Western Alliance Bancorporation (WAL) 10-Q 1 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Entity Information [Line Items]
Entity Address, Address Line One	One E. Washington Street, Suite 1400
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Type	10-Q
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Document Period End Date	Jun. 30, 2019
Entity File Number	001-32550
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	WESTERN ALLIANCE BANCORPORATION
City Area Code	602
Local Phone Number	389-3500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	true
Entity Central Index Key	0001212545
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		103,633,094
Document Transition Report	false
Entity Tax Identification Number	88-0365922
Entity Address, City or Town	Phoenix
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85004
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.0001 Par Value
Trading Symbol	WAL
Security Exchange Name	NYSE
Subordinated Debt [Member]
Entity Information [Line Items]
Title of 12(b) Security	6.25% Subordinated Debentures due 2056
Trading Symbol	WALA
Security Exchange Name	NYSE

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Cash and due from banks	$ 181,045	$ 180,053
Interest-bearing deposits in other financial institutions	796,662	318,519
Federal Funds Sold	90,000	0
Cash, cash equivalents, and restricted cash	1,067,707	498,572
Money Market Funds, at Carrying Value	144	7
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	435,997	302,905
Investment securities - equity	114,689	115,061
Investments in restricted stock, at cost	66,217	66,132
Loans:
Loans, net of deferred loan fees and costs	19,250,250	17,710,629
Less: Allowance for credit losses	(160,409)	(152,717)
Net loans held for investment	19,089,841	17,557,912
Premises and equipment, net	123,084	119,474
Operating Lease, Right-of-Use Asset	71,087	0
Other assets acquired through foreclosure, net	17,707	17,924
Bank owned life insurance	172,104	170,145
Goodwill	289,895	289,895
Other intangible assets, net	8,486	9,260
Deferred tax assets, net	9,319	31,990
Amortization Method Qualified Affordable Housing Project Investments	321,543	342,381
Other assets	273,871	310,840
Total assets	25,314,785	23,109,486
Deposits:
Non-interest-bearing demand	8,677,288	7,456,141
Interest-bearing	12,762,611	11,721,306
Total deposits	21,439,899	19,177,447
Customer repurchase agreements	13,921	22,411
Other borrowings	0	491,000
Qualifying debt	387,232	360,458
Operating Lease, Liability	76,191	0
Other liabilities	546,278	444,436
Total liabilities	22,463,521	20,495,752
Commitments and Contingencies
Stockholders’ equity:
Common stock - par value $0.0001; 200,000,000 authorized; 105,623,556 shares issued at June 30, 2019 and 106,741,870 at December 31, 2018	10	10
Treasury stock, at cost (1,969,432 shares at June 30, 2019 and 1,793,231 shares at December 31, 2018)	(61,134)	(53,083)
Additional paid in capital	1,372,037	1,417,724
Accumulated other comprehensive (loss)	26,381	(33,622)
Retained earnings	1,513,970	1,282,705
Total stockholders’ equity	2,851,264	2,613,734
Total liabilities and stockholders’ equity	$ 25,314,785	$ 23,109,486

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale, Amortized Cost	$ 3,226,756	$ 3,339,888
Debt Securities, Held-to-maturity, Fair Value	$ 466,858	$ 298,648
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	105,623,556	106,741,870
Common stock, shares outstanding	103,654,124	104,948,639

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income:
Loans, including fees	$ 270,349	$ 222,035	$ 529,167	$ 427,994
Investment securities	27,823	25,975	56,001	51,747
Dividends	1,530	2,197	3,163	3,675
Other	3,146	1,395	5,685	2,883
Total interest income	302,848	251,602	594,016	486,299
Interest expense:
Deposits	41,888	19,849	77,676	34,022
Other borrowings	33	1,936	1,310	3,262
Qualifying debt	6,008	5,695	12,113	10,664
Other	238	14	900	23
Total interest expense	48,167	27,494	91,999	47,971
Net interest income	254,681	224,108	502,017	438,328
Provision for credit losses	7,000	5,000	10,500	11,000
Net interest income after provision for credit losses	247,681	219,108	491,517	427,328
Non-interest income:
Service charges and fees	5,821	5,672	11,233	11,417
Card Income	1,625	2,033	3,466	4,005
Foreign currency income	1,148	1,181	2,243	2,383
Income from bank owned life insurance	978	1,167	1,959	2,095
Income from equity investments	868	2,517	2,877	3,977
Lending related income and gains (losses) on sale of loans, net	553	1,047	804	2,025
Unrealized gains (losses) on assets measured at fair value, net	1,572	(685)	4,406	(1,759)
Other income	1,653	512	2,640	944
Total non-interest income	14,218	13,444	29,628	25,087
Non-interest expense:
Salaries and employee benefits	65,794	61,785	134,350	123,918
Legal, professional, and directors' fees	11,105	7,946	18,637	13,949
Occupancy	7,761	7,401	15,988	14,265
Deposit costs	7,669	4,114	13,393	7,040
Data processing	6,793	5,586	13,468	10,793
Insurance	2,811	3,885	5,620	7,754
Loan and repossessed asset expenses	1,460	1,017	3,466	1,600
Business development	1,444	1,414	3,529	3,142
Marketing	1,057	1,146	1,798	1,742
Card expense	710	1,081	1,344	2,023
Intangible amortization	387	399	774	797
Net (gain) loss on sales / valuations of repossessed and other assets	(620)	(179)	(523)	(1,407)
Other expense	7,842	6,953	15,283	15,081
Total non-interest expense	114,213	102,548	227,127	200,697
Income before provision for income taxes	147,686	130,004	294,018	251,718
Income tax expense	24,750	25,325	50,286	46,139
Net income	$ 122,936	$ 104,679	$ 243,732	$ 205,579
Earnings per share:
Basic	$ 1.19	$ 1	$ 2.35	$ 1.97
Diluted	$ 1.19	$ 0.99	$ 2.34	$ 1.95
Weighted average number of common shares outstanding:
Basic	103,019	104,691	103,523	104,611
Diluted	103,501	105,420	103,985	105,372

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 122,936	$ 104,679	$ 243,732	$ 205,579
Other comprehensive income (loss), net:
Unrealized gain (loss) on AFS securities, net of tax effect of $(11,709), $3,387, $(21,931), $16,101, respectively	35,923	(10,389)	67,300	(49,303)
Unrealized (loss) gain on SERP, net of tax effect of $6, $4, $12, $6, respectively	(17)	(12)	(35)	(23)
Unrealized (loss) gain on junior subordinated debt, net of tax effect of $435, $(244), $2,369, $(722), respectively	(1,334)	748	(7,262)	2,214
Net other comprehensive income (loss)	34,572	(9,653)	60,003	(47,112)
Comprehensive income	$ 157,508	$ 95,026	$ 303,735	$ 158,467

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Unrealized gain on securities available-for-sale securities, tax	$ 11,709	$ (3,387)	$ 21,931	$ (16,101)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	6	4	12	6
Unrealized (loss) gain on junior subordinated debt, net of tax effect of $661, $(394), $(61), and $1,649, respectively	435	(244)	2,369	(722)
Realized gain on sale of securities, tax	$ 0	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated (Deficit) [Member]	Restricted Stock [Member]	Performance Shares [Member]	Executive Officer [Member]Restricted Stock [Member]
Allocated Share-based Compensation Expense							$ 9,000	$ 3,300	$ 1,300
Beginning balance at Dec. 31, 2017	$ 2,229,698	$ 10	$ 1,424,540	$ (40,173)	$ (3,145)	$ 848,466
Beginning balance, shares at Dec. 31, 2017		105,487,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	205,579					205,579
Exercise of stock options, shares		21,000
Exercise of stock options	534		534
Restricted stock grants, net, shares		551,000
Restricted stock grants, net	$ 13,783		13,783
Treasury Stock, Shares, Acquired	(182,952)	(183,000)
Treasury Stock Acquired, Average Cost Per Share	$ 59.02
Restricted Stock Award, Forfeitures	$ (10,798)			(10,798)
Other comprehensive (loss) income, net	(47,112)				(47,112)
Ending Balance at Jun. 30, 2018	2,391,684	$ 10	1,438,857	(50,971)	(51,315)	1,055,103
Ending balance, shares at Jun. 30, 2018		105,876,000
Allocated Share-based Compensation Expense							4,700	1,600	600
Beginning balance at Mar. 31, 2018	2,293,763	$ 10	1,431,460	(46,469)	(41,662)	950,424
Beginning balance, shares at Mar. 31, 2018		105,861,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	104,679					104,679
Exercise of stock options, shares		12,000
Exercise of stock options	319		319
Restricted stock grants, net, shares		5,000
Restricted stock grants, net	$ 7,078		7,078
Treasury Stock, Shares, Acquired	(2,085)	(2,000)
Treasury Stock Acquired, Average Cost Per Share	$ 59.46
Restricted Stock Award, Forfeitures	$ (4,502)			(4,502)
Other comprehensive (loss) income, net	(9,653)				(9,653)
Ending Balance at Jun. 30, 2018	2,391,684	$ 10	1,438,857	(50,971)	(51,315)	1,055,103
Ending balance, shares at Jun. 30, 2018		105,876,000
Retained earnings	1,282,705
Stock Granted, Value, Share-based Compensation, Gross							21,200
Allocated Share-based Compensation Expense							9,700	3,000	1,000
Beginning balance at Dec. 31, 2018	2,613,734	$ 10	1,417,724	(53,083)	(33,622)	1,282,705
Beginning balance, shares at Dec. 31, 2018		104,949,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	243,732					243,732
Exercise of stock options, shares		1,000
Exercise of stock options	36		36
Restricted stock grants, net, shares		614,000
Restricted stock grants, net	$ 13,723		13,723
Treasury Stock, Shares, Acquired	(176,152)	(176,000)
Treasury Stock Acquired, Average Cost Per Share	$ 45.69
Restricted Stock Award, Forfeitures	$ (8,051)			(8,051)
Stock Repurchased and Retired During Period, Shares	1,733,603	(1,734,000)
Stock Repurchased and Retired During Period, Value	$ (71,913)		(59,446)			(12,467)
Other comprehensive (loss) income, net	60,003				60,003
Ending Balance at Jun. 30, 2019	2,851,264	$ 10	1,372,037	(61,134)	26,381	1,513,970
Ending balance, shares at Jun. 30, 2019		103,654,000
Stock Granted, Value, Share-based Compensation, Gross							400
Allocated Share-based Compensation Expense							$ 5,400	$ 1,300	$ 500
Beginning balance at Mar. 31, 2019	2,720,620	$ 10	1,390,569	(60,983)	(8,191)	1,399,215
Beginning balance, shares at Mar. 31, 2019		104,483,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	122,936					122,936
Exercise of stock options, shares		0
Exercise of stock options	0		0
Restricted stock grants, net, shares		(33,000)
Restricted stock grants, net	$ 7,251		7,251
Treasury Stock, Shares, Acquired	(3,145)	(3,000)
Treasury Stock Acquired, Average Cost Per Share	$ 47.16
Restricted Stock Award, Forfeitures	$ (151)			(151)
Stock Repurchased and Retired During Period, Shares	792,688	(793,000)
Stock Repurchased and Retired During Period, Value	$ (33,964)		(25,783)			(8,181)
Other comprehensive (loss) income, net	34,572				34,572
Ending Balance at Jun. 30, 2019	2,851,264	$ 10	$ 1,372,037	$ (61,134)	$ 26,381	$ 1,513,970
Ending balance, shares at Jun. 30, 2019		103,654,000
Retained earnings	$ 1,513,970

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 243,732	$ 205,579
Adjustments to reconcile net income to cash provided by operating activities:
Provision for credit losses	10,500	11,000
Depreciation and amortization	8,798	6,815
Stock-based compensation	13,723	13,783
Deferred income taxes	3,117	(17,943)
Amortization of net premiums for investment securities	6,428	8,073
Amortization of tax credit investments	20,573	17,549
Operating Lease, Expense	2,585	0
Accretion of fair market value adjustments on loans acquired from business combinations	(7,413)	(10,806)
Accretion and amortization of fair market value adjustments on other assets and liabilities acquired from business combinations	927	950
Income from bank owned life insurance	(1,959)	(2,095)
Losses / (Gains) on:
Assets measured at fair value, net	(4,406)	1,759
Sale of loans	513	(1,443)
Other assets acquired through foreclosure, net	(627)	(1,390)
Valuation adjustments of other repossessed assets, net	99	33
Sale of premises, equipment, and other assets, net	5	(50)
Changes in:
Other assets	(27,439)	26,419
Other liabilities	61,124	(10,880)
Net cash provided by operating activities	330,280	247,353
Investment securities - AFS
Purchases	(123,848)	(86,316)
Principal pay downs and maturities	230,729	210,003
Debt Securities, Held-to-maturity [Abstract]
Purchases	56,060	26,025
Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities	4,660	489
Proceeds from Sale of Held-to-maturity Securities	10,000	0
Equity Securities, FV-NI, Gain (Loss) [Abstract]
Purchases	(283)	(41,660)
Reinvestments of dividend proceeds	4,695	0
Purchase of investment tax credits	(38,607)	(32,631)
Purchase of SBIC investments	3,137	1,351
(Purchase) sale of money market investments, net	(137)	(5)
(Purchase) sale of money market investments, net	0	1,112
(Purchase) liquidation of restricted stock, net	85	171
Loan fundings and principal collections, net	(1,463,570)	(968,748)
Purchase of premises, equipment, and other assets, net	(9,164)	(1,836)
Proceeds from sale of other real estate owned and repossessed assets, net	628	8,100
Net cash used in investing activities	(1,444,179)	(939,039)
Net cash used in investing activities
Net increase (decrease) in deposits	2,262,452	1,114,996
Net (decrease) increase in borrowings	(499,490)	(322,995)
Proceeds from exercise of common stock options	36	534
Cash paid for tax withholding on vested restricted stock	(8,051)	(10,799)
Payments for Repurchase of Common Stock	71,913	0
Net cash provided by financing activities	1,683,034	781,736
Net increase (decrease) in cash, cash equivalents, and restricted cash	569,135	90,050
Cash, cash equivalents, and restricted cash at beginning of period	498,572	416,768
Cash, cash equivalents, and restricted cash at end of period	1,067,707	506,818
Cash paid (received) during the period for:
Interest	90,507	46,358
Income Taxes Paid, Net	(26,994)	14,792
Non-cash operating, investing, and financing activity:
Transfers to other assets acquired through foreclosure, net	0	5,744
Unfunded commitments originated	97,552	58,639
Unrealized gain (loss) on AFS securities, net of tax effect of $(10,222) and $12,714, respectively	67,300	(49,303)
Unrealized (loss) gain on junior subordinated debt, net of tax effect of $435, $(244), $2,369, $(722), respectively	(7,262)	2,214
Net increase (decrease) in unfunded obligations	$ 43,500	$ 99,980

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
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. In addition, the Company has two non-bank subsidiaries, LVSP, which holds and manages certain OREO properties, and a captive insurance company formed and licensed under the laws of the State of Arizona, CSI. CSI was established as part of the Company's overall enterprise risk management strategy. 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; certain assets and liabilities carried at fair value; and accounting for income taxes. Principles of consolidation As of June 30, 2019 , WAL has the following significant 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, 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 reported in prior periods may have been reclassified in the Consolidated Financial Statements 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 and six months ended June 30, 2019 and 2018 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, 2018 . 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. Investment securities Investment securities include debt securities and equity securities. Debt 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 an HTM 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 are reported as an asset in the Consolidated Balance Sheet at their estimated fair value. As the fair value of AFS debt securities changes, the changes are reported net of income tax as an element of OCI, except for other-than-temporarily-impaired securities. When AFS debt 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 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 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 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 values of loans subject to a fair value hedge are 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 a 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 a 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. 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, which are used for all of the Company's portfolio segments. 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. Leases At inception, contracts are evaluated to determine whether the contract constitutes a lease agreement. For contracts that are determined to be an operating lease, a corresponding ROU asset and operating lease liability are recorded in separate line items on the consolidated balance sheets. A ROU asset represents the Company’s right to use an underlying asset during the lease term and a lease liability represents the Company’s commitment to make contractually obligated lease payments. Operating lease ROU assets and liabilities are recognized at the commencement date of the lease and are based on the present value of lease payments over the lease term. The measurement of the operating lease ROU asset includes any lease payments made and is reduced by lease incentives that are paid or are payable to the Company. Variable lease payments that depend on an index or rate such as the Consumer Price Index are included in lease payments based on the rate in effect at the commencement date of the lease. Lease payments are recognized on a straight-line basis as part of occupancy expense over the lease term. As the rate implicit in the lease is not readily determinable, the incremental collateralized borrowing rate is used to determine the present value of lease payments. This rate gives consideration to the applicable FHLB collateralized borrowing rates and is based on the information available at the commencement date. The Company has elected to apply the short-term lease measurement and recognition exemption to leases with an initial term of 12 months or less; therefore, these leases are not recorded on the Company’s consolidated balance sheet, but rather, lease expense is recognized over the lease term on a straight-line basis. The Company’s lease agreements may include options to extend or terminate the lease. These options are included in the lease term when it is reasonably certain that the options will be exercised. In addition to the package of practical expedients, the Company also elected the practical expedient that allows lessees to make an accounting policy election to not separate non-lease components from the associated lease component, and instead account for them all together as part of the applicable lease component. This practical expedient can be elected separately for each underlying class of asset. The majority of the Company’s non-lease components such as common area maintenance, parking, and taxes are variable, and are expensed as incurred. Variable payment amounts are determined in arrears by the landlord depending on actual costs incurred. See “ Note 4. Leases ” of these Notes to Unaudited Consolidated Financial Statements for further disclosures required under the new standard. 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. 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, a quantitative impairment test is necessary. If, based on the quantitative test, a reporting unit's carrying amount exceeds its fair value, a goodwill impairment charge for this difference is recorded 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 and six months ended June 30, 2019 or 2018 . Treasury shares 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. Treasury shares are carried at cost. Common Stock Repurchases On December 11, 2018, the Company adopted its common stock repurchase program, pursuant to which the Company is authorized to repurchase up to $250 million of its shares of common stock. All shares repurchased under the plan are retired upon settlement. The Company has elected the method to allocate the excess of the repurchase price over the par value of its common stock between APIC and retained earnings, with the portion allocated to APIC limited to the amount of APIC that was recorded at the time that the shares were initially issued, on a last-in, first-out basis. Derivative financial instruments The Company uses interest-rate swaps to mitigate interest-rate risk associated with changes to the fair value of certain fixed-rate financial instruments (fair value 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. 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. 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. Changes in the fair value of derivatives not considered to be highly effective in hedging the change in fair value 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 after the derivative contract is executed. At inception, the Company performs a quantitative assessment to determine whether the derivatives used in hedging transactions are highly effective (as defined in the guidance) in offsetting changes in the fair value of the hedged item. Retroactive effectiveness is assessed, as well as the continued expectation that the hedge will remain effective prospectively. After the initial quantitative assessment is performed, on a quarterly basis, the Company performs a qualitative hedge effectiveness assessment. This assessment takes into consideration any adverse developments related to the counterparty's risk of default and any negative events or circumstances that affect the factors that originally enabled the Company to assess that it could reasonably support, qualitatively, an expectation that the hedging relationship was and will continue to be highly effective. 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. 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 could 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 and, in certain instances, may be unconditionally cancelable. 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. 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 re

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investment Securities	d fair values of investment securities at June 30, 2019 and December 31, 2018 are summarized as follows: June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity debt securities Tax-exempt $ 435,997 $ 30,861 $ — $ 466,858 Available-for-sale debt securities CDO $ 50 $ 14,976 $ — $ 15,026 Commercial MBS issued by GSEs 102,444 758 (2,361 ) 100,841 Corporate debt securities 105,022 123 (6,817 ) 98,328 Municipal securities 7,488 265 — 7,753 Private label residential MBS 949,699 5,605 (5,542 ) 949,762 Residential MBS issued by GSEs 1,446,679 10,381 (3,744 ) 1,453,316 Tax-exempt 541,879 20,023 (172 ) 561,730 Trust preferred securities 32,000 — (7,061 ) 24,939 U.S. government sponsored agency securities 40,000 — (95 ) 39,905 U.S. treasury securities 1,495 2 (3 ) 1,494 Total AFS debt securities $ 3,226,756 $ 52,133 $ (25,795 ) $ 3,253,094 Equity securities CRA investments $ 52,516 $ — $ (375 ) $ 52,141 Preferred stock 60,871 1,964 (287 ) 62,548 Total equity securities $ 113,387 $ 1,964 $ (662 ) $ 114,689 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity debt securities Tax-exempt $ 302,905 $ 3,163 $ (7,420 ) $ 298,648 Available-for-sale debt securities CDO $ 50 $ 15,277 $ — $ 15,327 Commercial MBS issued by GSEs 106,385 82 (6,361 ) 100,106 Corporate debt securities 105,029 — (5,649 ) 99,380 Private label residential MBS 948,161 945 (24,512 ) 924,594 Residential MBS issued by GSEs 1,564,181 1,415 (35,472 ) 1,530,124 Tax-exempt 542,086 4,335 (7,753 ) 538,668 Trust preferred securities 32,000 — (3,383 ) 28,617 U.S. government sponsored agency securities 40,000 — (1,812 ) 38,188 U.S. treasury securities 1,996 — (12 ) 1,984 Total AFS debt securities $ 3,339,888 $ 22,054 $ (84,954 ) $ 3,276,988 Equity securities CRA investments $ 52,210 $ — $ (1,068 ) $ 51,142 Preferred stock 65,954 148 (2,183 ) 63,919 Total equity securities $ 118,164 $ 148 $ (3,251 ) $ 115,061 The Company conducts an OTTI analysis on a quarterly basis. The initial indication of OTTI 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 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), whether downgrades by bond rating agencies have occurred, 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. At June 30, 2019 and December 31, 2018 , the Company’s unrealized losses relate primarily to market interest rate increases since the securities' original purchase date. The total number of AFS securities in an unrealized loss position at June 30, 2019 is 154 , compared to 373 at December 31, 2018 . 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 and six months ended June 30, 2019 and 2018 . The Company does not consider any securities to be other-than-temporarily impaired as of June 30, 2019 and December 31, 2018 . No assurance can be made that OTTI will not occur in future periods. Information pertaining to securities with gross unrealized losses at June 30, 2019 and December 31, 2018 , aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: June 30, 2019 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) Available-for-sale debt securities Commercial MBS issued by GSEs $ — $ — $ 2,361 $ 79,102 $ 2,361 $ 79,102 Corporate debt securities — — 6,817 93,183 6,817 93,183 Private label residential MBS — 12,818 5,542 469,802 5,542 482,620 Residential MBS issued by GSEs 57 17,116 3,687 446,947 3,744 464,063 Tax-exempt 172 37,111 — — 172 37,111 Trust preferred securities — — 7,061 24,939 7,061 24,939 U.S. government sponsored agency securities — — 95 34,905 95 34,905 U.S. treasury securities — — 3 995 3 995 Total AFS securities $ 229 $ 67,045 $ 25,566 $ 1,149,873 $ 25,795 $ 1,216,918 December 31, 2018 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 debt securities Tax-exempt $ 3,868 $ 91,095 $ 3,552 $ 69,991 $ 7,420 $ 161,086 Available-for-sale debt securities Commercial MBS issued by GSEs $ — $ — $ 6,361 $ 98,275 $ 6,361 $ 98,275 Corporate debt securities 16 5,013 5,633 94,367 5,649 99,380 Private label residential MBS 5,173 217,982 19,339 537,316 24,512 755,298 Residential MBS issued by GSEs 1,363 141,493 34,109 1,215,490 35,472 1,356,983 Tax-exempt 3,562 209,767 4,191 72,382 7,753 282,149 Trust preferred securities — — 3,383 28,617 3,383 28,617 U.S. government sponsored agency securities — — 1,812 38,188 1,812 38,188 U.S. treasury securities — — 12 1,984 12 1,984 Total AFS securities $ 10,114 $ 574,255 $ 74,840 $ 2,086,619 $ 84,954 $ 2,660,874 The amortized cost and fair value of securities as of June 30, 2019 , 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. June 30, 2019 Amortized Cost Estimated Fair Value (in thousands) Held-to-maturity Due in one year or less $ 10,100 $ 10,139 After one year through five years 24,940 25,714 After ten years 400,957 431,005 Total HTM securities $ 435,997 $ 466,858 Available-for-sale Due in one year or less $ 3,781 $ 3,789 After one year through five years 16,012 16,173 After five years through ten years 209,275 203,657 After ten years 498,866 525,556 Mortgage-backed securities 2,498,822 2,503,919 Total AFS securities $ 3,226,756 $ 3,253,094 The following tables summarize the carrying amount of the Company’s investment ratings position as of June 30, 2019 and December 31, 2018 : June 30, 2019 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity debt securities Tax-exempt $ — $ — $ — $ — $ — $ — $ 435,997 $ 435,997 Available-for-sale debt securities CDO $ — $ — $ — $ — $ — $ 15,026 $ — $ 15,026 Commercial MBS issued by GSEs — 100,841 — — — — — 100,841 Corporate debt securities — — — 65,244 33,084 — — 98,328 Municipal securities — — — — — — 7,753 7,753 Private label residential MBS 926,847 — 20,454 256 881 1,324 — 949,762 Residential MBS issued by GSEs — 1,453,316 — — — — — 1,453,316 Tax-exempt 69,310 8,922 309,263 174,235 — — — 561,730 Trust preferred securities — — — — 24,939 — — 24,939 U.S. government sponsored agency securities — 39,905 — — — — — 39,905 U.S. treasury securities — 1,494 — — — — — 1,494 Total AFS securities $ 996,157 $ 1,604,478 $ 329,717 $ 239,735 $ 58,904 $ 16,350 $ 7,753 $ 3,253,094 Equity securities CRA investments $ — $ 25,375 $ — $ — $ — $ — $ 26,766 $ 52,141 Preferred stock — — — — 48,975 4,030 9,543 62,548 Total equity securities $ — $ 25,375 $ — $ — $ 48,975 $ 4,030 $ 36,309 $ 114,689 (1) Where ratings differ, the Company uses an average of the available ratings by major credit agencies. December 31, 2018 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity debt securities Tax-exempt $ — $ — $ — $ — $ — $ — $ 302,905 $ 302,905 Available-for-sale debt securities CDO $ — $ — $ — $ — $ — $ 15,327 $ — $ 15,327 Commercial MBS issued by GSEs — 100,106 — — — — — 100,106 Corporate debt securities — — — 66,515 32,865 — — 99,380 Private label residential MBS 887,520 — 34,342 343 947 1,442 — 924,594 Residential MBS issued by GSEs — 1,530,124 — — — — — 1,530,124 Tax-exempt 66,160 12,146 306,409 152,330 — — 1,623 538,668 Trust preferred securities — — — — 28,617 — — 28,617 U.S. government sponsored agency securities — 38,188 — — — — — 38,188 U.S. treasury securities — 1,984 — — — — — 1,984 Total AFS securities $ 953,680 $ 1,682,548 $ 340,751 $ 219,188 $ 62,429 $ 16,769 $ 1,623 $ 3,276,988 Equity securities CRA investments $ — $ 25,375 $ — $ — $ — $ — $ 25,767 $ 51,142 Preferred stock — — — — 45,771 3,693 14,455 63,919 Total equity securities $ — $ 25,375 $ — $ — $ 45,771 $ 3,693 $ 40,222 $ 115,061 (1) Where ratings differ, the Company uses an average of the available ratings by major credit agencies. Securities with carrying amounts of approximately $886.3 million and $788.4 million at June 30, 2019 and December 31, 2018 , respectively, were pledged for various purposes as required or permitted by law. During the three months ended June 30, 2019, the Company sold one of its securities classified as HTM. The security had a par value of $10.0 million and no gain or loss was realized upon the sale. The sale of this HTM security was made as a result of a significant change in the issuer’s creditworthiness, representative of a change in circumstance contemplated in ASC 320-10-25 that would not call into question the Company’s intent to hold other debt securities to maturity in the future. Accordingly, management concluded that the Company’s remaining HTM securities are appropriately classified as such as of June 30, 2019. With respect to the Company's AFS and equity securities, there were no gains and losses recognized on sales of these investment securities during the three and six months ended June 30, 2019 and June 30, 2018 .

Loans, Leases and Allowance for

Loans, Leases and Allowance for Credit Losses	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Loans, Leases and Allowance for Credit Losses	The composition of the Company’s held for investment loan portfolio is as follows: June 30, 2019 December 31, 2018 (in thousands) Commercial and industrial $ 8,454,161 $ 7,762,642 Commercial real estate - non-owner occupied 4,685,545 4,213,428 Commercial real estate - owner occupied 2,254,126 2,325,380 Construction and land development 2,210,355 2,134,753 Residential real estate 1,580,104 1,204,355 Consumer 65,959 70,071 Loans, net of deferred loan fees and costs 19,250,250 17,710,629 Allowance for credit losses (160,409 ) (152,717 ) Total loans HFI $ 19,089,841 $ 17,557,912 Net deferred loan fees/costs as of June 30, 2019 and December 31, 2018 total $40.2 million and $36.3 million , respectively, which is a reduction in the carrying value of loans. Net unamortized purchase premiums/discounts on secondary market loan purchases total $11.3 million and $2.0 million as of June 30, 2019 and December 31, 2018 , respectively. Total loans held for investment are also net of interest rate and credit marks on acquired loans, which are a net reduction in the carrying value of loans. Interest rate marks were $5.1 million and $7.1 million as of June 30, 2019 and December 31, 2018 , respectively. Credit marks were $10.6 million and $14.6 million as of June 30, 2019 and December 31, 2018 , respectively. The following table presents the contractual aging of the recorded investment in past due loans held for investment by class of loans: June 30, 2019 Current 30-59 Days 60-89 Days Over 90 Days Past Due Total Total (in thousands) Commercial and industrial $ 8,445,260 $ 555 $ 4,453 $ 3,893 $ 8,901 $ 8,454,161 Commercial real estate Owner occupied 2,252,389 1,097 640 — 1,737 2,254,126 Non-owner occupied 4,489,258 11,913 — — 11,913 4,501,171 Multi-family 184,374 — — — — 184,374 Construction and land development Construction 1,417,767 — — — — 1,417,767 Land 792,252 — 336 — 336 792,588 Residential real estate 1,567,204 7,539 159 5,202 12,900 1,580,104 Consumer 65,841 — — 118 118 65,959 Total loans $ 19,214,345 $ 21,104 $ 5,588 $ 9,213 $ 35,905 $ 19,250,250 December 31, 2018 Current 30-59 Days 60-89 Days Over 90 days Total Total (in thousands) Commercial and industrial $ 7,753,111 $ 3,187 $ 416 $ 5,928 $ 9,531 $ 7,762,642 Commercial real estate Owner occupied 2,320,321 4,441 — 618 5,059 2,325,380 Non-owner occupied 4,051,837 — — — — 4,051,837 Multi-family 161,591 — — — — 161,591 Construction and land development Construction 1,382,664 — — — — 1,382,664 Land 751,613 — 476 — 476 752,089 Residential real estate 1,182,933 9,316 4,010 8,096 21,422 1,204,355 Consumer 69,830 — — 241 241 70,071 Total loans $ 17,673,900 $ 16,944 $ 4,902 $ 14,883 $ 36,729 $ 17,710,629 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: June 30, 2019 December 31, 2018 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 and industrial $ 4,873 $ 8,295 $ 13,168 $ — $ 7,639 $ 7,451 $ 15,090 $ — Commercial real estate Owner occupied 8,539 640 9,179 — — — — 594 Non-owner occupied 7,508 11,913 19,421 — — — — — Multi-family — — — — — — — — Construction and land development Construction 2,277 — 2,277 — — 476 476 — Land — — — — — — — — Residential real estate 2,393 5,259 7,652 — 552 11,387 11,939 — Consumer 10 118 128 — — 241 241 — Total $ 25,600 $ 26,225 $ 51,825 $ — $ 8,191 $ 19,555 $ 27,746 $ 594 The reduction in interest income associated with loans on non-accrual status was approximately $0.5 million and $0.6 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.8 million and $1.2 million for the six months ended June 30, 2019 and 2018 , 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: June 30, 2019 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial and industrial $ 8,328,754 $ 62,078 $ 62,978 $ 351 $ — $ 8,454,161 Commercial real estate Owner occupied 2,162,788 29,932 61,406 — — 2,254,126 Non-owner occupied 4,400,274 70,157 30,740 — — 4,501,171 Multi-family 184,374 — — — — 184,374 Construction and land development Construction 1,365,231 33,237 19,299 — — 1,417,767 Land 790,004 2,570 14 — — 792,588 Residential real estate 1,571,753 — 8,351 — — 1,580,104 Consumer 65,809 22 128 — — 65,959 Total $ 18,868,987 $ 197,996 $ 182,916 $ 351 $ — $ 19,250,250 June 30, 2019 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 18,860,678 $ 196,966 $ 156,701 $ — $ — $ 19,214,345 Past due 30 - 59 days 7,539 980 12,585 — — 21,104 Past due 60 - 89 days 439 50 4,840 259 — 5,588 Past due 90 days or more 331 — 8,790 92 — 9,213 Total $ 18,868,987 $ 197,996 $ 182,916 $ 351 $ — $ 19,250,250 December 31, 2018 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial and industrial $ 7,574,506 $ 61,202 $ 126,356 $ 578 $ — $ 7,762,642 Commercial real estate Owner occupied 2,255,513 12,860 57,007 — — 2,325,380 Non-owner occupied 4,030,350 12,982 8,505 — — 4,051,837 Multi-family 161,591 — — — — 161,591 Construction and land development Construction 1,378,624 1,210 2,830 — — 1,382,664 Land 751,012 — 1,077 — — 752,089 Residential real estate 1,191,571 527 12,257 — — 1,204,355 Consumer 69,755 75 241 — — 70,071 Total $ 17,412,922 $ 88,856 $ 208,273 $ 578 $ — $ 17,710,629 December 31, 2018 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 17,400,616 $ 87,264 $ 186,020 $ — $ — $ 17,673,900 Past due 30 - 59 days 11,255 1,580 4,109 — — 16,944 Past due 60 - 89 days 719 12 3,767 404 — 4,902 Past due 90 days or more 332 — 14,377 174 — 14,883 Total $ 17,412,922 $ 88,856 $ 208,273 $ 578 $ — $ 17,710,629 The table below reflects the recorded investment in loans classified as impaired: June 30, 2019 December 31, 2018 (in thousands) Impaired loans with a specific valuation allowance under ASC 310 (1) $ 6,090 $ 986 Impaired loans without a specific valuation allowance under ASC 310 (2) 120,341 111,266 Total impaired loans $ 126,431 $ 112,252 Valuation allowance related to impaired loans $ (1,854 ) $ (681 ) (1) Includes no TDR loans at June 30, 2019 and December 31, 2018 . (2) Includes TDR loans of $61.7 million and $44.5 million at June 30, 2019 and December 31, 2018 , respectively. The following table presents impaired loans by class: June 30, 2019 December 31, 2018 (in thousands) Commercial and industrial $ 33,700 $ 63,896 Commercial real estate Owner occupied 20,663 6,530 Non-owner occupied 30,029 12,407 Multi-family — — Construction and land development Construction 19,299 — Land 7,622 9,403 Residential real estate 14,963 19,744 Consumer 155 272 Total $ 126,431 $ 112,252 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 June 30, 2019 and December 31, 2018 . The following table presents the average investment in impaired loans and income recognized on impaired loans: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Average balance on impaired loans $ 113,346 $ 104,403 $ 119,979 $ 98,743 Interest income recognized on impaired loans 1,201 1,122 2,694 1,995 The following table presents the average investment in impaired loans by loan class: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Commercial and industrial $ 40,367 $ 49,373 $ 53,755 $ 43,111 Commercial real estate Owner occupied 11,848 8,417 9,708 8,730 Non-owner occupied 17,826 17,524 15,068 18,225 Multi-family — — — — Construction and land development Construction 19,970 — 16,210 — Land 7,935 9,603 8,284 9,942 Residential real estate 15,252 19,109 16,766 18,454 Consumer 148 377 188 281 Total $ 113,346 $ 104,403 $ 119,979 $ 98,743 The average investment in TDR loans was $62.0 million and $55.3 million for the three months ended June 30, 2019 and 2018 , respectively, and $56.8 million and $51.8 million for the six months ended June 30, 2019 and 2018 , respectively. The following table presents interest income on impaired loans by class: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Commercial and industrial $ 386 $ 489 $ 1,154 $ 739 Commercial real estate Owner occupied 154 131 276 258 Non-owner occupied 169 265 356 526 Multi-family — — — — Construction and land development Construction 272 — 452 — Land 121 149 250 279 Residential real estate 99 88 205 192 Consumer — — 1 1 Total $ 1,201 $ 1,122 $ 2,694 $ 1,995 The Company is not committed to lend significant additional funds on these impaired loans. The following table summarizes nonperforming assets: June 30, 2019 December 31, 2018 (in thousands) Non-accrual loans (1) $ 51,825 $ 27,746 Loans past due 90 days or more on accrual status — 594 Accruing troubled debt restructured loans 52,200 36,458 Total nonperforming loans 104,025 64,798 Other assets acquired through foreclosure, net 17,707 17,924 Total nonperforming assets $ 121,732 $ 82,722 (1) Includes non-accrual TDR loans of $9.5 million and $8.0 million at June 30, 2019 and December 31, 2018 , respectively. Loans Acquired with Deteriorated Credit Quality Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Balance, at beginning of period $ 3,137 $ 8,108 $ 3,768 $ 9,324 Reclassifications from non-accretable to accretable yield (1) — — — 683 Accretion to interest income (142 ) (264 ) (302 ) (578 ) Reversal of fair value adjustments upon disposition of loans (17 ) (3,016 ) (488 ) (4,601 ) Balance, at end of period $ 2,978 $ 4,828 $ 2,978 $ 4,828 (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 June 30, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2019 Beginning Balance $ 26,083 $ 37,867 $ 13,006 $ 77,254 $ 777 $ 154,987 Charge-offs 141 — 397 2,018 — 2,556 Recoveries (9 ) (439 ) (27 ) (495 ) (8 ) (978 ) Provision 140 2,952 (30 ) 3,904 34 7,000 Ending balance $ 26,091 $ 41,258 $ 12,606 $ 79,635 $ 819 $ 160,409 2018 Beginning Balance $ 22,594 $ 32,868 $ 5,519 $ 82,878 $ 800 $ 144,659 Charge-offs 1 233 885 2,777 5 3,901 Recoveries (8 ) (246 ) (141 ) (916 ) (14 ) (1,325 ) Provision (442 ) (902 ) 2,074 4,227 43 5,000 Ending balance $ 22,159 $ 31,979 $ 6,849 $ 85,244 $ 852 $ 147,083 Six Months Ended June 30, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2019 Beginning Balance $ 22,513 $ 34,829 $ 11,276 $ 83,118 $ 981 $ 152,717 Charge-offs 141 — 585 4,142 1 4,869 Recoveries (64 ) (892 ) (120 ) (972 ) (13 ) (2,061 ) Provision 3,655 5,537 1,795 (313 ) (174 ) 10,500 Ending balance $ 26,091 $ 41,258 $ 12,606 $ 79,635 $ 819 $ 160,409 2018 Beginning Balance $ 19,511 $ 31,495 $ 5,478 $ 82,793 $ 773 $ 140,050 Charge-offs 1 233 992 6,295 5 7,526 Recoveries (1,397 ) (371 ) (390 ) (1,376 ) (25 ) (3,559 ) Provision 1,252 346 1,973 7,370 59 11,000 Ending balance $ 22,159 $ 31,979 $ 6,849 $ 85,244 $ 852 $ 147,083 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 Consumer Total Loans (in thousands) Loans as of June 30, 2019; Recorded Investment Impaired loans with an allowance recorded $ 791 $ — $ 1,692 $ 1,321 $ 2,277 $ 9 $ 6,090 Impaired loans with no allowance recorded 19,872 30,029 32,008 13,642 24,644 146 120,341 Total loans individually evaluated for impairment 20,663 30,029 33,700 14,963 26,921 155 126,431 Loans collectively evaluated for impairment 2,229,604 4,597,036 8,420,461 1,565,122 2,183,434 65,804 19,061,461 Loans acquired with deteriorated credit quality 3,859 58,480 — 19 — — 62,358 Total recorded investment $ 2,254,126 $ 4,685,545 $ 8,454,161 $ 1,580,104 $ 2,210,355 $ 65,959 $ 19,250,250 Unpaid Principal Balance Impaired loans with an allowance recorded $ 791 $ — $ 1,721 $ 1,321 $ 2,322 $ 9 $ 6,164 Impaired loans with no allowance recorded 20,619 30,953 37,427 16,597 25,262 175 131,033 Total loans individually evaluated for impairment 21,410 30,953 39,148 17,918 27,584 184 137,197 Loans collectively evaluated for impairment 2,230,441 4,613,466 8,390,353 1,554,316 2,204,253 66,170 19,058,999 Loans acquired with deteriorated credit quality 5,124 70,437 — 72 — — 75,633 Total unpaid principal balance $ 2,256,975 $ 4,714,856 $ 8,429,501 $ 1,572,306 $ 2,231,837 $ 66,354 $ 19,271,829 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 157 $ — $ 603 $ 275 $ 810 $ 9 $ 1,854 Impaired loans with no allowance recorded — — — — — — — Total loans individually evaluated for impairment 157 — 603 275 810 9 1,854 Loans collectively evaluated for impairment 14,615 26,389 79,030 12,331 25,281 810 158,456 Loans acquired with deteriorated credit quality — 97 2 — — — 99 Total allowance for credit losses $ 14,772 $ 26,486 $ 79,635 $ 12,606 $ 26,091 $ 819 $ 160,409 Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Consumer Total Loans (in thousands) Loans as of December 31, 2018; Recorded Investment Impaired loans with an allowance recorded $ — $ — $ 623 $ 363 $ — $ — $ 986 Impaired loans with no allowance recorded 6,530 12,407 63,273 19,381 9,403 272 111,266 Total loans individually evaluated for impairment 6,530 12,407 63,896 19,744 9,403 272 112,252 Loans collectively evaluated for impairment 2,314,871 4,121,464 7,698,746 1,184,592 2,125,350 69,799 17,514,822 Loans acquired with deteriorated credit quality 3,979 79,557 — 19 — — 83,555 Total recorded investment $ 2,325,380 $ 4,213,428 $ 7,762,642 $ 1,204,355 $ 2,134,753 $ 70,071 $ 17,710,629 Unpaid Principal Balance Impaired loans with an allowance recorded $ — $ — $ 1,482 $ 363 $ — $ — $ 1,845 Impaired loans with no allowance recorded 11,852 18,155 103,992 27,979 25,624 10,632 198,234 Total loans individually evaluated for impairment 11,852 18,155 105,474 28,342 25,624 10,632 200,079 Loans collectively evaluated for impairment 2,314,871 4,121,464 7,698,746 1,184,592 2,125,350 69,799 17,514,822 Loans acquired with deteriorated credit quality 5,315 95,680 4,352 72 — — 105,419 Total unpaid principal balance $ 2,332,038 $ 4,235,299 $ 7,808,572 $ 1,213,006 $ 2,150,974 $ 80,431 $ 17,820,320 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ — $ — $ 621 $ 60 $ — $ — $ 681 Impaired loans with no allowance recorded — — — — — — — Total loans individually evaluated for impairment — — 621 60 — — 681 Loans collectively evaluated for impairment 14,286 20,456 82,488 11,216 22,513 981 151,940 Loans acquired with deteriorated credit quality — 87 9 — — — 96 Total allowance for credit losses $ 14,286 $ 20,543 $ 83,118 $ 11,276 $ 22,513 $ 981 $ 152,717 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 June 30, 2019 , the Company had two new TDR loans with a recorded investment of $1.8 million and two new TDR loans during the three months ended June 30, 2018 with a recorded investment of $16.6 million . During the six months ended June 30, 2019 , the Company had four new TDR loans with a recorded investment of $28.9 million and seven new TDR loans with a recorded investment of $31.6 million during the six months ended June 30, 2018 . No principal amounts were forgiven and there were no waived fees or other expenses resulting from these TDRs. During the three and six months ended June 30, 2019 , there were 2 TDR loans with a recorded investment of $0.4 million for which there was a payment default. During the three and six months ended June 30, 2018 , there were no TDR loans 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 June 30, 2019 and December 31, 2018 , commitments outstanding on TDR loans totaled $2.1 million and $1.5 million , respectively. Loan Purchases and Sales For the three months ended June 30, 2019 and 2018 , secondary market loan purchases totaled $590.6 million and $316.8 million , respectively. For the six months ended June 30, 2019 and 2018 , secondary market loan purchases totaled $1.12 billion and $458.3 million , respectively. For 2019 , these purchased loans consisted of $530.5 million of residential real estate loans, $526.7 million of commercial and industrial loans, $33.9 million of construction and land loans, and $30.0 million CRE, non-owner occupied loans. For 2018 , these purchased loans consisted of $283.2 million of commercial and industrial loans and $175.1 million of residential real estate loans. During the three months ended June 30, 2019 , the Company sold commercial and industrial loans with a carrying value of $19.3 million and recognized a net loss of $0.1 million . During the three months ended June 30, 2018 , the Company sold loans which primarily consisted of CRE loans with a carrying value of $3.1 million and recognized a net gain of $0.8 million . During the six months ended June 30, 2019 , the Company sold loans which primarily consisted of commercial and industrial loans with a carrying value of $34.8 million and recognized a net loss of $0.5 million on the sales. During the six months ended June 30, 2018 , the Company sold loans, which consisted primarily of commercial and industrial loans with a carrying value of $34.1 million and recognized a net gain of $1.4 million on the sales.

Leases (Notes)

Leases (Notes)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Operating Leases [Text Block]	4. LEASES Adoption of ASU 2016-02, Leases On January 1, 2019, the Company adopted the amendments to ASC 842, Leases , which requires lessees to recognize lease assets and liabilities arising from operating leases on the balance sheet. The Company adopted the new lease guidance using the modified retrospective approach and elected the transition option issued under ASU 2018-11, Leases (Topic 842) Targeted Improvements , allowing entities to continue to apply the legacy guidance in ASC 840, Leases , to prior periods, including disclosure requirements. Accordingly, prior period financial results and disclosures have not been adjusted. The Company has operating leases under which it leases its branch offices, corporate headquarters, other offices, and data facility centers. Upon adoption of the new lease guidance, on January 1, 2019, the Company recorded a ROU asset and corresponding lease liability of $42.5 million and $46.1 million, respectively, on the consolidated balance sheet. As of June 30, 2019 , the Company's operating lease ROU asset and operating lease liability totaled $71.1 million and $76.2 million , respectively. The increase in the operating lease ROU asset and the operating lease liability from the adoption date is due to execution of a major office lease extension subsequent to the adoption date. A weighted average discount rate of 3.18% was used in the measurement of the ROU asset and lease liability as of June 30, 2019 . The Company's leases have remaining lease terms between one to twelve years, with a weighted average lease term of 8.9 years at June 30, 2019 . Some leases include multiple five-year renewal options. The Company’s decision to exercise these renewal options is based on an assessment of its current business needs and market factors at the time of the renewal. Currently, the Company has no leases for which the option to renew is reasonably certain and therefore, options to renew were not factored into the calculation of its ROU asset and lease liability as of June 30, 2019 . The following is a schedule of the Company's operating lease liabilities by contractual maturity as of June 30, 2019 : (in thousands) 2019 $ 6,018 2020 11,297 2021 9,243 2022 8,049 2023 8,068 Thereafter 46,320 Total lease payments $ 88,995 Less: imputed interest 12,804 Total present value of lease liabilities $ 76,191 The Company also has additional operating leases, primarily related to its branch offices and corporate headquarters that have not yet commenced as of June 30, 2019 . The aggregate future commitment related to these additional leases totals $3.9 million . These operating leases will commence within the next twelve months and have lease terms between six to eleven years. Total operating lease costs of $3.1 million and $6.3 million and other lease costs of $0.9 million and $2.0 million , which include common area maintenance, parking, and taxes during the three and six months ended June 30, 2019 , respectively, were included as part of occupancy expense. Short-term lease costs were not material for the three and six months ended June 30, 2019 . For the three and six months ended June 30, 2018 , rent expense associated with the Company's operating leases totaled $2.8 million and $5.3 million , respectively. The below table shows the supplemental cash flow information related to the Company's operating leases for the six months ended June 30, 2019 : (in thousands) Cash paid for amounts included in the measurement of operating lease liabilities $ 6,181 Right-of-use assets obtained in exchange for new operating lease liabilities 33,736 Lease Obligations as of December 31, 2018 As previously disclosed in the Company's Annual Report on Form 10-K as of and for the year ended December 31, 2018 , the following is a schedule of future minimum rental payments under its non-cancelable operating leases, expiring through 2030: (in thousands) 2019 $ 11,370 2020 10,322 2021 7,418 2022 6,294 2023 6,070 Thereafter 15,417 Total future minimum rental payments $ 56,891

Other Borrowings

Other Borrowings	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Other Borrowings	The following table summarizes the Company’s borrowings as of June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 (in thousands) Short-Term: Federal funds purchased $ — $ 256,000 FHLB advances — 235,000 Total short-term borrowings $ — $ 491,000 The Company maintains federal fund lines of credit totaling $1.01 billion as of June 30, 2019 , which have rates comparable to the federal funds effective rate plus 0.10% to 0.20%. As of June 30, 2019 , there were no outstanding balances on the Company's lines of credit. As of December 31, 2018 , outstanding balances on these federal fund lines of credit totaled $256.0 million . The Company also 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 June 30, 2019 , the Company had no FHLB overnight advances. At December 31, 2018 , the Company had $235.0 million of FHLB overnight advances, with an interest rate of 2.56% . Other short-term borrowing sources available to the Company include customer repurchase agreements, which have a weighted average rate of 0.14%. At June 30, 2019 and December 31, 2018 , customer repurchase agreements totaled $13.9 million and $22.4 million , respectively. As of June 30, 2019 and December 31, 2018 , the Company had additional available credit with the FHLB of approximately $3.03 billion and $2.52 billion , respectively, and with the FRB of approximately $1.33 billion and $1.31 billion , respectively.

Qualifying Debt

Qualifying Debt	6 Months Ended
	Jun. 30, 2019
Qualifying Debt Disclosure [Abstract]
Qualifying Debt	Subordinated Debt The Parent has $175.0 million of subordinated debentures, which were recorded net of issuance costs of $5.5 million , and mature 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 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 receive fixed/pay variable swaps. The carrying value of all subordinated debt issuances, which includes the fair value of the related hedges, totals $316.4 million and $299.4 million at June 30, 2019 and December 31, 2018 , 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 $70.8 million and $61.1 million as of June 30, 2019 and December 31, 2018 , respectively. The weighted average interest rate of all junior subordinated debt as of June 30, 2019 was 4.66% , which is three-month LIBOR plus the contractual spread of 2.34%, compared to a weighted average interest rate of 5.15% at December 31, 2018 .

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2019
Stockholders' Equity Note [Abstract]
Stockholder's Equity	Stock-Based Compensation Restricted Stock Awards Restricted stock awards granted to employees generally vest over a 3 -year period. Stock grants made to non-employee WAL directors in 2019 became fully vested on July 1, 2019. The Company estimates the compensation expense for stock grants based upon the grant date fair value. Stock compensation expense 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 during the three and six months ended June 30, 2019 was $0.4 million and $21.2 million , respectively. Stock compensation expense related to restricted stock awards and stock options granted to employees are included in Salaries and employee benefits in the Consolidated Income Statement. For restricted stock awards granted to WAL directors, the related stock compensation expense is included in Legal, professional, and directors' fees. For each of the three and six months ended June 30, 2019 , the Company recognized $5.4 million and $9.7 million in stock-based compensation expense related to all restricted stock award grants, compared to $4.7 million and $9.0 million , respectively, for the three and six months ended June 30, 2018 . In addition, the Company previously granted shares of restricted stock to certain members of executive management that had both performance and service conditions that affect vesting. There were no such grants made during the three and six months ended June 30, 2019 and 2018 , however expense is still being recognized for the grants made in 2017 as they also have a three-year vesting period. For the three and six months ended June 30, 2019 , the Company recognized $0.5 million and $1.0 million , respectively, in stock-based compensation expense related to these performance-based restricted stock grants, compared to $0.6 million and $1.3 million , respectively, for the three and six months ended June 30, 2018 . Performance Stock Units The Company grants members of its executive management 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 and six months ended June 30, 2019 , the Company recognized $1.3 million and $3.0 million , respectively, in stock-based compensation expense related to these performance stock units, compared to $1.6 million and $3.3 million , respectively, for the three and six months ended June 30, 2018 . The three-year performance period for the 2016 grant ended on December 31, 2018 , 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 members were entitled to the maximum award of 202,776 shares, which was paid out in the first quarter of 2019 . Common Stock Repurchase On December 12, 2018, the Company announced that it had adopted a common stock repurchase plan, pursuant to which the Company is authorized to repurchase up to $250.0 million of its shares of common stock. During the three and six months ended June 30, 2019 , the Company repurchased 792,688 and 1,733,603 shares of its common stock, respectively, in total representing approximately 2% of the Company's outstanding shares, pursuant to the repurchase plan. The shares were repurchased at a weighted average price of $42.81 and $41.45 , for a total payment of $34.0 million and $71.9 million during the three and six months ended June 30, 2019 , respectively. Treasury Shares Treasury share purchases 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. During the three and six months ended June 30, 2019 , the Company purchased treasury shares of 3,145 and 176,152 , respectively, at a weighted average price of $47.16 and $45.69 per share, respectively. During the three and six months ended June 30, 2018 , the Company purchased treasury shares of 2,085 and 182,952 at a weighted average price of $59.46 and $59.02

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
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: Three Months Ended June 30, Unrealized holding (losses) gains on AFS Unrealized holding gains (losses) on SERP Unrealized holding gains (losses) on junior subordinated debt Impairment loss on securities Total (in thousands) Balance, March 31, 2019 $ (16,214 ) $ 374 $ 7,505 $ 144 $ (8,191 ) Other comprehensive income (loss) before reclassifications 35,923 (17 ) (1,334 ) — 34,572 Amounts reclassified from AOCI — — — — — Net current-period other comprehensive income (loss) 35,923 (17 ) (1,334 ) — 34,572 Balance, June 30, 2019 $ 19,709 $ 357 $ 6,171 $ 144 $ 26,381 Balance, March 31, 2018 $ (51,470 ) $ 458 $ 9,206 $ 144 $ (41,662 ) Other comprehensive (loss) income before reclassifications (10,389 ) (12 ) 748 — (9,653 ) Amounts reclassified from AOCI — — — — — Net current-period other comprehensive (loss) income (10,389 ) (12 ) 748 — (9,653 ) Balance, June 30, 2018 $ (61,859 ) $ 446 $ 9,954 $ 144 $ (51,315 ) Six Months Ended June 30, 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, 2018 $ (47,591 ) $ 392 $ 13,433 $ 144 $ (33,622 ) Other comprehensive (loss) income before reclassifications 67,300 (35 ) (7,262 ) — 60,003 Amounts reclassified from AOCI — — — — — Net current-period other comprehensive (loss) income 67,300 (35 ) (7,262 ) — 60,003 Balance, June 30, 2019 $ 19,709 $ 357 $ 6,171 $ 144 $ 26,381 Balance, December 31, 2017 $ (10,026 ) $ 385 $ 6,352 $ 144 $ (3,145 ) Balance, January 1, 2018 (1) (12,556 ) 469 7,740 144 (4,203 ) Other comprehensive income (loss) before reclassifications (49,303 ) (23 ) 2,214 — (47,112 ) Amounts reclassified from AOCI — — — — — Net current-period other comprehensive income (loss) (49,303 ) (23 ) 2,214 — (47,112 ) Balance, June 30, 2018 $ (61,859 ) $ 446 $ 9,954 $ 144 $ (51,315 ) (1) As adjusted for adoption of ASU 2016-01 and ASU 2018-02. The cumulative effect of adoption of this guidance at January 1, 2018 resulted in an increase to retained earnings of $1.1 million and a corresponding decrease to accumulated other comprehensive income. During the three and six months ended June 30, 2019 and 2018

Derivatives and Hedging

Derivatives and Hedging	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
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 June 30, 2019 , December 31, 2018 , and June 30, 2018 , the Company does not have any outstanding cash flow hedges. 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 receive fixed/pay variable 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 Parent'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. Derivatives Not Designated in Hedge Relationships Management also enters into certain foreign exchange derivative contracts and back-to-back interest rate swaps which are not designated as accounting hedges. Foreign exchange derivative contracts include spot, forward, and forward window contracts. The purpose of these derivative contracts is to mitigate foreign currency risk on transactions entered into, or on behalf of customers. Contracts with customers, along with the related derivative trades that the Company places, are both remeasured at fair value, and are referred to as economic hedges since they economically offset the Company's exposure. The Company's back-to-back interest rate swaps are used to manage long-term interest rate risk. As of June 30, 2019 , derivatives not designated as hedging instruments were in a net asset position of $0.1 million , compared to a net asset position of $0.3 million and $0.2 million at December 31, 2018 and June 30, 2018 , respectively. For the three months ended June 30, 2019 and 2018 , net changes in the fair value related to these derivative contracts totaled $1.0 million and $1.2 million , respectively, and $2.3 million and $2.4 million for the six months ended June 30, 2019 and 2018 , respectively, are included as part of Foreign currency income in the Consolidated Income Statements. As of June 30, 2019 and December 31, 2018 , the following amounts are reflected in the Consolidated Balance Sheet related to cumulative basis adjustments for fair value hedges: June 30, 2019 December 31, 2018 Carrying Value of Hedged Assets/(Liabilities) Cumulative Fair Value Hedging Adjustment (1) Carrying Value of Hedged Assets/(Liabilities) Cumulative Fair Value Hedging Adjustment (1) (in thousands) Loans - HFI, net of deferred loan fees and costs $ 678,369 $ 58,355 $ 650,428 $ 23,039 Qualifying debt (316,392 ) 2,963 (299,401 ) 19,691 (1) Included in the carrying value of the hedged assets/(liabilities). For the Company's derivative instruments that are designated and qualify as a fair value hedge, the gain or loss on the derivative instrument as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in current earnings in the same line item as the offsetting loss or gain on the related interest rate swaps. For loans, the gain or loss on the hedged item is included in interest income and for subordinated debt, the gain or loss on the hedged item is included in interest expense. 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 June 30, 2019 , December 31, 2018 , and June 30, 2018 . 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: June 30, 2019 December 31, 2018 June 30, 2018 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 $ 958,298 $ 1,436 $ 62,754 $ 965,705 $ 2,162 $ 44,892 $ 986,867 $ 4,435 $ 41,015 Total 958,298 1,436 62,754 965,705 2,162 44,892 986,867 4,435 41,015 Netting adjustments (1) — 163 163 — 2,162 2,162 — 3,838 3,838 Net derivatives in the balance sheet $ 958,298 $ 1,273 $ 62,591 $ 965,705 $ — $ 42,730 $ 986,867 $ 597 $ 37,177 Derivatives not designated as hedging instruments: Foreign currency contracts $ 25,151 $ 263 $ 147 $ 49,690 $ 454 $ 201 $ 70,190 $ 1,274 $ 1,056 Interest rate swaps 2,348 83 83 2,378 27 27 1,763 74 74 Total $ 27,499 $ 346 $ 230 $ 52,068 $ 481 $ 228 $ 71,953 $ 1,348 $ 1,130 (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. 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 cash deposits or 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 $62.8 million at June 30, 2019 , $44.9 million at December 31, 2018 , and $39.8 million at June 30, 2018 . The following table summarizes the Company's largest exposure to an individual counterparty at the dates indicated: June 30, 2019 December 31, 2018 June 30, 2018 (in thousands) Largest gross exposure (derivative asset) to an individual counterparty $ 1,273 $ 1,411 $ 2,910 Collateral posted by this counterparty 1,100 — — Derivative liability with this counterparty — 23,906 16,809 Collateral pledged to this counterparty — 25,761 24,001 Net exposure after netting adjustments and collateral $ 173 $ — $ — 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 June 30, 2019 , December 31, 2018 , and June 30, 2018 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 $62.8 million , $44.9 million , and $41.0 million , respectively. As of June 30, 2019 , the Company was in an over-collateralized net position of $20.3 million after considering $83.1 million of collateral held in the form of cash and securities. As of December 31, 2018 and June 30, 2018 , the Company was in an over-collateralized position of $7.6 million and $11.6 million

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands, except per share amounts) Weighted average shares - basic 103,019 104,691 103,523 104,611 Dilutive effect of stock awards 482 729 462 761 Weighted average shares - diluted 103,501 105,420 103,985 105,372 Net income $ 122,936 $ 104,679 $ 243,732 $ 205,579 Earnings per share - basic 1.19 1.00 2.35 1.97 Earnings per share - diluted 1.19 0.99 2.34 1.95 The Company had no anti-dilutive stock options outstanding at each of the periods ended June 30, 2019 and 2018 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	The Company's effective tax rate was 16.76% and 19.48% for the three months ended June 30, 2019 and 2018 , respectively. For the six months ended June 30, 2019 and 2018 , the Company's effective tax rate was 17.10% and 18.33% , respectively. The decrease in the effective tax rate from the three and six months ended June 30, 2018 is due primarily to investments in solar tax credits and lower state tax accruals. As of June 30, 2019 , the net deferred tax asset was $9.3 million , a decrease of $22.7 million from December 31, 2018 . This overall decrease in the net deferred tax asset was primarily the result of an increase in the fair market value of AFS securities. Although realization is not assured, the Company believes that the realization of the recognized deferred tax asset of $9.3 million at June 30, 2019 is more-likely-than-not based on expectations as to future taxable income and based on available tax planning strategies that could be implemented if necessary to prevent a carryover from expiring. At June 30, 2019 and December 31, 2018 , the Company has a $2.4 million deferred tax valuation allowance related to net capital loss carryovers. As of June 30, 2019 , the Company’s gross federal NOL carryovers after current year-to-date utilization, all of which are subject to limitations under Section 382 of the IRC, totaled approximately $46.5 million for which a deferred tax asset of $5.6 million has been recorded, reflecting the expected benefit of these federal NOL carryovers remaining. The Company also has varying gross amounts of state NOL carryovers, with the most significant in Arizona. The gross Arizona NOL carryovers totaled approximately $2.3 million after current year-to-date utilization, resulting in a deferred tax asset balance of $0.1 million as of June 30, 2019 , reflecting the expected benefit of all state NOL carryovers remaining. 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 total $321.5 million and $342.4 million as of June 30, 2019 and December 31, 2018 , respectively. Unfunded LIHTC obligations are included as part of other liabilities in the Consolidated Balance Sheets and total $133.1 million and $171.7 million as of June 30, 2019 and December 31, 2018 , respectively. For the three months ended June 30, 2019 and 2018 , $10.5 million and $9.4 million , respectively, of amortization related to LIHTC investments was recognized as a component of income tax expense. For the six months ended June 30, 2019 and 2018 , $20.6 million and $17.5 million , respectively, of amortization related to LIHTC investments was recognized as a component of income tax expense.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
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 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 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 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. 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: June 30, 2019 December 31, 2018 (in thousands) Commitments to extend credit, including unsecured loan commitments of $900,291 at June 30, 2019 and $770,114 at December 31, 2018 $ 8,528,133 $ 7,556,741 Credit card commitments and financial guarantees 268,439 237,312 Letters of credit, including unsecured letters of credit of $16,225 at June 30, 2019 and $21,879 at December 31, 2018 285,266 390,161 Total $ 9,081,838 $ 8,184,214 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 Unaudited Consolidated Financial Statements. This loss contingency for unfunded loan commitments and letters of credit was $9.2 million and $8.2 million as of June 30, 2019 and December 31, 2018 , respectively. Changes to this liability are adjusted through other expense in the Consolidated Income Statement. 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 June 30, 2019 and December 31, 2018 , CRE related loans accounted for approximately 48% and 49% of total loans, respectively. Substantially all of these loans are secured by first liens with an initial loan to value ratio of generally not more than 75% . Approximately 32% and 36% of these CRE loans, excluding construction and land loans, were owner-occupied at June 30, 2019 and December 31, 2018 , respectively. Contingencies The Company is involved in various lawsuits of a routine nature that are being handled and defended in the ordinary course of the Company’s business. Expenses are being incurred in connection with 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.

Fair Value Accounting

Fair Value Accounting	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
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. These unrealized gains and losses are recognized as part of other comprehensive income rather than earnings. The Company did not elect FVO treatment for the junior subordinated debt assumed in the Bridge Capital Holdings acquisition. For the three and six months ended June 30, 2019 and 2018 , unrealized gains and losses from fair value changes on junior subordinated debt were as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) (in thousands) Unrealized gains/(losses) $ (1,769 ) $ 992 $ (9,631 ) $ 2,936 Changes included in OCI, net of tax (1,334 ) 748 (7,262 ) 2,214 Fair value on a recurring basis Financial assets and financial liabilities measured at fair value on a recurring basis include the following: AFS securities: Securities classified as AFS are primarily 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. Equity securities: Preferred stock and CRA investments are reported at fair value utilizing Level 1 inputs. Independent pricing service: The Company's independent pricing service provides pricing information on the majority of the Company's Level 1 and 2 AFS securities. For a small subset of securities, other pricing sources are used, including observed prices on publicly-traded securities and dealer quotes. 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 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, including other pricing services and safekeeping statements, and evaluates those with notable variances. In instances where there are discrepancies in pricing from various sources and management expectations, management may manually price securities using currently observed market data to determine whether they can develop similar prices or may utilize bid information from broker dealers. Any remaining discrepancies between management’s review and the prices provided by the vendor are discussed with the vendor and/or the Company’s other valuation advisors. 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. 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) June 30, 2019 Assets: Available-for-sale debt securities CDO $ — $ 15,026 $ — $ 15,026 Commercial MBS issued by GSEs — 100,841 — 100,841 Corporate debt securities 5,145 93,183 — 98,328 Municipal securities — 7,753 — 7,753 Private label residential MBS — 949,762 — 949,762 Residential MBS issued by GSEs — 1,453,316 — 1,453,316 Tax-exempt — 561,730 — 561,730 Trust preferred securities 24,939 — — 24,939 U.S. government sponsored agency securities — 39,905 — 39,905 U.S. treasury securities — 1,494 — 1,494 Total AFS debt securities $ 30,084 $ 3,223,010 $ — $ 3,253,094 Equity securities CRA investments $ 52,141 $ — $ — $ 52,141 Preferred stock 62,548 — — 62,548 Total equity securities $ 114,689 $ — $ — $ 114,689 Derivative assets (1) $ — $ 1,782 $ — $ 1,782 Liabilities: Junior subordinated debt (2) $ — $ — $ 58,315 $ 58,315 Derivative liabilities (1) — 62,984 — 62,984 (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 $58,355 and the net carrying value of subordinated debt is decreased by $2,963 as of June 30, 2019 for the effective portion of the hedge, which relates to the fair value 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 Significant Other Observable Inputs Significant Unobservable Inputs Fair Value (in thousands) December 31, 2018 Assets: Available-for-sale debt securities CDO $ — $ 15,327 $ — $ 15,327 Commercial MBS issued by GSEs — 100,106 — 100,106 Corporate debt securities — 99,380 — 99,380 Private label residential MBS — 924,594 — 924,594 Residential MBS issued by GSEs — 1,530,124 — 1,530,124 Tax-exempt — 538,668 — 538,668 Trust preferred securities — 28,617 — 28,617 U.S. government sponsored agency securities — 38,188 — 38,188 U.S. treasury securities — 1,984 — 1,984 Total AFS debt securities $ — $ 3,276,988 $ — $ 3,276,988 Equity securities CRA investments $ 51,142 $ — $ — $ 51,142 Preferred stock 63,919 — — 63,919 Total equity securities $ 115,061 $ — $ — $ 115,061 Derivative assets (1) $ — $ 2,643 $ — $ 2,643 Liabilities: Junior subordinated debt (2) $ — $ — $ 48,684 $ 48,684 Derivative liabilities (1) — 45,120 — 45,120 (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 $23,039 and the net carrying value of subordinated debt is decreased by $19,691 as of December 31, 2018 for the effective portion of the hedge, which relates to the fair value 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. For the three and six months ended June 30, 2019 and 2018 , the change in Level 3 liabilities measured at fair value on a recurring basis was as follows: Junior Subordinated Debt Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Beginning balance $ (56,546 ) $ (54,290 ) $ (48,684 ) $ (56,234 ) Change in fair value (1) (1,769 ) 992 (9,631 ) 2,936 Ending balance $ (58,315 ) $ (53,298 ) $ (58,315 ) $ (53,298 ) (1) Unrealized gains/(losses) attributable to changes in the fair value of junior subordinated debt are recorded as part of OCI, net of tax, and totaled $(1.3) million and $0.7 million for three months ended June 30, 2019 and 2018 , respectively, and $(7.3) million and $2.2 million for the six months ended June 30, 2019 and 2018 , respectively. For Level 3 liabilities measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 , the significant unobservable inputs used in the fair value measurements were as follows: June 30, 2019 Valuation Technique Significant Unobservable Inputs Input Value (in thousands) Junior subordinated debt $ 58,315 Discounted cash flow Implied credit rating of the Company 6.05 % December 31, 2018 Valuation Technique Significant Unobservable Inputs Input Value (in thousands) Junior subordinated debt $ 48,684 Discounted cash flow Implied credit rating of the Company 7.82 % The significant unobservable inputs used in the fair value measurement of the Company’s junior subordinated debt as of June 30, 2019 and December 31, 2018 was the implied credit risk for the Company, calculated as the difference between the 15-year 'BB' rated financial index over the corresponding swap index. As of June 30, 2019 , the Company estimates the discount rate at 6.05% , which represents an implied credit spread of 3.73% plus three-month LIBOR ( 2.32% ). As of December 31, 2018 , the Company estimated the discount rate at 7.82% , which was a 5.01% credit spread plus three-month LIBOR ( 2.81% ). 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 June 30, 2019; Impaired loans with specific valuation allowance $ 4,236 $ — $ — $ 4,236 Impaired loans without specific valuation allowance (1) 108,090 — — 108,090 Other assets acquired through foreclosure 17,707 — — 17,707 As of December 31, 2018: Impaired loans with specific valuation allowance $ 305 $ — $ — $ 305 Impaired loans without specific valuation allowance (1) 91,821 — — 91,821 Other assets acquired through foreclosure 17,924 — — 17,924 (1) Net of loan balances with charge-offs of $12.3 million and $19.4 million as of June 30, 2019 and December 31, 2018 , respectively. For Level 3 assets measured at fair value on a nonrecurring basis as of June 30, 2019 and December 31, 2018 , the significant unobservable inputs used in the fair value measurements were as follows: June 30, 2019 Valuation Technique(s) Significant Unobservable Inputs Range (in thousands) Impaired loans $ 112,326 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 17,707 Collateral method Third party appraisal Costs to sell 4.0% to 10.0% December 31, 2018 Valuation Technique(s) Significant Unobservable Inputs Range (in thousands) Impaired loans $ 92,126 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 17,924 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 $112.3 million and $92.1 million at June 30, 2019 and December 31, 2018 , respectively. Impaired loans with a specific valuation allowance had a gross estimated fair value of $6.1 million and $1.0 million at June 30, 2019 and December 31, 2018 , respectively, which was reduced by a specific valuation allowance of $1.9 million and $0.7 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 $17.7 million and $17.9 million of such assets at June 30, 2019 and December 31, 2018 , 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 and six months ended June 30, 2019 and 2018 , the Company determined that no securities experienced credit losses. There is no OTTI balance recognized in comprehensive income as of June 30, 2019 and 2018 . Fair Value of Financial Instruments The estimated fair value of the Company’s financial instruments is as follows: June 30, 2019 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Federal funds sold $ 90,000 $ — $ 90,000 $ — $ 90,000 Investment securities: HTM 435,997 — 466,858 — 466,858 AFS 3,253,094 30,084 3,223,010 — 3,253,094 Equity 114,689 114,689 — — 114,689 Derivative assets 1,782 — 1,782 — 1,782 Loans, net 19,089,841 — 18,427,885 112,326 18,540,211 Accrued interest receivable 105,469 — 105,469 — 105,469 Financial liabilities: Deposits $ 21,439,899 $ — $ 21,458,684 $ — $ 21,458,684 Customer repurchase agreements 13,921 — 13,921 — 13,921 Qualifying debt 387,232 — 333,430 69,937 403,367 Derivative liabilities 62,984 — 62,984 — 62,984 Accrued interest payable 21,956 — 21,956 — 21,956 December 31, 2018 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 302,905 $ — $ 298,648 $ — $ 298,648 AFS 3,276,988 — 3,276,988 — 3,276,988 Equity securities 115,061 115,061 — — 115,061 Derivative assets 2,643 — 2,643 — 2,643 Loans, net 17,557,912 — 16,857,852 92,126 16,949,978 Accrued interest receivable 101,275 — 101,275 — 101,275 Financial liabilities: Deposits $ 19,177,447 $ — $ 19,188,216 $ — $ 19,188,216 Customer repurchase agreements 22,411 — 22,411 — 22,411 Other borrowings 491,000 — 491,000 — 491,000 Qualifying debt 360,458 — 323,572 57,924 381,496 Derivative liabilities 45,120 — 45,120 — 45,120 Accrued interest payable 20,463 — 20,463 — 20,463 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. WAB has an ALCO charged with managing interest rate risk within the BOD-approved limits. Limits are structured to preclude an interest rate risk profile that does not conform to both management and BOD risk tolerances without ALCO approval. There is also ALCO reporting at the Parent 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 June 30, 2019 and December 31, 2018 is insignificant. Loan commitments on which the committed interest rates are less than the current market rate are also insignificant at June 30, 2019 and December 31, 2018 .

Segments

Segments	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
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 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 information for the periods indicated: Regional Segments Balance Sheet: Consolidated Company Arizona Nevada Southern California Northern California At June 30, 2019 (in millions) Assets: Cash, cash equivalents, and investment securities $ 4,937.8 $ 1.8 $ 7.6 $ 2.1 $ 1.9 Loans, net of deferred loan fees and costs 19,250.3 3,937.0 2,095.2 2,256.7 1,195.4 Less: allowance for credit losses (160.4 ) (33.2 ) (18.1 ) (19.5 ) (9.2 ) Total loans 19,089.9 3,903.8 2,077.1 2,237.2 1,186.2 Other assets acquired through foreclosure, net 17.7 0.7 13.9 — — Goodwill and other intangible assets, net 298.4 — 23.2 — 155.1 Other assets 971.0 46.8 57.6 16.1 17.0 Total assets $ 25,314.8 $ 3,953.1 $ 2,179.4 $ 2,255.4 $ 1,360.2 Liabilities: Deposits $ 21,439.9 $ 6,107.0 $ 4,188.6 $ 2,535.9 $ 2,008.9 Borrowings and qualifying debt 387.2 — — — — Other liabilities 636.4 13.2 11.9 0.5 14.7 Total liabilities 22,463.5 6,120.2 4,200.5 2,536.4 2,023.6 Allocated equity: 2,851.3 484.6 286.0 255.6 297.5 Total liabilities and stockholders' equity $ 25,314.8 $ 6,604.8 $ 4,486.5 $ 2,792.0 $ 2,321.1 Excess funds provided (used) — 2,651.7 2,307.1 536.6 960.9 Income Statement: Three Months Ended June 30, 2019 (in thousands) Net interest income $ 254,681 $ 59,719 $ 39,528 $ 31,644 $ 23,996 Provision for (recovery of) credit losses 7,000 1,443 (305 ) 67 (152 ) Net interest income after provision for credit losses 247,681 58,276 39,833 31,577 24,148 Non-interest income 14,218 1,707 2,677 974 2,162 Non-interest expense (114,213 ) (22,693 ) (14,107 ) (15,122 ) (12,549 ) Income (loss) before income taxes 147,686 37,290 28,403 17,429 13,761 Income tax expense (benefit) 24,750 9,322 5,965 4,880 3,853 Net income $ 122,936 $ 27,968 $ 22,438 $ 12,549 $ 9,908 Six Months Ended June 30, 2019 (in thousands) Net interest income $ 502,017 $ 114,945 $ 78,626 $ 62,120 $ 47,029 Provision for (recovery of) credit losses 10,500 1,604 228 800 (871 ) Net interest income after provision for credit losses 491,517 113,341 78,398 61,320 47,900 Non-interest income 29,628 3,229 5,250 1,975 4,382 Non-interest expense (227,127 ) (44,943 ) (29,888 ) (29,704 ) (26,040 ) Income (loss) before income taxes 294,018 71,627 53,760 33,591 26,242 Income tax expense (benefit) 50,286 17,907 11,289 9,406 7,348 Net income $ 243,732 $ 53,720 $ 42,471 $ 24,185 $ 18,894 National Business Lines Balance Sheet: HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other At June 30, 2019 Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ 10.4 $ 4,914.0 Loans, net of deferred loan fees and costs 214.7 1,626.6 1,246.5 1,655.7 5,015.5 7.0 Less: allowance for credit losses (1.8 ) (14.8 ) (10.2 ) (10.3 ) (43.2 ) (0.1 ) Total loans 212.9 1,611.8 1,236.3 1,645.4 4,972.3 6.9 Other assets acquired through foreclosure, net — — — — — 3.1 Goodwill and other intangible assets, net — — 120.0 0.1 — — Other assets 0.9 17.1 6.9 7.7 63.8 737.1 Total assets $ 213.8 $ 1,628.9 $ 1,363.2 $ 1,653.2 $ 5,046.5 $ 5,661.1 Liabilities: Deposits $ 3,047.5 $ — $ 2,853.2 $ — $ 32.4 $ 666.4 Borrowings and qualifying debt — — — — — 387.2 Other liabilities 1.3 58.3 — (0.2 ) 92.3 444.4 Total liabilities 3,048.8 58.3 2,853.2 (0.2 ) 124.7 1,498.0 Allocated equity: 79.9 132.3 277.5 138.4 414.1 485.4 Total liabilities and stockholders' equity $ 3,128.7 $ 190.6 $ 3,130.7 $ 138.2 $ 538.8 $ 1,983.4 Excess funds provided (used) 2,914.9 (1,438.3 ) 1,767.5 (1,515.0 ) (4,507.7 ) (3,677.7 ) Income Statement: Three Months Ended June 30, 2019 (in thousands) Net interest income $ 21,905 $ 3,461 $ 28,536 $ 13,490 $ 29,586 $ 2,816 Provision for (recovery of) credit losses (7 ) 96 2,657 832 2,369 — Net interest income after provision for credit losses 21,912 3,365 25,879 12,658 27,217 2,816 Non-interest income 88 — 2,163 — 1,549 2,898 Non-interest expense (9,549 ) (1,931 ) (10,015 ) (2,162 ) (11,073 ) (15,012 ) Income (loss) before income taxes 12,451 1,434 18,027 10,496 17,693 (9,298 ) Income tax expense (benefit) 2,864 330 4,146 2,414 4,069 (13,093 ) Net income $ 9,587 $ 1,104 $ 13,881 $ 8,082 $ 13,624 $ 3,795 Six Months Ended June 30, 2019 (in thousands) Net interest income $ 42,546 $ 6,884 $ 57,939 $ 26,434 $ 55,277 $ 10,217 Provision for (recovery of) credit losses (33 ) 55 1,739 1,631 5,347 — Net interest income after provision for credit losses 42,579 6,829 56,200 24,803 49,930 10,217 Non-interest income 184 — 5,525 — 2,207 6,876 Non-interest expense (18,008 ) (3,838 ) (21,903 ) (4,560 ) (20,409 ) (27,834 ) Income (loss) before income taxes 24,755 2,991 39,822 20,243 31,728 (10,741 ) Income tax expense (benefit) 5,694 688 9,159 4,656 7,297 (23,158 ) Net income $ 19,061 $ 2,303 $ 30,663 $ 15,587 $ 24,431 $ 12,417 Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At December 31, 2018 (in millions) Assets: Cash, cash equivalents, and investment securities $ 4,259.7 $ 2.5 $ 10.9 $ 2.5 $ 3.0 Loans, net of deferred loan fees and costs 17,710.6 3,647.9 2,003.5 2,161.1 1,300.2 Less: allowance for credit losses (152.7 ) (30.7 ) (18.7 ) (19.8 ) (10.7 ) Total loans 17,557.9 3,617.2 1,984.8 2,141.3 1,289.5 Other assets acquired through foreclosure, net 17.9 0.8 13.9 — — Goodwill and other intangible assets, net 299.2 — 23.2 — 155.5 Other assets 974.8 46.9 57.8 14.2 23.9 Total assets $ 23,109.5 $ 3,667.4 $ 2,090.6 $ 2,158.0 $ 1,471.9 Liabilities: Deposits $ 19,177.4 $ 5,090.2 $ 3,996.4 $ 2,347.5 $ 1,839.1 Borrowings and qualifying debt 851.5 — — — — Other liabilities 466.9 10.4 14.5 4.5 12.2 Total liabilities 20,495.8 5,100.6 4,010.9 2,352.0 1,851.3 Allocated equity: 2,613.7 441.0 277.4 242.9 304.1 Total liabilities and stockholders' equity $ 23,109.5 $ 5,541.6 $ 4,288.3 $ 2,594.9 $ 2,155.4 Excess funds provided (used) — 1,874.2 2,197.7 436.9 683.5 Income Statement: Three Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 224,108 $ 57,977 $ 35,276 $ 27,664 $ 23,001 Provision for (recovery of) credit losses 5,000 518 (243 ) (276 ) 13 Net interest income (expense) after provision for credit losses 219,108 57,459 35,519 27,940 22,988 Non-interest income 13,444 2,256 2,679 966 2,421 Non-interest expense (102,548 ) (22,419 ) (15,931 ) (14,491 ) (13,429 ) Income (loss) before income taxes 130,004 37,296 22,267 14,415 11,980 Income tax expense (benefit) 25,325 9,324 4,676 4,036 3,355 Net income $ 104,679 $ 27,972 $ 17,591 $ 10,379 $ 8,625 Six Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 438,328 $ 112,532 $ 71,966 $ 55,466 $ 45,256 Provision for (recovery of) credit losses 11,000 1,952 (1,967 ) 454 1,561 Net interest income (expense) after provision for credit losses 427,328 110,580 73,933 55,012 43,695 Non-interest income 25,087 3,672 6,012 1,967 4,969 Non-interest expense (200,697 ) (43,923 ) (30,015 ) (28,137 ) (25,932 ) Income (loss) before income taxes 251,718 70,329 49,930 28,842 22,732 Income tax expense (benefit) 46,139 17,645 10,579 8,171 6,452 Net income $ 205,579 $ 52,684 $ 39,351 $ 20,671 $ 16,280 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other At December 31, 2018 Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 4,240.8 Loans, net of deferred loan fees and costs 210.0 1,547.5 1,200.9 1,479.9 4,154.9 4.7 Less: allowance for credit losses (1.9 ) (14.2 ) (10.0 ) (8.5 ) (38.2 ) — Total loans 208.1 1,533.3 1,190.9 1,471.4 4,116.7 4.7 Other assets acquired through foreclosure, net — — — — — 3.2 Goodwill and other intangible assets, net — — 120.4 0.1 — — Other assets 0.9 20.1 6.3 7.2 37.1 760.4 Total assets $ 209.0 $ 1,553.4 $ 1,317.6 $ 1,478.7 $ 4,153.8 $ 5,009.1 Liabilities: Deposits $ 2,607.2 $ — $ 2,559.0 $ — $ — $ 738.0 Borrowings and qualifying debt — — — — — 851.5 Other liabilities 2.1 25.2 0.1 0.4 49.6 347.9 Total liabilities 2,609.3 25.2 2,559.1 0.4 49.6 1,937.4 Allocated equity: 70.7 123.9 268.7 122.3 340.0 422.7 Total liabilities and stockholders' equity $ 2,680.0 $ 149.1 $ 2,827.8 $ 122.7 $ 389.6 $ 2,360.1 Excess funds provided (used) 2,471.0 (1,404.3 ) 1,510.2 (1,356.0 ) (3,764.2 ) (2,649.0 ) Income Statement: Three Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 16,046 $ 3,794 $ 24,562 $ 13,874 $ 19,672 $ 2,242 Provision for (recovery of) credit losses 135 (27 ) 2,256 548 2,074 2 Net interest income (expense) after provision for credit losses 15,911 3,821 22,306 13,326 17,598 2,240 Non-interest income 179 — 3,630 — 409 904 Non-interest expense (8,033 ) (2,080 ) (9,899 ) (2,200 ) (6,250 ) (7,816 ) Income (loss) before income taxes 8,057 1,741 16,037 11,126 11,757 (4,672 ) Income tax expense (benefit) 1,853 401 3,688 2,559 2,704 (7,271 ) Net income $ 6,204 $ 1,340 $ 12,349 $ 8,567 $ 9,053 $ 2,599 Six Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 31,405 $ 7,539 $ 47,383 $ 28,060 $ 38,484 $ 237 Provision for (recovery of) credit losses 182 (233 ) 3,907 1,783 3,359 2 Net interest income (expense) after provision for credit losses 31,223 7,772 43,476 26,277 35,125 235 Non-interest income 328 — 6,681 13 633 812 Non-interest expense (15,836 ) (4,254 ) (19,733 ) (4,405 ) (11,912 ) (16,550 ) Income (loss) before income taxes 15,715 3,518 30,424 21,885 23,846 (15,503 ) Income tax expense (benefit) 3,615 809 6,998 5,033 5,484 (18,647 ) Net income $ 12,100 $ 2,709 $ 23,426 $ 16,852 $ 18,362 $ 3,144

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
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. In addition, the Company has two non-bank subsidiaries, LVSP, which holds and manages certain OREO properties, and a captive insurance company formed and licensed under the laws of the State of Arizona, CSI. CSI was established as part of the Company's overall enterprise risk management strategy.
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; certain assets and liabilities carried at fair value; and accounting for income taxes.
Principles of Consolidation	Principles of consolidation As of June 30, 2019 , WAL has the following significant 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, 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 reported in prior periods may have been reclassified in the Consolidated Financial Statements 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 include debt securities and equity securities. Debt 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 an HTM 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 are reported as an asset in the Consolidated Balance Sheet at their estimated fair value. As the fair value of AFS debt securities changes, the changes are reported net of income tax as an element of OCI, except for other-than-temporarily-impaired securities. When AFS debt 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 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 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
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 values of loans subject to a fair value hedge are 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 a 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 a 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. 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, which are used for all of the Company's portfolio segments. 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.
Lessee, Leases [Policy Text Block]	Leases At inception, contracts are evaluated to determine whether the contract constitutes a lease agreement. For contracts that are determined to be an operating lease, a corresponding ROU asset and operating lease liability are recorded in separate line items on the consolidated balance sheets. A ROU asset represents the Company’s right to use an underlying asset during the lease term and a lease liability represents the Company’s commitment to make contractually obligated lease payments. Operating lease ROU assets and liabilities are recognized at the commencement date of the lease and are based on the present value of lease payments over the lease term. The measurement of the operating lease ROU asset includes any lease payments made and is reduced by lease incentives that are paid or are payable to the Company. Variable lease payments that depend on an index or rate such as the Consumer Price Index are included in lease payments based on the rate in effect at the commencement date of the lease. Lease payments are recognized on a straight-line basis as part of occupancy expense over the lease term. As the rate implicit in the lease is not readily determinable, the incremental collateralized borrowing rate is used to determine the present value of lease payments. This rate gives consideration to the applicable FHLB collateralized borrowing rates and is based on the information available at the commencement date. The Company has elected to apply the short-term lease measurement and recognition exemption to leases with an initial term of 12 months or less; therefore, these leases are not recorded on the Company’s consolidated balance sheet, but rather, lease expense is recognized over the lease term on a straight-line basis. The Company’s lease agreements may include options to extend or terminate the lease. These options are included in the lease term when it is reasonably certain that the options will be exercised. In addition to the package of practical expedients, the Company also elected the practical expedient that allows lessees to make an accounting policy election to not separate non-lease components from the associated lease component, and instead account for them all together as part of the applicable lease component. This practical expedient can be elected separately for each underlying class of asset. The majority of the Company’s non-lease components such as common area maintenance, parking, and taxes are variable, and are expensed as incurred. Variable payment amounts are determined in arrears by the landlord depending on actual costs incurred. See “ Note 4. Leases ” of these Notes to Unaudited Consolidated Financial Statements for further disclosures required under the new standard.
Goodwill and Other Intangible Assets	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, a quantitative impairment test is necessary. If, based on the quantitative test, a reporting unit's carrying amount exceeds its fair value, a goodwill impairment charge for this difference is recorded 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 and six months ended June 30, 2019 or 2018 .
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 Shares	Treasury shares 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. 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 the fair value of certain fixed-rate financial instruments (fair value 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. 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. 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. Changes in the fair value of derivatives not considered to be highly effective in hedging the change in fair value 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 after the derivative contract is executed. At inception, the Company performs a quantitative assessment to determine whether the derivatives used in hedging transactions are highly effective (as defined in the guidance) in offsetting changes in the fair value of the hedged item. Retroactive effectiveness is assessed, as well as the continued expectation that the hedge will remain effective prospectively. After the initial quantitative assessment is performed, on a quarterly basis, the Company performs a qualitative hedge effectiveness assessment. This assessment takes into consideration any adverse developments related to the counterparty's risk of default and any negative events or circumstances that affect the factors that originally enabled the Company to assess that it could reasonably support, qualitatively, an expectation that the hedging relationship was and will continue to be highly effective. 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 could 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 and, in certain instances, may be unconditionally cancelable. 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 June 30, 2019 and 2018 . The estimated fair value amounts for June 30, 2019 and 2018 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, cash equivalents, and restricted cash 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 debt securities are primarily 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. For a small subset of securities, other pricing sources are used, including observed prices on publicly-traded securities and dealer quotes. 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 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	Recent accounting pronouncements In June 2016, the FASB issued guidance within ASU 2016-13, Measurement of Credit Losses on Financial Instruments . The new standard significantly changes the impairment model for most financial assets that are measured at amortized cost, including off-balance sheet credit exposures, from an incurred loss model to an expected loss model. 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 ASU are effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Management has formed a Steering Committee and established an implementation team made up of subject matter experts across different functions within the Company, including Finance, Risk, Credit, and IT, that will coordinate and facilitate all phases of planning and implementation of the new guidance. The Company has completed its loan portfolio stratification, with methodologies for measuring expected credit losses that include a combination of third-party vended models, internally-developed models, and simplified approaches and the Company is substantially complete with respect to model validation efforts, subject to addressing matters identified. In addition, the Company has completed three quarterly pre-production runs and in the remaining six months prior to the adoption of ASU 2016-13 will be addressing model findings and finalizing internal control design. The implementation team is also in the process of finalizing the Company's accounting policies, governance processes, and other related CECL impacts. In August 2018, the FASB issued guidance within ASU 2018-13, Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement . The amendments within ASU 2018-13 remove, modify, and supplement the disclosure requirements for fair value measurements. Disclosure requirements that were removed include: the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation processes for Level 3 fair value measurements. The amendments clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. Additional disclosure requirements include: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period, and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. With the exception of the above additional disclosure requirements, which will be applied prospectively, all other amendments should be applied retrospectively to all periods presented upon their effective date. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company's Consolidated Financial Statements. In August 2018, the FASB issued guidance within ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) . The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Accordingly, the amendments in this Update require an entity (customer) in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. The amendments in this Update also require that the capitalized implementation costs of a hosting arrangement that is a service contract be expensed over the term of the hosting arrangement. Presentation requirements include: expense related to the capitalized implementation costs should be presented in the same line item in the statement of income as the fees associated with the hosting element (service) of the arrangement, payments for capitalized implementation costs in the statement of cash flows should be classified in the same manner as payments made for fees associated with the hosting element, and capitalized implementation costs in the statement of financial position should be presented in the same line item that a prepayment for the fees of the associated hosting arrangement would be presented. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. The adoption of this guidance is not expected to have a significant impact on the Company's Consolidated Financial Statements. In April 2019, the FASB issued guidance within ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments . The amendments in ASU 2019-04 clarify or correct the guidance in these Topics. With respect to Topic 326, ASU 2019-04 addresses a number of issues as it relates to the CECL standard including consideration of accrued interest, recoveries, variable-rate financial instruments, prepayments, extension and renewal options, among other things, in the measurement of expected credit losses. The amendments to Topic 326 have the same effective dates as ASU 2016-13 and the Company is currently evaluating the potential impact of these amendments on the Company’s Consolidated Financial Statements. With respect to Topic 815, Derivatives and Hedging, ASU 2019-04 clarifies issues related to partial-term hedges, hedged debt securities, and transitioning from a quantitative method of assessing hedge effectiveness to a more simplified method. The Company does not have partial-term hedges or any hedged debt securities and the transition issues discussed in the ASU 2019-04 are not applicable to the Company. Accordingly, the amendments to Topic 815 will not have an impact on the Company's Consolidated Financial Statements. With respect to Topic 825, Financial Instruments, on recognizing and measuring financial instruments, ASU 2019-04 addresses the scope of the guidance, the requirement for remeasurement under ASC 820 when using the measurement alternative, certain disclosure requirements, and which equity securities have to be remeasured at historical exchange rates. The amendments to Topic 825 are effective for interim and annual reporting periods beginning after December 15, 2019 and are not expected to have a material impact on the Company’s Consolidated Financial Statements. In May 2019, the FASB issued guidance within ASU 2019-05, Financial Instruments - Credit Losses , to provide entities with an option to irrevocably elect the fair value option for eligible financial assets measured at amortized cost. The election is to be applied on an instrument-by-instrument basis upon adoption of Topic 326 and is not available for either AFS or HTM debt securities. The amendments in ASU 2019-05 should be applied on a modified-retrospective basis through a cumulative-effect adjustment to the opening balance of retained earnings as of the date that an entity adopts the amendments in ASU 2016-13, which will be on January 1, 2020. The adoption of this guidance is not expected to have a significant impact on the Company's Consolidated Financial Statements. Recently adopted accounting guidance 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 Company adopted the amendments to Topic 842 on January 1, 2019 using the modified retrospective approach. The Company elected the transition option issued under ASU 2018-11, Leases (Topic 842) Targeted Improvements , which allows entities to continue to apply the legacy guidance in ASC 840, Leases , to prior periods, including disclosure requirements. Accordingly, prior period financial results and disclosures have not been adjusted. The Company also elected to apply the package of practical expedients permitting entities to forgo reassessment of 1) expired or existing contracts that may contain leases; 2) lease classification of expired or existing leases; and 3) initial direct costs for any existing leases. The Company established internal controls and implemented lease accounting software to facilitate the preparation of financial information and disclosures related to leases. The most significant impact of the new standard on the Company’s consolidated financial statements was the recognition of a ROU asset and lease liability for operating leases for which the Company is the lessee. The accounting for finance and operating leases for which the Company is the lessor remains substantially unchanged. Upon adoption of this guidance, on January 1, 2019, the Company recorded a ROU asset and corresponding lease liability of $42.5 million and $46.1 million, respectively, on the consolidated balance sheet. No cumulative effect adjustment to retained earnings resulted from adoption of this guidance. The new standard did not have a material impact on the Company’s results of operations or cash flows. 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 ASU 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. As of June 30, 2019 , the Company does not hold these types of securities, therefore, adoption of this guidance did not have an impact on the Company's Consolidated Financial Statements. In June 2018, the FASB issued guidance within ASU 2018-07, Improvements to Nonemployee Share-Based Payment Accounting . The amendments in ASU 2018-07 to Topic 718, Compensation-Stock Compensation , are intended to align the accounting for share-based payment awards issued to employees and nonemployees. Changes to the accounting for nonemployee awards include: 1) equity classified share-based payment awards issued to nonemployees will now be measured on the grant date, instead of the previous requirement to remeasure the awards through the performance completion date; 2) for performance conditions, compensation cost associated with the award will be recognized when achievement of the performance condition is probable, rather than upon achievement of the performance condition; and 3) the current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. The new guidance also clarifies that any share-based payment awards issued to customers should be evaluated under ASC 606, Revenue from Contracts with Customers . The Company's share-based payment awards to nonemployees consist only of grants made to the Company's BOD as compensation solely related to the individual's role as a Director. As such, in accordance with ASC 718, the Company accounts for these share-based payment awards to its Directors in the same manner as share-based payment awards for its employees. Accordingly, the adoption of this guidance did not have an impact on the accounting for the Company's share-based payment awards to its Directors. In July 2018, the FASB issued guidance within ASU 2018-09, Codification Improvements

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Carrying Amounts and Fair Values of Investment Securities	The carrying amounts and fair values of investment securities at June 30, 2019 and December 31, 2018 are summarized as follows: June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity debt securities Tax-exempt $ 435,997 $ 30,861 $ — $ 466,858 Available-for-sale debt securities CDO $ 50 $ 14,976 $ — $ 15,026 Commercial MBS issued by GSEs 102,444 758 (2,361 ) 100,841 Corporate debt securities 105,022 123 (6,817 ) 98,328 Municipal securities 7,488 265 — 7,753 Private label residential MBS 949,699 5,605 (5,542 ) 949,762 Residential MBS issued by GSEs 1,446,679 10,381 (3,744 ) 1,453,316 Tax-exempt 541,879 20,023 (172 ) 561,730 Trust preferred securities 32,000 — (7,061 ) 24,939 U.S. government sponsored agency securities 40,000 — (95 ) 39,905 U.S. treasury securities 1,495 2 (3 ) 1,494 Total AFS debt securities $ 3,226,756 $ 52,133 $ (25,795 ) $ 3,253,094 Equity securities CRA investments $ 52,516 $ — $ (375 ) $ 52,141 Preferred stock 60,871 1,964 (287 ) 62,548 Total equity securities $ 113,387 $ 1,964 $ (662 ) $ 114,689 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (in thousands) Held-to-maturity debt securities Tax-exempt $ 302,905 $ 3,163 $ (7,420 ) $ 298,648 Available-for-sale debt securities CDO $ 50 $ 15,277 $ — $ 15,327 Commercial MBS issued by GSEs 106,385 82 (6,361 ) 100,106 Corporate debt securities 105,029 — (5,649 ) 99,380 Private label residential MBS 948,161 945 (24,512 ) 924,594 Residential MBS issued by GSEs 1,564,181 1,415 (35,472 ) 1,530,124 Tax-exempt 542,086 4,335 (7,753 ) 538,668 Trust preferred securities 32,000 — (3,383 ) 28,617 U.S. government sponsored agency securities 40,000 — (1,812 ) 38,188 U.S. treasury securities 1,996 — (12 ) 1,984 Total AFS debt securities $ 3,339,888 $ 22,054 $ (84,954 ) $ 3,276,988 Equity securities CRA investments $ 52,210 $ — $ (1,068 ) $ 51,142 Preferred stock 65,954 148 (2,183 ) 63,919 Total equity securities $ 118,164 $ 148 $ (3,251 ) $ 115,061
Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position	Information pertaining to securities with gross unrealized losses at June 30, 2019 and December 31, 2018 , aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: June 30, 2019 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) Available-for-sale debt securities Commercial MBS issued by GSEs $ — $ — $ 2,361 $ 79,102 $ 2,361 $ 79,102 Corporate debt securities — — 6,817 93,183 6,817 93,183 Private label residential MBS — 12,818 5,542 469,802 5,542 482,620 Residential MBS issued by GSEs 57 17,116 3,687 446,947 3,744 464,063 Tax-exempt 172 37,111 — — 172 37,111 Trust preferred securities — — 7,061 24,939 7,061 24,939 U.S. government sponsored agency securities — — 95 34,905 95 34,905 U.S. treasury securities — — 3 995 3 995 Total AFS securities $ 229 $ 67,045 $ 25,566 $ 1,149,873 $ 25,795 $ 1,216,918 December 31, 2018 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 debt securities Tax-exempt $ 3,868 $ 91,095 $ 3,552 $ 69,991 $ 7,420 $ 161,086 Available-for-sale debt securities Commercial MBS issued by GSEs $ — $ — $ 6,361 $ 98,275 $ 6,361 $ 98,275 Corporate debt securities 16 5,013 5,633 94,367 5,649 99,380 Private label residential MBS 5,173 217,982 19,339 537,316 24,512 755,298 Residential MBS issued by GSEs 1,363 141,493 34,109 1,215,490 35,472 1,356,983 Tax-exempt 3,562 209,767 4,191 72,382 7,753 282,149 Trust preferred securities — — 3,383 28,617 3,383 28,617 U.S. government sponsored agency securities — — 1,812 38,188 1,812 38,188 U.S. treasury securities — — 12 1,984 12 1,984 Total AFS securities $ 10,114 $ 574,255 $ 74,840 $ 2,086,619 $ 84,954 $ 2,660,874
Amortized Cost and Fair Value of Investment Securities by Contractual Maturities	The amortized cost and fair value of securities as of June 30, 2019 , 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. June 30, 2019 Amortized Cost Estimated Fair Value (in thousands) Held-to-maturity Due in one year or less $ 10,100 $ 10,139 After one year through five years 24,940 25,714 After ten years 400,957 431,005 Total HTM securities $ 435,997 $ 466,858 Available-for-sale Due in one year or less $ 3,781 $ 3,789 After one year through five years 16,012 16,173 After five years through ten years 209,275 203,657 After ten years 498,866 525,556 Mortgage-backed securities 2,498,822 2,503,919 Total AFS securities $ 3,226,756 $ 3,253,094
Investment Securities by Credit Rating Type	The following tables summarize the carrying amount of the Company’s investment ratings position as of June 30, 2019 and December 31, 2018 : June 30, 2019 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity debt securities Tax-exempt $ — $ — $ — $ — $ — $ — $ 435,997 $ 435,997 Available-for-sale debt securities CDO $ — $ — $ — $ — $ — $ 15,026 $ — $ 15,026 Commercial MBS issued by GSEs — 100,841 — — — — — 100,841 Corporate debt securities — — — 65,244 33,084 — — 98,328 Municipal securities — — — — — — 7,753 7,753 Private label residential MBS 926,847 — 20,454 256 881 1,324 — 949,762 Residential MBS issued by GSEs — 1,453,316 — — — — — 1,453,316 Tax-exempt 69,310 8,922 309,263 174,235 — — — 561,730 Trust preferred securities — — — — 24,939 — — 24,939 U.S. government sponsored agency securities — 39,905 — — — — — 39,905 U.S. treasury securities — 1,494 — — — — — 1,494 Total AFS securities $ 996,157 $ 1,604,478 $ 329,717 $ 239,735 $ 58,904 $ 16,350 $ 7,753 $ 3,253,094 Equity securities CRA investments $ — $ 25,375 $ — $ — $ — $ — $ 26,766 $ 52,141 Preferred stock — — — — 48,975 4,030 9,543 62,548 Total equity securities $ — $ 25,375 $ — $ — $ 48,975 $ 4,030 $ 36,309 $ 114,689 (1) Where ratings differ, the Company uses an average of the available ratings by major credit agencies. December 31, 2018 AAA Split-rated AAA/AA+ AA+ to AA- A+ to A- BBB+ to BBB- BB+ and below Unrated Totals (in thousands) Held-to-maturity debt securities Tax-exempt $ — $ — $ — $ — $ — $ — $ 302,905 $ 302,905 Available-for-sale debt securities CDO $ — $ — $ — $ — $ — $ 15,327 $ — $ 15,327 Commercial MBS issued by GSEs — 100,106 — — — — — 100,106 Corporate debt securities — — — 66,515 32,865 — — 99,380 Private label residential MBS 887,520 — 34,342 343 947 1,442 — 924,594 Residential MBS issued by GSEs — 1,530,124 — — — — — 1,530,124 Tax-exempt 66,160 12,146 306,409 152,330 — — 1,623 538,668 Trust preferred securities — — — — 28,617 — — 28,617 U.S. government sponsored agency securities — 38,188 — — — — — 38,188 U.S. treasury securities — 1,984 — — — — — 1,984 Total AFS securities $ 953,680 $ 1,682,548 $ 340,751 $ 219,188 $ 62,429 $ 16,769 $ 1,623 $ 3,276,988 Equity securities CRA investments $ — $ 25,375 $ — $ — $ — $ — $ 25,767 $ 51,142 Preferred stock — — — — 45,771 3,693 14,455 63,919 Total equity securities $ — $ 25,375 $ — $ — $ 45,771 $ 3,693 $ 40,222 $ 115,061 (1) Where ratings differ, the Company uses an average of the available ratings by major credit agencies.
Gross Gains and (Losses) on Sales of Investment Securities	here were no gains and losses recognized on sales of these investment securities during the three and six months ended June 30, 2019 and June 30, 2018

Loans, Leases and Allowance f_2

Loans, Leases and Allowance for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 (in thousands) Commercial and industrial $ 8,454,161 $ 7,762,642 Commercial real estate - non-owner occupied 4,685,545 4,213,428 Commercial real estate - owner occupied 2,254,126 2,325,380 Construction and land development 2,210,355 2,134,753 Residential real estate 1,580,104 1,204,355 Consumer 65,959 70,071 Loans, net of deferred loan fees and costs 19,250,250 17,710,629 Allowance for credit losses (160,409 ) (152,717 ) Total loans HFI $ 19,089,841 $ 17,557,912
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: June 30, 2019 Current 30-59 Days 60-89 Days Over 90 Days Past Due Total Total (in thousands) Commercial and industrial $ 8,445,260 $ 555 $ 4,453 $ 3,893 $ 8,901 $ 8,454,161 Commercial real estate Owner occupied 2,252,389 1,097 640 — 1,737 2,254,126 Non-owner occupied 4,489,258 11,913 — — 11,913 4,501,171 Multi-family 184,374 — — — — 184,374 Construction and land development Construction 1,417,767 — — — — 1,417,767 Land 792,252 — 336 — 336 792,588 Residential real estate 1,567,204 7,539 159 5,202 12,900 1,580,104 Consumer 65,841 — — 118 118 65,959 Total loans $ 19,214,345 $ 21,104 $ 5,588 $ 9,213 $ 35,905 $ 19,250,250 December 31, 2018 Current 30-59 Days 60-89 Days Over 90 days Total Total (in thousands) Commercial and industrial $ 7,753,111 $ 3,187 $ 416 $ 5,928 $ 9,531 $ 7,762,642 Commercial real estate Owner occupied 2,320,321 4,441 — 618 5,059 2,325,380 Non-owner occupied 4,051,837 — — — — 4,051,837 Multi-family 161,591 — — — — 161,591 Construction and land development Construction 1,382,664 — — — — 1,382,664 Land 751,613 — 476 — 476 752,089 Residential real estate 1,182,933 9,316 4,010 8,096 21,422 1,204,355 Consumer 69,830 — — 241 241 70,071 Total loans $ 17,673,900 $ 16,944 $ 4,902 $ 14,883 $ 36,729 $ 17,710,629
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: June 30, 2019 December 31, 2018 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 and industrial $ 4,873 $ 8,295 $ 13,168 $ — $ 7,639 $ 7,451 $ 15,090 $ — Commercial real estate Owner occupied 8,539 640 9,179 — — — — 594 Non-owner occupied 7,508 11,913 19,421 — — — — — Multi-family — — — — — — — — Construction and land development Construction 2,277 — 2,277 — — 476 476 — Land — — — — — — — — Residential real estate 2,393 5,259 7,652 — 552 11,387 11,939 — Consumer 10 118 128 — — 241 241 — Total $ 25,600 $ 26,225 $ 51,825 $ — $ 8,191 $ 19,555 $ 27,746 $ 594
Loans by Risk Rating	The following tables present gross loans by risk rating: June 30, 2019 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial and industrial $ 8,328,754 $ 62,078 $ 62,978 $ 351 $ — $ 8,454,161 Commercial real estate Owner occupied 2,162,788 29,932 61,406 — — 2,254,126 Non-owner occupied 4,400,274 70,157 30,740 — — 4,501,171 Multi-family 184,374 — — — — 184,374 Construction and land development Construction 1,365,231 33,237 19,299 — — 1,417,767 Land 790,004 2,570 14 — — 792,588 Residential real estate 1,571,753 — 8,351 — — 1,580,104 Consumer 65,809 22 128 — — 65,959 Total $ 18,868,987 $ 197,996 $ 182,916 $ 351 $ — $ 19,250,250 June 30, 2019 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 18,860,678 $ 196,966 $ 156,701 $ — $ — $ 19,214,345 Past due 30 - 59 days 7,539 980 12,585 — — 21,104 Past due 60 - 89 days 439 50 4,840 259 — 5,588 Past due 90 days or more 331 — 8,790 92 — 9,213 Total $ 18,868,987 $ 197,996 $ 182,916 $ 351 $ — $ 19,250,250 December 31, 2018 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Commercial and industrial $ 7,574,506 $ 61,202 $ 126,356 $ 578 $ — $ 7,762,642 Commercial real estate Owner occupied 2,255,513 12,860 57,007 — — 2,325,380 Non-owner occupied 4,030,350 12,982 8,505 — — 4,051,837 Multi-family 161,591 — — — — 161,591 Construction and land development Construction 1,378,624 1,210 2,830 — — 1,382,664 Land 751,012 — 1,077 — — 752,089 Residential real estate 1,191,571 527 12,257 — — 1,204,355 Consumer 69,755 75 241 — — 70,071 Total $ 17,412,922 $ 88,856 $ 208,273 $ 578 $ — $ 17,710,629 December 31, 2018 Pass Special Mention Substandard Doubtful Loss Total (in thousands) Current (up to 29 days past due) $ 17,400,616 $ 87,264 $ 186,020 $ — $ — $ 17,673,900 Past due 30 - 59 days 11,255 1,580 4,109 — — 16,944 Past due 60 - 89 days 719 12 3,767 404 — 4,902 Past due 90 days or more 332 — 14,377 174 — 14,883 Total $ 17,412,922 $ 88,856 $ 208,273 $ 578 $ — $ 17,710,629
Impaired Loans by Loan Class	The following table presents impaired loans by class: June 30, 2019 December 31, 2018 (in thousands) Commercial and industrial $ 33,700 $ 63,896 Commercial real estate Owner occupied 20,663 6,530 Non-owner occupied 30,029 12,407 Multi-family — — Construction and land development Construction 19,299 — Land 7,622 9,403 Residential real estate 14,963 19,744 Consumer 155 272 Total $ 126,431 $ 112,252
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Average balance on impaired loans $ 113,346 $ 104,403 $ 119,979 $ 98,743 Interest income recognized on impaired loans 1,201 1,122 2,694 1,995 The table below reflects the recorded investment in loans classified as impaired: June 30, 2019 December 31, 2018 (in thousands) Impaired loans with a specific valuation allowance under ASC 310 (1) $ 6,090 $ 986 Impaired loans without a specific valuation allowance under ASC 310 (2) 120,341 111,266 Total impaired loans $ 126,431 $ 112,252 Valuation allowance related to impaired loans $ (1,854 ) $ (681 ) (1) Includes no TDR loans at June 30, 2019 and December 31, 2018 . (2) Includes TDR loans of $61.7 million and $44.5 million at June 30, 2019 and December 31, 2018 , respectively.
Average Investment in Impaired Loans by Loan Class	The following table presents the average investment in impaired loans by loan class: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Commercial and industrial $ 40,367 $ 49,373 $ 53,755 $ 43,111 Commercial real estate Owner occupied 11,848 8,417 9,708 8,730 Non-owner occupied 17,826 17,524 15,068 18,225 Multi-family — — — — Construction and land development Construction 19,970 — 16,210 — Land 7,935 9,603 8,284 9,942 Residential real estate 15,252 19,109 16,766 18,454 Consumer 148 377 188 281 Total $ 113,346 $ 104,403 $ 119,979 $ 98,743
Interest Income on Impaired Loans by Loan Class	The following table presents interest income on impaired loans by class: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Commercial and industrial $ 386 $ 489 $ 1,154 $ 739 Commercial real estate Owner occupied 154 131 276 258 Non-owner occupied 169 265 356 526 Multi-family — — — — Construction and land development Construction 272 — 452 — Land 121 149 250 279 Residential real estate 99 88 205 192 Consumer — — 1 1 Total $ 1,201 $ 1,122 $ 2,694 $ 1,995
Tabular Disclosure of Nonperforming Assets	The following table summarizes nonperforming assets: June 30, 2019 December 31, 2018 (in thousands) Non-accrual loans (1) $ 51,825 $ 27,746 Loans past due 90 days or more on accrual status — 594 Accruing troubled debt restructured loans 52,200 36,458 Total nonperforming loans 104,025 64,798 Other assets acquired through foreclosure, net 17,707 17,924 Total nonperforming assets $ 121,732 $ 82,722 (1) Includes non-accrual TDR loans of $9.5 million and $8.0 million at June 30, 2019 and December 31, 2018 , respectively.
Accretable Yield Table	Changes in the accretable yield for loans acquired with deteriorated credit quality are as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Balance, at beginning of period $ 3,137 $ 8,108 $ 3,768 $ 9,324 Reclassifications from non-accretable to accretable yield (1) — — — 683 Accretion to interest income (142 ) (264 ) (302 ) (578 ) Reversal of fair value adjustments upon disposition of loans (17 ) (3,016 ) (488 ) (4,601 ) Balance, at end of period $ 2,978 $ 4,828 $ 2,978 $ 4,828 (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 summarizes the changes in the allowance for credit losses by portfolio type: Three Months Ended June 30, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2019 Beginning Balance $ 26,083 $ 37,867 $ 13,006 $ 77,254 $ 777 $ 154,987 Charge-offs 141 — 397 2,018 — 2,556 Recoveries (9 ) (439 ) (27 ) (495 ) (8 ) (978 ) Provision 140 2,952 (30 ) 3,904 34 7,000 Ending balance $ 26,091 $ 41,258 $ 12,606 $ 79,635 $ 819 $ 160,409 2018 Beginning Balance $ 22,594 $ 32,868 $ 5,519 $ 82,878 $ 800 $ 144,659 Charge-offs 1 233 885 2,777 5 3,901 Recoveries (8 ) (246 ) (141 ) (916 ) (14 ) (1,325 ) Provision (442 ) (902 ) 2,074 4,227 43 5,000 Ending balance $ 22,159 $ 31,979 $ 6,849 $ 85,244 $ 852 $ 147,083 Six Months Ended June 30, Construction and Land Development Commercial Real Estate Residential Real Estate Commercial and Industrial Consumer Total (in thousands) 2019 Beginning Balance $ 22,513 $ 34,829 $ 11,276 $ 83,118 $ 981 $ 152,717 Charge-offs 141 — 585 4,142 1 4,869 Recoveries (64 ) (892 ) (120 ) (972 ) (13 ) (2,061 ) Provision 3,655 5,537 1,795 (313 ) (174 ) 10,500 Ending balance $ 26,091 $ 41,258 $ 12,606 $ 79,635 $ 819 $ 160,409 2018 Beginning Balance $ 19,511 $ 31,495 $ 5,478 $ 82,793 $ 773 $ 140,050 Charge-offs 1 233 992 6,295 5 7,526 Recoveries (1,397 ) (371 ) (390 ) (1,376 ) (25 ) (3,559 ) Provision 1,252 346 1,973 7,370 59 11,000 Ending balance $ 22,159 $ 31,979 $ 6,849 $ 85,244 $ 852 $ 147,083 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 Consumer Total Loans (in thousands) Loans as of June 30, 2019; Recorded Investment Impaired loans with an allowance recorded $ 791 $ — $ 1,692 $ 1,321 $ 2,277 $ 9 $ 6,090 Impaired loans with no allowance recorded 19,872 30,029 32,008 13,642 24,644 146 120,341 Total loans individually evaluated for impairment 20,663 30,029 33,700 14,963 26,921 155 126,431 Loans collectively evaluated for impairment 2,229,604 4,597,036 8,420,461 1,565,122 2,183,434 65,804 19,061,461 Loans acquired with deteriorated credit quality 3,859 58,480 — 19 — — 62,358 Total recorded investment $ 2,254,126 $ 4,685,545 $ 8,454,161 $ 1,580,104 $ 2,210,355 $ 65,959 $ 19,250,250 Unpaid Principal Balance Impaired loans with an allowance recorded $ 791 $ — $ 1,721 $ 1,321 $ 2,322 $ 9 $ 6,164 Impaired loans with no allowance recorded 20,619 30,953 37,427 16,597 25,262 175 131,033 Total loans individually evaluated for impairment 21,410 30,953 39,148 17,918 27,584 184 137,197 Loans collectively evaluated for impairment 2,230,441 4,613,466 8,390,353 1,554,316 2,204,253 66,170 19,058,999 Loans acquired with deteriorated credit quality 5,124 70,437 — 72 — — 75,633 Total unpaid principal balance $ 2,256,975 $ 4,714,856 $ 8,429,501 $ 1,572,306 $ 2,231,837 $ 66,354 $ 19,271,829 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ 157 $ — $ 603 $ 275 $ 810 $ 9 $ 1,854 Impaired loans with no allowance recorded — — — — — — — Total loans individually evaluated for impairment 157 — 603 275 810 9 1,854 Loans collectively evaluated for impairment 14,615 26,389 79,030 12,331 25,281 810 158,456 Loans acquired with deteriorated credit quality — 97 2 — — — 99 Total allowance for credit losses $ 14,772 $ 26,486 $ 79,635 $ 12,606 $ 26,091 $ 819 $ 160,409 Commercial Real Estate-Owner Occupied Commercial Real Estate-Non-Owner Occupied Commercial and Industrial Residential Real Estate Construction and Land Development Consumer Total Loans (in thousands) Loans as of December 31, 2018; Recorded Investment Impaired loans with an allowance recorded $ — $ — $ 623 $ 363 $ — $ — $ 986 Impaired loans with no allowance recorded 6,530 12,407 63,273 19,381 9,403 272 111,266 Total loans individually evaluated for impairment 6,530 12,407 63,896 19,744 9,403 272 112,252 Loans collectively evaluated for impairment 2,314,871 4,121,464 7,698,746 1,184,592 2,125,350 69,799 17,514,822 Loans acquired with deteriorated credit quality 3,979 79,557 — 19 — — 83,555 Total recorded investment $ 2,325,380 $ 4,213,428 $ 7,762,642 $ 1,204,355 $ 2,134,753 $ 70,071 $ 17,710,629 Unpaid Principal Balance Impaired loans with an allowance recorded $ — $ — $ 1,482 $ 363 $ — $ — $ 1,845 Impaired loans with no allowance recorded 11,852 18,155 103,992 27,979 25,624 10,632 198,234 Total loans individually evaluated for impairment 11,852 18,155 105,474 28,342 25,624 10,632 200,079 Loans collectively evaluated for impairment 2,314,871 4,121,464 7,698,746 1,184,592 2,125,350 69,799 17,514,822 Loans acquired with deteriorated credit quality 5,315 95,680 4,352 72 — — 105,419 Total unpaid principal balance $ 2,332,038 $ 4,235,299 $ 7,808,572 $ 1,213,006 $ 2,150,974 $ 80,431 $ 17,820,320 Related Allowance for Credit Losses Impaired loans with an allowance recorded $ — $ — $ 621 $ 60 $ — $ — $ 681 Impaired loans with no allowance recorded — — — — — — — Total loans individually evaluated for impairment — — 621 60 — — 681 Loans collectively evaluated for impairment 14,286 20,456 82,488 11,216 22,513 981 151,940 Loans acquired with deteriorated credit quality — 87 9 — — — 96 Total allowance for credit losses $ 14,286 $ 20,543 $ 83,118 $ 11,276 $ 22,513 $ 981 $ 152,717

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following is a schedule of the Company's operating lease liabilities by contractual maturity as of June 30, 2019 : (in thousands) 2019 $ 6,018 2020 11,297 2021 9,243 2022 8,049 2023 8,068 Thereafter 46,320 Total lease payments $ 88,995 Less: imputed interest 12,804 Total present value of lease liabilities $ 76,191
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Lease Obligations as of December 31, 2018 As previously disclosed in the Company's Annual Report on Form 10-K as of and for the year ended December 31, 2018 , the following is a schedule of future minimum rental payments under its non-cancelable operating leases, expiring through 2030: (in thousands) 2019 $ 11,370 2020 10,322 2021 7,418 2022 6,294 2023 6,070 Thereafter 15,417 Total future minimum rental payments $ 56,891

Other Borrowings (Tables)

Other Borrowings (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Company's Borrowings	The following table summarizes the Company’s borrowings as of June 30, 2019 and December 31, 2018 : June 30, 2019 December 31, 2018 (in thousands) Short-Term: Federal funds purchased $ — $ 256,000 FHLB advances — 235,000 Total short-term borrowings $ — $ 491,000

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2019
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: Three Months Ended June 30, Unrealized holding (losses) gains on AFS Unrealized holding gains (losses) on SERP Unrealized holding gains (losses) on junior subordinated debt Impairment loss on securities Total (in thousands) Balance, March 31, 2019 $ (16,214 ) $ 374 $ 7,505 $ 144 $ (8,191 ) Other comprehensive income (loss) before reclassifications 35,923 (17 ) (1,334 ) — 34,572 Amounts reclassified from AOCI — — — — — Net current-period other comprehensive income (loss) 35,923 (17 ) (1,334 ) — 34,572 Balance, June 30, 2019 $ 19,709 $ 357 $ 6,171 $ 144 $ 26,381 Balance, March 31, 2018 $ (51,470 ) $ 458 $ 9,206 $ 144 $ (41,662 ) Other comprehensive (loss) income before reclassifications (10,389 ) (12 ) 748 — (9,653 ) Amounts reclassified from AOCI — — — — — Net current-period other comprehensive (loss) income (10,389 ) (12 ) 748 — (9,653 ) Balance, June 30, 2018 $ (61,859 ) $ 446 $ 9,954 $ 144 $ (51,315 ) Six Months Ended June 30, 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, 2018 $ (47,591 ) $ 392 $ 13,433 $ 144 $ (33,622 ) Other comprehensive (loss) income before reclassifications 67,300 (35 ) (7,262 ) — 60,003 Amounts reclassified from AOCI — — — — — Net current-period other comprehensive (loss) income 67,300 (35 ) (7,262 ) — 60,003 Balance, June 30, 2019 $ 19,709 $ 357 $ 6,171 $ 144 $ 26,381 Balance, December 31, 2017 $ (10,026 ) $ 385 $ 6,352 $ 144 $ (3,145 ) Balance, January 1, 2018 (1) (12,556 ) 469 7,740 144 (4,203 ) Other comprehensive income (loss) before reclassifications (49,303 ) (23 ) 2,214 — (47,112 ) Amounts reclassified from AOCI — — — — — Net current-period other comprehensive income (loss) (49,303 ) (23 ) 2,214 — (47,112 ) Balance, June 30, 2018 $ (61,859 ) $ 446 $ 9,954 $ 144 $ (51,315 ) (1) As adjusted for adoption of ASU 2016-01 and ASU 2018-02. The cumulative effect of adoption of this guidance at January 1, 2018 resulted in an increase to retained earnings of $1.1 million and a corresponding decrease to accumulated other comprehensive income.
Schedule of Reclassifications Out of Accumulated Other Comprehensive Income	-02. The cumulative effect of adoption of this guidance at

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 June 30, 2018 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 $ 958,298 $ 1,436 $ 62,754 $ 965,705 $ 2,162 $ 44,892 $ 986,867 $ 4,435 $ 41,015 Total 958,298 1,436 62,754 965,705 2,162 44,892 986,867 4,435 41,015 Netting adjustments (1) — 163 163 — 2,162 2,162 — 3,838 3,838 Net derivatives in the balance sheet $ 958,298 $ 1,273 $ 62,591 $ 965,705 $ — $ 42,730 $ 986,867 $ 597 $ 37,177 Derivatives not designated as hedging instruments: Foreign currency contracts $ 25,151 $ 263 $ 147 $ 49,690 $ 454 $ 201 $ 70,190 $ 1,274 $ 1,056 Interest rate swaps 2,348 83 83 2,378 27 27 1,763 74 74 Total $ 27,499 $ 346 $ 230 $ 52,068 $ 481 $ 228 $ 71,953 $ 1,348 $ 1,130 (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.
Largest Exposure To Individual Counterparty	The following table summarizes the Company's largest exposure to an individual counterparty at the dates indicated: June 30, 2019 December 31, 2018 June 30, 2018 (in thousands) Largest gross exposure (derivative asset) to an individual counterparty $ 1,273 $ 1,411 $ 2,910 Collateral posted by this counterparty 1,100 — — Derivative liability with this counterparty — 23,906 16,809 Collateral pledged to this counterparty — 25,761 24,001 Net exposure after netting adjustments and collateral $ 173 $ — $ —

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands, except per share amounts) Weighted average shares - basic 103,019 104,691 103,523 104,611 Dilutive effect of stock awards 482 729 462 761 Weighted average shares - diluted 103,501 105,420 103,985 105,372 Net income $ 122,936 $ 104,679 $ 243,732 $ 205,579 Earnings per share - basic 1.19 1.00 2.35 1.97 Earnings per share - diluted 1.19 0.99 2.34 1.95

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 (in thousands) Commitments to extend credit, including unsecured loan commitments of $900,291 at June 30, 2019 and $770,114 at December 31, 2018 $ 8,528,133 $ 7,556,741 Credit card commitments and financial guarantees 268,439 237,312 Letters of credit, including unsecured letters of credit of $16,225 at June 30, 2019 and $21,879 at December 31, 2018 285,266 390,161 Total $ 9,081,838 $ 8,184,214

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations	For the three and six months ended June 30, 2019 and 2018 , unrealized gains and losses from fair value changes on junior subordinated debt were as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) (in thousands) Unrealized gains/(losses) $ (1,769 ) $ 992 $ (9,631 ) $ 2,936 Changes included in OCI, net of tax (1,334 ) 748 (7,262 ) 2,214
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) June 30, 2019 Assets: Available-for-sale debt securities CDO $ — $ 15,026 $ — $ 15,026 Commercial MBS issued by GSEs — 100,841 — 100,841 Corporate debt securities 5,145 93,183 — 98,328 Municipal securities — 7,753 — 7,753 Private label residential MBS — 949,762 — 949,762 Residential MBS issued by GSEs — 1,453,316 — 1,453,316 Tax-exempt — 561,730 — 561,730 Trust preferred securities 24,939 — — 24,939 U.S. government sponsored agency securities — 39,905 — 39,905 U.S. treasury securities — 1,494 — 1,494 Total AFS debt securities $ 30,084 $ 3,223,010 $ — $ 3,253,094 Equity securities CRA investments $ 52,141 $ — $ — $ 52,141 Preferred stock 62,548 — — 62,548 Total equity securities $ 114,689 $ — $ — $ 114,689 Derivative assets (1) $ — $ 1,782 $ — $ 1,782 Liabilities: Junior subordinated debt (2) $ — $ — $ 58,315 $ 58,315 Derivative liabilities (1) — 62,984 — 62,984 (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 $58,355 and the net carrying value of subordinated debt is decreased by $2,963 as of June 30, 2019 for the effective portion of the hedge, which relates to the fair value 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 Significant Other Observable Inputs Significant Unobservable Inputs Fair Value (in thousands) December 31, 2018 Assets: Available-for-sale debt securities CDO $ — $ 15,327 $ — $ 15,327 Commercial MBS issued by GSEs — 100,106 — 100,106 Corporate debt securities — 99,380 — 99,380 Private label residential MBS — 924,594 — 924,594 Residential MBS issued by GSEs — 1,530,124 — 1,530,124 Tax-exempt — 538,668 — 538,668 Trust preferred securities — 28,617 — 28,617 U.S. government sponsored agency securities — 38,188 — 38,188 U.S. treasury securities — 1,984 — 1,984 Total AFS debt securities $ — $ 3,276,988 $ — $ 3,276,988 Equity securities CRA investments $ 51,142 $ — $ — $ 51,142 Preferred stock 63,919 — — 63,919 Total equity securities $ 115,061 $ — $ — $ 115,061 Derivative assets (1) $ — $ 2,643 $ — $ 2,643 Liabilities: Junior subordinated debt (2) $ — $ — $ 48,684 $ 48,684 Derivative liabilities (1) — 45,120 — 45,120 (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 $23,039 and the net carrying value of subordinated debt is decreased by $19,691 as of December 31, 2018 for the effective portion of the hedge, which relates to the fair value 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.
Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis	For the three and six months ended June 30, 2019 and 2018 , the change in Level 3 liabilities measured at fair value on a recurring basis was as follows: Junior Subordinated Debt Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in thousands) Beginning balance $ (56,546 ) $ (54,290 ) $ (48,684 ) $ (56,234 ) Change in fair value (1) (1,769 ) 992 (9,631 ) 2,936 Ending balance $ (58,315 ) $ (53,298 ) $ (58,315 ) $ (53,298 )
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 June 30, 2019; Impaired loans with specific valuation allowance $ 4,236 $ — $ — $ 4,236 Impaired loans without specific valuation allowance (1) 108,090 — — 108,090 Other assets acquired through foreclosure 17,707 — — 17,707 As of December 31, 2018: Impaired loans with specific valuation allowance $ 305 $ — $ — $ 305 Impaired loans without specific valuation allowance (1) 91,821 — — 91,821 Other assets acquired through foreclosure 17,924 — — 17,924 (1) Net of loan balances with charge-offs of $12.3 million and $19.4 million as of June 30, 2019 and December 31, 2018 , respectively.
Estimated Fair Value of Financial Instruments	The estimated fair value of the Company’s financial instruments is as follows: June 30, 2019 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Federal funds sold $ 90,000 $ — $ 90,000 $ — $ 90,000 Investment securities: HTM 435,997 — 466,858 — 466,858 AFS 3,253,094 30,084 3,223,010 — 3,253,094 Equity 114,689 114,689 — — 114,689 Derivative assets 1,782 — 1,782 — 1,782 Loans, net 19,089,841 — 18,427,885 112,326 18,540,211 Accrued interest receivable 105,469 — 105,469 — 105,469 Financial liabilities: Deposits $ 21,439,899 $ — $ 21,458,684 $ — $ 21,458,684 Customer repurchase agreements 13,921 — 13,921 — 13,921 Qualifying debt 387,232 — 333,430 69,937 403,367 Derivative liabilities 62,984 — 62,984 — 62,984 Accrued interest payable 21,956 — 21,956 — 21,956 December 31, 2018 Carrying Amount Fair Value Level 1 Level 2 Level 3 Total (in thousands) Financial assets: Investment securities: HTM $ 302,905 $ — $ 298,648 $ — $ 298,648 AFS 3,276,988 — 3,276,988 — 3,276,988 Equity securities 115,061 115,061 — — 115,061 Derivative assets 2,643 — 2,643 — 2,643 Loans, net 17,557,912 — 16,857,852 92,126 16,949,978 Accrued interest receivable 101,275 — 101,275 — 101,275 Financial liabilities: Deposits $ 19,177,447 $ — $ 19,188,216 $ — $ 19,188,216 Customer repurchase agreements 22,411 — 22,411 — 22,411 Other borrowings 491,000 — 491,000 — 491,000 Qualifying debt 360,458 — 323,572 57,924 381,496 Derivative liabilities 45,120 — 45,120 — 45,120 Accrued interest payable 20,463 — 20,463 — 20,463

Segments (Tables)

Segments (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Operating Segment Information	The following is a summary of operating segment information for the periods indicated: Regional Segments Balance Sheet: Consolidated Company Arizona Nevada Southern California Northern California At June 30, 2019 (in millions) Assets: Cash, cash equivalents, and investment securities $ 4,937.8 $ 1.8 $ 7.6 $ 2.1 $ 1.9 Loans, net of deferred loan fees and costs 19,250.3 3,937.0 2,095.2 2,256.7 1,195.4 Less: allowance for credit losses (160.4 ) (33.2 ) (18.1 ) (19.5 ) (9.2 ) Total loans 19,089.9 3,903.8 2,077.1 2,237.2 1,186.2 Other assets acquired through foreclosure, net 17.7 0.7 13.9 — — Goodwill and other intangible assets, net 298.4 — 23.2 — 155.1 Other assets 971.0 46.8 57.6 16.1 17.0 Total assets $ 25,314.8 $ 3,953.1 $ 2,179.4 $ 2,255.4 $ 1,360.2 Liabilities: Deposits $ 21,439.9 $ 6,107.0 $ 4,188.6 $ 2,535.9 $ 2,008.9 Borrowings and qualifying debt 387.2 — — — — Other liabilities 636.4 13.2 11.9 0.5 14.7 Total liabilities 22,463.5 6,120.2 4,200.5 2,536.4 2,023.6 Allocated equity: 2,851.3 484.6 286.0 255.6 297.5 Total liabilities and stockholders' equity $ 25,314.8 $ 6,604.8 $ 4,486.5 $ 2,792.0 $ 2,321.1 Excess funds provided (used) — 2,651.7 2,307.1 536.6 960.9 Income Statement: Three Months Ended June 30, 2019 (in thousands) Net interest income $ 254,681 $ 59,719 $ 39,528 $ 31,644 $ 23,996 Provision for (recovery of) credit losses 7,000 1,443 (305 ) 67 (152 ) Net interest income after provision for credit losses 247,681 58,276 39,833 31,577 24,148 Non-interest income 14,218 1,707 2,677 974 2,162 Non-interest expense (114,213 ) (22,693 ) (14,107 ) (15,122 ) (12,549 ) Income (loss) before income taxes 147,686 37,290 28,403 17,429 13,761 Income tax expense (benefit) 24,750 9,322 5,965 4,880 3,853 Net income $ 122,936 $ 27,968 $ 22,438 $ 12,549 $ 9,908 Six Months Ended June 30, 2019 (in thousands) Net interest income $ 502,017 $ 114,945 $ 78,626 $ 62,120 $ 47,029 Provision for (recovery of) credit losses 10,500 1,604 228 800 (871 ) Net interest income after provision for credit losses 491,517 113,341 78,398 61,320 47,900 Non-interest income 29,628 3,229 5,250 1,975 4,382 Non-interest expense (227,127 ) (44,943 ) (29,888 ) (29,704 ) (26,040 ) Income (loss) before income taxes 294,018 71,627 53,760 33,591 26,242 Income tax expense (benefit) 50,286 17,907 11,289 9,406 7,348 Net income $ 243,732 $ 53,720 $ 42,471 $ 24,185 $ 18,894 National Business Lines Balance Sheet: HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other At June 30, 2019 Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ 10.4 $ 4,914.0 Loans, net of deferred loan fees and costs 214.7 1,626.6 1,246.5 1,655.7 5,015.5 7.0 Less: allowance for credit losses (1.8 ) (14.8 ) (10.2 ) (10.3 ) (43.2 ) (0.1 ) Total loans 212.9 1,611.8 1,236.3 1,645.4 4,972.3 6.9 Other assets acquired through foreclosure, net — — — — — 3.1 Goodwill and other intangible assets, net — — 120.0 0.1 — — Other assets 0.9 17.1 6.9 7.7 63.8 737.1 Total assets $ 213.8 $ 1,628.9 $ 1,363.2 $ 1,653.2 $ 5,046.5 $ 5,661.1 Liabilities: Deposits $ 3,047.5 $ — $ 2,853.2 $ — $ 32.4 $ 666.4 Borrowings and qualifying debt — — — — — 387.2 Other liabilities 1.3 58.3 — (0.2 ) 92.3 444.4 Total liabilities 3,048.8 58.3 2,853.2 (0.2 ) 124.7 1,498.0 Allocated equity: 79.9 132.3 277.5 138.4 414.1 485.4 Total liabilities and stockholders' equity $ 3,128.7 $ 190.6 $ 3,130.7 $ 138.2 $ 538.8 $ 1,983.4 Excess funds provided (used) 2,914.9 (1,438.3 ) 1,767.5 (1,515.0 ) (4,507.7 ) (3,677.7 ) Income Statement: Three Months Ended June 30, 2019 (in thousands) Net interest income $ 21,905 $ 3,461 $ 28,536 $ 13,490 $ 29,586 $ 2,816 Provision for (recovery of) credit losses (7 ) 96 2,657 832 2,369 — Net interest income after provision for credit losses 21,912 3,365 25,879 12,658 27,217 2,816 Non-interest income 88 — 2,163 — 1,549 2,898 Non-interest expense (9,549 ) (1,931 ) (10,015 ) (2,162 ) (11,073 ) (15,012 ) Income (loss) before income taxes 12,451 1,434 18,027 10,496 17,693 (9,298 ) Income tax expense (benefit) 2,864 330 4,146 2,414 4,069 (13,093 ) Net income $ 9,587 $ 1,104 $ 13,881 $ 8,082 $ 13,624 $ 3,795 Six Months Ended June 30, 2019 (in thousands) Net interest income $ 42,546 $ 6,884 $ 57,939 $ 26,434 $ 55,277 $ 10,217 Provision for (recovery of) credit losses (33 ) 55 1,739 1,631 5,347 — Net interest income after provision for credit losses 42,579 6,829 56,200 24,803 49,930 10,217 Non-interest income 184 — 5,525 — 2,207 6,876 Non-interest expense (18,008 ) (3,838 ) (21,903 ) (4,560 ) (20,409 ) (27,834 ) Income (loss) before income taxes 24,755 2,991 39,822 20,243 31,728 (10,741 ) Income tax expense (benefit) 5,694 688 9,159 4,656 7,297 (23,158 ) Net income $ 19,061 $ 2,303 $ 30,663 $ 15,587 $ 24,431 $ 12,417 Regional Segments Consolidated Company Arizona Nevada Southern California Northern California At December 31, 2018 (in millions) Assets: Cash, cash equivalents, and investment securities $ 4,259.7 $ 2.5 $ 10.9 $ 2.5 $ 3.0 Loans, net of deferred loan fees and costs 17,710.6 3,647.9 2,003.5 2,161.1 1,300.2 Less: allowance for credit losses (152.7 ) (30.7 ) (18.7 ) (19.8 ) (10.7 ) Total loans 17,557.9 3,617.2 1,984.8 2,141.3 1,289.5 Other assets acquired through foreclosure, net 17.9 0.8 13.9 — — Goodwill and other intangible assets, net 299.2 — 23.2 — 155.5 Other assets 974.8 46.9 57.8 14.2 23.9 Total assets $ 23,109.5 $ 3,667.4 $ 2,090.6 $ 2,158.0 $ 1,471.9 Liabilities: Deposits $ 19,177.4 $ 5,090.2 $ 3,996.4 $ 2,347.5 $ 1,839.1 Borrowings and qualifying debt 851.5 — — — — Other liabilities 466.9 10.4 14.5 4.5 12.2 Total liabilities 20,495.8 5,100.6 4,010.9 2,352.0 1,851.3 Allocated equity: 2,613.7 441.0 277.4 242.9 304.1 Total liabilities and stockholders' equity $ 23,109.5 $ 5,541.6 $ 4,288.3 $ 2,594.9 $ 2,155.4 Excess funds provided (used) — 1,874.2 2,197.7 436.9 683.5 Income Statement: Three Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 224,108 $ 57,977 $ 35,276 $ 27,664 $ 23,001 Provision for (recovery of) credit losses 5,000 518 (243 ) (276 ) 13 Net interest income (expense) after provision for credit losses 219,108 57,459 35,519 27,940 22,988 Non-interest income 13,444 2,256 2,679 966 2,421 Non-interest expense (102,548 ) (22,419 ) (15,931 ) (14,491 ) (13,429 ) Income (loss) before income taxes 130,004 37,296 22,267 14,415 11,980 Income tax expense (benefit) 25,325 9,324 4,676 4,036 3,355 Net income $ 104,679 $ 27,972 $ 17,591 $ 10,379 $ 8,625 Six Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 438,328 $ 112,532 $ 71,966 $ 55,466 $ 45,256 Provision for (recovery of) credit losses 11,000 1,952 (1,967 ) 454 1,561 Net interest income (expense) after provision for credit losses 427,328 110,580 73,933 55,012 43,695 Non-interest income 25,087 3,672 6,012 1,967 4,969 Non-interest expense (200,697 ) (43,923 ) (30,015 ) (28,137 ) (25,932 ) Income (loss) before income taxes 251,718 70,329 49,930 28,842 22,732 Income tax expense (benefit) 46,139 17,645 10,579 8,171 6,452 Net income $ 205,579 $ 52,684 $ 39,351 $ 20,671 $ 16,280 National Business Lines HOA Public & Nonprofit Finance Technology & Innovation Hotel Franchise Finance Other NBLs Corporate & Other At December 31, 2018 Assets: (in millions) Cash, cash equivalents, and investment securities $ — $ — $ — $ — $ — $ 4,240.8 Loans, net of deferred loan fees and costs 210.0 1,547.5 1,200.9 1,479.9 4,154.9 4.7 Less: allowance for credit losses (1.9 ) (14.2 ) (10.0 ) (8.5 ) (38.2 ) — Total loans 208.1 1,533.3 1,190.9 1,471.4 4,116.7 4.7 Other assets acquired through foreclosure, net — — — — — 3.2 Goodwill and other intangible assets, net — — 120.4 0.1 — — Other assets 0.9 20.1 6.3 7.2 37.1 760.4 Total assets $ 209.0 $ 1,553.4 $ 1,317.6 $ 1,478.7 $ 4,153.8 $ 5,009.1 Liabilities: Deposits $ 2,607.2 $ — $ 2,559.0 $ — $ — $ 738.0 Borrowings and qualifying debt — — — — — 851.5 Other liabilities 2.1 25.2 0.1 0.4 49.6 347.9 Total liabilities 2,609.3 25.2 2,559.1 0.4 49.6 1,937.4 Allocated equity: 70.7 123.9 268.7 122.3 340.0 422.7 Total liabilities and stockholders' equity $ 2,680.0 $ 149.1 $ 2,827.8 $ 122.7 $ 389.6 $ 2,360.1 Excess funds provided (used) 2,471.0 (1,404.3 ) 1,510.2 (1,356.0 ) (3,764.2 ) (2,649.0 ) Income Statement: Three Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 16,046 $ 3,794 $ 24,562 $ 13,874 $ 19,672 $ 2,242 Provision for (recovery of) credit losses 135 (27 ) 2,256 548 2,074 2 Net interest income (expense) after provision for credit losses 15,911 3,821 22,306 13,326 17,598 2,240 Non-interest income 179 — 3,630 — 409 904 Non-interest expense (8,033 ) (2,080 ) (9,899 ) (2,200 ) (6,250 ) (7,816 ) Income (loss) before income taxes 8,057 1,741 16,037 11,126 11,757 (4,672 ) Income tax expense (benefit) 1,853 401 3,688 2,559 2,704 (7,271 ) Net income $ 6,204 $ 1,340 $ 12,349 $ 8,567 $ 9,053 $ 2,599 Six Months Ended June 30, 2018 (in thousands) Net interest income (expense) $ 31,405 $ 7,539 $ 47,383 $ 28,060 $ 38,484 $ 237 Provision for (recovery of) credit losses 182 (233 ) 3,907 1,783 3,359 2 Net interest income (expense) after provision for credit losses 31,223 7,772 43,476 26,277 35,125 235 Non-interest income 328 — 6,681 13 633 812 Non-interest expense (15,836 ) (4,254 ) (19,733 ) (4,405 ) (11,912 ) (16,550 ) Income (loss) before income taxes 15,715 3,518 30,424 21,885 23,846 (15,503 ) Income tax expense (benefit) 3,615 809 6,998 5,033 5,484 (18,647 ) Net income $ 12,100 $ 2,709 $ 23,426 $ 16,852 $ 18,362 $ 3,144

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)Subsidiary	Dec. 31, 2018USD ($)
Significant Of Accounting Policies [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018 | $	$ 3,253,094	$ 3,276,988
Number Of Wholly Owned Subsidiaries Non Bank Subsidiaries	2
Number Of Unconsolidated Subsidiaries	8

Investment Securities - Carryin

Investment Securities - Carrying Amounts and Fair Values of Investment Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	$ 114,689	$ 115,061
Debt Securities, Held-to-maturity	435,997	302,905
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	30,861	3,163
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	(7,420)
Debt Securities, Held-to-maturity, Fair Value	466,858	298,648
Securities available for sale Total, Amortized Cost	3,226,756	3,339,888
Securities available-for-sale, Gross Unrealized Gains	52,133	22,054
Securities available-for-sale, Gross Unrealized (Losses)	(25,795)	(84,954)
Securities available for sale Total, Estimated Fair Value	3,253,094	3,276,988
Equity Securities, FV-NI, Cost	113,387	118,164
Equity Securities, FV-NI, Unrealized Gain	1,964	148
Equity Securities, FV-NI, Unrealized Loss	662	3,251
Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	50	50
Securities available-for-sale, Gross Unrealized Gains	14,976	15,277
Securities available-for-sale, Gross Unrealized (Losses)	0	0
Securities available for sale Total, Estimated Fair Value	15,026	15,327
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	102,444	106,385
Securities available-for-sale, Gross Unrealized Gains	758	82
Securities available-for-sale, Gross Unrealized (Losses)	(2,361)	(6,361)
Securities available for sale Total, Estimated Fair Value	100,841	100,106
Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	105,022	105,029
Securities available-for-sale, Gross Unrealized Gains	123	0
Securities available-for-sale, Gross Unrealized (Losses)	(6,817)	(5,649)
Securities available for sale Total, Estimated Fair Value	98,328	99,380
Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	7,488
Securities available-for-sale, Gross Unrealized Gains	265
Securities available-for-sale, Gross Unrealized (Losses)	0
Securities available for sale Total, Estimated Fair Value	7,753
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	949,699	948,161
Securities available-for-sale, Gross Unrealized Gains	5,605	945
Securities available-for-sale, Gross Unrealized (Losses)	(5,542)	(24,512)
Securities available for sale Total, Estimated Fair Value	949,762	924,594
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	1,446,679	1,564,181
Securities available-for-sale, Gross Unrealized Gains	10,381	1,415
Securities available-for-sale, Gross Unrealized (Losses)	(3,744)	(35,472)
Securities available for sale Total, Estimated Fair Value	1,453,316	1,530,124
Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	541,879	542,086
Securities available-for-sale, Gross Unrealized Gains	20,023	4,335
Securities available-for-sale, Gross Unrealized (Losses)	(172)	(7,753)
Securities available for sale Total, Estimated Fair Value	561,730	538,668
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	32,000	32,000
Securities available-for-sale, Gross Unrealized Gains	0	0
Securities available-for-sale, Gross Unrealized (Losses)	(7,061)	(3,383)
Securities available for sale Total, Estimated Fair Value	24,939	28,617
US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	40,000	40,000
Securities available-for-sale, Gross Unrealized Gains	0	0
Securities available-for-sale, Gross Unrealized (Losses)	(95)	(1,812)
Securities available for sale Total, Estimated Fair Value	39,905	38,188
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Amortized Cost	1,495	1,996
Securities available-for-sale, Gross Unrealized Gains	2	0
Securities available-for-sale, Gross Unrealized (Losses)	(3)	(12)
Securities available for sale Total, Estimated Fair Value	1,494	1,984
CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	52,141	51,142
Equity Securities, FV-NI, Cost	52,516	52,210
Equity Securities, FV-NI, Unrealized Gain	0	0
Equity Securities, FV-NI, Unrealized Loss	375	1,068
Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	62,548	63,919
Equity Securities, FV-NI, Cost	60,871	65,954
Equity Securities, FV-NI, Unrealized Gain	1,964	148
Equity Securities, FV-NI, Unrealized Loss	287	2,183
AAA [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Securities available for sale Total, Estimated Fair Value	996,157	953,680
AAA [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
AAA [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	926,847	887,520
AAA [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	69,310
AAA [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AAA [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
AAA [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Split-rated AAA/AA Plus [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	25,375	25,375
Securities available for sale Total, Estimated Fair Value	1,604,478	1,682,548
Split-rated AAA/AA Plus [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	100,841	100,106
Split-rated AAA/AA Plus [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Split-rated AAA/AA Plus [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
Split-rated AAA/AA Plus [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Split-rated AAA/AA Plus [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	1,453,316	1,530,124
Split-rated AAA/AA Plus [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	8,922
Split-rated AAA/AA Plus [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Split-rated AAA/AA Plus [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	39,905	38,188
Split-rated AAA/AA Plus [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	1,494	1,984
Split-rated AAA/AA Plus [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	25,375	25,375
Split-rated AAA/AA Plus [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
AA Plus to AA- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Securities available for sale Total, Estimated Fair Value	329,717	340,751
AA Plus to AA- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
AA Plus to AA- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	20,454	34,342
AA Plus to AA- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	309,263
AA Plus to AA- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
AA Plus to AA- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
AA Plus to AA- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
A Plus to A- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Securities available for sale Total, Estimated Fair Value	239,735	219,188
A Plus to A- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
A Plus to A- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	65,244	66,515
A Plus to A- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
A Plus to A- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	256	343
A Plus to A- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
A Plus to A- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	174,235
A Plus to A- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
A Plus to A- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
A Plus to A- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
A Plus to A- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
A Plus to A- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
BBB Plus to BBB- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	48,975	45,771
Securities available for sale Total, Estimated Fair Value	58,904	62,429
BBB Plus to BBB- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BBB Plus to BBB- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	33,084	32,865
BBB Plus to BBB- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
BBB Plus to BBB- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	881	947
BBB Plus to BBB- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BBB Plus to BBB- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
BBB Plus to BBB- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	24,939	28,617
BBB Plus to BBB- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BBB Plus to BBB- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BBB Plus to BBB- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
BBB Plus to BBB- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	48,975	45,771
BB Plus and below [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	4,030	3,693
Securities available for sale Total, Estimated Fair Value	16,350	16,769
BB Plus and below [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	15,026	15,327
BB Plus and below [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
BB Plus and below [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	1,324	1,442
BB Plus and below [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
BB Plus and below [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
BB Plus and below [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
BB Plus and below [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	4,030	3,693
Corporate Credit Quality Indicator Unrated [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	36,309	40,222
Securities available for sale Total, Estimated Fair Value	7,753	1,623
Corporate Credit Quality Indicator Unrated [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [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]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	7,753
Corporate Credit Quality Indicator Unrated [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0
Corporate Credit Quality Indicator Unrated [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Securities available for sale Total, Estimated Fair Value	0	0
Corporate Credit Quality Indicator Unrated [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	26,766	25,767
Corporate Credit Quality Indicator Unrated [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	$ 9,543	$ 14,455

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019USD ($)positions	Dec. 31, 2018USD ($)positions
Investment Identifier [Line Items]
Gain (Loss) on Sale of Investments	$ 0
Number Of Securities In Unrealized Position | positions	154	373
Amount of impairment losses reclassified out of accumulated other comprehensive income into earnings	$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	25,795,000	$ 84,954,000
Securities with carrying amounts were pledged	$ 886,300,000	$ 788,400,000

Investment Securities - Unreali

Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss					$ 3,868
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value					91,095
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss					3,552
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value					69,991
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain					7,420
Held-to-maturity Securities, Fair Value					161,086
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	$ 229		$ 229		10,114
Available-for-sale securities, Less Than Twelve Months, Fair Value	67,045		67,045		574,255
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	25,566		25,566		74,840
Available-for-sale securities, Twelve Months or Longer, Fair Value	1,149,873		1,149,873		2,086,619
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	25,795		25,795		84,954
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	1,216,918		1,216,918		2,660,874
Unrealized gains (losses) on assets measured at fair value, net	1,572	$ (685)	4,406	$ (1,759)
US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0		0		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	95		95		1,812
Available-for-sale securities, Twelve Months or Longer, Fair Value	34,905		34,905		38,188
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	95		95		1,812
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	34,905		34,905		38,188
Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		16
Available-for-sale securities, Less Than Twelve Months, Fair Value	0		0		5,013
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	6,817		6,817		5,633
Available-for-sale securities, Twelve Months or Longer, Fair Value	93,183		93,183		94,367
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	6,817		6,817		5,649
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	93,183		93,183		99,380
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	57		57		1,363
Available-for-sale securities, Less Than Twelve Months, Fair Value	17,116		17,116		141,493
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	3,687		3,687		34,109
Available-for-sale securities, Twelve Months or Longer, Fair Value	446,947		446,947		1,215,490
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	3,744		3,744		35,472
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	464,063		464,063		1,356,983
Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	172		172		3,562
Available-for-sale securities, Less Than Twelve Months, Fair Value	37,111		37,111		209,767
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0		0		4,191
Available-for-sale securities, Twelve Months or Longer, Fair Value	0		0		72,382
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	172		172		7,753
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	37,111		37,111		282,149
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		5,173
Available-for-sale securities, Less Than Twelve Months, Fair Value	12,818		12,818		217,982
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	5,542		5,542		19,339
Available-for-sale securities, Twelve Months or Longer, Fair Value	469,802		469,802		537,316
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	5,542		5,542		24,512
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	482,620		482,620		755,298
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0		0		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	7,061		7,061		3,383
Available-for-sale securities, Twelve Months or Longer, Fair Value	24,939		24,939		28,617
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	7,061		7,061		3,383
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	24,939		24,939		28,617
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0		0		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	2,361		2,361		6,361
Available-for-sale securities, Twelve Months or Longer, Fair Value	79,102		79,102		98,275
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	2,361		2,361		6,361
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	79,102		79,102		98,275
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0		0		0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0		0		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	3		3		12
Available-for-sale securities, Twelve Months or Longer, Fair Value	995		995		1,984
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	3		3		12
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 995		$ 995		$ 1,984

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Fair Value of Investment Securities by Contractual Maturities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost	$ 10,100
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value	10,139
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	24,940
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	25,714
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost	400,957
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	431,005
Debt Securities, Held-to-maturity	435,997	$ 302,905
Debt Securities, Held-to-maturity, Fair Value	466,858	298,648
Securities available for sale, Due in one year or less, Amortized Cost	3,781
Securities available for sale, After one year through five years, Amortized Cost	16,012
Securities available for sale, After five years through ten years, Amortized Cost	209,275
Securities available for sale, After ten years, Amortized Cost	498,866
Securities available for sale, Mortgage backed securities, Amortized Cost	2,498,822
Securities available for sale Total, Amortized Cost	3,226,756	3,339,888
Securities available for sale, Due in one year or less, Estimated Fair Value	3,789
Securities available for sale, After one year through five years, Estimated Fair Value	16,173
Securities available for sale, After five years through ten years, Estimated Fair Value	203,657
Securities available for sale, After ten years, Estimated Fair Value	525,556
Securities available for sale, Mortgage backed securities, Estimated Fair Value	2,503,919
Securities available for sale Total, Estimated Fair Value	$ 3,253,094	$ 3,276,988

Investment Securities - Investm

Investment Securities - Investment Securities by Credit Rating Type (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	$ 435,997	$ 302,905
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - equity	114,689	115,061
Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	435,997	302,905
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		538,668
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,453,316	1,530,124
Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	561,730	538,668
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	100,841	100,106
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	949,762	924,594
US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	39,905	38,188
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,494	1,984
Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	62,548	63,919
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	24,939	28,617
Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	15,026	15,327
Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	98,328	99,380
Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	7,753
CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	52,141	51,142
AAA [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	996,157	953,680
Investment securities - equity	0	0
AAA [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		66,160
AAA [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	69,310
AAA [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	926,847	887,520
AAA [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
AAA [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AAA [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
AAA [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Split-rated AAA/AA Plus [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,604,478	1,682,548
Investment securities - equity	25,375	25,375
Split-rated AAA/AA Plus [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		12,146
Split-rated AAA/AA Plus [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,453,316	1,530,124
Split-rated AAA/AA Plus [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	8,922
Split-rated AAA/AA Plus [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	100,841	100,106
Split-rated AAA/AA Plus [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Split-rated AAA/AA Plus [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	39,905	38,188
Split-rated AAA/AA Plus [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,494	1,984
Split-rated AAA/AA Plus [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Split-rated AAA/AA Plus [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Split-rated AAA/AA Plus [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Split-rated AAA/AA Plus [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Split-rated AAA/AA Plus [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
Split-rated AAA/AA Plus [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	25,375	25,375
AA Plus to AA- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	329,717	340,751
Investment securities - equity	0	0
AA Plus to AA- [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		306,409
AA Plus to AA- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	309,263
AA Plus to AA- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	20,454	34,342
AA Plus to AA- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
AA Plus to AA- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
AA Plus to AA- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
AA Plus to AA- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
A Plus to A- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	239,735	219,188
Investment securities - equity	0	0
A Plus to A- [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		152,330
A Plus to A- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	174,235
A Plus to A- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	256	343
A Plus to A- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
A Plus to A- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
A Plus to A- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	65,244	66,515
A Plus to A- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
A Plus to A- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
BBB Plus to BBB- [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	58,904	62,429
Investment securities - equity	48,975	45,771
BBB Plus to BBB- [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		0
BBB Plus to BBB- [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BBB Plus to BBB- [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
BBB Plus to BBB- [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BBB Plus to BBB- [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	881	947
BBB Plus to BBB- [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BBB Plus to BBB- [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BBB Plus to BBB- [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	48,975	45,771
BBB Plus to BBB- [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	24,939	28,617
BBB Plus to BBB- [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BBB Plus to BBB- [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	33,084	32,865
BBB Plus to BBB- [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
BBB Plus to BBB- [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
BB Plus and below [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	16,350	16,769
Investment securities - equity	4,030	3,693
BB Plus and below [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		0
BB Plus and below [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
BB Plus and below [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	1,324	1,442
BB Plus and below [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	4,030	3,693
BB Plus and below [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	15,026	15,327
BB Plus and below [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
BB Plus and below [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
BB Plus and below [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	0	0
Corporate Credit Quality Indicator Unrated [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	7,753	1,623
Investment securities - equity	36,309	40,222
Corporate Credit Quality Indicator Unrated [Member] | Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	435,997	302,905
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018		1,623
Corporate Credit Quality Indicator Unrated [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0
Corporate Credit Quality Indicator Unrated [Member] | Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Preferred Stock [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	9,543	14,455
Corporate Credit Quality Indicator Unrated [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Corporate Credit Quality Indicator Unrated [Member] | Taxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	7,753
Corporate Credit Quality Indicator Unrated [Member] | CRA investments [Member]
Debt Securities, Available-for-sale [Line Items]
Investment securities - equity	$ 26,766	$ 25,767

Investment Securities - Gross G

Investment Securities - Gross Gains and (Losses) on Sales of Investments (Detail)	3 Months Ended
	Jun. 30, 2019USD ($)
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity, Sold, Amount	$ 10,000,000
Debt Securities, Held-to-maturity, Sold, Realized Gain (Loss)	$ 0
Debt Securities, Held-to-maturity, Sold, Circumstance for Decision to Sell	The sale of this HTM security was made as a result of a significant change in the issuer’s creditworthiness, representative of a change in circumstance contemplated in ASC 320-10-25 that would not call into question the Company’s intent to hold other debt securities to maturity in the future. Accordingly, management concluded that the Company’s remaining HTM securities are appropriately classified as such as of June 30, 2019.

Loans, Leases and Allowance f_3

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	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Credit Mark on Acquired Loans	$ 10,600	$ 14,600
Net deferred loan fees and costs	(40,200)	(36,300)
Receivable with Imputed Interest, Discount	11,300	2,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield		3,768	$ 9,324
Loans, net of deferred loan fees and costs	19,250,250	17,710,629
Allowance for credit losses	(160,409)	(152,717)
Loans, net	19,089,841	17,557,912
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	8,454,161	7,762,642
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	4,685,545	4,213,428
Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	2,254,126	2,325,380
Allowance for credit losses	(14,772)	(14,286)
Construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	2,210,355	2,134,753
Allowance for credit losses	(26,091)	(22,513)
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	1,580,104	1,204,355
Allowance for credit losses	(12,606)	(11,276)
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, net of deferred loan fees and costs	65,959	70,071
Allowance for credit losses	$ (819)	$ (981)

Loans, Leases and Allowance f_4

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	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 19,214,345	$ 17,673,900
Past Due	35,905	36,729
Total	19,250,250	17,710,629
Financing Receivable, Recorded Investment, Nonaccrual Status	51,825	27,746
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	594
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,252,389	2,320,321
Past Due	1,737	5,059
Total	2,254,126	2,325,380
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	594
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4,489,258	4,051,837
Past Due	11,913	0
Total	4,501,171	4,051,837
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	184,374	161,591
Past Due	0	0
Total	184,374	161,591
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	8,445,260	7,753,111
Past Due	8,901	9,531
Total	8,454,161	7,762,642
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,417,767	1,382,664
Past Due	0	0
Total	1,417,767	1,382,664
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	792,252	751,613
Past Due	336	476
Total	792,588	752,089
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	1,567,204	1,182,933
Past Due	12,900	21,422
Total	1,580,104	1,204,355
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	65,841	69,830
Past Due	118	241
Total	65,959	70,071
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Non-accrual loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	25,600	8,191
Past Due	26,225	19,555
Financing Receivable, Recorded Investment, Nonaccrual Status	51,825	27,746
Non-accrual loans [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	8,539	0
Past Due	640	0
Financing Receivable, Recorded Investment, Nonaccrual Status	9,179	0
Non-accrual loans [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	7,508	0
Past Due	11,913	0
Financing Receivable, Recorded Investment, Nonaccrual Status	19,421	0
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]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4,873	7,639
Past Due	8,295	7,451
Financing Receivable, Recorded Investment, Nonaccrual Status	13,168	15,090
Non-accrual loans [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,277	0
Past Due	0	476
Financing Receivable, Recorded Investment, Nonaccrual Status	2,277	476
Non-accrual loans [Member] | Construction and land development [Member] | Land [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] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,393	552
Past Due	5,259	11,387
Financing Receivable, Recorded Investment, Nonaccrual Status	7,652	11,939
Non-accrual loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	10	0
Past Due	118	241
Financing Receivable, Recorded Investment, Nonaccrual Status	128	241
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	21,104	16,944
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	1,097	4,441
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	11,913	0
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]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	555	3,187
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	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,539	9,316
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,588	4,902
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	640	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	0
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]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,453	416
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	336	476
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	159	4,010
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	9,213	14,883
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	0	618
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	0	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]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,893	5,928
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	0	0
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	5,202	8,096
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 118	$ 241

Loans, Leases and Allowance f_5

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	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 500	$ 800	$ 600	$ 1,200
Total Past Due	35,905				$ 36,729
Total Non-accrual	51,825				27,746
Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,901				9,531
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,737				5,059
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,913				0
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0				0
Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0				0
Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	336				476
Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,900				21,422
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	118				241
Non-accrual loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	26,225				19,555
Total Non-accrual	51,825				27,746
Non-accrual loans [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,295				7,451
Total Non-accrual	13,168				15,090
Non-accrual loans [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	640				0
Total Non-accrual	9,179				0
Non-accrual loans [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,913				0
Total Non-accrual	19,421				0
Non-accrual loans [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0				0
Total Non-accrual	0				0
Non-accrual loans [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0				476
Total Non-accrual	2,277				476
Non-accrual loans [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0				0
Total Non-accrual	0				0
Non-accrual loans [Member] | Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,259				11,387
Total Non-accrual	7,652				11,939
Non-accrual loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	118				241
Total Non-accrual	$ 128				$ 241

Loans, Leases and Allowance f_6

Loans, Leases and Allowance for Credit Losses - Additional Information (Detail) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)SecurityLoan	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)SecurityLoan	Jun. 30, 2019USD ($)SecurityLoan	Jun. 30, 2018USD ($)SecurityLoan	Dec. 31, 2018USD ($)
Leases [Line Items]
Loans and Leases Receivable, Deferred Income	$ 40,200				$ 40,200		$ 36,300
Receivable with Imputed Interest, Discount	11,300				11,300		2,000
Interest Rate and Credit Marks on Acquired Loans	5,100				5,100		7,100
Credit Mark on Acquired Loans	10,600				10,600		14,600
Reduction in interest income due to nonaccrual loans	500	$ 800	$ 600	$ 1,200
Impaired loans with an allowance recorded	6,090				6,090		986
Impaired loans with no allowance recorded	120,341				120,341		111,266
Impaired loans with an allowance recorded	1,854				1,854		681
Impaired Financing Receivable, Average Recorded Investment	113,346		104,403		119,979	$ 98,743
Financing Receivable, Recorded Investment, Nonaccrual Status	51,825				51,825		27,746
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0				0		594
Financing Receivable, Net	19,250,250				$ 19,250,250		17,710,629
Financing Receivable, Modifications, Number of Contracts | SecurityLoan		2		2	4	7
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 1,800		$ 16,600	$ 28,900	$ 31,600
Financing Receivable, Modifications, Subsequent Default, Recorded Investment					400	0
Loans And Loans Receivable Purchases	590,600	1,120,000	316,800	458,300
Financing Receivable, Significant Sales	19,300		3,100		34,800	34,100
Loans and Leases Receivable, Gain (Loss) on Sales, Net	(100)		800		(500)	1,400
Troubled Debt Restructured Loans [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	0				0
Impaired loans with no allowance recorded	61,700				61,700		44,500
Impaired Financing Receivable, Average Recorded Investment	62,000	$ 56,800	55,300	$ 51,800
Financing Receivable, Recorded Investment, Nonaccrual Status	9,500				9,500		8,000
Loan commitments outstanding	2,100				2,100		1,500
Non-owner occupied [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	0				0		0
Impaired loans with no allowance recorded	30,029				30,029		12,407
Impaired loans with an allowance recorded	0				0		0
Loans And Loans Receivable Purchases					30,000
Construction and land development [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	2,277				2,277		0
Impaired loans with no allowance recorded	24,644				24,644		9,403
Impaired loans with an allowance recorded	810				810		0
Loans And Loans Receivable Purchases					33,900
Residential real estate [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	1,321				1,321		363
Impaired loans with no allowance recorded	13,642				13,642		19,381
Impaired loans with an allowance recorded	275				275		60
Loans And Loans Receivable Purchases					530,500	175,100
Commercial and industrial [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	1,692				1,692		623
Impaired loans with no allowance recorded	32,008				32,008		63,273
Impaired loans with an allowance recorded	603				603		621
Loans And Loans Receivable Purchases					526,700	283,200
Consumer [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	9				9		0
Impaired loans with no allowance recorded	146				146		272
Impaired loans with an allowance recorded	9				9		0
Non-owner occupied [Member] | Commercial real estate [Member]
Leases [Line Items]
Impaired Financing Receivable, Average Recorded Investment	17,826		$ 17,524		15,068	$ 18,225
Financing Receivable, Net	4,501,171				4,501,171		4,051,837
Financial Asset Acquired with Credit Deterioration [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	99				99		96
Financial Asset Acquired with Credit Deterioration [Member] | Non-owner occupied [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	97				97		87
Financial Asset Acquired with Credit Deterioration [Member] | Construction and land development [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	0				0		0
Financial Asset Acquired with Credit Deterioration [Member] | Residential real estate [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	0				0		0
Financial Asset Acquired with Credit Deterioration [Member] | Commercial and industrial [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	2				2		9
Financial Asset Acquired with Credit Deterioration [Member] | Consumer [Member]
Leases [Line Items]
Impaired loans with an allowance recorded	$ 0				$ 0		$ 0

Loans, Leases and Allowance f_7

Loans, Leases and Allowance for Credit Losses - Loans by Risk Rating (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	$ 19,250,250,000	$ 17,710,629,000
Current	19,214,345,000	17,673,900,000
Past Due	35,905,000	36,729,000
Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	8,454,161,000	7,762,642,000
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	1,580,104,000	1,204,355,000
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	65,959,000	70,071,000
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	2,254,126,000	2,325,380,000
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	4,501,171,000	4,051,837,000
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	184,374,000	161,591,000
Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	1,417,767,000	1,382,664,000
Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	792,588,000	752,089,000
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	18,868,987,000	17,412,922,000
Current	18,860,678,000	17,400,616,000
Pass [Member] | Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	8,328,754,000	7,574,506,000
Pass [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	1,571,753,000	1,191,571,000
Pass [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	65,809,000	69,755,000
Pass [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	2,162,788,000	2,255,513,000
Pass [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	4,400,274,000	4,030,350,000
Pass [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	184,374,000	161,591,000
Pass [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	1,365,231,000	1,378,624,000
Pass [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	790,004,000	751,012,000
Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	197,996,000	88,856,000
Current	196,966,000	87,264,000
Watch [Member] | Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	62,078,000	61,202,000
Watch [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	527,000
Watch [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	22,000	75,000
Watch [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	29,932,000	12,860,000
Watch [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	70,157,000	12,982,000
Watch [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Watch [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	33,237,000	1,210,000
Watch [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	2,570,000	0
Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	182,916,000	208,273,000
Current	156,701,000	186,020,000
Substandard [Member] | Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	62,978,000	126,356,000
Substandard [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	8,351,000	12,257,000
Substandard [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	128,000	241,000
Substandard [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	61,406,000	57,007,000
Substandard [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	30,740,000	8,505,000
Substandard [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Substandard [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	19,299,000	2,830,000
Substandard [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	14,000	1,077,000
Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	351,000	578,000
Current	0	0
Doubtful [Member] | Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	351,000	578,000
Doubtful [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Doubtful [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Current	0	0
Loss [Member] | Commercial and industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Construction and land development [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Loss [Member] | Construction and land development [Member] | Land [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Net	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	21,104,000	16,944,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	7,539,000	11,255,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	980,000	1,580,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	12,585,000	4,109,000
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	5,588,000	4,902,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	439,000	719,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Watch [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	50,000	12,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	4,840,000	3,767,000
Financing Receivables, 60 to 89 Days Past Due [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	259,000	404,000
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	9,213,000	14,883,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	331,000	332,000
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	8,790,000	14,377,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Past Due	92,000	174,000
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 f_8

Loans, Leases and Allowance for Credit Losses - Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	$ 126,431	$ 112,252
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	33,700	63,896
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	14,963	19,744
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	155	272
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	20,663	6,530
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	30,029	12,407
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	33,700	63,896
Construction and land development [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	19,299	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Impaired [Line Items]
Total impaired loans by class	$ 7,622	$ 9,403

Loans, Leases and Allowance f_9

Loans, Leases and Allowance for Credit Losses - Recorded Investment in Loans Classified as Impaired (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Impaired loans with an allowance recorded	$ 6,090	$ 986
Impaired loans with no allowance recorded	120,341	111,266
Total impaired loans	126,431	112,252
Valuation allowance related to impaired loans	$ (1,854)	$ (681)

Loans, Leases and Allowance _10

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Receivables [Abstract]
Impaired Financing Receivable, Average Recorded Investment	$ 113,346	$ 104,403	$ 119,979	$ 98,743
Interest income recognized on impaired loans	$ 1,201	$ 1,122	$ 2,694	$ 1,995

Loans, Leases and Allowance _11

Loans, Leases and Allowance for Credit Losses - Average Investment in Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	$ 113,346		$ 104,403		$ 119,979	$ 98,743
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	40,367		49,373		53,755	43,111
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	15,252		19,109		16,766	18,454
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	148		377		188	281
Commercial real estate [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	11,848		8,417		9,708	8,730
Commercial real estate [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	17,826		17,524		15,068	18,225
Commercial real estate [Member] | Multi-family [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	0		0		0	0
Construction and land development [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	19,970		0		16,210	0
Construction and land development [Member] | Land [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	7,935		9,603		$ 8,284	$ 9,942
Troubled Debt Restructured Loans [Member]
Financing Receivable, Impaired [Line Items]
Total average investment in impaired loans by loan class	$ 62,000	$ 56,800	$ 55,300	$ 51,800

Loans, Leases and Allowance _12

Loans, Leases and Allowance for Credit Losses - Interest Income on Impaired Loans by Loan Class (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	$ 1,201	$ 1,122	$ 2,694	$ 1,995
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	386	489	1,154	739
Owner occupied [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	154	131	276	258
Non-owner occupied [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	169	265	356	526
Multi-family [Member] | Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	0	0	0	0
Construction [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	272	0	452	0
Land [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	121	149	250	279
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	99	88	205	192
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Total interest income on impaired loans by class	$ 0	$ 0	$ 1	$ 1

Loans, Leases and Allowance _13

Loans, Leases and Allowance for Credit Losses - Tabular Disclosure of Nonperforming Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 51,825	$ 27,746
Loans past due 90 days or more on accrual status	0	594
Troubled debt restructured loans	52,200	36,458
Total nonperforming loans	104,025	64,798
Other assets acquired through foreclosure, net	17,707	17,924
Total nonperforming assets	121,732	82,722
Troubled Debt Restructured Loans [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 9,500	$ 8,000

Loans, Leases and Allowance _14

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period			$ 3,768	$ 9,324
Reclassifications from non-accretable to accretable yield (1)	$ 0
Accretion to interest income	(142)	$ (264)
Financial Asset Acquired with Credit Deterioration [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period			3,137	8,108
Reclassifications from non-accretable to accretable yield (1)		0	0	683
Accretion to interest income			(302)	(578)
Reversal of fair value adjustments upon disposition of loans	(17)	(3,016)	(488)	(4,601)
Balance at end of period	$ 2,978	$ 4,828	$ 2,978	$ 4,828

Loans, Leases and Allowance _15

Loans, Leases and Allowance for Credit Losses - Allowances for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Valuation Allowance [Line Items]
Beginning Balance	$ 154,987	$ 144,659	$ 152,717	$ 140,050
Charge-offs	2,556	3,901	4,869	7,526
Recoveries	(978)	(1,325)	(2,061)	(3,559)
Provision for credit losses	7,000	5,000	10,500	11,000
Ending balance	160,409	147,083	160,409	147,083
Construction and land development [Member]
Valuation Allowance [Line Items]
Beginning Balance	26,083	22,594	22,513	19,511
Charge-offs	141	1	141	1
Recoveries	(9)	(8)	(64)	(1,397)
Provision for credit losses	140	(442)	3,655	1,252
Ending balance	26,091	22,159	26,091	22,159
Commercial real estate [Member]
Valuation Allowance [Line Items]
Beginning Balance	37,867	32,868	34,829	31,495
Charge-offs	0	233	0	233
Recoveries	(439)	(246)	(892)	(371)
Provision for credit losses	2,952	(902)	5,537	346
Ending balance	41,258	31,979	41,258	31,979
Residential real estate [Member]
Valuation Allowance [Line Items]
Beginning Balance	13,006	5,519	11,276	5,478
Charge-offs	397	885	585	992
Recoveries	(27)	(141)	(120)	(390)
Provision for credit losses	(30)	2,074	1,795	1,973
Ending balance	12,606	6,849	12,606	6,849
Commercial and industrial [Member]
Valuation Allowance [Line Items]
Beginning Balance	77,254	82,878	83,118	82,793
Charge-offs	2,018	2,777	4,142	6,295
Recoveries	(495)	(916)	(972)	(1,376)
Provision for credit losses	3,904	4,227	(313)	7,370
Ending balance	79,635	85,244	79,635	85,244
Consumer [Member]
Valuation Allowance [Line Items]
Beginning Balance	777	800	981	773
Charge-offs	0	5	1	5
Recoveries	(8)	(14)	(13)	(25)
Provision for credit losses	34	43	(174)	59
Ending balance	$ 819	$ 852	$ 819	$ 852

Loans, Leases and Allowance _16

Loans, Leases and Allowance for Credit Losses - Summary of Impairment Method Information Related to Loans and Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 113,346		$ 104,403		$ 119,979	$ 98,743
Impaired loans with an allowance recorded	6,090				6,090		$ 986
Impaired loans with no allowance recorded	120,341				120,341		111,266
Total loans individually evaluated for impairment	126,431				126,431		112,252
Loans collectively evaluated for impairment	19,061,461				19,061,461		17,514,822
Impaired Financing Receivable, Recorded Investment	126,431				126,431		112,252
Total recorded investment	19,250,250				19,250,250		17,710,629
Impaired loans with an allowance recorded	6,164				6,164		1,845
Impaired loans with no allowance recorded	131,033				131,033		198,234
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	137,197				137,197		200,079
Loans collectively evaluated for impairment	19,058,999				19,058,999		17,514,822
Financing Receivable Unpaid Principal Balance	19,271,829				19,271,829		17,820,320
Impaired loans with an allowance recorded	1,854				1,854		681
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	1,854				1,854		681
Loans collectively evaluated for impairment	158,456				158,456		151,940
Total loans held for investment	160,409				160,409		152,717
Troubled Debt Restructured Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment	62,000	$ 56,800	$ 55,300	$ 51,800
Impaired loans with an allowance recorded	0				0
Impaired loans with no allowance recorded	61,700				61,700		44,500
Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	791				791		0
Impaired loans with no allowance recorded	19,872				19,872		6,530
Total loans individually evaluated for impairment	20,663				20,663		6,530
Loans collectively evaluated for impairment	2,229,604				2,229,604		2,314,871
Total recorded investment	2,254,126				2,254,126		2,325,380
Impaired loans with an allowance recorded	791				791		0
Impaired loans with no allowance recorded	20,619				20,619		11,852
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	21,410				21,410		11,852
Loans collectively evaluated for impairment	2,230,441				2,230,441		2,314,871
Financing Receivable Unpaid Principal Balance	2,256,975				2,256,975		2,332,038
Impaired loans with an allowance recorded	157				157		0
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	157				157		0
Loans collectively evaluated for impairment	14,615				14,615		14,286
Total loans held for investment	14,772				14,772		14,286
Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	0				0		0
Impaired loans with no allowance recorded	30,029				30,029		12,407
Total loans individually evaluated for impairment	30,029				30,029		12,407
Loans collectively evaluated for impairment	4,597,036				4,597,036		4,121,464
Total recorded investment	4,685,545				4,685,545		4,213,428
Impaired loans with an allowance recorded	0				0		0
Impaired loans with no allowance recorded	30,953				30,953		18,155
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	30,953				30,953		18,155
Loans collectively evaluated for impairment	4,613,466				4,613,466		4,121,464
Financing Receivable Unpaid Principal Balance	4,714,856				4,714,856		4,235,299
Impaired loans with an allowance recorded	0				0		0
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	0				0		0
Loans collectively evaluated for impairment	26,389				26,389		20,456
Total loans held for investment	26,486				26,486		20,543
Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	1,692				1,692		623
Impaired loans with no allowance recorded	32,008				32,008		63,273
Total loans individually evaluated for impairment	33,700				33,700		63,896
Loans collectively evaluated for impairment	8,420,461				8,420,461		7,698,746
Total recorded investment	8,454,161				8,454,161		7,762,642
Impaired loans with an allowance recorded	1,721				1,721		1,482
Impaired loans with no allowance recorded	37,427				37,427		103,992
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	39,148				39,148		105,474
Loans collectively evaluated for impairment	8,390,353				8,390,353		7,698,746
Financing Receivable Unpaid Principal Balance	8,429,501				8,429,501		7,808,572
Impaired loans with an allowance recorded	603				603		621
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	603				603		621
Loans collectively evaluated for impairment	79,030				79,030		82,488
Total loans held for investment	79,635				79,635		83,118
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	1,321				1,321		363
Impaired loans with no allowance recorded	13,642				13,642		19,381
Total loans individually evaluated for impairment	14,963				14,963		19,744
Loans collectively evaluated for impairment	1,565,122				1,565,122		1,184,592
Total recorded investment	1,580,104				1,580,104		1,204,355
Impaired loans with an allowance recorded	1,321				1,321		363
Impaired loans with no allowance recorded	16,597				16,597		27,979
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	17,918				17,918		28,342
Loans collectively evaluated for impairment	1,554,316				1,554,316		1,184,592
Financing Receivable Unpaid Principal Balance	1,572,306				1,572,306		1,213,006
Impaired loans with an allowance recorded	275				275		60
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	275				275		60
Loans collectively evaluated for impairment	12,331				12,331		11,216
Total loans held for investment	12,606				12,606		11,276
Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	2,277				2,277		0
Impaired loans with no allowance recorded	24,644				24,644		9,403
Total loans individually evaluated for impairment	26,921				26,921		9,403
Loans collectively evaluated for impairment	2,183,434				2,183,434		2,125,350
Total recorded investment	2,210,355				2,210,355		2,134,753
Impaired loans with an allowance recorded	2,322				2,322		0
Impaired loans with no allowance recorded	25,262				25,262		25,624
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	27,584				27,584		25,624
Loans collectively evaluated for impairment	2,204,253				2,204,253		2,125,350
Financing Receivable Unpaid Principal Balance	2,231,837				2,231,837		2,150,974
Impaired loans with an allowance recorded	810				810		0
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	810				810		0
Loans collectively evaluated for impairment	25,281				25,281		22,513
Total loans held for investment	26,091				26,091		22,513
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance recorded	9				9		0
Impaired loans with no allowance recorded	146				146		272
Total loans individually evaluated for impairment	155				155		272
Loans collectively evaluated for impairment	65,804				65,804		69,799
Total recorded investment	65,959				65,959		70,071
Impaired loans with an allowance recorded	9				9		0
Impaired loans with no allowance recorded	175				175		10,632
Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment	184				184		10,632
Loans collectively evaluated for impairment	66,170				66,170		69,799
Financing Receivable Unpaid Principal Balance	66,354				66,354		80,431
Impaired loans with an allowance recorded	9				9		0
Impaired loans with no allowance recorded	0				0		0
Total loans individually evaluated for impairment	9				9		0
Loans collectively evaluated for impairment	810				810		981
Total loans held for investment	819				819		981
Financial Asset Acquired with Credit Deterioration [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	62,358				62,358		83,555
Loans acquired with deteriorated credit quality	75,633				75,633		105,419
Impaired loans with an allowance recorded	99				99		96
Financial Asset Acquired with Credit Deterioration [Member] | Owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	3,859				3,859		3,979
Loans acquired with deteriorated credit quality	5,124				5,124		5,315
Impaired loans with an allowance recorded	0				0		0
Financial Asset Acquired with Credit Deterioration [Member] | Non-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	58,480				58,480		79,557
Loans acquired with deteriorated credit quality	70,437				70,437		95,680
Impaired loans with an allowance recorded	97				97		87
Financial Asset Acquired with Credit Deterioration [Member] | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0				0		0
Loans acquired with deteriorated credit quality	0				0		4,352
Impaired loans with an allowance recorded	2				2		9
Financial Asset Acquired with Credit Deterioration [Member] | Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	19				19		19
Loans acquired with deteriorated credit quality	72				72		72
Impaired loans with an allowance recorded	0				0		0
Financial Asset Acquired with Credit Deterioration [Member] | Construction and land development [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0				0		0
Loans acquired with deteriorated credit quality	0				0		0
Impaired loans with an allowance recorded	0				0		0
Financial Asset Acquired with Credit Deterioration [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	0				0		0
Loans acquired with deteriorated credit quality	0				0		0
Impaired loans with an allowance recorded	$ 0				$ 0		$ 0

Loans, Leases and Allowance _17

Loans, Leases and Allowance for Credit Losses Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019USD ($)SecurityLoan	Mar. 31, 2018USD ($)SecurityLoan	Jun. 30, 2019USD ($)SecurityLoan	Jun. 30, 2018USD ($)SecurityLoan
Troubled Debt Restructurings [Abstract]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment			$ 400	$ 0
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,800	$ 16,600	$ 28,900	$ 31,600
Financing Receivable, Modifications, Number of Contracts | SecurityLoan	2	2	4	7

Leases (Details)

Leases (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating Lease, Payments					$ 6,181,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 33,736,000
Operating Lease, Right-of-Use Asset	$ 71,087,000		$ 71,087,000			$ 0
Lessee, Operating Lease, Discount Rate	3.18%		3.18%
Operating Lease, Weighted Average Remaining Lease Term	8 years 10 months 24 days		8 years 10 months 24 days
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 6,018,000		$ 6,018,000
Operating Leases, Future Minimum Payments, Due in Two Years	11,297,000		11,297,000
Operating Leases, Future Minimum Payments, Due in Three Years	9,243,000		9,243,000
Operating Leases, Future Minimum Payments, Due in Four Years	8,049,000		8,049,000
Operating Leases, Future Minimum Payments, Due in Five Years	8,068,000		8,068,000
Operating Leases, Future Minimum Payments, Due Thereafter	46,320,000		46,320,000
Operating Leases, Future Minimum Payments Due	88,995,000		88,995,000
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	12,804,000		12,804,000
Operating Lease, Liability	76,191,000		76,191,000			0
Lessee, operating lease, leases not yet commenced, aggregated commitment	3,900,000		3,900,000
Lease, Cost	3,100,000	$ 2,800,000	6,300,000	$ 5,300,000
Lessee, operating lease, other cost	$ 900,000		$ 2,000,000
Operating Leases, Future Minimum Payments Due, Next Twelve Months						11,370,000
Operating Leases, Future Minimum Payments, Due in Two Years						10,322,000
Operating Leases, Future Minimum Payments, Due in Three Years						7,418,000
Operating Leases, Future Minimum Payments, Due in Four Years						6,294,000
Operating Leases, Future Minimum Payments, Due in Five Years						6,070,000
Operating Leases, Future Minimum Payments, Due Thereafter						15,417,000
Operating Leases, Future Minimum Payments Due						$ 56,891,000

Other Borrowings - Additional I

Other Borrowings - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Jun. 30, 2019
Debt [Line Items]
FHLB advances	$ 235,000	$ 0
Short-term Debt	$ 491,000	0
Weighted average interest rate of FHLB and FRB Short-term advances	2.56%
Customer repurchase agreements	$ 22,411	13,921
Federal Funds Purchased	256,000	0
Federal Home Loan Bank Advances [Member]
Debt [Line Items]
Additional available credit with the entity	2,520,000	3,030,000
FRB [Member]
Debt [Line Items]
Additional available credit with the entity	$ 1,310,000	1,330,000
Unsecured Credit Facility [Member]
Debt [Line Items]
Secured borrowing credit line		$ 1,010,000

Qualifying Debt (Details)

Qualifying Debt (Details)	6 Months Ended
	Jun. 30, 2019USD ($)Trust	Dec. 31, 2018USD ($)	Jun. 16, 2016USD ($)	Jun. 29, 2015USD ($)
Debt Instrument [Line Items]
Subordinated Debt	$ 316,400,000	$ 299,400,000
Number of Statutory Business Trusts Formed or Acquired | Trust	8
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	$ 70,800,000	$ 61,100,000
Subordinated Debt [Member] | Subordinated Debentures Maturing July 2056 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 175,000,000
Debt Issuance Cost			$ 5,500,000
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
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time	4.66%	5.15%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury Stock, Shares, Acquired	3,145	2,085	176,152	182,952
Treasury Stock Acquired, Average Cost Per Share	$ 47.16	$ 59.46	$ 45.69	$ 59.02
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 1.3	$ 1.6	$ 3	$ 3.3
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Granted, Value, Share-based Compensation, Gross	0.4		21.2
Allocated Share-based Compensation Expense	5.4	4.7	9.7	9
Executive Officer [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 0.5	$ 0.6	$ 1	$ 1.3

Stockholders' Equity Common Sto

Stockholders' Equity Common Stock Repurchase (Details) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2019USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount | $	$ 250,000	$ 250,000
Stock Repurchased and Retired During Period, Shares | shares	792,688	1,733,603
Weighted Average Selling Price Per Share | $ / shares	$ 42.81	$ 41.45
Stock Repurchased and Retired During Period, Value | $	$ 33,964	$ 71,913
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchased and Retired During Period, Shares | shares	(793,000)	(1,734,000)

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (8,191)	$ (41,662)	$ (33,622)	$ (3,145)
Other comprehensive income before reclassifications	34,572	(9,653)	60,003	(47,112)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net other comprehensive income (loss)	34,572	(9,653)	60,003	(47,112)
Ending balance	26,381	(51,315)	26,381	(51,315)
Unrealized holding gains (losses) on AFS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(16,214)	(51,470)	(47,591)	(10,026)
Other comprehensive income before reclassifications	35,923	(10,389)	67,300	(49,303)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net other comprehensive income (loss)	35,923	(10,389)	67,300	(49,303)
Ending balance	19,709	(61,859)	19,709	(61,859)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	7,505	9,206	13,433	6,352
Other comprehensive income before reclassifications	(1,334)	748	(7,262)	2,214
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net other comprehensive income (loss)	(1,334)	748	(7,262)	2,214
Ending balance	6,171	9,954	6,171	9,954
Impairment loss on securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	144	144	144	144
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net other comprehensive income (loss)	0	0	0	0
Ending balance	144	144	144	144
Supplemental Employee Retirement Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	374	458	392	385
Other comprehensive income before reclassifications	(17)	(12)	(35)	(23)
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Net other comprehensive income (loss)	(17)	(12)	(35)	(23)
Ending balance	$ 357	$ 446	$ 357	$ 446

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income	$ 0	$ 0	$ 0	$ 0

Derivatives and Hedging Fair Va

Derivatives and Hedging Fair Value of Derivative Contracts (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Derivatives, Fair Value [Line Items]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net	$ 100	$ 300	$ 200
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	27,499	52,068	71,953
Derivative Asset, Fair Value	346	481	1,348
Derivative Liability, Fair Value	230	228	1,130
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	2,348	2,378	1,763
Derivative Asset, Fair Value	83	27	74
Derivative Liability, Fair Value	83	27	74
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	25,151	49,690	70,190
Derivative Asset, Fair Value	263	454	1,274
Derivative Liability, Fair Value	147	201	1,056
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	958,298	965,705	986,867
Derivative Asset, Fair Value	1,436	2,162	4,435
Derivative Liability, Fair Value	62,754	44,892	41,015
Notional Amount, Netting Adjustments	0	0	0
Derivative Netting Adjustments	163	2,162	3,838
Positive NPVs	1,273	0	597
Negative NPVs	62,591	42,730	37,177
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	958,298	965,705	986,867
Derivative Asset, Fair Value	1,436	2,162	4,435
Derivative Liability, Fair Value	$ 62,754	$ 44,892	$ 41,015

Derivatives and Hedging Largest

Derivatives and Hedging Largest Exposure to Individual Counterparty (Detail) - Largest individual counterparty [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Largest gross exposure (positive derivative NPV) to an individual counterparty	$ 1,273	$ 1,411	$ 2,910
Collateral posted by this counterparty	1,100	0	0
Negative derivative NPV with this counterparty	0	23,906	16,809
Collateral pledged to this counterparty	0	25,761	24,001
Net exposure after netting adjustments and collateral	$ 173	$ 0	$ 0

Derivatives and Hedging Additio

Derivatives and Hedging Additional Information (Detail) - USD ($)	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018
Derivative [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 1,000,000	$ 2,300,000	$ 1,200,000	$ 2,400,000
Collateral netted against derivative liabilities	62,800,000		39,800,000		$ 44,900,000
Over collateralization net position	20,300,000		11,600,000		7,600,000
Additional collateral held in securities	83,100,000
Derivative, Amount of Hedged Item, Loans	678,369,000				650,428,000
Fair Value Hedge Assets, Loans	58,355,000				23,039,000
Derivative, Amount of Hedged Item	(316,392,000)				(299,401,000)
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	2,963,000				19,691,000
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
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value	62,754,000		41,015,000		44,892,000
Negative NPVs	$ 62,591,000		$ 37,177,000		$ 42,730,000

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Basic	103,019		104,691	103,523	104,611
Dilutive Effect Of Stock Options Restricted Stock And Equity Settled Awards	482		729	462	761
Diluted	103,501		105,420	103,985	105,372
Net income available to common shareholders	$ 122,936		$ 104,679	$ 243,732	$ 205,579
Earnings (loss) per share - basic	$ 1.19		$ 1	$ 2.35	$ 1.97
Earnings (loss) per share - diluted	$ 1.19		$ 0.99	$ 2.34	$ 1.95
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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Percent	16.76%	19.48%	17.10%	18.33%
Deferred tax assets, net	$ 9,319		$ 9,319		$ 31,990
Increase (Decrease) in Deferred Income Taxes			(22,700)
Operating Loss Carryforwards, Valuation Allowance	2,400		2,400
Amortization Method Qualified Affordable Housing Project Investments	321,543		321,543		342,381
Affordable Housing Program Obligation	133,100		133,100		$ 171,700
Amortization of tax credit investments	10,500	$ 9,400	20,573	$ 17,549
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	46,500		46,500
Deferred Tax Assets, Operating Loss Carryforwards	5,600		5,600
ARIZONA
Operating Loss Carryforwards [Line Items]
Tax Credit Carryforward, Amount	2,300		2,300
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	$ 100		$ 100

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
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	32.00%	36.00%
Commercial Real Estate Portfolio Segment [Member] | Loans Receivable [Member] | Credit Concentration Risk [Member]
Loss Contingencies [Line Items]
Percent of commercial real estate related loans	48.00%	49.00%
Unfunded Loan Commitment [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	$ 9.2	$ 8.2

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Contractual Amounts for Unfunded Commitments and Letters of Credit (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Other Commitments [Line Items]
Total amount	$ 9,081,838	$ 8,184,214
Percentage Of Commercial Real Estate Loans Occupied By Owners	32.00%	36.00%
Commitments to extend credit [Member]
Other Commitments [Line Items]
Unsecured Loan Commitments	$ 900,291	$ 770,114
Total amount	8,528,133	7,556,741
Credit card guarantees [Member]
Other Commitments [Line Items]
Total amount	268,439	237,312
Standby letters of credit [Member]
Other Commitments [Line Items]
Total amount	285,266	390,161
Unsecured Letters Of Credit	$ 16,225	$ 21,879
Commercial Real Estate Portfolio Segment [Member] | Credit Concentration Risk [Member] | Loans Receivable [Member]
Other Commitments [Line Items]
Concentration Risk, Percentage	48.00%	49.00%

Fair Value Accounting - Gains a

Fair Value Accounting - Gains and Losses from Fair Value Changes Included in Consolidated Statement of Operations (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Subordinated Debt Obligations, Fair Value Disclosure	$ 58,315		$ 58,315		$ 48,684
Unrealized (loss) gain on junior subordinated debt, net of tax effect of $435, $(244), $2,369, $(722), respectively	$ (1,334)	$ 748	$ (7,262)	$ 2,214
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Measurement Input	0.0605		0.0605		0.0782
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ (1,769)	$ 992	$ (9,631)	$ 2,936
Period of basis point spread			3.73%	5.01%
Percentage of LIBOR			2.32%	2.81%

Fair Value Accounting - Fair Va

Fair Value Accounting - Fair Value of Assets and Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 3,253,094		$ 3,253,094		$ 3,276,988
Investment securities - equity	114,689		114,689		115,061
Subordinated Debt Obligations, Fair Value Disclosure	58,315		58,315		48,684
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	3,253,094		3,253,094		3,276,988
Investment securities - equity	114,689		114,689		115,061
Derivative Liability	62,984		62,984		45,120
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	30,084		30,084		0
Investment securities - equity	114,689		114,689		115,061
Subordinated Debt Obligations, Fair Value Disclosure	0		0		0
Derivative Liability	0		0		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	3,223,010		3,223,010		3,276,988
Investment securities - equity	0		0		0
Subordinated Debt Obligations, Fair Value Disclosure	0		0		0
Derivative Liability	62,984		62,984		45,120
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		0
Investment securities - equity	0		0		0
Subordinated Debt Obligations, Fair Value Disclosure	58,315		58,315		48,684
Derivative Liability	0		0		0
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,453,316		1,453,316		1,530,124
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		0
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,453,316		1,453,316		1,530,124
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		0
Fair Value, Measurements, Recurring [Member] | Nontaxable Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	561,730		561,730		538,668
Fair Value, Measurements, Recurring [Member] | Nontaxable Municipal Bonds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		0
Fair Value, Measurements, Recurring [Member] | Nontaxable Municipal Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	561,730		561,730		538,668
Fair Value, Measurements, Recurring [Member] | Nontaxable Municipal Bonds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		0
Fair Value, Measurements, Recurring [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	949,762		949,762		924,594
Fair Value, Measurements, Recurring [Member] | 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		0
Fair Value, Measurements, Recurring [Member] | 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	949,762		949,762		924,594
Fair Value, Measurements, Recurring [Member] | 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		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	100,841		100,841		100,106
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		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	100,841		100,841		100,106
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		0
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	98,328		98,328		99,380
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	5,145		5,145		0
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	93,183		93,183		99,380
Fair Value, Measurements, Recurring [Member] | Corporate Bond Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		0
Fair Value, Measurements, Recurring [Member] | Taxable Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	7,753		7,753
Fair Value, Measurements, Recurring [Member] | Taxable Municipal Bonds [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] | Taxable Municipal Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	7,753		7,753
Fair Value, Measurements, Recurring [Member] | Taxable Municipal Bonds [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]
Investment securities - equity	62,548		62,548		63,919
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - equity	62,548		62,548		63,919
Fair Value, Measurements, Recurring [Member] | Preferred Stock [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - equity	0		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]
Investment securities - equity	0		0		0
Fair Value, Measurements, Recurring [Member] | CRA investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - equity	52,141		52,141		51,142
Fair Value, Measurements, Recurring [Member] | CRA investments [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - equity	52,141		52,141		51,142
Fair Value, Measurements, Recurring [Member] | CRA investments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - equity	0		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]
Investment securities - equity	0		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	15,026		15,026		15,327
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		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	15,026		15,026		15,327
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		0
Fair Value, Measurements, Recurring [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	24,939		24,939		28,617
Fair Value, Measurements, Recurring [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	24,939		24,939		0
Fair Value, Measurements, Recurring [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		0		28,617
Fair Value, Measurements, Recurring [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0		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	39,905		39,905		38,188
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		0		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	39,905		39,905		38,188
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		0		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	1,494		1,494		1,984
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		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	1,494		1,494		1,984
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		0
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings Fair Value Disclosure					491,000
Securities available for sale	3,253,094		3,253,094		3,276,988
Investment securities - equity	114,689		114,689		115,061
Derivative Liability	62,984		62,984		45,120
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings Fair Value Disclosure					491,000
Securities available for sale	3,253,094		3,253,094		3,276,988
Investment securities - equity	114,689		114,689		115,061
Derivative Liability	62,984		62,984		45,120
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings Fair Value Disclosure					0
Securities available for sale	30,084		30,084		0
Investment securities - equity	114,689		114,689		115,061
Derivative Liability	0		0		0
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings Fair Value Disclosure					491,000
Securities available for sale	3,223,010		3,223,010		3,276,988
Investment securities - equity	0		0		0
Derivative Liability	62,984		62,984		45,120
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Borrowings Fair Value Disclosure					0
Securities available for sale	0		0		0
Investment securities - equity	0		0		0
Derivative Liability	0		0		0
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)	(1,769)	$ 992	(9,631)	$ 2,936
Junior Subordinated Debt [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Subordinated Debt Obligations, Fair Value Disclosure	$ 58,315		$ 58,315		$ 48,684

Fair Value Accounting - Change

Fair Value Accounting - Change in Level 3 Liabilities Measured at Fair Value on Recurring Basis (Detail) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized (loss) gain on junior subordinated debt, net of tax effect of $435, $(244), $2,369, $(722), respectively	$ (1,334)	$ 748	$ (7,262)	$ 2,214
Junior subordinated debt	58,315		58,315		$ 48,684
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt	58,315		$ 58,315		$ 48,684
Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			Collateral method		Collateral method
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	$ (1,769)	992	$ (9,631)	2,936
Debt Instrument, Measurement Input	0.0605		0.0605		0.0782
Junior Subordinated Debt [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Junior subordinated debt	$ 58,315		$ 58,315		$ 48,684
Fair Value Measurements, Valuation Processes, Description			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	(56,546)	54,290	$ (48,684)	(56,234)	$ (56,234)
Closing balance	$ (58,315)	$ (53,298)	$ (58,315)	$ (53,298)	$ (48,684)
Valuation Technique, Discounted Cash Flow [Member] | Junior Subordinated Debt [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Valuation Processes, Description			Discounted cash flow		Discounted cash flow
Collateral Method [Member] | Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			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]
Fair Value Measurements, Valuation Processes, Description			Proceeds from non-real estate collateral		Proceeds from non-real estate collateral

Fair Value Accounting - Assets

Fair Value Accounting - Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans without specific valuation allowance	$ 120,341	$ 111,266
Other assets acquired through foreclosure	17,707	17,924
Impaired Financing Receivables, With No related Allowance, Balances with Charge-offs	12,300	19,400
Impaired Financing Receivable, Recorded Investment	126,431	112,252
Impaired loans with an allowance recorded	6,090	986
Impaired loans with an allowance recorded	1,854	681
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded	1,900	700
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans without specific valuation allowance	108,090	91,821
Other assets acquired through foreclosure	17,707	17,924
Impaired loans with an allowance recorded	4,236	305
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans without specific valuation allowance	0	0
Other assets acquired through foreclosure	0	0
Impaired loans with an allowance recorded	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 without specific valuation allowance	0	0
Other assets acquired through foreclosure	0	0
Impaired loans with an allowance recorded	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 without specific valuation allowance	108,090	91,821
Other assets acquired through foreclosure	17,707	17,924
Impaired Financing Receivable, Recorded Investment	112,326	92,126
Impaired loans with an allowance recorded	$ 4,236	$ 305
Loans and Finance Receivables [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Valuation Processes, Description	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]
Fair Value Measurements, Valuation Processes, Description	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]
Fair Value Measurements, Valuation Processes, Description	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]
Fair Value Measurements, Valuation Processes, Description	Third party appraisal	Third party appraisal
Level 3 Fair Value Measurement Inputs	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]
Fair Value Measurements, Valuation Processes, Description	Third party appraisal	Third party appraisal
Level 3 Fair Value Measurement Inputs	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]
Fair Value Measurements, Valuation Processes, Description	Discount rate	Discount rate
Level 3 Fair Value Measurement Inputs	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]
Fair Value Measurements, Valuation Processes, Description	Scheduled cash collections	Scheduled cash collections
Level 3 Fair Value Measurement Inputs	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]
Fair Value Measurements, Valuation Processes, Description	Proceeds from non-real estate collateral	Proceeds from non-real estate collateral
Level 3 Fair Value Measurement Inputs	Loss given default	Loss given default

Fair Value Accounting - Estimat

Fair Value Accounting - Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	$ 90,000	$ 0
Impaired Financing Receivable, Recorded Investment	126,431	112,252
Other Repossessed Assets	17,700	17,900
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	435,997	302,905
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - equity	114,689	115,061
Loans, net	19,089,841	17,557,912
Financial liabilities
Deposits	21,439,899	19,177,447
Customer repurchase agreements	13,921	22,411
Junior subordinated debt	58,315	48,684
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	112,326	92,126
Fair Value, Measurements, Nonrecurring [Member] | Reported Value Measurement [Member]
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	435,997	302,905
Loans, net	19,089,841	17,557,912
Financial liabilities
Deposits	21,439,899	19,177,447
Junior subordinated debt	387,232	360,458
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member]
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	466,858	298,648
Loans, net	18,540,211	16,949,978
Financial liabilities
Deposits	21,458,684	19,188,216
Junior subordinated debt	403,367	381,496
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Loans, net	0	0
Financial liabilities
Deposits	0	0
Junior subordinated debt	0	0
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	466,858	298,648
Loans, net	18,427,885	16,857,852
Financial liabilities
Deposits	21,458,684	19,188,216
Junior subordinated debt	333,430	323,572
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Financial assets
Investment securities - HTM, at amortized cost; fair value of $466,858 at June 30, 2019 and $298,648 at December 31, 2018	0	0
Loans, net	112,326	92,126
Financial liabilities
Deposits	0	0
Junior subordinated debt	69,937	57,924
Fair Value, Measurements, Recurring [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - equity	114,689	115,061
Derivative Asset	1,782	2,643
Financial liabilities
Derivative Liability	62,984	45,120
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	30,084	0
Investment securities - equity	114,689	115,061
Derivative Asset	0	0
Financial liabilities
Junior subordinated debt	0	0
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,223,010	3,276,988
Investment securities - equity	0	0
Derivative Asset	1,782	2,643
Financial liabilities
Junior subordinated debt	0	0
Derivative Liability	62,984	45,120
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Investment securities - equity	0	0
Derivative Asset	0	0
Financial liabilities
Junior subordinated debt	58,315	48,684
Derivative Liability	0	0
Fair Value, Measurements, Recurring [Member] | Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	90,000
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - equity	114,689	115,061
Derivative Asset	1,782	2,643
Accrued Investment Income Receivable	105,469	101,275
Financial liabilities
Customer repurchase agreements	13,921	22,411
Derivative Liability	62,984	45,120
Interest Payable, Current	21,956	20,463
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	90,000
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,253,094	3,276,988
Investment securities - equity	114,689	115,061
Derivative Asset	1,782	2,643
Accrued Investment Income Receivable	105,469	101,275
Financial liabilities
Customer repurchase agreements	13,921	22,411
Derivative Liability	62,984	45,120
Interest Payable, Current	21,956	20,463
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	0
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	30,084	0
Investment securities - equity	114,689	115,061
Derivative Asset	0	0
Accrued Investment Income Receivable	0	0
Financial liabilities
Customer repurchase agreements	0	0
Derivative Liability	0	0
Interest Payable, Current	0	0
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	90,000
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	3,223,010	3,276,988
Investment securities - equity	0	0
Derivative Asset	1,782	2,643
Accrued Investment Income Receivable	105,469	101,275
Financial liabilities
Customer repurchase agreements	13,921	22,411
Derivative Liability	62,984	45,120
Interest Payable, Current	21,956	20,463
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Federal Funds Sold	0
Financial assets
Investment securities - AFS, at fair value; amortized cost of $3,226,756 at June 30, 2019 and $3,339,888 at December 31, 2018	0	0
Investment securities - equity	0	0
Derivative Asset	0	0
Accrued Investment Income Receivable	0	0
Financial liabilities
Customer repurchase agreements	0	0
Derivative Liability	0	0
Interest Payable, Current	$ 0	$ 0

Fair Value Accounting - Additio

Fair Value Accounting - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 126,431		$ 112,252
Impaired loans with an allowance recorded	6,090		986
Impaired loans with an allowance recorded	(1,854)		(681)
Other assets acquired through foreclosure	17,700		17,900
Goodwill	$ 289,895		$ 289,895
Common Stock, Shares, Issued	105,623,556		106,741,870
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	$ (1,900)		$ (700)
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Period of basis point spread	3.73%	5.01%
Percentage of LIBOR	2.32%	2.81%
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans with an allowance recorded	$ 4,236		305
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	112,326		92,126
Impaired loans with an allowance recorded	$ 4,236		$ 305

Segments - Operating Segment In

Segments - Operating Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Operating Statistics [Line Items]
Service charges and fees	$ 5,821	$ 5,672	$ 11,233	$ 11,417
Cash, Cash Equivalents and Investment Securities	4,937,800		4,937,800			$ 4,259,700
Loans, net of deferred loan fees and costs	19,250,250		19,250,250			17,710,629
Less: Allowance for credit losses	(160,409)		(160,409)			(152,717)
Loans, net	19,089,841		19,089,841			17,557,912
Total loans held for investment	19,089,900		19,089,900
Other Repossessed Assets	17,700		17,700			17,900
Intangible Assets, Net (Including Goodwill)	298,400		298,400			299,200
Other Assets Segment	971,000		971,000			974,800
Assets	25,314,785		25,314,785			23,109,486
Deposits	21,439,899		21,439,899			19,177,447
Other borrowings	387,200		387,200			851,500
Other Liabilities Segment	636,400		636,400			466,900
Total liabilities	22,463,521		22,463,521			20,495,752
Stockholders' equity	2,851,264	2,391,684	2,851,264	2,391,684	$ 2,720,620	2,613,734	$ 2,293,763	$ 2,229,698	$ 2,229,698
Liabilities and Equity	25,314,785		25,314,785			23,109,486
Excess Funds Provided by (Used in) Segment Basis	0		0			0
Net interest income	254,681	224,108	502,017	438,328
Provision for Loan, Lease, and Other Losses	7,000	5,000	10,500	11,000
Net interest income (loss) after provision for credit losses	247,681	219,108	491,517	427,328
Total non-interest income	14,218	13,444	29,628	25,087
Non-interest expense	(114,213)	(102,548)	(227,127)	(200,697)
Income from continuing operations before income taxes	147,686	130,004	294,018	251,718
Income tax expense (benefit)	24,750	25,325	50,286	46,139
Net income	122,936	104,679	243,732	205,579
Debit and credit card interchange fees	1,986	1,648	3,853	3,155
Success fees (2)	85	914	520	1,695
Other income	(14)	175	105	411
Total revenue from contracts with customers	7,878	8,409	15,711	16,678
Revenues outside the scope of ASC 606 (3)	6,340	5,035	13,917	8,409
Operating Segments [Member] | HOA Services [Member]
Operating Statistics [Line Items]
Service charges and fees	75	171	163	317
Cash, Cash Equivalents and Investment Securities	0		0			0
Loans, net of deferred loan fees and costs	214,700		214,700			210,000
Less: Allowance for credit losses	(1,800)		(1,800)			(1,900)
Loans, net	212,900		212,900			208,100
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	900		900			900
Assets	213,800		213,800			209,000
Deposits	3,047,500		3,047,500			2,607,200
Other borrowings	0		0			0
Other Liabilities Segment	1,300		1,300			2,100
Total liabilities	3,048,800		3,048,800			2,609,300
Stockholders' equity	79,900		79,900			70,700
Liabilities and Equity	3,128,700		3,128,700			2,680,000
Excess Funds Provided by (Used in) Segment Basis	2,914,900		2,914,900			2,471,000
Net interest income	21,905	16,046	42,546	31,405
Provision for Loan, Lease, and Other Losses	(7)	135	(33)	182
Net interest income (loss) after provision for credit losses	21,912	15,911	42,579	31,223
Total non-interest income	88	179	184	328
Non-interest expense	(9,549)	(8,033)	(18,008)	(15,836)
Income from continuing operations before income taxes	12,451	8,057	24,755	15,715
Income tax expense (benefit)	2,864	1,853	5,694	3,615
Net income	9,587	6,204	19,061	12,100
Debit and credit card interchange fees	11	6	19	9
Success fees (2)	0	0	0	0
Other income	4	2	4	2
Total revenue from contracts with customers	90	179	186	328
Revenues outside the scope of ASC 606 (3)	(2)	0	(2)	0
Operating Segments [Member] | Public and Non-Profit Finance [Member]
Operating Statistics [Line Items]
Service charges and fees	0	0	0	0
Cash, Cash Equivalents and Investment Securities	0		0			0
Loans, net of deferred loan fees and costs	1,626,600		1,626,600			1,547,500
Less: Allowance for credit losses	(14,800)		(14,800)			(14,200)
Loans, net	1,611,800		1,611,800			1,533,300
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	17,100		17,100			20,100
Assets	1,628,900		1,628,900			1,553,400
Deposits	0		0			0
Other borrowings	0		0			0
Other Liabilities Segment	58,300		58,300			25,200
Total liabilities	58,300		58,300			25,200
Stockholders' equity	132,300		132,300			123,900
Liabilities and Equity	190,600		190,600			149,100
Excess Funds Provided by (Used in) Segment Basis	(1,438,300)		(1,438,300)			(1,404,300)
Net interest income	3,461	3,794	6,884	7,539
Provision for Loan, Lease, and Other Losses	96	(27)	55	(233)
Net interest income (loss) after provision for credit losses	3,365	3,821	6,829	7,772
Total non-interest income	0	0	0	0
Non-interest expense	(1,931)	(2,080)	(3,838)	(4,254)
Income from continuing operations before income taxes	1,434	1,741	2,991	3,518
Income tax expense (benefit)	330	401	688	809
Net income	1,104	1,340	2,303	2,709
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	0	0	0	0
Total revenue from contracts with customers	0	0	0	0
Revenues outside the scope of ASC 606 (3)	0	0	0	0
Operating Segments [Member] | Technology and Innovation [Member]
Operating Statistics [Line Items]
Service charges and fees	806	739	1,520	1,554
Cash, Cash Equivalents and Investment Securities	0		0			0
Loans, net of deferred loan fees and costs	1,246,500		1,246,500			1,200,900
Less: Allowance for credit losses	(10,200)		(10,200)			(10,000)
Loans, net	1,236,300		1,236,300			1,190,900
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	120,000		120,000			120,400
Other Assets Segment	6,900		6,900			6,300
Assets	1,363,200		1,363,200			1,317,600
Deposits	2,853,200		2,853,200			2,559,000
Other borrowings	0		0			0
Other Liabilities Segment	0		0			100
Total liabilities	2,853,200		2,853,200			2,559,100
Stockholders' equity	277,500		277,500			268,700
Liabilities and Equity	3,130,700		3,130,700			2,827,800
Excess Funds Provided by (Used in) Segment Basis	1,767,500		1,767,500			1,510,200
Net interest income	28,536	24,562	57,939	47,383
Provision for Loan, Lease, and Other Losses	2,657	2,256	1,739	3,907
Net interest income (loss) after provision for credit losses	25,879	22,306	56,200	43,476
Total non-interest income	2,163	3,630	5,525	6,681
Non-interest expense	(10,015)	(9,899)	(21,903)	(19,733)
Income from continuing operations before income taxes	18,027	16,037	39,822	30,424
Income tax expense (benefit)	4,146	3,688	9,159	6,998
Net income	13,881	12,349	30,663	23,426
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	85	895	520	1,674
Other income	4	0	4	0
Total revenue from contracts with customers	895	1,634	2,044	3,228
Revenues outside the scope of ASC 606 (3)	1,268	1,996	3,481	3,453
Operating Segments [Member] | HFF Loan Portfolio [Member]
Operating Statistics [Line Items]
Service charges and fees	0	0	0	0
Cash, Cash Equivalents and Investment Securities	0		0			0
Loans, net of deferred loan fees and costs	1,655,700		1,655,700			1,479,900
Less: Allowance for credit losses	(10,300)		(10,300)			(8,500)
Loans, net	1,645,400		1,645,400			1,471,400
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	100		100			100
Other Assets Segment	7,700		7,700			7,200
Assets	1,653,200		1,653,200			1,478,700
Deposits	0		0			0
Other borrowings	0		0			0
Other Liabilities Segment	(200)		(200)			400
Total liabilities	(200)		(200)			400
Stockholders' equity	138,400		138,400			122,300
Liabilities and Equity	138,200		138,200			122,700
Excess Funds Provided by (Used in) Segment Basis	(1,515,000)		(1,515,000)			(1,356,000)
Net interest income	13,490	13,874	26,434	28,060
Provision for Loan, Lease, and Other Losses	832	548	1,631	1,783
Net interest income (loss) after provision for credit losses	12,658	13,326	24,803	26,277
Total non-interest income	0	0	0	13
Non-interest expense	(2,162)	(2,200)	(4,560)	(4,405)
Income from continuing operations before income taxes	10,496	11,126	20,243	21,885
Income tax expense (benefit)	2,414	2,559	4,656	5,033
Net income	8,082	8,567	15,587	16,852
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	0	0	0	0
Total revenue from contracts with customers	0	0	0	0
Revenues outside the scope of ASC 606 (3)	0	0	0	13
Operating Segments [Member] | Other National Business Lines [Member]
Operating Statistics [Line Items]
Service charges and fees	1	0	2	0
Cash, Cash Equivalents and Investment Securities	10,400		10,400			0
Loans, net of deferred loan fees and costs	5,015,500		5,015,500			4,154,900
Less: Allowance for credit losses	(43,200)		(43,200)			(38,200)
Loans, net	4,972,300		4,972,300			4,116,700
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	63,800		63,800			37,100
Assets	5,046,500		5,046,500			4,153,800
Deposits	32,400		32,400			0
Other borrowings	0		0			0
Other Liabilities Segment	92,300		92,300			49,600
Total liabilities	124,700		124,700			49,600
Stockholders' equity	414,100		414,100			340,000
Liabilities and Equity	538,800		538,800			389,600
Excess Funds Provided by (Used in) Segment Basis	(4,507,700)		(4,507,700)			(3,764,200)
Net interest income	29,586	19,672	55,277	38,484
Provision for Loan, Lease, and Other Losses	2,369	2,074	5,347	3,359
Net interest income (loss) after provision for credit losses	27,217	17,598	49,930	35,125
Total non-interest income	1,549	409	2,207	633
Non-interest expense	(11,073)	(6,250)	(20,409)	(11,912)
Income from continuing operations before income taxes	17,693	11,757	31,728	23,846
Income tax expense (benefit)	4,069	2,704	7,297	5,484
Net income	13,624	9,053	24,431	18,362
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	35	0	74	1
Total revenue from contracts with customers	36	0	76	1
Revenues outside the scope of ASC 606 (3)	1,513	409	2,131	632
Corporate & Other
Operating Statistics [Line Items]
Service charges and fees	0	1	0	3
Cash, Cash Equivalents and Investment Securities	4,914,000		4,914,000			4,240,800
Loans, net of deferred loan fees and costs	7,000		7,000			4,700
Less: Allowance for credit losses	(100)		(100)			0
Loans, net	6,900		6,900			4,700
Other Repossessed Assets	3,100		3,100			3,200
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	737,100		737,100			760,400
Assets	5,661,100		5,661,100			5,009,100
Deposits	666,400		666,400			738,000
Other borrowings	387,200		387,200			851,500
Other Liabilities Segment	444,400		444,400			347,900
Total liabilities	1,498,000		1,498,000			1,937,400
Stockholders' equity	485,400		485,400			422,700
Liabilities and Equity	1,983,400		1,983,400			2,360,100
Excess Funds Provided by (Used in) Segment Basis	(3,677,700)		(3,677,700)			(2,649,000)
Net interest income	2,816	2,242	10,217	237
Provision for Loan, Lease, and Other Losses	0	2	0	2
Net interest income (loss) after provision for credit losses	2,816	2,240	10,217	235
Total non-interest income	2,898	904	6,876	812
Non-interest expense	(15,012)	(7,816)	(27,834)	(16,550)
Income from continuing operations before income taxes	(9,298)	(4,672)	(10,741)	(15,503)
Income tax expense (benefit)	(13,093)	(7,271)	(23,158)	(18,647)
Net income	3,795	2,599	12,417	3,144
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	(10)	15	4	20
Total revenue from contracts with customers	(10)	16	4	23
Revenues outside the scope of ASC 606 (3)	2,908	888	6,872	789
Reportable Geographical Components [Member] | ARIZONA
Operating Statistics [Line Items]
Service charges and fees	1,219	992	2,298	1,909
Cash, Cash Equivalents and Investment Securities	1,800		1,800			2,500
Loans, net of deferred loan fees and costs	3,937,000		3,937,000			3,647,900
Less: Allowance for credit losses	(33,200)		(33,200)			(30,700)
Loans, net						3,617,200
Total loans held for investment	3,903,800		3,903,800
Other Repossessed Assets	700		700			800
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	46,800		46,800			46,900
Assets	3,953,100		3,953,100			3,667,400
Deposits	6,107,000		6,107,000			5,090,200
Other borrowings	0		0			0
Other Liabilities Segment	13,200		13,200			10,400
Total liabilities	6,120,200		6,120,200			5,100,600
Stockholders' equity	484,600		484,600			441,000
Liabilities and Equity	6,604,800		6,604,800			5,541,600
Excess Funds Provided by (Used in) Segment Basis	2,651,700		2,651,700			1,874,200
Net interest income	59,719	57,977	114,945	112,532
Provision for Loan, Lease, and Other Losses	1,443	518	1,604	1,952
Net interest income (loss) after provision for credit losses	58,276	57,459	113,341	110,580
Total non-interest income	1,707	2,256	3,229	3,672
Non-interest expense	(22,693)	(22,419)	(44,943)	(43,923)
Income from continuing operations before income taxes	37,290	37,296	71,627	70,329
Income tax expense (benefit)	9,322	9,324	17,907	17,645
Net income	27,968	27,972	53,720	52,684
Debit and credit card interchange fees	337	281	675	538
Success fees (2)	0	0	0	0
Other income	(8)	49	1	110
Total revenue from contracts with customers	1,548	1,322	2,974	2,557
Revenues outside the scope of ASC 606 (3)	159	934	255	1,115
Reportable Geographical Components [Member] | NEVADA
Operating Statistics [Line Items]
Service charges and fees	2,031	2,107	3,946	4,177
Cash, Cash Equivalents and Investment Securities	7,600		7,600			10,900
Loans, net of deferred loan fees and costs	2,095,200		2,095,200			2,003,500
Less: Allowance for credit losses	(18,100)		(18,100)			(18,700)
Loans, net						1,984,800
Total loans held for investment	2,077,100		2,077,100
Other Repossessed Assets	13,900		13,900			13,900
Intangible Assets, Net (Including Goodwill)	23,200		23,200			23,200
Other Assets Segment	57,600		57,600			57,800
Assets	2,179,400		2,179,400			2,090,600
Deposits	4,188,600		4,188,600			3,996,400
Other borrowings	0		0			0
Other Liabilities Segment	11,900		11,900			14,500
Total liabilities	4,200,500		4,200,500			4,010,900
Stockholders' equity	286,000		286,000			277,400
Liabilities and Equity	4,486,500		4,486,500			4,288,300
Excess Funds Provided by (Used in) Segment Basis	2,307,100		2,307,100			2,197,700
Net interest income	39,528	35,276	78,626	71,966
Provision for Loan, Lease, and Other Losses	(305)	(243)	228	(1,967)
Net interest income (loss) after provision for credit losses	39,833	35,519	78,398	73,933
Total non-interest income	2,677	2,679	5,250	6,012
Non-interest expense	(14,107)	(15,931)	(29,888)	(30,015)
Income from continuing operations before income taxes	28,403	22,267	53,760	49,930
Income tax expense (benefit)	5,965	4,676	11,289	10,579
Net income	22,438	17,591	42,471	39,351
Debit and credit card interchange fees	383	342	759	613
Success fees (2)	0	0	0	0
Other income	(31)	50	(7)	119
Total revenue from contracts with customers	2,383	2,499	4,698	4,909
Revenues outside the scope of ASC 606 (3)	294	180	552	1,103
Reportable Geographical Components [Member] | Southern California [Member]
Operating Statistics [Line Items]
Service charges and fees	722	681	1,447	1,418
Cash, Cash Equivalents and Investment Securities	2,100		2,100			2,500
Loans, net of deferred loan fees and costs	2,256,700		2,256,700			2,161,100
Less: Allowance for credit losses	(19,500)		(19,500)			(19,800)
Loans, net						2,141,300
Total loans held for investment	2,237,200		2,237,200
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	0		0			0
Other Assets Segment	16,100		16,100			14,200
Assets	2,255,400		2,255,400			2,158,000
Deposits	2,535,900		2,535,900			2,347,500
Other borrowings	0		0			0
Other Liabilities Segment	500		500			4,500
Total liabilities	2,536,400		2,536,400			2,352,000
Stockholders' equity	255,600		255,600			242,900
Liabilities and Equity	2,792,000		2,792,000			2,594,900
Excess Funds Provided by (Used in) Segment Basis	536,600		536,600			436,900
Net interest income	31,644	27,664	62,120	55,466
Provision for Loan, Lease, and Other Losses	67	(276)	800	454
Net interest income (loss) after provision for credit losses	31,577	27,940	61,320	55,012
Total non-interest income	974	966	1,975	1,967
Non-interest expense	(15,122)	(14,491)	(29,704)	(28,137)
Income from continuing operations before income taxes	17,429	14,415	33,591	28,842
Income tax expense (benefit)	4,880	4,036	9,406	8,171
Net income	12,549	10,379	24,185	20,671
Debit and credit card interchange fees	193	161	367	300
Success fees (2)	0	0	0	0
Other income	(6)	17	2	44
Total revenue from contracts with customers	909	859	1,816	1,762
Revenues outside the scope of ASC 606 (3)	65	107	159	205
Reportable Geographical Components [Member] | Northern California [Member]
Operating Statistics [Line Items]
Service charges and fees	967	981	1,857	2,039
Cash, Cash Equivalents and Investment Securities	1,900		1,900			3,000
Loans, net of deferred loan fees and costs	1,195,400		1,195,400			1,300,200
Less: Allowance for credit losses	(9,200)		(9,200)			(10,700)
Loans, net						1,289,500
Total loans held for investment	1,186,200		1,186,200
Other Repossessed Assets	0		0			0
Intangible Assets, Net (Including Goodwill)	155,100		155,100			155,500
Other Assets Segment	17,000		17,000			23,900
Assets	1,360,200		1,360,200			1,471,900
Deposits	2,008,900		2,008,900			1,839,100
Other borrowings	0		0			0
Other Liabilities Segment	14,700		14,700			12,200
Total liabilities	2,023,600		2,023,600			1,851,300
Stockholders' equity	297,500		297,500			304,100
Liabilities and Equity	2,321,100		2,321,100			2,155,400
Excess Funds Provided by (Used in) Segment Basis	960,900		960,900			$ 683,500
Net interest income	23,996	23,001	47,029	45,256
Provision for Loan, Lease, and Other Losses	(152)	13	(871)	1,561
Net interest income (loss) after provision for credit losses	24,148	22,988	47,900	43,695
Total non-interest income	2,162	2,421	4,382	4,969
Non-interest expense	(12,549)	(13,429)	(26,040)	(25,932)
Income from continuing operations before income taxes	13,761	11,980	26,242	22,732
Income tax expense (benefit)	3,853	3,355	7,348	6,452
Net income	9,908	8,625	18,894	16,280
Debit and credit card interchange fees	1,062	858	2,033	1,695
Success fees (2)	0	19	0	21
Other income	(2)	42	23	115
Total revenue from contracts with customers	2,027	1,900	3,913	3,870
Revenues outside the scope of ASC 606 (3)	$ 135	$ 521	$ 469	$ 1,099

Revenue from Contracts with Cus

Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Service charges and fees	$ 5,821	$ 5,672	$ 11,233	$ 11,417
Accounts Receivable, Net	1,500		1,500		$ 1,400
Debit and credit card interchange fees	1,986	1,648	3,853	3,155
Success fees (2)	85	914	520	1,695
Other income	(14)	175	105	411
Total revenue from contracts with customers	7,878	8,409	15,711	16,678
Revenues outside the scope of ASC 606 (3)	6,340	5,035	13,917	8,409
Total non-interest income	14,218	13,444	29,628	25,087
Operating Segments [Member] | HOA Services [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	75	171	163	317
Debit and credit card interchange fees	11	6	19	9
Success fees (2)	0	0	0	0
Other income	4	2	4	2
Total revenue from contracts with customers	90	179	186	328
Revenues outside the scope of ASC 606 (3)	(2)	0	(2)	0
Total non-interest income	88	179	184	328
Operating Segments [Member] | Public and Non-Profit Finance [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	0	0	0	0
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	0	0	0	0
Total revenue from contracts with customers	0	0	0	0
Revenues outside the scope of ASC 606 (3)	0	0	0	0
Total non-interest income	0	0	0	0
Operating Segments [Member] | Technology and Innovation [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	806	739	1,520	1,554
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	85	895	520	1,674
Other income	4	0	4	0
Total revenue from contracts with customers	895	1,634	2,044	3,228
Revenues outside the scope of ASC 606 (3)	1,268	1,996	3,481	3,453
Total non-interest income	2,163	3,630	5,525	6,681
Operating Segments [Member] | HFF Loan Portfolio [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	0	0	0	0
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	0	0	0	0
Total revenue from contracts with customers	0	0	0	0
Revenues outside the scope of ASC 606 (3)	0	0	0	13
Total non-interest income	0	0	0	13
Operating Segments [Member] | Other National Business Lines [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	1	0	2	0
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	35	0	74	1
Total revenue from contracts with customers	36	0	76	1
Revenues outside the scope of ASC 606 (3)	1,513	409	2,131	632
Total non-interest income	1,549	409	2,207	633
Reportable Geographical Components [Member] | ARIZONA
Disaggregation of Revenue [Line Items]
Service charges and fees	1,219	992	2,298	1,909
Debit and credit card interchange fees	337	281	675	538
Success fees (2)	0	0	0	0
Other income	(8)	49	1	110
Total revenue from contracts with customers	1,548	1,322	2,974	2,557
Revenues outside the scope of ASC 606 (3)	159	934	255	1,115
Total non-interest income	1,707	2,256	3,229	3,672
Reportable Geographical Components [Member] | NEVADA
Disaggregation of Revenue [Line Items]
Service charges and fees	2,031	2,107	3,946	4,177
Debit and credit card interchange fees	383	342	759	613
Success fees (2)	0	0	0	0
Other income	(31)	50	(7)	119
Total revenue from contracts with customers	2,383	2,499	4,698	4,909
Revenues outside the scope of ASC 606 (3)	294	180	552	1,103
Total non-interest income	2,677	2,679	5,250	6,012
Reportable Geographical Components [Member] | Southern California [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	722	681	1,447	1,418
Debit and credit card interchange fees	193	161	367	300
Success fees (2)	0	0	0	0
Other income	(6)	17	2	44
Total revenue from contracts with customers	909	859	1,816	1,762
Revenues outside the scope of ASC 606 (3)	65	107	159	205
Total non-interest income	974	966	1,975	1,967
Reportable Geographical Components [Member] | Northern California [Member]
Disaggregation of Revenue [Line Items]
Service charges and fees	967	981	1,857	2,039
Debit and credit card interchange fees	1,062	858	2,033	1,695
Success fees (2)	0	19	0	21
Other income	(2)	42	23	115
Total revenue from contracts with customers	2,027	1,900	3,913	3,870
Revenues outside the scope of ASC 606 (3)	135	521	469	1,099
Total non-interest income	2,162	2,421	4,382	4,969
Corporate & Other
Disaggregation of Revenue [Line Items]
Service charges and fees	0	1	0	3
Debit and credit card interchange fees	0	0	0	0
Success fees (2)	0	0	0	0
Other income	(10)	15	4	20
Total revenue from contracts with customers	(10)	16	4	23
Revenues outside the scope of ASC 606 (3)	2,908	888	6,872	789
Total non-interest income	$ 2,898	$ 904	$ 6,876	$ 812

Uncategorized Items - wal630201

Label	Element	Value
Supplemental Employee Retirement Plan [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	$ 469,000
Accumulated Other-than-Temporary Impairment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	144,000
Retained Earnings [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	849,524,000
Additional Paid-in Capital [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	1,424,540,000
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	(12,556,000)
Common Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	$ 10,000
Shares, Issued	us-gaap_SharesIssued	105,487,000
AOCI Attributable to Parent [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	$ (4,203,000)
Treasury Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(40,173,000)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax	$ 7,740,000