 20,000 44,144 — 64,144 CRA investments 37,113 — — 37,113 Preferred stock 94,662 — — 94,662 Private label residential MBS — 433,685 — 433,685 Residential MBS issued by GSEs — 1,355,205 — 1,355,205 Tax-exempt — 408,233 — 408,233 Trust preferred securities — 26,532 — 26,532 U.S. government sponsored agency securities 56,022 56,022 U.S. treasury securities — 2,502 — 2,502 Total AFS securities $ 151,775 $ 2,457,605 $ — $ 2,609,380 Loans - HFS $ — $ 18,909 $ — $ 18,909 Derivative assets (1) — 4,220 — 4,220 Liabilities: Junior subordinated debt $ — $ — $ 50,410 $ 50,410 Derivative liabilities (1) — 65,749 $ — 65,749 (1) Derivative assets and liabilities relate to interest rate swaps, see " Note 9. Derivatives and Hedging Activities ." In addition, the carrying value of loans is increased by $ 48,161 and the net carrying value of subordinated debt is decreased by $12,325 as of December 31, 2016 , which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates.
Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis	For the three months ended March 31, 2017 and 2016 , the change in Level 3 assets and liabilities measured at fair value on a recurring basis was as follows: Junior Subordinated Debt Three Months Ended March 31, 2017 2016 (in thousands) Beginning balance $ (50,410 ) $ (46,928 ) Transfers into Level 3 — — Total gains (losses) for the period Included in other comprehensive income (1,986 ) 1,212 Ending balance $ (52,396 ) $ (45,716 ) CDO Securities Three Months Ended March 31, 2017 2016 (in thousands) Beginning balance $ — $ 10,060 Transfers into Level 3 — — Total gains (losses) for the period Included in other comprehensive income — (984 ) Ending balance $ — $ 9,076 The Company transferred all CDO securities from Level 3 to Level 2 during the year ended December 31, 2016 as a result of an increase in the availability and reliability of the observable inputs utilized in the securities' fair value measurement. The Company recognized this transfer between levels on October 31, 2016, in accordance with its policy to recognize transfers between levels in the fair value hierarchy as of the end of the month following the event or change in circumstance that caused the transfer. For Level 3 assets and liabilities measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 , the significant unobservable inputs used in the fair value measurements were as follows: March 31, 2017 Valuation Technique Significant Unobservable Inputs Input Value (in thousands) Junior subordinated debt $ 52,396 Discounted cash flow Implied credit rating of the Company 5.54 %
Assets Measured at Fair Value on Nonrecurring Basis	The following table presents such assets carried on the 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 in Active Markets for Identical Assets (Level 1) Active Markets for Similar Assets (Level 2) Unobservable Inputs (Level 3) (in thousands) As of March 31, 2017: Impaired loans with specific valuation allowance $ 6,954 $ — $ — $ 6,954 Impaired loans without specific valuation allowance (1) 79,351 — — 79,351 Other assets acquired through foreclosure 45,200 — — 45,200 As of December 31, 2016: Impaired loans with specific valuation allowance $ 6,670 $ — $ — $ 6,670 Impaired loans without specific valuation allowance (1) 60,738 — — 60,738 Other assets acquired through foreclosure 47,815 — — 47,815 (1) Net of loan balances with charge-offs of $23.4 million and $27.6 million as of March 31, 2017 and December 31, 2016 , respectively
Estimated Fair Value of Financial Instruments	The estimated fair value of the Company’s financial instruments is as follows: March 31, 2017 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 102,590 $ — $ 103,666 $ — $ 103,666 AFS 2,700,011 145,810 2,554,201 — 2,700,011 Trading 1,019 — 1,019 — 1,019 Derivative assets 1,985 — 1,985 — 1,985 Loans, net 13,535,099 — 13,365,680 86,305 13,451,985 Accrued interest receivable 66,453 — 66,453 — 66,453 Financial liabilities: Deposits $ 15,355,970 $ — $ 15,361,363 $ — $ 15,361,363 Customer repurchase agreements 35,711 — 35,711 — 35,711 Qualifying debt 366,885 — — 390,689 390,689 Derivative liabilities 59,136 — 59,136 — 59,136 Accrued interest payable 10,459 — 10,459 — 10,459 December 31, 2016 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 92,079 $ — $ 91,966 $ — $ 91,966 AFS 2,609,380 151,775 2,457,605 — 2,609,380 Trading 1,053 — 1,053 — 1,053 Derivative assets 4,220 — 4,220 — 4,220 Loans, net 13,083,732 — 12,736,336 67,408 12,803,744 Accrued interest receivable 70,320 — 70,320 — 70,320 Financial liabilities: Deposits $ 14,549,863 $ — $ 14,553,931 $ — $ 14,553,931 Customer repurchase agreements 41,728 — 41,728 — 41,728 FHLB advances 80,000 — 80,000 — 80,000 Qualifying debt 367,937 — — 375,626 375,626 Derivative liabilities 65,749 — 65,749 — 65,749 Accrued interest payable 15,354 — 15,354 — 15,354

Segments (Tables)

Segments (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Operating Segment Information	The following is a summary of operating segment balance sheet information for the periods indicated: Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At March 31, 2017 (in millions) Assets: Cash, cash equivalents, and investment securities $ 3,516.1 $ 1.8 $ 8.9 $ 1.9 $ 1.7 Loans, net of deferred loan fees and costs 13,662.7 3,039.7 1,769.3 1,806.7 1,130.1 Less: allowance for credit losses (127.6 ) (30.3 ) (18.7 ) (20.1 ) (9.4 ) Total loans 13,535.1 3,009.4 1,750.6 1,786.6 1,120.7 Other assets acquired through foreclosure, net 45.2 5.0 17.1 — 0.2 Goodwill and other intangible assets, net 302.1 — 23.4 — 157.2 Other assets 724.0 42.3 58.9 13.9 13.5 Total assets $ 18,122.5 $ 3,058.5 $ 1,858.9 $ 1,802.4 $ 1,293.3 Liabilities: Deposits $ 15,356.0 $ 4,255.0 $ 3,896.1 $ 2,397.2 $ 1,461.3 Borrowings and qualifying debt 366.9 — — — — Other liabilities 430.6 13.4 27.4 4.5 13.6 Total liabilities 16,153.5 4,268.4 3,923.5 2,401.7 1,474.9 Allocated equity: 1,969.0 365.7 259.0 205.2 284.6 Total liabilities and stockholders' equity $ 18,122.5 $ 4,634.1 $ 4,182.5 $ 2,606.9 $ 1,759.5 Excess funds provided (used) — 1,575.6 2,323.6 804.5 466.2 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 3,501.8 Loans, net of deferred loan fees and costs 132.7 1,528.7 1,011.2 1,279.6 1,955.1 9.6 Less: allowance for credit losses (1.4 ) (16.0 ) (9.7 ) (1.3 ) (20.0 ) (0.7 ) Total loans 131.3 1,512.7 1,001.5 1,278.3 1,935.1 8.9 Other assets acquired through foreclosure, net — — — — — 22.9 Goodwill and other intangible assets, net — — 121.4 0.1 — — Other assets 0.4 11.9 5.7 5.4 2.8 569.2 Total assets $ 131.7 $ 1,524.6 $ 1,128.6 $ 1,283.8 $ 1,937.9 $ 4,102.8 Liabilities: Deposits $ 2,112.8 $ — $ 1,142.2 $ — $ — $ 91.4 Borrowings and qualifying debt — — — — — 366.9 Other liabilities 1.8 43.1 0.8 0.6 132.6 192.8 Total liabilities 2,114.6 43.1 1,143.0 0.6 132.6 651.1 Allocated equity: 72.9 122.3 225.5 105.5 162.2 166.1 Total liabilities and stockholders' equity $ 2,187.5 $ 165.4 $ 1,368.5 $ 106.1 $ 294.8 $ 817.2 Excess funds provided (used) 2,055.8 (1,359.2 ) 239.9 (1,177.7 ) (1,643.1 ) (3,285.6 ) Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At December 31, 2016 (in millions) Assets: Cash, cash equivalents, and investment securities $ 3,052.3 $ 1.9 $ 10.1 $ 2.1 $ 1.9 Loans, net of deferred loan fees and costs 13,208.5 2,955.9 1,725.5 1,766.8 1,095.4 Less: allowance for credit losses (124.7 ) (30.1 ) (18.5 ) (19.4 ) (8.8 ) Total loans 13,083.8 2,925.8 1,707.0 1,747.4 1,086.6 Other assets acquired through foreclosure, net 47.8 6.2 18.0 — 0.3 Goodwill and other intangible assets, net 302.9 — 23.7 — 157.5 Other assets 714.0 42.9 58.8 14.5 14.3 Total assets $ 17,200.8 $ 2,976.8 $ 1,817.6 $ 1,764.0 $ 1,260.6 Liabilities: Deposits $ 14,549.8 $ 3,843.4 $ 3,731.5 $ 2,382.6 $ 1,543.6 Borrowings and qualifying debt 447.9 — — — — Other liabilities 311.6 12.8 28.3 12.9 12.4 Total liabilities 15,309.3 3,856.2 3,759.8 2,395.5 1,556.0 Allocated equity: 1,891.5 346.6 250.7 201.6 283.7 Total liabilities and stockholders' equity $ 17,200.8 $ 4,202.8 $ 4,010.5 $ 2,597.1 $ 1,839.7 Excess funds provided (used) — 1,226.0 2,192.9 833.1 579.1 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 3,036.3 Loans, net of deferred loan fees and costs 116.8 1,454.3 1,011.4 1,292.1 1,776.9 13.4 Less: allowance for credit losses (1.3 ) (15.6 ) (10.6 ) (0.8 ) (19.0 ) (0.6 ) Total loans 115.5 1,438.7 1,000.8 1,291.3 1,757.9 12.8 Other assets acquired through foreclosure, net — — — — — 23.3 Goodwill and other intangible assets, net — — 121.5 0.2 — — Other assets 0.3 15.6 7.2 5.3 11.1 544.0 Total assets $ 115.8 $ 1,454.3 $ 1,129.5 $ 1,296.8 $ 1,769.0 $ 3,616.4 Liabilities: Deposits $ 1,890.3 $ — $ 1,038.2 $ — $ — $ 120.2 Borrowings and qualifying debt — — — — — 447.9 Other liabilities 0.7 50.5 2.0 1.4 17.5 173.1 Total liabilities 1,891.0 50.5 1,040.2 1.4 17.5 741.2 Allocated equity: 65.6 117.1 224.1 107.1 145.5 149.5 Total liabilities and stockholders' equity $ 1,956.6 $ 167.6 $ 1,264.3 $ 108.5 $ 163.0 $ 890.7 Excess funds provided (used) 1,840.8 (1,286.7 ) 134.8 (1,188.3 ) (1,606.0 ) (2,725.7 ) The following is a summary of operating segment income statement information for the periods indicated: Regional Segments Consolidated Company Arizona Nevada Southern California Northern California Three Months Ended March 31, 2017: (in thousands) Net interest income (expense) $ 179,309 $ 43,907 $ 35,296 $ 25,218 $ 22,035 Provision for (recovery of) credit losses 4,250 14 (211 ) 91 396 Net interest income (expense) after provision for credit losses 175,059 43,893 35,507 25,127 21,639 Non-interest income 10,544 1,113 2,133 743 2,113 Non-interest expense (87,757 ) (18,622 ) (15,870 ) (12,703 ) (12,709 ) Income (loss) before income taxes 97,846 26,384 21,770 13,167 11,043 Income tax expense (benefit) 24,489 10,350 7,620 5,537 4,643 Net income (loss) $ 73,357 $ 16,034 $ 14,150 $ 7,630 $ 6,400 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other (in thousands) Net interest income (expense) $ 12,748 $ 6,485 $ 18,166 $ 13,581 $ 14,143 $ (12,270 ) Provision for (recovery of) credit losses 127 509 296 — 3,527 (499 ) Net interest income (expense) after provision for credit losses 12,621 5,976 17,870 13,581 10,616 (11,771 ) Non-interest income 141 15 1,873 — 721 1,692 Non-interest expense (7,147 ) (2,253 ) (8,779 ) (2,988 ) (4,721 ) (1,965 ) Income (loss) before income taxes 5,615 3,738 10,964 10,593 6,616 (12,044 ) Income tax expense (benefit) 2,106 1,402 4,111 3,972 2,481 (17,733 ) Net income (loss) $ 3,509 $ 2,336 $ 6,853 $ 6,621 $ 4,135 $ 5,689 Regional Segments Consolidated Company Arizona Nevada Southern California Northern California Three Months Ended March 31, 2016: (in thousands) Net interest income (expense) $ 145,711 $ 38,456 $ 32,575 $ 24,428 $ 23,195 Provision for (recovery of) credit losses 2,500 6,773 (813 ) 30 1,042 Net interest income (expense) after provision for credit losses 143,211 31,683 33,388 24,398 22,153 Non-interest income 13,133 3,681 2,059 660 2,426 Non-interest expense (75,493 ) (14,456 ) (14,746 ) (11,234 ) (13,967 ) Income (loss) before income taxes 80,851 20,908 20,701 13,824 10,612 Income tax expense (benefit) 19,519 8,202 7,245 5,813 4,463 Net income (loss) $ 61,332 $ 12,706 $ 13,456 $ 8,011 $ 6,149 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Other NBLs Corporate & Other (in thousands) Net interest income (expense) $ 8,632 $ 5,221 $ 16,309 $ 10,637 $ (13,742 ) Provision for (recovery of) credit losses 78 (369 ) (1,165 ) 238 (3,314 ) Net interest income (expense) after provision for credit losses 8,554 5,590 17,474 10,399 (10,428 ) Non-interest income 105 (4 ) 1,637 635 1,934 Non-interest expense (5,541 ) (2,024 ) (6,906 ) (3,437 ) (3,182 ) Income (loss) before income taxes 3,118 3,562 12,205 7,597 (11,676 ) Income tax expense (benefit) 1,169 1,336 4,577 2,849 (16,135 ) Net income (loss) $ 1,949 $ 2,226 $ 7,628 $ 4,748 $ 4,459

Mergers, Acquisitions and Dis35

Mergers, Acquisitions and Dispositions (Tables)	3 Months Ended
	Mar. 31, 2017
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The recognized amounts of identifiable assets acquired and liabilities assumed, at their as adjusted acquisition date fair values, are as follows: April 20, 2016 (in thousands) Assets: Loans $ 1,280,997 Other assets 3,632 Total assets $ 1,284,629 Liabilities: Other liabilities $ 12,559 Total liabilities 12,559 Net assets acquired $ 1,272,070 Consideration paid Cash $ 1,272,187 Goodwill $ 117
Business Acquisition, Pro Forma Information [Table Text Block]	The following table presents pro forma information as if the acquisition was completed on January 1, 2015. The pro forma information includes adjustments for interest income on loans acquired and excludes acquisition / restructure expense. 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 March 31, 2016 (in thousands, except per share amounts) Interest income $ 170,885 Non-interest income 13,133 Net income available to common stockholders 68,491 Earnings per share - basic 0.67 Earnings per share - diluted 0.67

Summary of Significant Accoun36

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016Subsidiary
Significant Of Accounting Policies [Line Items]
Number Of Wholly Owned Subsidiaries Non Bank Subsidiaries	1
Number of wholly-owned subsidiaries	10
Number Of Unconsolidated Subsidiaries	8

Investment Securities - Carryin

Investment Securities - Carrying Amounts and Fair Values of Investment Securities (Detail) - USD ($)	Mar. 31, 2017		Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	$ 102,590,000		$ 92,079,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,388,000		433,000
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	312,000		546,000
Held-to-maturity Securities, Fair Value	103,666,000		91,966,000
Securities available for sale Total, Amortized Cost	2,709,686,000		2,633,298,000
Securities available-for-sale, Gross Unrealized Gains	36,711,000		26,355,000
Securities available-for-sale, Gross Unrealized (Losses)	(46,386,000)		(50,273,000)
Securities available for sale Total, Estimated Fair Value	2,700,011,000		2,609,380,000
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	59,000,000		59,000,000
Securities available-for-sale, Gross Unrealized Gains	0		0
Securities available-for-sale, Gross Unrealized (Losses)	(3,080,000)		(2,978,000)
Securities available for sale Total, Estimated Fair Value	55,920,000		56,022,000
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	2,496,000		2,496,000
Securities available-for-sale, Gross Unrealized Gains	6,000		6,000
Securities available-for-sale, Gross Unrealized (Losses)	0		0
Securities available for sale Total, Estimated Fair Value	2,502,000		2,502,000
Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	403,302,000		409,693,000
Securities available-for-sale, Gross Unrealized Gains	9,760,000		8,477,000
Securities available-for-sale, Gross Unrealized (Losses)	(8,947,000)		(9,937,000)
Securities available for sale Total, Estimated Fair Value	404,115,000		408,233,000
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	96,030,000		96,071,000
Securities available-for-sale, Gross Unrealized Gains	2,819,000		833,000
Securities available-for-sale, Gross Unrealized (Losses)	(247,000)		(2,242,000)
Securities available for sale Total, Estimated Fair Value	98,602,000		94,662,000
Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	1,375,584,000		1,369,289,000
Securities available-for-sale, Gross Unrealized Gains	3,349,000		3,046,000
Securities available-for-sale, Gross Unrealized (Losses)	(16,133,000)		(17,130,000)
Securities available for sale Total, Estimated Fair Value	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	504,213,000		440,272,000
Securities available-for-sale, Gross Unrealized Gains	419,000		182,000
Securities available-for-sale, Gross Unrealized (Losses)	(7,566,000)		(6,769,000)
Securities available for sale Total, Estimated Fair Value	497,066,000		433,685,000
Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	32,000,000		32,000,000
Securities available-for-sale, Gross Unrealized Gains	0		0
Securities available-for-sale, Gross Unrealized (Losses)	(4,320,000)		(5,468,000)
Securities available for sale Total, Estimated Fair Value	27,680,000		26,532,000
Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	50,000		50,000
Securities available-for-sale, Gross Unrealized Gains	19,973,000		13,440,000
Securities available-for-sale, Gross Unrealized (Losses)	0		0
Securities available for sale Total, Estimated Fair Value	20,023,000		13,490,000
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	119,646,000		121,742,000
Securities available-for-sale, Gross Unrealized Gains	15,000		0
Securities available-for-sale, Gross Unrealized (Losses)	(3,961,000)		(3,950,000)
Securities available for sale Total, Estimated Fair Value	115,700,000		117,792,000
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	69,643,000		65,058,000
Securities available-for-sale, Gross Unrealized Gains	370,000		371,000
Securities available-for-sale, Gross Unrealized (Losses)	(1,618,000)		(1,285,000)
Securities available for sale Total, Estimated Fair Value	68,395,000		64,144,000
CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Amortized Cost	47,722,000		37,627,000
Securities available-for-sale, Gross Unrealized Gains	0		0
Securities available-for-sale, Gross Unrealized (Losses)	(514,000)		(514,000)
Securities available for sale Total, Estimated Fair Value	47,208,000		37,113,000
AAA [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	500,150,000	[1]	479,875,000	[2]
AAA [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	36,121,000		80,862,000
AAA [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
AAA [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	464,029,000		399,013,000
AAA [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AAA [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	1,586,847,000	[1]	1,531,521,000	[2]
Split-rated AAA/AA Plus [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	55,920,000		56,022,000
Split-rated AAA/AA Plus [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	2,502,000		2,502,000
Split-rated AAA/AA Plus [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	24,985,000		0
Split-rated AAA/AA Plus [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Split-rated AAA/AA Plus [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	115,700,000		117,792,000
Split-rated AAA/AA Plus [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Split-rated AAA/AA Plus [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	24,940,000		0
AA Plus to AA- [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	249,809,000	[1]	303,599,000	[2]
AA Plus to AA- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	222,352,000		268,249,000
AA Plus to AA- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
AA Plus to AA- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	27,457,000		29,921,000
AA Plus to AA- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
AA Plus to AA- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		5,429,000
AA Plus to AA- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	177,664,000	[1]	99,954,000	[2]
A Plus to A- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	120,657,000		59,122,000
A Plus to A- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	10,550,000		0
A Plus to A- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
A Plus to A- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	1,896,000		2,117,000
A Plus to A- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
A Plus to A- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	44,561,000		38,715,000
A Plus to A- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	115,379,000	[1]	113,652,000	[2]
BBB Plus to BBB- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	64,715,000		64,486,000
BBB Plus to BBB- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
BBB Plus to BBB- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	3,684,000		2,634,000
BBB Plus to BBB- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	27,680,000		26,532,000
BBB Plus to BBB- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BBB Plus to BBB- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	19,300,000		20,000,000
BBB Plus to BBB- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	27,334,000	[1]	28,148,000	[2]
BB Plus and below [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	7,311,000		14,658,000
BB Plus and below [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
BB Plus and below [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	20,023,000		13,490,000
BB Plus and below [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
BB Plus and below [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	42,828,000	[1]	52,631,000	[2]
Corporate Credit Quality Indicator Unrated [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	102,590,000		92,079,000
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	16,026,000		15,518,000
Corporate Credit Quality Indicator Unrated [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Securities measured at fair value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	4,534,000		0
Corporate Credit Quality Indicator Unrated [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	22,268,000		37,113,000
Rated Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	2,700,011,000	[1]	2,609,380,000	[2]
Rated Securities [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	55,920,000		56,022,000
Rated Securities [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	2,502,000		2,502,000
Rated Securities [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	102,590,000		92,079,000
Securities available for sale Total, Estimated Fair Value	404,115,000		408,233,000
Rated Securities [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	98,602,000		94,662,000
Rated Securities [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Rated Securities [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	497,066,000		433,685,000
Rated Securities [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	27,680,000		26,532,000
Rated Securities [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	20,023,000		13,490,000
Rated Securities [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	115,700,000		117,792,000
Rated Securities [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	68,395,000		64,144,000
Rated Securities [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale Total, Estimated Fair Value	$ 47,208,000		$ 37,113,000
[1]	he Company uses an average of the ratings by S&P, Moody’s, and/or Fitch
[2]	Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch.

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)positions	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)positions
Investment Identifier [Line Items]
Amount of impairment losses reclassified out of accumulated other comprehensive income into earnings	$ 0	$ 0
Total number of securities in an unrealized loss position | positions	204		244
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 46,386,000		$ 50,273,000
Securities with carrying amounts were pledged	$ 902,600,000		$ 763,000,000

Investment Securities - Unreali

Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 312	$ 546
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	30,542	30,364
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	312	546
Held-to-maturity Securities, Fair Value	30,542	30,364
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	41,632	44,012
Available-for-sale securities, Less Than Twelve Months, Fair Value	1,693,462	1,789,692
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	4,754	6,261
Available-for-sale securities, Twelve Months or Longer, Fair Value	61,342	50,298
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	46,386	50,273
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	1,754,804	1,839,990
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	3,080	2,978
Available-for-sale securities, Less Than Twelve Months, Fair Value	55,920	56,022
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	3,080	2,978
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	55,920	56,022
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	1,618	1,285
Available-for-sale securities, Less Than Twelve Months, Fair Value	62,971	38,716
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	1,618	1,285
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	62,971	38,716
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	247	2,188
Available-for-sale securities, Less Than Twelve Months, Fair Value	11,946	63,151
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	54
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	1,471
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	247	2,242
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	11,946	64,622
Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	15,699	16,990
Available-for-sale securities, Less Than Twelve Months, Fair Value	868,033	950,480
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	434	140
Available-for-sale securities, Twelve Months or Longer, Fair Value	33,662	5,326
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	16,133	17,130
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	901,695	955,806
Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	8,947	9,937
Available-for-sale securities, Less Than Twelve Months, Fair Value	142,516	148,780
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	8,947	9,937
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	142,516	148,780
Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	7,566	6,170
Available-for-sale securities, Less Than Twelve Months, Fair Value	391,073	377,638
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	599
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	16,969
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	7,566	6,769
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	391,073	394,607
Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0	0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0	0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	4,320	5,468
Available-for-sale securities, Twelve Months or Longer, Fair Value	27,680	26,532
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	4,320	5,468
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	27,680	26,532
CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	514	514
Available-for-sale securities, Less Than Twelve Months, Fair Value	47,208	37,113
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	514	514
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	47,208	37,113
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	3,961	3,950
Available-for-sale securities, Less Than Twelve Months, Fair Value	113,795	117,792
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	3,961	3,950
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 113,795	$ 117,792

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Fair Value of Investment Securities by Contractual Maturities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount	$ 102,590
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	103,666
Securities available for sale, Due in one year or less, Amortized Cost	50,000
Securities available for sale, After one year through five years, Amortized Cost	52,331
Securities available for sale, After five years through ten years, Amortized Cost	214,862
Securities available for sale, After ten years, Amortized Cost	393,050
Securities available for sale, Mortgage backed securities, Amortized Cost	1,999,443
Securities available for sale Total, Amortized Cost	2,709,686	$ 2,633,298
Securities available for sale, Due in one year or less, Estimated Fair Value	49,549
Securities available for sale, After one year through five years, Estimated Fair Value	53,380
Securities available for sale, After five years through ten years, Estimated Fair Value	214,145
Securities available for sale, After ten years, Estimated Fair Value	407,371
Securities available for sale, Mortgage backed securities, Estimated Fair Value	1,975,566
Securities available for sale Total, Estimated Fair Value	$ 2,700,011	$ 2,609,380

Investment Securities - Investm

Investment Securities - Investment Securities by Credit Rating Type (Detail) - USD ($)	Mar. 31, 2017		Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	$ 102,590,000		$ 92,079,000
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011,000		2,609,380,000
Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	404,115,000		408,233,000
Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	115,700,000		117,792,000
Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	497,066,000		433,685,000
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	55,920,000		56,022,000
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,502,000		2,502,000
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	98,602,000		94,662,000
Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	27,680,000		26,532,000
Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	20,023,000		13,490,000
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	68,395,000		64,144,000
CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	47,208,000		37,113,000
Rated Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011,000	[1]	2,609,380,000	[2]
Rated Securities [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	102,590,000		92,079,000
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	404,115,000		408,233,000
Rated Securities [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Rated Securities [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	115,700,000		117,792,000
Rated Securities [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	497,066,000		433,685,000
Rated Securities [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	55,920,000		56,022,000
Rated Securities [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,502,000		2,502,000
Rated Securities [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	98,602,000		94,662,000
Rated Securities [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	27,680,000		26,532,000
Rated Securities [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	20,023,000		13,490,000
Rated Securities [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	68,395,000		64,144,000
Rated Securities [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	47,208,000		37,113,000
AAA [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	500,150,000	[1]	479,875,000	[2]
AAA [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	36,121,000		80,862,000
AAA [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
AAA [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	464,029,000		399,013,000
AAA [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AAA [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	1,586,847,000	[1]	1,531,521,000	[2]
Split-rated AAA/AA Plus [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	24,985,000		0
Split-rated AAA/AA Plus [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	1,362,800,000		1,355,205,000
Securities measured at fair value	1,019,000		1,053,000
Split-rated AAA/AA Plus [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	115,700,000		117,792,000
Split-rated AAA/AA Plus [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	55,920,000		56,022,000
Split-rated AAA/AA Plus [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,502,000		2,502,000
Split-rated AAA/AA Plus [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Split-rated AAA/AA Plus [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	24,940,000		0
AA Plus to AA- [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	249,809,000	[1]	303,599,000	[2]
AA Plus to AA- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	222,352,000		268,249,000
AA Plus to AA- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
AA Plus to AA- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	27,457,000		29,921,000
AA Plus to AA- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
AA Plus to AA- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		5,429,000
AA Plus to AA- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	177,664,000	[1]	99,954,000	[2]
A Plus to A- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	120,657,000		59,122,000
A Plus to A- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
A Plus to A- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	1,896,000		2,117,000
A Plus to A- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	10,550,000		0
A Plus to A- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
A Plus to A- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	44,561,000		38,715,000
A Plus to A- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	115,379,000	[1]	113,652,000	[2]
BBB Plus to BBB- [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
BBB Plus to BBB- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	3,684,000		2,634,000
BBB Plus to BBB- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	64,715,000		64,486,000
BBB Plus to BBB- [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	27,680,000		26,532,000
BBB Plus to BBB- [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BBB Plus to BBB- [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	19,300,000		20,000,000
BBB Plus to BBB- [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	27,334,000	[1]	28,148,000	[2]
BB Plus and below [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	0		0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
BB Plus and below [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	7,311,000		14,658,000
BB Plus and below [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	20,023,000		13,490,000
BB Plus and below [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
BB Plus and below [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	42,828,000	[1]	52,631,000	[2]
Corporate Credit Quality Indicator Unrated [Member] | Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities	102,590,000		92,079,000
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Securities measured at fair value	0		0
Corporate Credit Quality Indicator Unrated [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	16,026,000		15,518,000
Corporate Credit Quality Indicator Unrated [Member] | Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Corporate Credit Quality Indicator Unrated [Member] | Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	4,534,000		0
Corporate Credit Quality Indicator Unrated [Member] | CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	$ 22,268,000		$ 37,113,000
[1]	he Company uses an average of the ratings by S&P, Moody’s, and/or Fitch
[2]	Where ratings differ, the Company uses an average of the ratings by S&P, Moody’s, and/or Fitch.

Investment Securities - Gross G

Investment Securities - Gross Gains and (Losses) on Sales of Investments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Gross gains	$ 636	$ 2,057
Gross (losses)	(1)	(1,056)
Net (losses) gains	$ 635	$ 1,001

Loans, Leases and Allowance f43

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 ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Interest Rate and Credit Marks on Acquired Loans	$ 65,100	$ 69,500
Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group	17,865	18,909
Net deferred loan fees and costs	(21,500)	(22,300)
Loans, net of deferred loan fees and costs	13,644,883	13,189,527
Allowance for credit losses	(127,649)	(124,704)
Loans, net	13,517,234	13,064,823
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	5,948,307	5,755,021
Commercial Real Estate Non Owner Occupied Multi Family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	3,607,783	3,543,956
Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	2,043,431	2,013,276
Allowance for credit losses	(12,999)	(12,340)
Construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	1,601,721	1,478,114
Allowance for credit losses	(21,097)	(21,175)
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	309,870	259,432
Allowance for credit losses	(4,412)	(3,851)
Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	90,722	100,765
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	43,049	38,963
Allowance for credit losses	$ (707)	$ (672)

Loans, Leases and Allowance f44

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 ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		$ 13,617,297	$ 13,166,460
Past Due		27,586	23,067
Total		13,644,883	13,189,527
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	34,458	40,272
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		3,659	1,067
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		2,037,324	2,009,728
Past Due		6,107	3,548
Total		2,043,431	2,013,276
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	285
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		3,388,556	3,339,121
Past Due		311	674
Total		3,388,867	3,339,795
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		218,916	204,161
Past Due		0	0
Total		218,916	204,161
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		5,936,803	5,747,368
Past Due		11,504	7,653
Total		5,948,307	5,755,021
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		51	775
Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		90,581	100,761
Past Due		141	4
Total		90,722	100,765
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		49	0
Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		1,053,336	973,242
Past Due		0	0
Total		1,053,336	973,242
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		547,039	503,588
Past Due		1,346	1,284
Total		548,385	504,872
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		301,868	249,726
Past Due		8,002	9,706
Total		309,870	259,432
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		3,559	0
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		42,874	38,765
Past Due		175	198
Total		43,049	38,963
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	7
Non-accrual loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		20,500	24,421
Past Due		13,958	15,851
Financing Receivable, Recorded Investment, Nonaccrual Status			40,272
Non-accrual loans [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		4,210	5,084
Past Due		4,499	3,264
Financing Receivable, Recorded Investment, Nonaccrual Status		8,709	8,348
Non-accrual loans [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		2,524	8,317
Past Due		3	1
Financing Receivable, Recorded Investment, Nonaccrual Status		2,527	8,318
Non-accrual loans [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Past Due		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Non-accrual loans [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		12,528	10,893
Past Due		3,839	6,043
Financing Receivable, Recorded Investment, Nonaccrual Status		16,367	16,936
Non-accrual loans [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		24	28
Past Due		54	3
Financing Receivable, Recorded Investment, Nonaccrual Status		78	31
Non-accrual loans [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Past Due		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status		0	0
Non-accrual loans [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Past Due		1,284	1,284
Financing Receivable, Recorded Investment, Nonaccrual Status		1,284	1,284
Non-accrual loans [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		1,214	99
Past Due		4,115	5,093
Financing Receivable, Recorded Investment, Nonaccrual Status		5,329	5,192
Non-accrual loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Past Due		164	163
Financing Receivable, Recorded Investment, Nonaccrual Status		164	163
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		4,710	5,651
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		302	71
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		308	672
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,692	549
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		14	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		56	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		328	4,333
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		10	26
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		6,618	869
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,947	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	2
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		4,322	584
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		24	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		6	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		319	281
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	2
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		16,258	16,547
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,858	3,477
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,490	6,520
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		103	4
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,284	1,284
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		7,355	5,092
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		$ 165	$ 170
[1]	Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016, respectively.

Loans, Leases and Allowance f45

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 ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		$ 13,617,297	$ 13,166,460
Total Past Due		27,586	23,067
Total Non-accrual	[1]	34,458	40,272
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		3,659	1,067
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		2,037,324	2,009,728
Total Past Due		6,107	3,548
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	285
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		3,388,556	3,339,121
Total Past Due		311	674
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		218,916	204,161
Total Past Due		0	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		5,936,803	5,747,368
Total Past Due		11,504	7,653
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		51	775
Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		90,581	100,761
Total Past Due		141	4
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		49	0
Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		1,053,336	973,242
Total Past Due		0	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		547,039	503,588
Total Past Due		1,346	1,284
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	0
Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		301,868	249,726
Total Past Due		8,002	9,706
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		3,559	0
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		42,874	38,765
Total Past Due		175	198
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		0	7
Non-accrual loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		20,500	24,421
Total Past Due		13,958	15,851
Total Non-accrual			40,272
Non-accrual loans [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		4,210	5,084
Total Past Due		4,499	3,264
Total Non-accrual		8,709	8,348
Non-accrual loans [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		2,524	8,317
Total Past Due		3	1
Total Non-accrual		2,527	8,318
Non-accrual loans [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Total Past Due		0	0
Total Non-accrual		0	0
Non-accrual loans [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		12,528	10,893
Total Past Due		3,839	6,043
Total Non-accrual		16,367	16,936
Non-accrual loans [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		24	28
Total Past Due		54	3
Total Non-accrual		78	31
Non-accrual loans [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Total Past Due		0	0
Total Non-accrual		0	0
Non-accrual loans [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Total Past Due		1,284	1,284
Total Non-accrual		1,284	1,284
Non-accrual loans [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		1,214	99
Total Past Due		4,115	5,093
Total Non-accrual		5,329	5,192
Non-accrual loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		0	0
Total Past Due		164	163
Total Non-accrual		$ 164	$ 163
[1]	Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016, respectively.

Loans, Leases and Allowance f46

Loans, Leases and Allowance for Credit Losses - Additional Information (Detail) $ in Thousands		3 Months Ended
		Mar. 31, 2017USD ($)SecurityLoan	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Leases [Line Items]
Financing Receivable, Modifications, Number of Contracts | SecurityLoan		1
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 4,900
Receivable with Imputed Interest, Discount		(7,300)		$ (5,200)
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	34,458		40,272
Impaired Financing Receivable, Average Recorded Investment		103,387	$ 122,545
Aggregate carrying amount of impaired loans	[2]	10,919		10,909
Reduction in interest income due to nonaccrual loans		600	400
Loans And Loans Receivable Purchases		253,300	33,800
Financing Receivable, Significant Sales		9,200	23,800
Impaired loans with no allowance recorded	[3]	102,787		88,300
Impaired loans with an allowance recorded		3,965		4,239
Loans and Leases Receivable, Gain (Loss) on Sales, Net		100	2,500
Troubled Debt Restructured Loans [Member]
Leases [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		12,000		7,100
Impaired Financing Receivable, Average Recorded Investment		60,400	78,000
Aggregate carrying amount of impaired loans		7,100		2,500
Loan commitments outstanding				0
Impaired loans with no allowance recorded		54,300		58,300
Impaired loans with an allowance recorded		2,600		600
Construction and land development [Member]
Leases [Line Items]
Aggregate carrying amount of impaired loans		0		0
Impaired loans with no allowance recorded		14,117		14,838
Impaired loans with an allowance recorded		0		0
Residential real estate [Member]
Leases [Line Items]
Aggregate carrying amount of impaired loans		0		0
Loans And Loans Receivable Purchases		53,000
Impaired loans with no allowance recorded		18,806		16,391
Impaired loans with an allowance recorded		0		0
Commercial and industrial [Member]
Leases [Line Items]
Aggregate carrying amount of impaired loans		7,831		7,766
Loans And Loans Receivable Purchases		200,280
Impaired loans with no allowance recorded		28,452		13,340
Impaired loans with an allowance recorded		3,033		3,301
Consumer [Member]
Leases [Line Items]
Aggregate carrying amount of impaired loans		0		18
Impaired loans with no allowance recorded		214		228
Impaired loans with an allowance recorded		0		1
Commercial leases [Member]
Leases [Line Items]
Aggregate carrying amount of impaired loans		0		0
Impaired loans with no allowance recorded		400		355
Impaired loans with an allowance recorded		$ 0		$ 0
Commercial [Member] | Commercial and industrial [Member]
Leases [Line Items]
Financing Receivable, Modifications, Number of Contracts | SecurityLoan		1
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 87
Impaired Financing Receivable, Average Recorded Investment		$ 25,734	31,733
Non-owner occupied [Member] | Commercial real estate [Member]
Leases [Line Items]
Financing Receivable, Modifications, Number of Contracts | SecurityLoan		1
Financing Receivable, Modifications, Post-Modification Recorded Investment			5,381
Impaired Financing Receivable, Average Recorded Investment		$ 24,399	$ 33,033
[1]	Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016, respectively.
[2]	Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016, respectively.
[3]	Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016, respectively.

Loans, Leases and Allowance f47

Loans, Leases and Allowance for Credit Losses - Loans by Risk Rating (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	$ 13,644,883,000	$ 13,189,527,000
Current	13,617,297,000	13,166,460,000
Past Due	27,586,000	23,067,000
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	309,870,000	259,432,000
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	43,049,000	38,963,000
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	2,043,431,000	2,013,276,000
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	3,388,867,000	3,339,795,000
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	218,916,000	204,161,000
Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	5,948,303,000	5,755,021,000
Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	90,726,000	100,765,000
Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	1,053,336,000	973,242,000
Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	548,385,000	504,872,000
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	13,301,117,000	12,893,422,000
Current	13,296,590,000	12,887,308,000
Pass [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	299,302,000	252,304,000
Pass [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	42,803,000	38,698,000
Pass [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	1,971,261,000	1,935,322,000
Pass [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	3,336,170,000	3,278,090,000
Pass [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	218,723,000	203,964,000
Pass [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	5,773,313,000	5,621,448,000
Pass [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	87,012,000	100,737,000
Pass [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	1,041,338,000	961,290,000
Pass [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	531,195,000	501,569,000
Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	175,080,000	148,144,000
Current	171,409,000	147,838,000
Watch [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	928,000	929,000
Watch [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	54,000	64,000
Watch [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	49,568,000	53,634,000
Watch [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	13,775,000	22,972,000
Watch [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	193,000	197,000
Watch [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	92,556,000	70,011,000
Watch [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	3,640,000	0
Watch [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Watch [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	14,366,000	337,000
Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	166,409,000	140,731,000
Current	147,764,000	124,084,000
Substandard [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	9,640,000	6,199,000
Substandard [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	192,000	201,000
Substandard [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	20,325,000	22,090,000
Substandard [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	38,922,000	38,733,000
Substandard [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Substandard [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	82,434,000	58,562,000
Substandard [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	74,000	28,000
Substandard [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	11,998,000	11,952,000
Substandard [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	2,824,000	2,966,000
Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	2,277,000	7,230,000
Current	1,534,000	7,230,000
Doubtful [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	2,277,000	2,230,000
Doubtful [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	5,000,000
Doubtful [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Doubtful [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Current	0	0
Loss [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Loss [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	4,710,000	5,651,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	2,993,000	5,433,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	1,058,000	96,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	659,000	122,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Loss [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	6,618,000	869,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	1,342,000	410,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	2,613,000	210,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	2,663,000	249,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Loss [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	16,258,000	16,547,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	192,000	271,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	15,323,000	16,276,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	743,000	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Loss [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	$ 0	$ 0

Loans, Leases and Allowance f48

Loans, Leases and Allowance for Credit Losses - Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	$ 113,706	$ 99,209
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	18,806	16,391
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	214	246
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	21,321	20,748
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	22,565	25,524
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	0	0
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	36,283	21,106
Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	36,283	21,107
Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	400	355
Construction and land development [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	0	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	$ 14,117	$ 14,838

Loans, Leases and Allowance f49

Loans, Leases and Allowance for Credit Losses - Recorded Investment in Loans Classified as Impaired (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Impaired loans with an allowance recorded	[1]	$ 10,919	$ 10,909
Impaired loans with no allowance recorded	[2]	102,787	88,300
Total impaired loans		113,706	99,209
Valuation allowance related to impaired loans		$ (3,965)	$ (4,239)
[1]	Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016, respectively.
[2]	Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016, respectively.

Loans, Leases and Allowance f50

Loans, Leases and Allowance for Credit Losses - Schedule of Average Investment in Impaired Loans and Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Receivables [Abstract]
Impaired Financing Receivable, Average Recorded Investment	$ 103,387	$ 122,545
Interest income recognized on impaired loans	921	1,113
Interest recognized on nonaccrual loans, cash basis	$ 332	$ 172

Loans, Leases and Allowance f51

Loans, Leases and Allowance for Credit Losses - Average Investment in Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	$ 103,387	$ 122,545
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	17,103	15,764
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	224	329
Troubled Debt Restructured Loans [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	60,400	78,000
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	21,128	21,737
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	24,399	33,033
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	0	0
Commercial and industrial [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	25,734	31,733
Commercial and industrial [Member] | Leases [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	367	2,049
Construction and land development [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	0	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	$ 14,432	$ 17,900

Loans, Leases and Allowance f52

Loans, Leases and Allowance for Credit Losses - Interest Income on Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	$ 921	$ 1,113
Owner occupied [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	177	295
Non-owner occupied [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	239	338
Multi-family [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	0	0
Commercial [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	140	108
Leases [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	4	32
Construction [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	0	0
Land [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	221	207
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	139	131
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	$ 1	$ 2

Loans, Leases and Allowance f53

Loans, Leases and Allowance for Credit Losses - Tabular Disclosure of Nonperforming Assets (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	$ 34,458	$ 40,272
Loans past due 90 days or more on accrual status		3,659	1,067
Troubled debt restructured loans		49,292	53,637
Total nonperforming loans		87,409	94,976
Other assets acquired through foreclosure, net		45,200	47,815	$ 52,776	$ 43,942
Total nonperforming assets		132,609	142,791
Troubled Debt Restructured Loans [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		12,000	7,100
Receivables Acquired with Deteriorated Credit Quality [Member]
Loans past due 90 days or more on accrual status		$ 100	$ 100
[1]	Includes non-accrual TDR loans of $12.0 million and $7.1 million at March 31, 2017 and December 31, 2016, respectively.

Loans, Leases and Allowance f54

Loans, Leases and Allowance for Credit Losses - Changes in Accretable Discount for Loans Purchased with Credit Quality Deterioration (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period		$ 15,177	$ 15,925
Reclassifications from non-accretable to accretable yield (1)	[1]	0	0
Accretion to interest income		(907)	(782)
Reversal of fair value adjustments upon disposition of loans		(458)	(1,602)
Balance at end of period		$ 13,812	$ 13,541
[1]	The primary drivers of reclassification from non-accretable to accretable yield resulted from changes in estimated cash flows.

Loans, Leases and Allowance f55

Loans, Leases and Allowance for Credit Losses - Allowances for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Valuation Allowance [Line Items]
Beginning Balance	$ 124,704	$ 119,068
Charge-offs	2,743	8,001
Recoveries	(1,438)	(5,660)
Provision for credit losses	4,250	2,500
Ending balance	127,649	119,227
Construction and land development [Member]
Valuation Allowance [Line Items]
Beginning Balance	21,175	18,976
Charge-offs	0	0
Recoveries	277	(95)
Provision for credit losses	(355)	354
Ending balance	21,097	19,425
Commercial real estate [Member]
Valuation Allowance [Line Items]
Beginning Balance	25,673	23,160
Charge-offs	0	410
Recoveries	533	(3,665)
Provision for credit losses	1,798	(3,311)
Ending balance	28,004	23,104
Residential real estate [Member]
Valuation Allowance [Line Items]
Beginning Balance	3,851	5,278
Charge-offs	115	26
Recoveries	251	(257)
Provision for credit losses	425	(571)
Ending balance	4,412	4,938
Commercial and industrial [Member]
Valuation Allowance [Line Items]
Beginning Balance	73,333	71,181
Charge-offs	2,594	7,491
Recoveries	328	(1,576)
Provision for credit losses	2,362	5,890
Ending balance	73,429	71,156
Consumer [Member]
Valuation Allowance [Line Items]
Beginning Balance	672	473
Charge-offs	34	74
Recoveries	49	(67)
Provision for credit losses	20	138
Ending balance	$ 707	$ 604

Loans, Leases and Allowance f56

Loans, Leases and Allowance for Credit Losses - Summary of Impairment Method Information Related to Loans and Allowance for Credit Losses (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	[1]	$ 10,919	$ 10,909
Impaired loans with no allowance recorded	[2]	102,787	88,300
Total loans individually evaluated for impairment		113,706	99,209
Loans collectively evaluated for impairment		13,370,118	12,924,164
Impaired Financing Receivable, Recorded Investment		113,706	99,209
Total recorded investment		13,644,883	13,189,527
Impaired loans with an allowance recorded		10,919	11,162
Impaired loans with no allowance recorded		186,642	164,721
Total loans individually evaluated for impairment		197,561	175,883
Loans collectively evaluated for impairment		13,370,118	12,924,164
Total unpaid principal balance		13,769,070	13,301,721
Impaired loans with an allowance recorded		3,965	4,239
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		3,965	4,239
Loans collectively evaluated for impairment		121,803	118,642
Total loans held for investment		127,649	124,704
Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		3,088	3,125
Impaired loans with no allowance recorded		18,233	17,624
Total loans individually evaluated for impairment		21,321	20,749
Loans collectively evaluated for impairment		2,010,916	1,981,176
Total recorded investment		2,043,431	2,013,276
Impaired loans with an allowance recorded		3,088	3,125
Impaired loans with no allowance recorded		26,599	26,336
Total loans individually evaluated for impairment		29,687	29,461
Loans collectively evaluated for impairment		2,010,916	1,981,176
Total unpaid principal balance		2,055,565	2,025,515
Impaired loans with an allowance recorded		932	937
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		932	937
Loans collectively evaluated for impairment		12,067	11,403
Total loans held for investment		12,999	12,340
Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		22,565	25,524
Total loans individually evaluated for impairment		22,565	25,524
Loans collectively evaluated for impairment		3,435,971	3,383,585
Total recorded investment		3,607,783	3,543,956
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		30,204	33,632
Total loans individually evaluated for impairment		30,204	33,632
Loans collectively evaluated for impairment		3,435,971	3,383,585
Total unpaid principal balance		3,646,922	3,582,492
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		0	0
Loans collectively evaluated for impairment		13,124	12,646
Total loans held for investment		15,005	13,333
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		7,831	7,766
Impaired loans with no allowance recorded		28,452	13,340
Total loans individually evaluated for impairment		36,283	21,106
Loans collectively evaluated for impairment		5,912,024	5,733,915
Total recorded investment		5,948,307	5,755,021
Impaired loans with an allowance recorded		7,831	8,019
Impaired loans with no allowance recorded		57,433	43,176
Total loans individually evaluated for impairment		65,264	51,195
Loans collectively evaluated for impairment		5,912,024	5,733,915
Total unpaid principal balance		5,982,237	5,786,035
Impaired loans with an allowance recorded		3,033	3,301
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		3,033	3,301
Loans collectively evaluated for impairment		70,396	69,673
Total loans held for investment		73,429	73,333
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		18,806	16,391
Total loans individually evaluated for impairment		18,806	16,391
Loans collectively evaluated for impairment		290,446	242,409
Total recorded investment		309,870	259,432
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		28,275	26,225
Total loans individually evaluated for impairment		28,275	26,225
Loans collectively evaluated for impairment		290,446	242,409
Total unpaid principal balance		319,454	269,372
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		0	0
Loans collectively evaluated for impairment		4,412	3,851
Total loans held for investment		4,412	3,851
Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		14,117	14,838
Total loans individually evaluated for impairment		14,117	14,838
Loans collectively evaluated for impairment		1,587,604	1,443,952
Total recorded investment		1,601,721	1,478,114
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		32,767	33,487
Total loans individually evaluated for impairment		32,767	33,487
Loans collectively evaluated for impairment		1,587,604	1,443,952
Total unpaid principal balance		1,620,371	1,497,297
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		0	0
Loans collectively evaluated for impairment		21,097	20,398
Total loans held for investment		21,097	21,175
Commercial leases [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		400	355
Total loans individually evaluated for impairment		400	355
Loans collectively evaluated for impairment		90,322	100,410
Total recorded investment		90,722	100,765
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		551	507
Total loans individually evaluated for impairment		551	507
Loans collectively evaluated for impairment		90,322	100,410
Total unpaid principal balance		90,873	100,917
Impaired loans with an allowance recorded		0	0
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		0	0
Loans collectively evaluated for impairment		0	0
Total loans held for investment		0	0
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded		0	18
Impaired loans with no allowance recorded		214	228
Total loans individually evaluated for impairment		214	246
Loans collectively evaluated for impairment		42,835	38,717
Total recorded investment		43,049	38,963
Impaired loans with an allowance recorded		0	18
Impaired loans with no allowance recorded		10,813	1,358
Total loans individually evaluated for impairment		10,813	1,376
Loans collectively evaluated for impairment		42,835	38,717
Total unpaid principal balance		53,648	40,093
Impaired loans with an allowance recorded		0	1
Impaired loans with no allowance recorded		0	0
Total loans individually evaluated for impairment		0	1
Loans collectively evaluated for impairment		707	671
Total loans held for investment		707	672
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Impaired [Line Items]
Loans acquired with deteriorated credit quality		201,391	201,674
Impaired loans with an allowance recorded		1,881	1,823
Receivables Acquired with Deteriorated Credit Quality [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		11,194	11,351
Loans acquired with deteriorated credit quality		14,962	14,878
Impaired loans with an allowance recorded		0	0
Receivables Acquired with Deteriorated Credit Quality [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		161,059	166,154
Receivables Acquired with Deteriorated Credit Quality [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		149,247	134,847
Loans acquired with deteriorated credit quality		180,747	165,275
Impaired loans with an allowance recorded		1,881	687
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0	0
Loans acquired with deteriorated credit quality		4,949	925
Impaired loans with an allowance recorded		0	359
Receivables Acquired with Deteriorated Credit Quality [Member] | Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		618	632
Loans acquired with deteriorated credit quality		733	738
Impaired loans with an allowance recorded		0	0
Receivables Acquired with Deteriorated Credit Quality [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0	19,324
Loans acquired with deteriorated credit quality		0	19,858
Impaired loans with an allowance recorded		0	777
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial leases [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0	0
Loans acquired with deteriorated credit quality		0	0
Impaired loans with an allowance recorded		0	0
Receivables Acquired with Deteriorated Credit Quality [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment		0	0
Loans acquired with deteriorated credit quality		0	0
Impaired loans with an allowance recorded		$ 0	$ 0
[1]	Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016, respectively.
[2]	Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016, respectively.

Other Assets Acquired through57

Other Assets Acquired through Foreclosure - Changes in Other Assets Acquired through Foreclosure (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017USD ($)Property	Mar. 31, 2016USD ($)Property	Dec. 31, 2016USD ($)Property
Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]
Balance, beginning of the period, Gross Balance	$ 54,138	$ 52,984	$ 52,984
Transfers to other assets acquired through foreclosure, net, Gross Balance	0	10,638
Proceeds from sale of other real estate owned and repossessed assets, net, Gross Balance	3,113	2,436
Gains (losses), net, Gross Balance	(106)	160
Balance, end of period, Gross Balance	50,919	61,346	54,138
Balance, beginning of the period, Valuation Allowance	6,323	9,042	9,042
Proceeds from sale of other real estate owned and repossessed assets, net, Valuation Allowance	224	295
Valuation adjustments, net, Valuation Allowance	(380)	(177)
Balance, end of period, Valuation Allowance	5,719	8,570	6,323
Balance, beginning of the period, Net Balance	47,815	43,942	43,942
Transfers to other assets acquired through foreclosure, net, Net Balance	0	10,638
Proceeds from sale of other real estate owned and repossessed assets, net, Net Balance	2,889	2,141
Valuation adjustments of other repossessed assets, net	380	177
Gains (losses), net, Net Balance	(106)	160
Balance, end of period, Net Balance	$ 45,200	$ 52,776	47,815
Gains Losses On Transfers To Other Real Estate And Foreclosed Assets			$ 0
Number of Real Estate Properties | Property	25	37	31

Other Borrowings - Additional I

Other Borrowings - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Debt [Line Items]
FHLB advances	$ 0	$ 80,000
Short-term Debt	0	80,000
Revolving line of credit	$ 0
Weighted average interest rate of FHLB and FRB Short-term advances	0.55%
Fed Funds With Other Institutions [Member]
Debt [Line Items]
Long-term Line of Credit		0
FRB [Member]
Debt [Line Items]
Additional available credit with the entity	$ 1,030,000	997,000
Other Credit Facilities [Member]
Debt [Line Items]
Secured borrowing credit line	168,300
Secured Credit Facility [Member]
Debt [Line Items]
Secured borrowing credit line	23,300
Unsecured Credit Facility [Member]
Debt [Line Items]
Secured borrowing credit line	145,000
FHLB [Member]
Debt [Line Items]
Additional available credit with the entity	$ 2,290,000	$ 2,150,000

Qualifying Debt (Details)

Qualifying Debt (Details)	3 Months Ended
	Mar. 31, 2017USD ($)Trust	Dec. 31, 2016USD ($)	Jun. 16, 2016USD ($)	Jun. 29, 2015USD ($)
Debt Instrument [Line Items]
Subordinated Debt	$ 302,700,000	$ 305,800,000
Number of Statutory Business Trusts Formed or Acquired | Trust	8
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	$ 64,225,000	$ 62,161,000
Subordinated Debt [Member] | Subordinated Debentures Maturing July 2056 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 175,000,000
Debt Issuance Cost			$ 5,530,000
Debt Instrument, Interest Rate, Stated Percentage			6.25%
Subordinated Debt [Member] | Subordinated Debentures Maturing July 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 150,000,000
Debt Issuance Cost				$ 1,800,000
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate	3.49%	3.34%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]	15,877,000
Treasury Stock, Shares, Acquired	(201,306)	(290,432)
Treasury Stock Acquired, Average Cost Per Share	$ 50.88	$ 30.81
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 1.3	$ 1.2
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	4.5	3.8
Executive Officer [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 0.4	$ 0.3	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	40,451
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Aggregate Intrinsic Value	$ 2
Bridge Capital Holdings [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 0.2

Accumulated Other Comprehensi61

Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (4,695)	$ 22,260
Other comprehensive income before reclassifications	7,939	11,784
Amounts reclassified from accumulated other comprehensive income	(393)	(711)
Net other comprehensive income (loss)	7,546	11,073
Ending balance	2,851	33,333
Unrealized holding gains (losses) on AFS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(14,916)	9,993
Other comprehensive income before reclassifications	9,169	11,019
Amounts reclassified from accumulated other comprehensive income	(393)	(711)
Net other comprehensive income (loss)	8,776	10,308
Ending balance	(6,140)	20,301
Financial Liability Instruments, Fair Value Option [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	9,956	12,033
Other comprehensive income before reclassifications	(1,229)	759
Amounts reclassified from accumulated other comprehensive income	0	0
Net other comprehensive income (loss)	(1,229)	759
Ending balance	8,727	12,792
Impairment loss on securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	144	144
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	0	0
Net other comprehensive income (loss)	0	0
Ending balance	144	144
Supplemental Employee Retirement Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	121	90
Other comprehensive income before reclassifications	(1)	6
Amounts reclassified from accumulated other comprehensive income	0	0
Net other comprehensive income (loss)	(1)	6
Ending balance	$ 120	$ 96

Accumulated Other Comprehensi62

Accumulated Other Comprehensive Income - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income	$ (242)	$ (290)
Amount reclassified from accumulated other comprehensive income	393	711
Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income	393	711
Realized Gain Loss On Sale Of Investment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Realized gains on sales of investment securities	635	1,001
Income Tax Expense [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income	$ (242)	$ (290)

Derivatives and Hedging Fair Va

Derivatives and Hedging Fair Value of Derivative Contracts (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Amount		$ 1,035,151	$ 993,485	$ 797,304
Derivative Asset, Fair Value		1,985	4,220	4,733
Derivative Liability, Fair Value		59,136	65,749	88,981
Notional Amount, Netting Adjustments	[1]	0	0	0
Derivative Netting Adjustments	[1]	1,947	1,869	0
Positive NPVs		38	2,351	4,733
Negative NPVs		57,189	63,880	88,981
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Amount		1,035,151	993,485	797,304
Derivative Asset, Fair Value		1,985	4,220	4,733
Derivative Liability, Fair Value		$ 59,136	$ 65,749	$ 88,981
[1]	Netting adjustments represent the amounts recorded to convert the Company's derivative balances from a gross basis to a net basis in accordance with the applicable accounting guidance.

Derivatives and Hedging Pre-Tax

Derivatives and Hedging Pre-Tax Net Gains (Losses) on Fair Value Hedges (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	$ 15	$ 0
Subordinated Debt [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	0	0
Fixed Rate Loans [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Gain (Loss) on Derivatives	7,568	(24,197)
Increase (Decrease) to Basis of Hedged Assets	(7,553)	24,197
Subordinated Debt [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Gain (Loss) on Derivatives	(3,191)	1,164
Increase (Decrease) to Basis of Hedged Assets	$ 3,191	$ (1,164)

Derivatives and Hedging Largest

Derivatives and Hedging Largest Exposure to Individual Counterparty (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Largest gross exposure (positive derivative NPV) to an individual counterparty	$ 38	$ 2,351	$ 4,733
Largest individual counterparty [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Largest gross exposure (positive derivative NPV) to an individual counterparty	1,150	2,351	4,733
Collateral posted by this counterparty	0	1,691	4,292
Negative derivative NPV with this counterparty	41,220	0	0
Collateral pledged to this counterparty	50,165	0	0
Net exposure after netting adjustments and collateral	$ 0	$ 660	$ 441

Derivatives and Hedging Additio

Derivatives and Hedging Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Jun. 16, 2016	Mar. 31, 2016	Jun. 29, 2015
Derivative [Line Items]
Collateral netted against derivative liabilities	$ 59,100,000	$ 65,700,000		$ 85,000,000
Negative NPVs	57,189,000	63,880,000		88,981,000
Over collateralization net position	11,700,000	$ 24,300,000		$ 9,200,000
Additional collateral held in securities	$ 70,800,000
Subordinated Debentures Maturing July 2025 [Member] | Subordinated Debt [Member]
Derivative [Line Items]
Debt Instrument, Face Amount					$ 150,000,000
Subordinated Debentures Maturing July 2056 [Member] | Subordinated Debt [Member]
Derivative [Line Items]
Debt Instrument, Face Amount			$ 175,000,000

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Basic	103,987,000	101,895,000
Dilutive Effect Of Stock Options Restricted Stock And Equity Settled Awards	849,000	643,000
Diluted	104,836,000	102,538,000
Net income available to common shareholders	$ 73,357	$ 61,332
Earnings (loss) per share - basic	$ 0.71	$ 0.60
Earnings (loss) per share - diluted	$ 0.70	$ 0.60
Anti-dilutive stock options outstanding that were not included in computation of diluted earnings per common share	0

Income Taxes Additional Informa

Income Taxes Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2015	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	25.03%	24.14%
Investment in Low Income Housing Tax Credit	$ 206,500			$ 187,400
Unfunded Low Income Housing Tax Credit Obligations	105,800			84,400
Amortization of Low Income Housing Tax Credits	5,800	$ 4,400	$ 0
Deferred tax assets, net	88,083			95,194
Operating Loss Carryforwards, Valuation Allowance	$ 0
Increase (Decrease) in Deferred Income Taxes				$ 7,100

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Loss Contingencies [Line Items]
Letters of credit expiration period	1 year
Percentage of first liens initial loan to value ratio	75.00%
Percentage Of Commercial Real Estate Loans Occupied By Owners	36.00%		36.00%
Operating Leases, Rent Expense, Net	$ 2.6	$ 2.5
Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Credit Concentration Risk [Member]
Loss Contingencies [Line Items]
Percent of commercial real estate related loans	53.00%		53.00%
Unfunded Loan Commitment [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	$ 6.4		$ 7

Commitments and Contingencies70

Commitments and Contingencies - Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Other Commitments [Line Items]
Total amount	$ 5,172,897	$ 4,622,607
Percentage Of Commercial Real Estate Loans Occupied By Owners	36.00%	36.00%
Commitments to extend credit [Member]
Other Commitments [Line Items]
Unsecured Loan Commitments	$ 357,462	$ 360,840
Total amount	4,951,254	4,428,495
Credit card guarantees [Member]
Other Commitments [Line Items]
Total amount	122,969	115,536
Standby letters of credit [Member]
Other Commitments [Line Items]
Total amount	98,674	78,576
Unsecured Letters Of Credit	$ 9,396	$ 6,431
Commercial Real Estate Portfolio Segment [Member] | Credit Concentration Risk [Member] | Loans Receivable [Member]
Other Commitments [Line Items]
Concentration Risk, Percentage	53.00%	53.00%

Fair Value Accounting - Gains a

Fair Value Accounting - Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Subordinated Debt Obligations, Fair Value Disclosure	$ 52,396	[1]		$ 50,410
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(1,987)		$ 1,207
Interest Income on Securities	7		11
Interest Expense on Junior Subordinated Debt	(749)		(680)
Total Changes Included in Current-Period Earnings	(743)		(674)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	(1,229)		759
Securities measured at fair value [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(1)		(5)
Interest Income on Securities	7		11
Interest Expense on Junior Subordinated Debt	0		0
Total Changes Included in Current-Period Earnings	6		6
Junior Subordinated Debt [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(1,986)		1,212
Interest Income on Securities	0		0
Interest Expense on Junior Subordinated Debt	(749)		(680)
Total Changes Included in Current-Period Earnings	(749)		(680)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	$ (1,229)		$ 759
Junior Subordinated Debt [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Junior subordinated debt, Input Value	5.54%			5.66%
Level 3 [Member] | Junior Subordinated Debt [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Subordinated Debt Obligations, Fair Value Disclosure	$ 52,396			$ 50,410
Junior subordinated debt, Valuation Technique	Discounted cash flow			Discounted cash flow
Junior subordinated debt, Significant Unobservable Inputs	Implied credit rating of the Company			Implied credit rating of the Company
[1]	Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment.

Fair Value Accounting - Fair Va

Fair Value Accounting - Fair Value of Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017		Dec. 31, 2016		Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 2,700,011		$ 2,609,380
Derivative Liability	57,189		63,880		$ 88,981
Derivative Asset	38		2,351		$ 4,733
Subordinated Debt Obligations, Fair Value Disclosure	52,396	[1]	50,410
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,700,011		2,609,380
Loans Held-for-sale, Fair Value Disclosure	17,865		18,909
Derivative Liability	59,136	[2]	65,749	[3]
Derivative Asset	1,985	[2]	4,220	[3]
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	145,810		151,775
Loans Held-for-sale, Fair Value Disclosure	0		0
Derivative Liability	0	[2]	0	[3]
Derivative Asset	0	[2]	0	[3]
Subordinated Debt Obligations, Fair Value Disclosure	0	[1]	0
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	2,554,201		2,457,605
Loans Held-for-sale, Fair Value Disclosure	17,865		18,909
Derivative Liability	59,136	[2]	65,749	[3]
Derivative Asset	1,985	[2]	4,220	[3]
Subordinated Debt Obligations, Fair Value Disclosure	0	[1]	0
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	0		0
Loans Held-for-sale, Fair Value Disclosure	0		0
Derivative Liability	0	[2]	0	[3]
Derivative Asset	0	[2]	0	[3]
Subordinated Debt Obligations, Fair Value Disclosure	52,396	[1]	50,410
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed securities issued by GSEs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities measured at fair value	1,019		1,053
Securities available for sale	1,362,800		1,355,205
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed securities issued by GSEs | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities measured at fair value	0		0
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed securities issued by GSEs | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities measured at fair value	1,019		1,053
Securities available for sale	1,362,800		1,355,205
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed securities issued by GSEs | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities measured at fair value	0		0
Securities available for sale	0		0
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	497,066		433,685
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	0		0
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	497,066		433,685
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	0		0
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	115,700		117,792
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	115,700		117,792
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	68,395		64,144
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		20,000
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	68,395		44,144
Fair Value, Measurements, Recurring [Member] | Corporate debt securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
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	404,115		408,233
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	0		0
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	404,115		408,233
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	0		0
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	98,602		94,662
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	98,602		94,662
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | CRA investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	47,208
Fair Value, Measurements, Recurring [Member] | CRA investments [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	47,208		37,113
Fair Value, Measurements, Recurring [Member] | CRA investments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | CRA investments [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	20,023		13,490
Fair Value, Measurements, Recurring [Member] | Collateralized debt obligations [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | Collateralized debt obligations [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	20,023		13,490
Fair Value, Measurements, Recurring [Member] | Collateralized debt obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
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	27,680		26,532
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	0		0
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	27,680		26,532
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	0		0
Fair Value, Measurements, Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	55,920		56,022
Fair Value, Measurements, Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0
Fair Value, Measurements, Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	55,920		56,022
Fair Value, Measurements, Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,502		2,502
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	2,502		2,502
Fair Value, Measurements, Recurring [Member] | US Treasury Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 0		$ 0
[1]	Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment.
[2]	Derivative assets and liabilities relate to interest rate swaps, see "Note 9. Derivatives and Hedging Activities." In addition, the carrying value of loans is increased by $40,886 and the net carrying value of subordinated debt is decreased by $15,517 as of March 31, 2017, which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates.
[3]	Derivative assets and liabilities relate to interest rate swaps, see "Note 9. Derivatives and Hedging Activities." In addition, the carrying value of loans is increased by $48,161 and the net carrying value of subordinated debt is decreased by $12,325 as of December 31, 2016, which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates.

Fair Value Accounting - Change

Fair Value Accounting - Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ (1,987)		$ 1,207
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0
Junior subordinated debt	52,396	[1]		$ 50,410
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt	$ 52,396	[1]		$ 50,410
Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Discounted cash flow method			Discounted cash flow method
Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0		9,076	$ 0	$ 10,060
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0		(984)
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ (1,986)		1,212
Other Assets [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Collateral method			Collateral method
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Input Value	5.54%			5.66%
Junior Subordinated Debt [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt	$ 52,396			$ 50,410
Junior subordinated debt, Valuation Technique	Discounted cash flow			Discounted cash flow
Junior subordinated debt, Significant Unobservable Inputs	Implied credit rating of the Company			Implied credit rating of the Company
Junior Subordinated Debt [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ (50,410)		(46,928)	$ (46,928)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	0		0
Closing balance	$ (52,396)		$ (45,716)	$ (50,410)
Collateral Method [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Collateral method			Collateral method
Third Party Appraisal [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Third party appraisal			Third party appraisal
Third Party Appraisal [Member] | Other Assets [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Third party appraisal			Third party appraisal
Discount Rate [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Discount rate			Discount rate
Scheduled Cash Collections [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Scheduled cash collections			Scheduled cash collections
Proceeds from Non-Real Estate Collateral [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Proceeds from non-real estate collateral			Proceeds from non-real estate collateral
[1]	Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment.

Fair Value Accounting - Assets

Fair Value Accounting - Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded	[1]	$ 10,919	$ 10,909
Impaired loans without specific valuation allowance	[2]	102,787	88,300
Other Repossessed Assets		45,200	47,800
Impaired Financing Receivables, With No related Allowance, Balances with Charge-offs		23,400	27,600
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded		6,954	6,670
Impaired loans without specific valuation allowance	[3]	79,351	60,738
Other Repossessed Assets		45,200	47,815
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans without specific valuation allowance	[3]	0	0
Other Repossessed Assets		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded		0	0
Impaired loans without specific valuation allowance	[3]	0	0
Other Repossessed Assets		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded		6,954	6,670
Impaired loans without specific valuation allowance	[3]	79,351	60,738
Other Repossessed Assets		$ 45,200	$ 47,815
[1]	Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016, respectively.
[2]	Includes TDR loans of $54.3 million and $58.3 million at March 31, 2017 and December 31, 2016, respectively.
[3]	Certain assets are measured at fair value on a nonrecurring basis. That is, the assets 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 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 in Active Markets for Identical Assets(Level 1) Active Markets for Similar Assets(Level 2) Unobservable Inputs(Level 3) (in thousands)As of March 31, 2017: Impaired loans with specific valuation allowance $6,954 $— $— $6,954Impaired loans without specific valuation allowance (1) 79,351 — — 79,351Other assets acquired through foreclosure 45,200 — — 45,200As of December 31, 2016: Impaired loans with specific valuation allowance $6,670 $— $— $6,670Impaired loans without specific valuation allowance (1) 60,738 — — 60,738Other assets acquired through foreclosure 47,815 — — 47,815(1)Net of loan balances with charge-offs of $23.4 million and $27.6 million as of March 31, 2017 and December 31, 2016, respectively

Fair Value Accounting - Estimat

Fair Value Accounting - Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017		Dec. 31, 2016		Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 113,706		$ 99,209
Other Repossessed Assets	45,200		47,800
Financial assets
Held-to-maturity Securities	102,590		92,079
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011		2,609,380
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	1,019		1,053
Derivative Asset	38		2,351		$ 4,733
Loans, net	13,517,234		13,064,823
Financial liabilities
Deposits	15,355,970		14,549,863
Customer repurchase agreements	35,711		41,728
Junior subordinated debt	52,396	[1]	50,410
Derivative Liability	57,189		63,880		$ 88,981
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	45,200		47,815
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	0		0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Repossessed Assets	0		0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment	86,305		67,408
Other Repossessed Assets	45,200		47,815
Fair Value, Measurements, Nonrecurring [Member] | Carrying Amount [Member]
Financial assets
Held-to-maturity Securities	102,590		2,609,380
Loans, net	13,535,099		70,320
Financial liabilities
Deposits	15,355,970		14,549,863
Junior subordinated debt	366,885		367,937
Fair Value, Measurements, Nonrecurring [Member] | Fair Value [Member]
Financial assets
Held-to-maturity Securities	103,666		2,609,380
Loans, net	13,451,985		70,320
Financial liabilities
Deposits	15,361,363		14,553,931
Junior subordinated debt	390,689		375,626
Fair Value, Measurements, Nonrecurring [Member] | Fair Value [Member] | Level 1 [Member]
Financial assets
Held-to-maturity Securities	0		151,775
Loans, net	0		0
Financial liabilities
Deposits	0		0
Junior subordinated debt	0		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value [Member] | Level 2 [Member]
Financial assets
Held-to-maturity Securities	103,666		2,457,605
Loans, net	13,365,680		70,320
Financial liabilities
Deposits	15,361,363		14,553,931
Junior subordinated debt	0		0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value [Member] | Level 3 [Member]
Financial assets
Held-to-maturity Securities	0		0
Loans, net	86,305		0
Financial liabilities
Deposits	0		0
Junior subordinated debt	390,689		375,626
Fair Value, Measurements, Recurring [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011		2,609,380
Derivative Asset	1,985	[2]	4,220	[3]
Financial liabilities
Derivative Liability	59,136	[2]	65,749	[3]
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	145,810		151,775
Derivative Asset	0	[2]	0	[3]
Financial liabilities
Junior subordinated debt	0	[1]	0
Derivative Liability	0	[2]	0	[3]
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,554,201		2,457,605
Derivative Asset	1,985	[2]	4,220	[3]
Financial liabilities
Junior subordinated debt	0	[1]	0
Derivative Liability	59,136	[2]	65,749	[3]
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Derivative Asset	0	[2]	0	[3]
Financial liabilities
Junior subordinated debt	52,396	[1]	50,410
Derivative Liability	0	[2]	0	[3]
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member]
Financial assets
Held-to-maturity Securities			92,079
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011		1,053
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	1,019		4,220
Derivative Asset	1,985		13,083,732
Accrued Investment Income Receivable	66,453
Financial liabilities
Customer repurchase agreements	35,711		41,728
Federal Home Loan Bank Borrowings, Fair Value Disclosure			80,000
Derivative Liability	59,136		65,749
Interest Payable, Current	10,459		15,354
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Financial assets
Held-to-maturity Securities			91,966
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,700,011		1,053
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	1,019		4,220
Derivative Asset	1,985		12,803,744
Accrued Investment Income Receivable	66,453
Financial liabilities
Customer repurchase agreements	35,711		41,728
Federal Home Loan Bank Borrowings, Fair Value Disclosure			80,000
Derivative Liability	59,136		65,749
Interest Payable, Current	10,459		15,354
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Level 1 [Member]
Financial assets
Held-to-maturity Securities			0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	145,810		0
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	0		0
Derivative Asset	0		0
Accrued Investment Income Receivable	0
Financial liabilities
Customer repurchase agreements	0		0
Federal Home Loan Bank Borrowings, Fair Value Disclosure			0
Derivative Liability	0		0
Interest Payable, Current	0		0
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Level 2 [Member]
Financial assets
Held-to-maturity Securities			91,966
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	2,554,201		1,053
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	1,019		4,220
Derivative Asset	1,985		12,736,336
Accrued Investment Income Receivable	66,453
Financial liabilities
Customer repurchase agreements	35,711		41,728
Federal Home Loan Bank Borrowings, Fair Value Disclosure			80,000
Derivative Liability	59,136		65,749
Interest Payable, Current	10,459		15,354
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Level 3 [Member]
Financial assets
Held-to-maturity Securities			0
Investment securities - AFS, at fair value; amortized cost of $2,709,686 at March 31, 2017 and $2,633,298 at December 31, 2016	0		0
Investment securities - measured at fair value; amortized cost of $1,019 at March 31, 2017 and $1,055 at December 31, 2016	0		0
Derivative Asset	0		67,408
Accrued Investment Income Receivable	0
Financial liabilities
Customer repurchase agreements	0		0
Federal Home Loan Bank Borrowings, Fair Value Disclosure			0
Derivative Liability	0		0
Interest Payable, Current	$ 0		$ 0
Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Discounted cash flow method		Discounted cash flow method
Other Assets [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Collateral method		Collateral method
Collateral Method [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Collateral method		Collateral method
Third Party Appraisal [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Third party appraisal		Third party appraisal
Fair Value Measurements, Significant Assumptions	Costs to sell		Costs to sell
Third Party Appraisal [Member] | Other Assets [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Third party appraisal		Third party appraisal
Fair Value Measurements, Significant Assumptions	Costs to sell		Costs to sell
Discount Rate [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Discount rate		Discount rate
Fair Value Measurements, Significant Assumptions	Contractual loan rate		Contractual loan rate
Scheduled Cash Collections [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Scheduled cash collections		Scheduled cash collections
Fair Value Measurements, Significant Assumptions	Probability of default		Probability of default
Proceeds from Non-Real Estate Collateral [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Valuation Technique	Proceeds from non-real estate collateral		Proceeds from non-real estate collateral
Fair Value Measurements, Significant Assumptions	Loss given default		Loss given default
[1]	Includes only the portion of junior subordinated debt that is recorded at fair value at each reporting period pursuant to the election of FVO treatment.
[2]	Derivative assets and liabilities relate to interest rate swaps, see "Note 9. Derivatives and Hedging Activities." In addition, the carrying value of loans is increased by $40,886 and the net carrying value of subordinated debt is decreased by $15,517 as of March 31, 2017, which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates.
[3]	Derivative assets and liabilities relate to interest rate swaps, see "Note 9. Derivatives and Hedging Activities." In addition, the carrying value of loans is increased by $48,161 and the net carrying value of subordinated debt is decreased by $12,325 as of December 31, 2016, which relates to the effective portion of the hedges put in place to mitigate against fluctuations in interest rates.

Fair Value Accounting - Additio

Fair Value Accounting - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment		$ 113,706	$ 99,209
Aggregate carrying amount of impaired loans	[1]	10,919	10,909
Impaired loans with an allowance recorded		(3,965)	(4,239)
Other assets acquired through foreclosure		45,200	47,800
Goodwill		$ 289,895	$ 289,967
Common Stock, Shares, Issued		106,929,801	106,371,093
Collateralized debt obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities contained credit losses		0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded		$ (4,000)	$ (4,200)
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt, Input Value		5.54%	5.66%
Period of basis point spread		4.39%	4.66%
Percentage of LIBOR		1.14956%	1.00%
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate carrying amount of impaired loans		$ 6,954	$ 6,670
Other assets acquired through foreclosure		45,200	47,815
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment		86,305	67,408
Aggregate carrying amount of impaired loans		6,954	6,670
Other assets acquired through foreclosure		$ 45,200	$ 47,815
[1]	Includes TDR loans of $7.1 million and $2.5 million at March 31, 2017 and December 31, 2016, respectively.

Segments - Operating Segment In

Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	$ 3,516,100		$ 3,052,300
Loans, net of deferred loan fees and costs	13,662,700		13,208,500
Less: Allowance for credit losses	(127,649)		(124,704)
Total loans held for investment	13,535,100		13,083,800
Other Repossessed Assets	45,200		47,800
Intangible Assets, Net (Including Goodwill)	302,100		302,900
Other Assets Segment	724,000		714,000
Assets	18,122,506		17,200,842
Deposits	15,355,970		14,549,863
Other borrowings	366,900		447,900
Other Liabilities Segment	430,600		311,600
Liabilities	16,153,514		15,309,313
Stockholders' equity	1,968,992	$ 1,660,163	1,891,529	$ 1,591,502
Liabilities and Equity	18,122,506		17,200,842
Excess Funds Provided by (Used in) Segment Basis	0		0
Net interest income	179,309	145,711
Provision for Loan, Lease, and Other Losses	4,250	2,500
Net interest income (loss) after provision for credit losses	175,059	143,211
Non-interest income	10,544	13,133
Non-interest expense	(87,757)	(75,493)
Income from continuing operations before income taxes	97,846	80,851
Income tax expense (benefit)	24,489	19,519
Net income available to common stockholders	73,357	61,332
Operating Segments [Member] | HOA Services [Member]
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	0		0
Loans, net of deferred loan fees and costs	132,700		116,800
Less: Allowance for credit losses	(1,400)		(1,300)
Total loans held for investment	131,300		115,500
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	400		300
Assets	131,700		115,800
Deposits	2,112,800		1,890,300
Other borrowings	0		0
Other Liabilities Segment	1,800		700
Liabilities	2,114,600		1,891,000
Stockholders' equity	72,900		65,600
Liabilities and Equity	2,187,500		1,956,600
Excess Funds Provided by (Used in) Segment Basis	2,055,800		1,840,800
Net interest income	12,748	8,632
Provision for Loan, Lease, and Other Losses	127	78
Net interest income (loss) after provision for credit losses	12,621	8,554
Non-interest income	141	105
Non-interest expense	7,147	(5,541)
Income from continuing operations before income taxes	5,615	3,118
Income tax expense (benefit)	2,106	1,169
Net income available to common stockholders	3,509	1,949
Operating Segments [Member] | Public and Non-Profit Finance [Member]
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	0		0
Loans, net of deferred loan fees and costs	1,528,700		1,454,300
Less: Allowance for credit losses	(16,000)		(15,600)
Total loans held for investment	1,512,700		1,438,700
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	11,900		15,600
Assets	1,524,600		1,454,300
Deposits	0		0
Other borrowings	0		0
Other Liabilities Segment	43,100		50,500
Liabilities	43,100		50,500
Stockholders' equity	122,300		117,100
Liabilities and Equity	165,400		167,600
Excess Funds Provided by (Used in) Segment Basis	(1,359,200)		(1,286,700)
Net interest income	6,485	5,221
Provision for Loan, Lease, and Other Losses	509	(369)
Net interest income (loss) after provision for credit losses	5,976	5,590
Non-interest income	15	(4)
Non-interest expense	2,253	(2,024)
Income from continuing operations before income taxes	3,738	3,562
Income tax expense (benefit)	1,402	1,336
Net income available to common stockholders	2,336	2,226
Operating Segments [Member] | Technology and Innovation [Member]
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	0		0
Loans, net of deferred loan fees and costs	1,011,200		1,011,400
Less: Allowance for credit losses	(9,700)		(10,600)
Total loans held for investment	1,001,500		1,000,800
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	121,400		121,500
Other Assets Segment	5,700		7,200
Assets	1,128,600		1,129,500
Deposits	1,142,200		1,038,200
Other borrowings	0		0
Other Liabilities Segment	800		2,000
Liabilities	1,143,000		1,040,200
Stockholders' equity	225,500		224,100
Liabilities and Equity	1,368,500		1,264,300
Excess Funds Provided by (Used in) Segment Basis	239,900		134,800
Net interest income	18,166	16,309
Provision for Loan, Lease, and Other Losses	296	(1,165)
Net interest income (loss) after provision for credit losses	17,870	17,474
Non-interest income	1,873	1,637
Non-interest expense	8,779	(6,906)
Income from continuing operations before income taxes	10,964	12,205
Income tax expense (benefit)	4,111	4,577
Net income available to common stockholders	6,853	7,628
Operating Segments [Member] | HFF Loan Portfolio [Member]
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	0		0
Loans, net of deferred loan fees and costs	1,279,600		1,292,100
Less: Allowance for credit losses	(1,300)		(800)
Total loans held for investment	1,278,300		1,291,300
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	100		200
Other Assets Segment	5,400		5,300
Assets	1,283,800		1,296,800
Deposits	0		0
Other borrowings	0		0
Other Liabilities Segment	600		1,400
Liabilities	600		1,400
Stockholders' equity	105,500		107,100
Liabilities and Equity	106,100		108,500
Excess Funds Provided by (Used in) Segment Basis	(1,177,700)		(1,188,300)
Net interest income	13,581
Provision for Loan, Lease, and Other Losses	0
Net interest income (loss) after provision for credit losses	13,581
Non-interest income	0
Non-interest expense	(2,988)
Income from continuing operations before income taxes	10,593
Income tax expense (benefit)	3,972
Net income available to common stockholders	6,621
Operating Segments [Member] | Other National Business Lines [Member]
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	0		0
Loans, net of deferred loan fees and costs	1,955,100		1,776,900
Less: Allowance for credit losses	(20,000)		(19,000)
Total loans held for investment	1,935,100		1,757,900
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	2,800		11,100
Assets	1,937,900		1,769,000
Deposits	0		0
Other borrowings	0		0
Other Liabilities Segment	132,600		17,500
Liabilities	132,600		17,500
Stockholders' equity	162,200		145,500
Liabilities and Equity	294,800		163,000
Excess Funds Provided by (Used in) Segment Basis	(1,643,100)		(1,606,000)
Net interest income	14,143	10,637
Provision for Loan, Lease, and Other Losses	3,527	238
Net interest income (loss) after provision for credit losses	10,616	10,399
Non-interest income	721	635
Non-interest expense	4,721	(3,437)
Income from continuing operations before income taxes	6,616	7,597
Income tax expense (benefit)	2,481	2,849
Net income available to common stockholders	4,135	4,748
Reportable Geographical Components [Member] | ARIZONA
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	1,800		1,900
Loans, net of deferred loan fees and costs	3,039,700		2,955,900
Less: Allowance for credit losses	(30,300)		(30,100)
Total loans held for investment	3,009,400		2,925,800
Other Repossessed Assets	5,000		6,200
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	42,300		42,900
Assets	3,058,500		2,976,800
Deposits	4,255,000		3,843,400
Other borrowings	0		0
Other Liabilities Segment	13,400		12,800
Liabilities	4,268,400		3,856,200
Stockholders' equity	365,700		346,600
Liabilities and Equity	4,634,100		4,202,800
Excess Funds Provided by (Used in) Segment Basis	1,575,600		1,226,000
Net interest income	43,907	38,456
Provision for Loan, Lease, and Other Losses	14	6,773
Net interest income (loss) after provision for credit losses	43,893	31,683
Non-interest income	1,113	3,681
Non-interest expense	(18,622)	(14,456)
Income from continuing operations before income taxes	26,384	20,908
Income tax expense (benefit)	10,350	8,202
Net income available to common stockholders	16,034	12,706
Reportable Geographical Components [Member] | NEVADA
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	8,900		10,100
Loans, net of deferred loan fees and costs	1,769,300		1,725,500
Less: Allowance for credit losses	(18,700)		(18,500)
Total loans held for investment	1,750,600		1,707,000
Other Repossessed Assets	17,100		18,000
Intangible Assets, Net (Including Goodwill)	23,400		23,700
Other Assets Segment	58,900		58,800
Assets	1,858,900		1,817,600
Deposits	3,896,100		3,731,500
Other borrowings	0		0
Other Liabilities Segment	27,400		28,300
Liabilities	3,923,500		3,759,800
Stockholders' equity	259,000		250,700
Liabilities and Equity	4,182,500		4,010,500
Excess Funds Provided by (Used in) Segment Basis	2,323,600		2,192,900
Net interest income	35,296	32,575
Provision for Loan, Lease, and Other Losses	(211)	(813)
Net interest income (loss) after provision for credit losses	35,507	33,388
Non-interest income	2,133	2,059
Non-interest expense	15,870	(14,746)
Income from continuing operations before income taxes	21,770	20,701
Income tax expense (benefit)	7,620	7,245
Net income available to common stockholders	14,150	13,456
Reportable Geographical Components [Member] | CALIFORNIA
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	1,900		2,100
Loans, net of deferred loan fees and costs	1,806,700		1,766,800
Less: Allowance for credit losses	(20,100)		(19,400)
Total loans held for investment	1,786,600		1,747,400
Other Repossessed Assets	0		0
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	13,900		14,500
Assets	1,802,400		1,764,000
Deposits	2,397,200		2,382,600
Other borrowings	0		0
Other Liabilities Segment	4,500		12,900
Liabilities	2,401,700		2,395,500
Stockholders' equity	205,200		201,600
Liabilities and Equity	2,606,900		2,597,100
Excess Funds Provided by (Used in) Segment Basis	804,500		833,100
Net interest income	25,218	24,428
Provision for Loan, Lease, and Other Losses	91	30
Net interest income (loss) after provision for credit losses	25,127	24,398
Non-interest income	743	660
Non-interest expense	12,703	(11,234)
Income from continuing operations before income taxes	13,167	13,824
Income tax expense (benefit)	5,537	5,813
Net income available to common stockholders	7,630	8,011
Reportable Geographical Components [Member] | Northern California
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	1,700		1,900
Loans, net of deferred loan fees and costs	1,130,100		1,095,400
Less: Allowance for credit losses	(9,400)		(8,800)
Total loans held for investment	1,120,700		1,086,600
Other Repossessed Assets	200		300
Intangible Assets, Net (Including Goodwill)	157,200		157,500
Other Assets Segment	13,500		14,300
Assets	1,293,300		1,260,600
Deposits	1,461,300		1,543,600
Other borrowings	0		0
Other Liabilities Segment	13,600		12,400
Liabilities	1,474,900		1,556,000
Stockholders' equity	284,600		283,700
Liabilities and Equity	1,759,500		1,839,700
Excess Funds Provided by (Used in) Segment Basis	466,200		579,100
Net interest income	22,035	23,195
Provision for Loan, Lease, and Other Losses	396	1,042
Net interest income (loss) after provision for credit losses	21,639	22,153
Non-interest income	2,113	2,426
Non-interest expense	12,709	(13,967)
Income from continuing operations before income taxes	11,043	10,612
Income tax expense (benefit)	4,643	4,463
Net income available to common stockholders	6,400	6,149
Corporate & Other
Operating Statistics [Line Items]
Cash, Cash Equivalents and Investment Securities	3,501,800		3,036,300
Loans, net of deferred loan fees and costs	9,600		13,400
Less: Allowance for credit losses	(700)		(600)
Total loans held for investment	8,900		12,800
Other Repossessed Assets	22,900		23,300
Intangible Assets, Net (Including Goodwill)	0		0
Other Assets Segment	569,200		544,000
Assets	4,102,800		3,616,400
Deposits	91,400		120,200
Other borrowings	366,900		447,900
Other Liabilities Segment	192,800		173,100
Liabilities	651,100		741,200
Stockholders' equity	166,100		149,500
Liabilities and Equity	817,200		890,700
Excess Funds Provided by (Used in) Segment Basis	(3,285,600)		$ (2,725,700)
Net interest income	(12,270)	(13,742)
Provision for Loan, Lease, and Other Losses	(499)	(3,314)
Net interest income (loss) after provision for credit losses	(11,771)	(10,428)
Non-interest income	1,692	1,934
Non-interest expense	1,965	(3,182)
Income from continuing operations before income taxes	(12,044)	(11,676)
Income tax expense (benefit)	(17,733)	(16,135)
Net income available to common stockholders	$ 5,689	$ 4,459

Mergers, Acquisitions and Dis78

Mergers, Acquisitions and Dispositions Assets Acquired and Liabilities Assumed in Acquisition (Details) - USD ($) $ in Thousands	Apr. 20, 2016	Dec. 31, 2016	Mar. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 289,967	$ 289,895
GE Capital US Holdings, Inc. [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 1,272,187
Acquisition / restructure expense		$ 0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	1,280,997
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other	3,632
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	1,284,629
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	12,559
Non-cash liabilities acquired in acquisition	12,559
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	1,272,070
Goodwill	$ 117

Mergers, Acquisitions and Dis79

Mergers, Acquisitions and Dispositions Business Combination, Pro Forma Information (Details) - GE Capital US Holdings, Inc. [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Acquisition / restructure expense		$ 0
Business Acquisition, Pro Forma Interest Income	$ 170,885
Business Acquisition, Pro Forma Non-Interest Income	13,133
Business Acquisition, Pro Forma Net Income (Loss)	$ 68,491
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 0.67
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 0.67