Pacwest Bancorp (PACW) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 07, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	PACWEST BANCORP
Entity Central Index Key	1,102,112
Document Period End Date	Mar. 31, 2018
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		125,133,358

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS:
Cash and due from banks	$ 235,061	$ 233,215
Interest-earning deposits in financial institutions	312,735	165,222
Total cash, cash equivalents, and restricted cash	547,796	398,437
Securities available-for-sale, at fair value	3,801,986	3,774,431
Federal Home Loan Bank stock, at cost	17,250	20,790
Total investment securities	3,819,236	3,795,221
Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group	0	481,100
Gross loans and leases held for investment	16,516,627	17,032,221
Deferred fees, net	(61,342)	(59,478)
Allowance for loan and lease losses	(134,275)	(139,456)
Total loans and leases held for investment, net	16,321,010	16,833,287
Equipment leased to others under operating leases	280,648	284,631
Premises and equipment, net	33,686	31,852
Foreclosed assets, net	1,236	1,329
Deferred tax asset, net	12,584	0
Goodwill	2,548,670	2,548,670
Core deposit and customer relationship intangibles, net	73,280	79,626
Other assets	511,184	540,723
Total assets	24,149,330	24,994,876
LIABILITIES AND STOCKHOLDERS' EQUITY
Noninterest-bearing deposits	8,232,140	8,508,044
Interest-bearing deposits	9,846,648	10,357,492
Total deposits	18,078,788	18,865,536
Borrowings	575,284	467,342
Subordinated debentures	452,223	462,437
Accrued interest payable and other liabilities	175,545	221,963
Total liabilities	19,281,840	20,017,278
Commitments and contingencies
Preferred stock ($0.01 par value; 5,000,000 shares authorized; none issued and outstanding)	0	0
Common stock ($0.01 par value, 200,000,000 shares authorized at March 31, 2018 and December 31, 2017; 126,537,871 and 130,491,108 shares issued, respectively, including 1,383,914 and 1,436,120 shares of unvested restricted stock, respectively)	1,283	1,305
Additional paid-in capital	4,111,226	4,287,487
Retained earnings	835,611	723,471
Treasury stock, at cost (1,763,416 and 1,708,230 shares at March 31, 2018 and December 31, 2017)	(68,694)	(65,836)
Accumulated other comprehensive income, net	(11,936)	31,171
Total stockholders' equity	4,867,490	4,977,598
Total liabilities and stockholders' equity	$ 24,149,330	$ 24,994,876

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Preferred stock par value (usd per share)	$ 0.01	$ 0.01
Preferred stock authorized (shares)	5,000,000	5,000,000
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Common Stock par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	200,000,000	200,000,000
Common stock issued (shares)	126,537,871	130,491,108
Unvested restricted shares (shares)	1,383,914	1,436,120
Treasury Stock (shares)	1,763,416	1,708,320

Condensed Consolidated Statemen

Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Interest income:
Loans and leases	$ 251,085	$ 258,309	$ 224,178
Investment securities	26,138	25,712	23,039
Deposits in financial institutions	552	576	192
Total interest income	277,775	284,597	247,409
Interest expense:
Deposits	13,818	14,041	8,377
Borrowings	920	1,366	1,018
Subordinated debentures	6,537	6,234	5,562
Total interest expense	21,275	21,641	14,957
Net interest income	256,500	262,956	232,452
Provision for credit losses	4,000	6,406	24,728
Net interest income after provision for credit losses	252,500	256,550	207,724
Noninterest income:
Service charges on deposit accounts	4,174	4,574	3,758
Other commissions and fees	10,265	10,505	10,390
Leased equipment income	9,587	8,258	9,475
Gain on sale of loans and leases	4,569	1,988	712
Gain (loss) on sale of securities	6,311	(3,329)	(99)
Other income	3,653	4,799	10,878
Total noninterest income	38,559	26,795	35,114
Noninterest expense:
Compensation	71,023	71,986	64,880
Occupancy	13,223	12,715	11,608
Data processing	6,659	6,764	7,015
Other professional services	4,439	5,786	3,378
Insurance and assessments	5,727	5,384	4,791
Intangible asset amortization	6,346	5,062	3,064
Leased equipment depreciation	5,375	5,048	5,625
Foreclosed assets (income) expense, net	(122)	(475)	143
Acquisition, integration and reorganization costs	0	16,085	500
Loan expense	2,271	3,140	3,387
Other expense	12,454	11,373	12,153
Total noninterest expense	127,395	142,868	116,544
Earnings before income taxes	163,664	140,477	126,294
Income tax expense	(45,388)	(56,440)	(47,626)
Net earnings	$ 118,276	$ 84,037	$ 78,668
Earnings per share:
Net earnings (usd per share)	$ 0.93	$ 0.66	$ 0.65
Net earnings (usd per share)	0.93	0.66	0.65
Dividends declared per share (usd per share)	$ 0.50	$ 0.5	$ 0.5

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net earnings		$ 118,276	$ 84,037	$ 78,668
Other comprehensive (loss) income, net of tax:
Unrealized net holding gains (losses) on securities available-for-sale arising during the period		(62,669)	(7,146)	11,184
Income tax (expense) benefit related to unrealized holding gains (losses) arising during the period		17,931	2,574	(4,507)
Unrealized net holding gains (losses) on securities available-for-sale, net of tax		(44,738)	(4,572)	6,677
Reclassification adjustment for net (gains) losses included in net earnings	[1]	(6,311)	3,329	99
Income tax expense (benefit) related to reclassification adjustment		1,806	(1,199)	(40)
Reclassification adjustment for net (gains) losses included in net earnings, net of tax		(4,505)	2,130	59
Other comprehensive (loss) income, net of tax		(49,243)	(2,442)	6,736
Comprehensive income		$ 69,033	$ 81,595	$ 85,404
[1]	Entire amounts are recognized in "Gain (loss) on sale of securities" on the Condensed Consolidated Statements of Earnings.

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Shareholders' Equity - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Shares Of Common Stock [Member]	Accumulated Other Comprehensive Income (Loss)
Balance, December 31, 2017 at Dec. 31, 2017		$ 4,977,598	$ 1,305	$ 4,287,487	$ 723,471	$ (65,836)		$ 31,171
Shares outstanding, beginning balance (shares) at Dec. 31, 2017			128,782,878
Stockholders' Equity Disclosure [Rollforward]
Cumulative effect of change in accounting principle	[1]	0		0	(6,136)
Net earnings		118,276			118,276
Other comprehensive income - net unrealized gain on securities available-for-sale, net of tax		(49,243)						(49,243)
Restricted stock awarded and earned compensation, net of shares forfeited (shares)			96,034
Restricted stock awarded and earned stock compensation, net of shares forfeited		7,199	$ 1	7,198
Restricted stock surrendered (shares)			(55,186)				(2,285,855)
Restricted stock surrendered		(2,858)				(2,858)
Cash dividends paid		(63,689)		(63,689)
Balance, March 31, 2018 at Mar. 31, 2018		$ 4,867,490	$ 1,283	4,111,226	$ 835,611	(68,694)		$ (11,936)
Shares outstanding, ending balance (shares) at Mar. 31, 2018			126,537,871
Stockholders' Equity Disclosure [Rollforward]
Stock Repurchased During Period, Shares		23,000
Common Stock Repurchased Under Stock Repurchase Program, Amount Repurchased		$ 119,793		$ 119,770		$ 0
[1]	Impact due to adoption on January 1, 2018 of

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Cash flows from operating activities:
Net earnings	$ 118,276		$ 78,668
Depreciation and amortization	8,751		8,496
Amortization of net premiums on securities available-for-sale	8,432		10,601
Amortization of intangible assets	6,346	$ 5,062	3,064
Provision for credit losses	4,000	6,406	24,728
Provision for losses on foreclosed assets	65		0
Gain on sale of loans and leases	(4,569)	(1,988)	(712)
Loss (gain) on sale of premises and equipment	7		(560)
(Gain) loss on sale of securities	(6,311)		99
Gain on BOLI death benefit	0		(471)
Unrealized (gain) loss on derivatives and foreign currencies, net	(605)		202
Earned stock compensation	7,199		6,470
Decrease in deferred income taxes, net	7,153		1,091
Decrease in other assets	38,208		661
(Decrease) increase in accrued interest payable and other liabilities	(50,969)		10,852
Net cash provided by operating activities	135,983		143,189
Cash flows from investing activities:
Net decrease (increase) in loans and leases	382,590		(157,244)
Proceeds from sales of loans and leases	615,376		37,173
Proceeds from maturities and paydowns of securities available-for-sale	75,125		92,612
Proceeds from sales of securities available-for-sale	306,253		42,996
Purchases of securities available-for-sale	(487,105)		(248,187)
Net redemptions of Federal Home Loan Bank stock	3,540		3,969
Proceeds from sales of foreclosed assets	28		212
Purchases of premises and equipment, net	(3,997)		(1,944)
Proceeds from sales of premises and equipment	0		10,290
Proceeds from BOLI death benefit	0		1,192
Net (increase) decrease in equipment leased to others under operating leases	(1,241)		114
Net cash provided by (used in) investing activities	890,569		(218,817)
Cash flows from financing activities:
Net (decrease) increase in noninterest-bearing deposits	(275,579)		131,170
Net (decrease) increase in interest-bearing deposits	(510,844)		329,605
Net increase (decrease) in borrowings	107,942		(445,203)
Early Repayment of Subordinated Debt	(12,372)		0
Common stock repurchased and restricted stock surrendered	(122,651)		(2,281)
Cash dividends paid	(63,689)		(60,833)
Net cash (used in) financing activities	(877,193)		(47,542)
Net increase (decrease) in cash, cash equivalents, and restricted cash	149,359		(123,170)
Cash, cash equivalents, and restricted cash, beginning of period	398,437		419,670
Cash, cash equivalents, and restricted cash, end of period	547,796	$ 398,437	296,500
Supplemental disclosures of cash flow information:
Cash paid for interest	17,515		14,352
Cash paid for income taxes	3,790		2,834
Loans transferred to foreclosed assets	$ 0		$ 78

Organization

Organization	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	ORGANIZATION PacWest Bancorp, a Delaware corporation, is a bank holding company registered under the BHCA, with our corporate headquarters located in Beverly Hills, California. Our principal business is to serve as the holding company for our wholly-owned subsidiary, Pacific Western Bank. References to "Pacific Western" or the "Bank" refer to Pacific Western Bank together with its wholly-owned subsidiaries. References to "we," "us," or the "Company" refer to PacWest Bancorp together with its subsidiaries on a consolidated basis. When we refer to "PacWest" or to the "holding company," we are referring to PacWest Bancorp, the parent company, on a stand-alone basis. We are focused on relationship-based business banking to small, middle-market and venture-backed businesses nationwide. At March 31, 2018 , the Bank offers a broad range of loan and lease and deposit products and services through 75 full-service branches located throughout the State of California, one branch located in Durham, North Carolina, and several loan production offices located in cities across the country. We provide commercial banking services, including real estate, construction, and commercial loans, and comprehensive deposit and treasury management services to small and middle-market businesses. We offer additional products and services through our CapitalSource and Square 1 Bank Divisions. Our CapitalSource Division provides asset-based, equipment, real estate, security cash flow loans and treasury management services to established middle-market businesses on a national basis. Our Square 1 Bank Division offers a comprehensive suite of financial services focused on entrepreneurial businesses and their venture capital and private equity investors, with offices located in key innovation hubs across the United States. In addition, we provide investment advisory and asset management services to select clients through Square 1 Asset Management, Inc., a wholly-owned subsidiary of the Bank and a SEC-registered investment adviser. We generate our revenue primarily from interest received on loans and leases and, to a lesser extent, from interest received on investment securities, and fees received in connection with deposit services, extending credit and other services offered, including foreign exchange services. Our major operating expenses are compensation, occupancy, general operating expenses, and the interest paid by the Bank on deposits and borrowings. We have completed 29 acquisitions from May 1, 2000 through March 31, 2018 . Our acquisitions have been accounted for using the acquisition method of accounting and, accordingly, the operating results of the acquired entities have been included in the consolidated financial statements from their respective acquisition dates. See Note 3. Acquisitions, for more information about the CUB acquisition. Significant Accounting Policies Our accounting policies are described in Note 1. Nature of Operations and Summary of Significant Accounting Policies , of our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017 as filed with the Securities and Exchange Commission ("Form 10-K"). Updates to our significant accounting policies described below reflect the impact of the adoption of ASU 2016-01, " Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities " and ASU 2018-03, “ Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” Investment Securities Our significant accounting policy for investment securities applied to both debt and equity securities in prior periods. Effective January 1, 2018, upon the adoption of ASUs 2016-01 and 2018-03, our significant accounting policy for investment securities applies only to debt securities. Equity Investments Investments in common or preferred stock that are not publicly traded and certain investments in limited partnerships are considered equity investments that do not have a readily determinable fair value. If we have the ability to significantly influence the operating and financial policies of the investee, the investment is accounted for pursuant to the equity method of accounting. This is generally presumed to exist when we own between 20% and 50% of a corporation, or when we own greater than 5% of a limited partnership or similarly structured entity. Our equity investment carrying values are included in other assets and our share of earnings and losses in equity method investees is included in "Noninterest income - other" on the condensed consolidated statements of earnings. Prior to January 1, 2018, if we did not have significant influence over the investee, the cost method was used to account for the equity interest. Effective January 1, 2018 with the adoption of ASU 2016-01, our accounting treatment for equity investments differs for those with and without readily determinable fair values. Equity investments with readily determinable fair values are recorded at fair value with changes in fair value recorded in “Noninterest income - other.” For equity investments without readily determinable fair values we have elected the “measurement alternative,” and therefore carry these investments at cost, less impairment (if any), plus or minus changes in observable prices. On a quarterly basis, we review our equity investments without readily determinable fair values for impairment. We consider a number of qualitative factors such as whether there is a significant deterioration in earnings performance, credit rating, asset quality, or business prospects of the investee in determining if impairment exists. If the investment is considered impaired, an impairment loss equal to the amount by which the carrying value exceeds its fair value is recorded through a charge to earnings. The impairment loss may be reversed in a subsequent period if there are observable transactions for the identical or similar investment of the same issuer at a higher amount than the carrying amount that was established when the impairment was recognized. Realized gains or losses resulting from the sale of equity investments are calculated using the specific identification method and are included in "Noninterest income - other." Comprehensive Income Comprehensive income consists of net earnings and net unrealized gains (losses) on debt securities available‑for‑sale, net, and is presented in the consolidated statements of comprehensive income. Accounting Standards Adopted in 2018 Effective January 1, 2018, the Company adopted ASU 2014-09, " Revenue Recognition (Topic 606): Revenue from Contracts with Customers ." ASU 2014-09 supersedes Topic 605, " Revenue Recognition " and requires an entity to recognize revenue at an amount that reflects the consideration to which it expects to be entitled to in exchange for the transfer of promised goods or services to customers. Substantially all of the Company's revenue is interest income on loans, investment securities, and deposits at other financial institutions which are specifically outside the scope of ASU 2014-09. ASU 2014-09 applies primarily to certain noninterest income items in the Company's condensed consolidated statement of earnings. The Company adopted ASU 2014-09 as of January 1, 2018 using the cumulative effect transition method, which resulted in no adjustment to retained earnings and no material impact on the Company's consolidated financial position, results of operations, or cash flows. The Company did make minor changes to accounting operations and internal controls as part of adopting this new standard. See Note 13. Revenue From Contracts With Customers for further details. Effective January 1, 2018, the Company adopted ASU 2016-01, " Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities " and ASU 2018-03, “ Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-01 contained a number of changes which are applicable to the Company including the following: (1) requires equity investments to be measured at fair value with changes in fair value recognized in net income; (2) allows equity investments without readily determinable fair values to be measured at cost less impairment, if any, plus or minus changes in observable prices (referred to as the "measurement alternative"); and (3) changes certain presentation and disclosure requirements for financial instruments, including using the exit price notion when measuring the fair value of financial instruments (see Note 11. Fair Value Measurements) . ASU 2018-03 also clarified certain aspects of the guidance issued in ASU 2016-01, including requiring a prospective transition approach for equity investments without readily determinable fair value in which the measurement alternative is applied. ASU 2016-01 does not apply to investments accounted for using the equity method, investments in consolidated subsidiaries, FHLB stock, and investments in low income housing tax credit projects. Upon adoption of ASU 2016-01, the Company recorded a transition adjustment to reclassify $529,000 in net unrealized gains from accumulated other comprehensive income ("AOCI") to retained earnings. The ASU also eliminated the requirement to classify equity investments into different categories such as “Available-for-Sale.” The adoption of this ASU may result in more earnings volatility as changes in fair value of certain equity investments will now be recorded in the statement of earnings as opposed to AOCI. Effective January 1, 2018, the Company adopted ASU 2016-15, " Classification of Certain Cash Receipts and Cash Payments." Upon adoption , the Company applied the retrospective transition method to each period presented. ASU 2016-15 addressed eight issues related to the statement of cash flows, the most relevant to the Company being the classification of proceeds from the settlement of BOLI policies. As the Company classified proceeds from the settlement of BOLI policies in the manner required by ASU 2016-15 in the prior periods presented, there was no change to the Company's consolidated financial position, results of operations, or cash flows for both current and prior periods upon adoption. Effective January 1, 2018, the Company adopted ASU 2016-18, " Statement of Cash Flows (Topic 230): Restricted Cash ." Upon adoption, the Company applied the retrospective transition method to each period presented. As the Company does not present restricted cash as a separate line in the statement of financial position, there is no change to the presentation of cash on the statement of cash flows. The nature and amount of our restricted cash is shown in Note 2. Restricted Cash Balances . Effective January 1, 2018, the Company adopted ASU 2017-01, " Business Combinations (Topic 805): Clarifying the Definition of a Business." ASU 2017-01 provides a new framework for determining whether transactions should be accounted for as acquisitions of assets or businesses. The Company had no acquisitions or purchases of components of a business in the first quarter of 2018, thus, the impact of adopting the new standard had no impact on the Company's consolidated financial position, results of operations, or cash flows. Effective January 1, 2018, the Company adopted ASU 2017-09, " Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting." ASU 2017-09 provided clarification of what constitutes a modification of a share-based payment award. The Company did not modify any share-based payment awards in the first quarter of 2018, thus, the impact of adopting the new standard had no impact on the Company's consolidated financial position, results of operations, or cash flows. Effective January 1, 2018, the Company early-adopted ASU 2018-02, " Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The TCJA required deferred tax assets and liabilities to be re-measured at its enactment date for the effect of the change in the federal corporate tax rate. This process resulted in "stranded tax effects" in AOCI for deferred tax asset or liabilities which were established with an offsetting amount in AOCI. ASU 2018-02 allows for a reclassification of the stranded tax effects resulting from the enactment of the TCJA from AOCI to retained earnings. The Company elected to reclassify its stranded tax effects of $6.665 million from AOCI to retained earnings effective January 1, 2018, while no other income tax effects related to the application of the TCJA were reclassified. Basis of Presentation Our interim condensed consolidated financial statements are prepared in accordance with U.S. GAAP for interim financial information and pursuant to the requirements for reporting on Form 10-Q and Article 10 of Regulation S-X of the Securities Exchange Act of 1934. Accordingly, certain disclosures accompanying annual consolidated financial statements are omitted. In the opinion of management, all significant intercompany accounts and transactions have been eliminated and adjustments, consisting solely of normal recurring accruals and considered necessary for the fair presentation of financial statements for the interim periods, have been included. The current period's results of operations are not necessarily indicative of the results that ultimately may be achieved for the year. The interim condensed consolidated financial statements and notes thereto should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Form 10-K. Use of Estimates We have made a number of estimates and assumptions related to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period to prepare these condensed consolidated financial statements in conformity with U.S. GAAP. Actual results could differ from those estimates. Material estimates subject to change in the near term include, among other items, the allowance for credit losses, the carrying value of intangible assets, the realization of deferred tax assets, and the fair value estimates of assets acquired and liabilities assumed in acquisitions. These estimates may be adjusted as more current information becomes available, and any adjustment may be significant. Reclassifications Certain prior period amounts have been reclassified to conform to the current period’s presentation format. In our loan and allowance tables, we realigned our commercial loan portfolio classes and subclasses to better reflect and report our lending, especially in light of the fourth quarter of 2017 cash flow loan sale and the exiting of the origination operations related to general, technology, and healthcare cash flow loans. Prior to the realignment, our commercial portfolio classes were: (1) asset-based, (2) venture capital, (3) cash flow, and (4) equipment finance. After the realignment, our commercial portfolio classes are (1) asset-based (which includes equipment finance), (2) venture capital, and (3) other commercial (which includes retained cash flow). All of the loan and allowance tables, both current period and prior periods, reflect this realignment. In prior periods, our credit quality disclosures were only for Non-PCI loans and leases. As our gross PCI loan portfolio reduced to less than 0.4% of total loans as of the end of 2017, beginning in 2018 the credit quality disclosures reflect our entire loan and lease portfolio. Accordingly, for the credit quality tables in Note 6. Loans and Leases, amounts related to the 2018 period are for total loans and leases, while amounts related to the 2017 period are for Non-PCI loans and leases only.

Restricted Cash

Restricted Cash	3 Months Ended
	Mar. 31, 2018
Restricted Cash [Abstract]
Restrictions on Cash and Cash Equivalents	RESTRICTED CASH BALANCES The Company is required to maintain reserve balances with the FRBSF. Such reserve requirements are based on a percentage of deposit liabilities and may be satisfied by cash on hand. The average reserves required to be held at the FRBSF for the three months ended March 31, 2018 and year ended December 31, 2017 were $80.7 million and $77.6 million . As of March 31, 2018 and December 31, 2017 , we pledged cash collateral for our derivative contracts of $3.7 million and $2.7 million .

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2018
Acquisitions [Abstract]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustments	ACQUISITIONS CUB Acquisition On October 20, 2017 , we completed the acquisition of CUB. As part of the acquisition, CU Bank, a wholly-owned subsidiary of CUB, was merged with and into PacWest's wholly-owned banking subsidiary, Pacific Western Bank. We completed the acquisition to, among other things, enhance our Southern California community bank franchise by adding a $2.1 billion loan portfolio and $2.7 billion of core deposits. The CUB acquisition has been accounted for under the acquisition method of accounting. We acquired $3.5 billion of assets and assumed $2.8 billion of liabilities upon closing of the acquisition. The assets and liabilities, both tangible and intangible, were recorded at their estimated fair values as of the acquisition date. We made significant estimates and exercised significant judgment in estimating fair values and accounting for such acquired assets and liabilities. Such fair values are preliminary estimates and are subject to adjustment for up to one year after the acquisition date or when additional information relative to the closing date fair values becomes available and such information is considered final, whichever is earlier. The application of the acquisition method of accounting resulted in goodwill of $374.7 million . All of the recognized goodwill is non-deductible fo r tax purposes.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill and other intangible assets arise from the acquisition method of accounting for business combinations. Goodwill and other intangible assets generated from business combinations and deemed to have indefinite lives are not subject to amortization and instead are tested for impairment at least annually. Goodwill represents the excess of the purchase price over the fair value of the net assets and other identifiable intangible assets acquired. Impairment exists when the carrying value of the goodwill exceeds its implied fair value. An impairment loss would be recognized in an amount equal to that excess as a charge to "Noninterest expense" in the condensed consolidated statements of earnings. Our other intangible assets with definite lives include CDI and CRI. CDI and CRI are amortized over their respective estimated useful lives and reviewed for impairment at least quarterly. The amortization expense represents the estimated decline in the value of the underlying deposits or loan and lease customers acquired. The aggregate amortization expense is expected to be $22.5 million for 2018 . The estimated aggregate amortization expense related to these intangible assets for each of the next five years is $18.7 million for 2019 , $14.6 million for 2020 , $10.8 million for 2021 , $7.5 million for 2022 , and $1.4 million for 2023 . The following table presents the changes in CDI and CRI and the related accumulated amortization for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (In thousands) Gross Amount of CDI and CRI: Balance, beginning of period $ 119,497 $ 61,997 $ 64,187 Addition from CUB acquisition — 57,500 — Balance, end of period 119,497 119,497 64,187 Accumulated Amortization: Balance, beginning of period (39,871 ) (34,809 ) (27,821 ) Amortization (6,346 ) (5,062 ) (3,064 ) Balance, end of period (46,217 ) (39,871 ) (30,885 ) Net CDI and CRI, end of period $ 73,280 $ 79,626 $ 33,302

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	INVESTMENT SECURITIES Securities Available-for-Sale The following table presents amortized cost, gross unrealized gains and losses, and fair values of securities available-for-sale as of the dates indicated: March 31, 2018 December 31, 2017 Gross Gross Gross Gross Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair Security Type Cost Gains Losses Value Cost Gains Losses Value (In thousands) Residential MBS and CMOs: Agency MBS $ 251,585 $ 2,748 $ (2,557 ) $ 251,776 $ 243,375 $ 3,743 $ (844 ) $ 246,274 Agency CMOs 551,021 840 (5,916 ) 545,945 277,638 968 (2,897 ) 275,709 Private label CMOs 114,386 3,071 (1,212 ) 116,245 122,816 3,813 (642 ) 125,987 Municipal securities 1,392,261 19,389 (8,064 ) 1,403,586 1,627,707 53,700 (1,339 ) 1,680,068 Agency commercial MBS 1,114,430 121 (25,057 ) 1,089,494 1,169,969 2,758 (8,758 ) 1,163,969 U.S. Treasury securities 148,217 365 — 148,582 — — — — SBA securities 148,787 706 (1,229 ) 148,264 160,214 695 (575 ) 160,334 Asset-backed securities 81,022 11 (1,299 ) 79,734 89,425 159 (874 ) 88,710 Corporate debt securities 17,000 1,360 — 18,360 17,000 2,295 — 19,295 Collateralized loan obligations — — — — 6,960 55 — 7,015 Equity investments — — — — 6,421 779 (130 ) 7,070 Total $ 3,818,709 $ 28,611 $ (45,334 ) $ 3,801,986 $ 3,721,525 $ 68,965 $ (16,059 ) $ 3,774,431 In connection with our adoption of ASU 2016-01 and ASU 2018-03 on January 1, 2018, we reclassified $7.1 million of equity investments from securities available-for-sale to other assets in the first quarter of 2018. The reclassification was applied prospectively without prior period amounts being restated. As of March 31, 2018 , securities available-for-sale with a fair value of $433.3 million were pledged as collateral for borrowings, public deposits and other purposes as required by various statutes and agreements. During the three months ended March 31, 2018 , we sold $299.9 million of securities available-for-sale for a gross realized gain of $6.8 million and a gross realized loss of $515,000 . During the three months ended March 31, 2017 , we sold $43.1 million of securities available-for-sale for a gross realized gain of $204,000 and a gross realized loss of $303,000 . Unrealized Losses on Securities Available-for-Sale The following tables present the gross unrealized losses and fair values of securities available-for-sale that were in unrealized loss positions, for which other-than-temporary impairments have not been recognized in earnings, as of the dates indicated: March 31, 2018 Less Than 12 Months 12 Months or More Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized Security Type Value Losses Value Losses Value Losses (In thousands) Residential MBS and CMOs: Agency MBS $ 104,277 $ (1,649 ) $ 24,518 $ (908 ) $ 128,795 $ (2,557 ) Agency CMOs 251,805 (5,359 ) 18,377 (557 ) 270,182 (5,916 ) Private label CMOs 92,396 (1,105 ) 4,446 (107 ) 96,842 (1,212 ) Municipal securities 364,270 (6,320 ) 30,973 (1,744 ) 395,243 (8,064 ) Agency commercial MBS 1,006,897 (21,302 ) 67,387 (3,755 ) 1,074,284 (25,057 ) SBA securities 87,303 (1,229 ) — — 87,303 (1,229 ) Asset-backed securities 64,382 (1,199 ) 7,630 (100 ) 72,012 (1,299 ) Total $ 1,971,330 $ (38,163 ) $ 153,331 $ (7,171 ) $ 2,124,661 $ (45,334 ) December 31, 2017 Less Than 12 Months 12 Months or More Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized Security Type Value Losses Value Losses Value Losses (In thousands) Residential MBS and CMOs: Agency MBS $ 44,795 $ (311 ) $ 26,010 $ (533 ) $ 70,805 $ (844 ) Agency CMOs 163,014 (2,452 ) 20,928 (445 ) 183,942 (2,897 ) Private label CMOs 50,521 (500 ) 5,035 (142 ) 55,556 (642 ) Municipal securities 67,936 (365 ) 32,326 (974 ) 100,262 (1,339 ) Agency commercial MBS 579,373 (3,777 ) 129,060 (4,981 ) 708,433 (8,758 ) SBA securities 74,904 (575 ) — — 74,904 (575 ) Asset-backed securities 45,198 (818 ) 10,473 (56 ) 55,671 (874 ) Equity investments 1,039 (130 ) — — 1,039 (130 ) Total $ 1,026,780 $ (8,928 ) $ 223,832 $ (7,131 ) $ 1,250,612 $ (16,059 ) We reviewed the securities that were in an unrealized loss position at March 31, 2018 , and concluded their unrealized losses were a result of the level of market interest rates relative to the types of securities and pricing changes caused by shifting supply and demand dynamics and not a result of downgraded credit ratings or other indicators of deterioration of the underlying issuers' ability to repay. Accordingly, we determined the securities were temporarily impaired and we did not recognize such impairment in the condensed consolidated statements of earnings. Although we periodically sell securities for portfolio management purposes, we do not foresee having to sell any temporarily impaired securities strictly for liquidity needs and believe that it is more likely than not we would not be required to sell any temporarily impaired securities before recovery of their amortized cost. Contractual Maturities of Securities Available-for-Sale The following table presents the contractual maturities of our securities available-for-sale portfolio based on amortized cost and carrying value as of the date indicated: March 31, 2018 Amortized Fair Maturity Cost Value (In thousands) Due in one year or less $ 10,384 $ 10,517 Due after one year through five years 486,326 483,913 Due after five years through ten years 1,053,610 1,035,714 Due after ten years 2,268,389 2,271,842 Total securities available-for-sale $ 3,818,709 $ 3,801,986 Mortgage-backed securities have contractual terms to maturity, but require periodic payments to reduce principal. In addition, expected maturities may differ from contractual maturities because obligors and/or issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Interest Income on Investment Securities The following table presents the composition of our interest income on investment securities for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (In thousands) Taxable interest $ 14,599 $ 13,724 $ 12,166 Non-taxable interest 11,107 11,429 10,381 Dividend income 432 559 492 Total interest income on investment securities $ 26,138 $ 25,712 $ 23,039

Loans and Leases

Loans and Leases	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Loans and Leases	LOANS AND LEASES Our loans are carried at the principal amount outstanding, net of deferred fees and costs, and in the case of acquired loans, net of purchase discounts and premiums. Deferred fees and costs and purchase discounts and premiums on acquired non-impaired loans are recognized as an adjustment to interest income over the contractual life of the loans primarily using the effective interest method or taken into income when the related loans are paid off or included in the carrying amount of loans that are sold. Prior to January 1, 2018, our loan and lease portfolio consisted of Non-PCI loans and leases and PCI loans. Non-PCI loans and leases were those we originated or those we acquired that were not credit impaired at the dates of acquisition. PCI loans were purchased loans for which there was, at the acquisition date, evidence of credit deterioration since their origination and for which it was probable that collection of all contractually required payments was unlikely. As our gross PCI loan portfolio represented less than 0.4% of total loans as of the end of 2017, beginning in 2018 the PCI loans were accounted for as Non-PCI loans. Accordingly, in the credit quality tables below under " Loans and leases held for investment, " amounts related to the 2018 period are for total loans and leases, and amounts related to the 2017 period are for Non-PCI loans and leases. Loans Held for Sale In the fourth quarter of 2017, we sold $1.5 billion of cash flow loans and exited our CapitalSource Division origination operations related to general, technology, and healthcare cash flow loans. As of December 31, 2017, $1.0 billion of the loans sold had settled, while $481.1 million were classified as held for sale. In connection with the loan sale and transfer of loans to held for sale, we recognized $2.2 million in charge-offs during the fourth quarter of 2017 to record the loans at the lower of cost or fair value. The loans held for sale at December 31, 2017 settled in the first quarter of 2018 and we recorded a gain of $1.3 million . Loans and Leases Held for Investment The following table summarizes the composition of our loans and leases held for investment as of the dates indicated: March 31, 2018 December 31, 2017 Total Non-PCI Total Loans Loans PCI Loans and Leases and Leases Loans and Leases (In thousands) Real estate mortgage $ 7,570,526 $ 7,815,355 $ 53,658 $ 7,869,013 Real estate construction and land 1,699,630 1,611,287 — 1,611,287 Commercial 6,848,576 7,137,978 4,158 7,142,136 Consumer 397,895 409,551 234 409,785 Gross loans and leases held for investment 16,516,627 16,974,171 58,050 17,032,221 Deferred fees, net (61,342 ) (59,464 ) (14 ) (59,478 ) Loans and leases held for investment, net of deferred fees 16,455,285 16,914,707 58,036 16,972,743 Allowance for loan and lease losses (134,275 ) (133,012 ) (6,444 ) (139,456 ) Total loans and leases held for investment, net $ 16,321,010 $ 16,781,695 $ 51,592 $ 16,833,287 The following tables present an aging analysis of our loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated: March 31, 2018 30 - 89 90 or More Days Days Total Past Due Past Due Past Due Current Total (In thousands) Real estate mortgage: Commercial $ 26,262 $ 6,849 $ 33,111 $ 4,999,895 $ 5,033,006 Residential 1,512 1,976 3,488 2,517,749 2,521,237 Total real estate mortgage 27,774 8,825 36,599 7,517,644 7,554,243 Real estate construction and land: Commercial — — — 789,892 789,892 Residential 2,605 — 2,605 884,505 887,110 Total real estate construction and land 2,605 — 2,605 1,674,397 1,677,002 Commercial: Asset-based — 680 680 2,957,210 2,957,890 Venture capital 737 1,492 2,229 1,918,414 1,920,643 Other commercial 5,133 1,388 6,521 1,941,069 1,947,590 Total commercial 5,870 3,560 9,430 6,816,693 6,826,123 Consumer 1,000 — 1,000 396,917 397,917 Total $ 37,249 $ 12,385 $ 49,634 $ 16,405,651 $ 16,455,285 December 31, 2017 30 - 89 90 or More Days Days Total Past Due Past Due Past Due Current Total (In thousands) Real estate mortgage: Commercial $ 29,070 $ 9,107 $ 38,177 $ 5,323,310 $ 5,361,487 Residential 6,999 2,022 9,021 2,428,483 2,437,504 Total real estate mortgage 36,069 11,129 47,198 7,751,793 7,798,991 Real estate construction and land: Commercial — — — 769,075 769,075 Residential 2,081 — 2,081 820,073 822,154 Total real estate construction and land 2,081 — 2,081 1,589,148 1,591,229 Commercial: Asset-based 344 690 1,034 2,923,837 2,924,871 Venture capital 6,533 760 7,293 2,115,418 2,122,711 Other commercial 2,846 1,586 4,432 2,062,906 2,067,338 Total commercial 9,723 3,036 12,759 7,102,161 7,114,920 Consumer 562 — 562 409,005 409,567 Total (1) $ 48,435 $ 14,165 $ 62,600 $ 16,852,107 $ 16,914,707 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. It is our policy to discontinue accruing interest when principal or interest payments are past due 90 days or more (unless the loan is both well secured and in the process of collection) or when, in the opinion of management, there is a reasonable doubt as to the collectability of a loan or lease in the normal course of business. Interest income on nonaccrual loans is recognized only to the extent cash is received and the principal balance of the loan is deemed collectable. The following table presents our nonaccrual and performing loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated: March 31, 2018 December 31, 2017 (1) Nonaccrual Performing Total Nonaccrual Performing Total (In thousands) Real estate mortgage: Commercial $ 19,116 $ 5,013,890 $ 5,033,006 $ 65,563 $ 5,295,924 $ 5,361,487 Residential 5,225 2,516,012 2,521,237 3,350 2,434,154 2,437,504 Total real estate mortgage 24,341 7,529,902 7,554,243 68,913 7,730,078 7,798,991 Real estate construction and land: Commercial — 789,892 789,892 — 769,075 769,075 Residential — 887,110 887,110 — 822,154 822,154 Total real estate construction and land — 1,677,002 1,677,002 — 1,591,229 1,591,229 Commercial: Asset-based 32,838 2,925,052 2,957,890 33,553 2,891,318 2,924,871 Venture capital 21,861 1,898,782 1,920,643 29,424 2,093,287 2,122,711 Other commercial 24,434 1,923,156 1,947,590 23,874 2,043,464 2,067,338 Total commercial 79,133 6,746,990 6,826,123 86,851 7,028,069 7,114,920 Consumer 251 397,666 397,917 20 409,547 409,567 Total $ 103,725 $ 16,351,560 $ 16,455,285 $ 155,784 $ 16,758,923 $ 16,914,707 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. At March 31, 2018 , nonaccrual loans and leases totaled $103.7 million and included $11.9 million of loans and leases 90 or more days past due, $8.7 million of loans and leases 30 to 89 days past due, and $83.1 million of loans and leases current with respect to contractual payments that were placed on nonaccrual status based on management’s judgment regarding their collectability. Nonaccrual loans and leases totaled $155.8 million at December 31, 2017 , including $14.2 million of the loans and leases 90 or more days past due, $3.2 million of loans and leases 30 to 89 days past due, and $138.4 million of current loans and leases that were placed on nonaccrual status based on management’s judgment regarding their collectability. As of March 31, 2018 , our ten largest loan relationships on nonaccrual status had an aggregate carrying value of $68.8 million and represented 66.3% of total nonaccrual loans and leases. The following table presents the credit risk rating categories for loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated. Classified loans and leases are those with a credit risk rating of either substandard or doubtful. March 31, 2018 Classified Special Mention Pass Total (In thousands) Real estate mortgage: Commercial $ 44,635 $ 158,496 $ 4,829,875 $ 5,033,006 Residential 12,436 1,672 2,507,129 2,521,237 Total real estate mortgage 57,071 160,168 7,337,004 7,554,243 Real estate construction and land: Commercial 453 — 789,439 789,892 Residential — 30,626 856,484 887,110 Total real estate construction and land 453 30,626 1,645,923 1,677,002 Commercial: Asset-based 49,913 54,882 2,853,095 2,957,890 Venture capital 31,364 124,303 1,764,976 1,920,643 Other commercial 68,813 43,681 1,835,096 1,947,590 Total commercial 150,090 222,866 6,453,167 6,826,123 Consumer 428 1,456 396,033 397,917 Total $ 208,042 $ 415,116 $ 15,832,127 $ 16,455,285 December 31, 2017 (1) Classified Special Mention Pass Total (In thousands) Real estate mortgage: Commercial $ 93,795 $ 122,488 $ 5,145,204 $ 5,361,487 Residential 8,425 4,582 2,424,497 2,437,504 Total real estate mortgage 102,220 127,070 7,569,701 7,798,991 Real estate construction and land: Commercial — — 769,075 769,075 Residential — 619 821,535 822,154 Total real estate construction and land — 619 1,590,610 1,591,229 Commercial: Asset-based 51,000 37,256 2,836,615 2,924,871 Venture capital 49,671 114,210 1,958,830 2,122,711 Other commercial 75,251 21,883 1,970,204 2,067,338 Total commercial 175,922 173,349 6,765,649 7,114,920 Consumer 263 1,130 408,174 409,567 Total $ 278,405 $ 302,168 $ 16,334,134 $ 16,914,707 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. In addition to our internal risk rating process, our federal and state banking regulators, as an integral part of their examination process, periodically review the Company’s loan and lease risk rating classifications. Our regulators may require the Company to recognize rating downgrades based on their judgments related to information available to them at the time of their examinations. Risk rating downgrades generally result in increases in the provisions for credit losses and the allowance for credit losses. Nonaccrual loans and leases and performing troubled debt restructured loans are considered impaired for reporting purposes. Troubled debt restructurings are a result of rate reductions, term extensions, fee concessions, and debt forgiveness, or a combination thereof. The following table presents the composition of our impaired loans and leases held for investment, net of deferred fees, by portfolio segment as of the dates indicated: March 31, 2018 December 31, 2017 (1) Performing Total Performing Total Nonaccrual Troubled Impaired Nonaccrual Troubled Impaired Loans Debt Loans Loans Debt Loans and Restructured and and Restructured and Leases Loans Leases Leases Loans Leases (In thousands) Real estate mortgage $ 24,341 $ 51,031 $ 75,372 $ 68,913 $ 47,560 $ 116,473 Real estate construction and land — 5,670 5,670 — 5,690 5,690 Commercial 79,133 3,349 82,482 86,851 3,488 90,339 Consumer 251 123 374 20 100 120 Total $ 103,725 $ 60,173 $ 163,898 $ 155,784 $ 56,838 $ 212,622 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. The following tables present information regarding our impaired loans and leases held for investment, net of deferred fees, by portfolio segment and class as of and for the dates indicated: March 31, 2018 December 31, 2017 (1) Unpaid Unpaid Recorded Principal Related Recorded Principal Related Impaired Loans and Leases Investment Balance Allowance Investment Balance Allowance (In thousands) With An Allowance Recorded: Real estate mortgage: Commercial $ 13,884 $ 14,690 $ 576 $ 15,750 $ 16,548 $ 628 Residential 4,295 4,926 512 2,787 2,957 342 Commercial: Venture capital 17,367 18,312 4,970 16,565 17,203 4,267 Other commercial 18,048 31,672 8,171 20,404 29,951 8,368 Consumer 295 355 16 100 100 16 With No Related Allowance Recorded: Real estate mortgage: Commercial $ 48,729 $ 63,283 $ 93,827 $ 105,923 Residential 8,464 10,674 4,109 4,481 Real estate construction and land: Commercial 5,670 5,670 5,690 5,689 Commercial: Asset-based 32,838 55,890 33,553 54,911 Venture capital 6,129 29,786 14,534 40,029 Other commercial 8,100 27,819 5,283 9,351 Consumer 79 179 20 93 Total Loans and Leases With and Without an Allowance Recorded: Real estate mortgage $ 75,372 $ 93,573 $ 1,088 $ 116,473 $ 129,909 $ 970 Real estate construction and land 5,670 5,670 — 5,690 5,689 — Commercial 82,482 163,479 13,141 90,339 151,445 12,635 Consumer 374 534 16 120 193 16 Total $ 163,898 $ 263,256 $ 14,245 $ 212,622 $ 287,236 $ 13,621 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. Three Months Ended March 31, 2018 2017 Weighted Interest Weighted Interest Average Income Average Income Impaired Loans and Leases Balance (1) Recognized Balance (1) Recognized (In thousands) With An Allowance Recorded: Real estate mortgage: Commercial $ 13,884 $ 201 $ 14,350 $ 206 Residential 4,295 23 3,501 12 Commercial: Venture capital 14,598 — 4,693 — Other commercial 16,851 15 44,333 15 Consumer 295 2 187 — With No Related Allowance Recorded: Real estate mortgage: Commercial $ 46,782 $ 765 $ 92,753 $ 560 Residential 8,464 45 5,216 15 Real estate construction and land: Commercial 5,670 89 6,111 67 Residential — — 572 2 Commercial: Asset-based 32,838 — 30,739 — Venture capital 4,474 — 2,429 — Other commercial 7,859 1,147 4,750 30 Consumer 79 — 127 2 Total Loans and Leases With and Without an Allowance Recorded: Real estate mortgage $ 73,425 $ 1,034 $ 115,820 $ 793 Real estate construction and land 5,670 89 6,683 69 Commercial 76,620 1,162 86,944 45 Consumer 374 2 314 2 Total $ 156,089 $ 2,287 $ 209,761 $ 909 _________________________ (1) For loans and leases reported as impaired at March 31, 2018 and 2017 , amounts were calculated based on the period of time such loans and leases were impaired during the reported period. The following table presents our troubled debt restructurings of loans held for investment by portfolio segment and class for the periods indicated: Three Months Ended March 31, 2018 2017 Pre- Post- Pre- Post- Modification Modification Modification Modification Outstanding Outstanding Outstanding Outstanding Number Recorded Recorded Number Recorded Recorded Troubled Debt Restructurings of Loans Investment Investment of Loans Investment Investment (Dollars in thousands) Real estate mortgage: Commercial — $ — $ — 1 $ 64 $ — Residential — — — 2 42 42 Commercial: Venture capital — — — 3 13,065 13,065 Other commercial 2 11,783 11,783 4 719 719 Consumer — — — 1 97 97 Total 2 $ 11,783 $ 11,783 11 $ 13,987 $ 13,923 The following table presents troubled debt restructurings of loans held for investment by portfolio segment and class that subsequently defaulted for the periods indicated: Three Months Ended March 31, 2018 2017 Troubled Debt Restructurings Number Recorded Number Recorded That Subsequently Defaulted of Loans Investment (1) of Loans Investment (1) (Dollars in thousands) Commercial: Other commercial 1 $ 2,250 — $ — Consumer — — 1 28 Total 1 $ 2,250 (2) 1 $ 28 (3) _________________________ (1) The population of defaulted restructured loans for the period indicated includes only those loans restructured during the preceding 12-month period. For example, for the 12-month period ended March 31, 2018 , the population of defaulted restructured loans includes only those loans restructured after March 31, 2017 . The table excludes defaulted troubled debt restructurings in those classes for which the recorded investment was zero at the end of the period. (2) Represents the balance at March 31, 2018 , and there were no charge-offs. (3) Represents the balance at March 31, 2017 , and there were no charge-offs. Allowance for Loan and Lease Losses The following tables present a summary of the activity in the allowance for loan and lease losses on loans and leases held for investment by portfolio segment for the periods indicated: Three Months Ended March 31, 2018 Real Estate Real Estate Construction Mortgage and Land Commercial Consumer Total (In thousands) Allowance for Loan and Lease Losses: Balance, beginning of period $ 40,051 $ 13,055 $ 84,022 $ 2,328 $ 139,456 Charge-offs (2,598 ) — (9,524 ) (31 ) (12,153 ) Recoveries 1,657 9 5,487 45 7,198 Provision (negative provision) 1,048 5,126 (6,205 ) (195 ) (226 ) Balance, end of period $ 40,158 $ 18,190 $ 73,780 $ 2,147 $ 134,275 Ending Allowance by Impairment Methodology: Individually evaluated for impairment $ 1,088 $ — $ 13,141 $ 16 $ 14,245 Collectively evaluated for impairment $ 39,070 $ 18,190 $ 60,639 $ 2,131 $ 120,030 Ending Loans and Leases by Impairment Methodology: Individually evaluated for impairment $ 74,390 $ 5,670 $ 82,434 $ 324 $ 162,818 Collectively evaluated for impairment 7,479,853 1,671,332 6,743,689 397,593 16,292,467 Ending balance $ 7,554,243 $ 1,677,002 $ 6,826,123 $ 397,917 $ 16,455,285 Three Months Ended March 31, 2017 Real Estate Real Estate Construction Total Total Mortgage and Land Commercial Consumer Non-PCI PCI Total (In thousands) Allowance for Loan and Lease Losses: Balance, beginning of period $ 37,765 $ 10,045 $ 93,853 $ 2,092 $ 143,755 $ 13,483 $ 157,238 Charge-offs (1,544 ) — (19,285 ) (99 ) (20,928 ) (2,230 ) (23,158 ) Recoveries 230 8 2,448 53 2,739 — 2,739 Provision (negative provision) (1,083 ) 423 25,118 (198 ) 24,260 228 24,488 Balance, end of period $ 35,368 $ 10,476 $ 102,134 $ 1,848 $ 149,826 $ 11,481 $ 161,307 Ending Allowance by Impairment Methodology: Individually evaluated for impairment $ 1,070 $ — $ 12,267 $ 90 $ 13,427 Collectively evaluated for impairment $ 34,298 $ 10,476 $ 89,867 $ 1,758 $ 136,399 Acquired loans with deteriorated credit quality $ 11,481 Ending Loans and Leases by Impairment Methodology: Individually evaluated for impairment $ 118,275 $ 6,683 $ 103,221 $ 281 $ 228,460 Collectively evaluated for impairment 5,768,694 1,101,553 7,979,457 382,190 15,231,894 Acquired loans with deteriorated credit quality $ 96,335 Ending balance $ 5,886,969 $ 1,108,236 $ 8,082,678 $ 382,471 $ 15,460,354 $ 96,335 $ 15,556,689 Allowance for Credit Losses The allowance for credit losses is the combination of the allowance for loan and lease losses and the reserve for unfunded loan commitments. The reserve for unfunded loan commitments is included within "Accrued interest payable and other liabilities" on the condensed consolidated balance sheets. The following tables present a summary of the activity in the allowance for loan and lease losses, reserve for unfunded loan commitments for the periods indicated: Three Months Ended March 31, 2018 Allowance for Reserve for Total Loan and Unfunded Loan Allowance for Lease Losses Commitments Credit Losses (In thousands) Balance, beginning of period $ 139,456 $ 28,635 $ 168,091 Charge-offs (12,153 ) — (12,153 ) Recoveries 7,198 — 7,198 Net charge-offs (4,955 ) — (4,955 ) Provision (negative provision) (226 ) 4,226 4,000 Balance, end of period $ 134,275 $ 32,861 $ 167,136 Three Months Ended March 31, 2017 Non-PCI Allowance for Reserve for PCI Total Loan and Unfunded Loan Allowance for Allowance for Allowance for Lease Losses Commitments Credit Losses Loan Losses Credit Losses (In thousands) Balance, beginning of period $ 143,755 $ 17,523 $ 161,278 $ 13,483 $ 174,761 Charge-offs (20,928 ) — (20,928 ) (2,230 ) (23,158 ) Recoveries 2,739 — 2,739 — 2,739 Net charge-offs (18,189 ) — (18,189 ) (2,230 ) (20,419 ) Provision 24,260 240 24,500 228 24,728 Balance, end of period $ 149,826 $ 17,763 $ 167,589 $ 11,481 $ 179,070

Foreclosed Assets

Foreclosed Assets	3 Months Ended
	Mar. 31, 2018
Other Real Estate Owned Net Covered and NonCovered Including Foreclosed Assets [Abstract]
Foreclosed Assets	FORECLOSED ASSETS The following table summarizes foreclosed assets as of the dates indicated: March 31, December 31, Property Type 2018 2017 (In thousands) Construction and land development $ 219 $ 219 Commercial real estate 64 64 Single family residence 953 1,019 Total other real estate owned, net 1,236 1,302 Other foreclosed assets — 27 Total foreclosed assets, net $ 1,236 $ 1,329 The following table presents the changes in foreclosed assets, net of the valuation allowance, for the period indicated: Foreclosed Assets (In thousands) Balance, December 31, 2017 $ 1,329 Provision for losses (65 ) Reductions related to sales (28 ) Balance, March 31, 2018 $ 1,236

Other Assets

Other Assets	3 Months Ended
	Mar. 31, 2018
Other Assets [Abstract]
Other Assets Disclosure	OTHER ASSETS The following table presents the detail of our other assets as of the dates indicated: March 31, December 31, Other Assets 2018 2017 (In thousands) Cash surrender value of BOLI $ 195,163 $ 193,917 Interest receivable 78,822 82,935 Taxes receivable 64,739 98,998 CRA investments 53,838 49,432 Low income housing tax credit ("LIHTC") investments 43,793 39,235 Equity investments without readily determinable fair values 15,642 14,856 Equity investments with readily determinable fair values 5,028 — Other assets 54,159 61,350 Total other assets $ 511,184 $ 540,723 The Company has purchased life insurance policies on certain employees and has also acquired life insurance policies through acquisitions. BOLI is recorded at the amount that can be realized under the insurance contract, which is the cash surrender value. The increase in the cash surrender value each period is recorded to " Noninterest income - other." The Company makes various investments for CRA investment purposes including, but not limited to, CRA-related loan pool investments, CRA-related equity investments and investments in LIHTC partnerships. The loan pool and other CRA equity investments primarily consist of investments in partnerships which provide affordable housing and participations in loan pools which provide low-cost loans to low and moderate income applicants. The Company invests as a limited partner in LIHTC partnerships that operate qualified affordable housing projects and generate tax benefits for investors, including federal low income housing tax credits. The partnerships are deemed to be VIEs because they do not have sufficient equity investment at risk and are structured with non-substantive voting rights. We are not the primary beneficiary of the VIEs and do not consolidate them. As a practical expedient, we amortize the investment in proportion to the allocated tax benefits using the proportional amortization method of accounting and record such benefits net of investment amortization in income tax expense. Our equity investments without readily determinable fair values include investments in privately held companies and limited partnerships as well as investments in entities from which we issued trust preferred securities. On January 1, 2018, we adopted ASU 2016-01 and ASU 2018-03 which changed the way we account for equity investments without readily determinable fair values previously accounted for using the cost method. Upon adoption, we have elected to measure our equity investments without readily determinable fair values using the measurement alternative. The Company reclassified $1.2 million of equity securities without readily determinable fair values previously included in securities available-for-sale to other assets on our condensed consolidated balance sheet in the first quarter of 2018. The reclassification was applied prospectively without prior period amounts being restated. Carrying values of these investments are adjusted to fair value upon observable transactions for identical or similar investments of the same issuer. We did not identify any observable transactions for our equity investments without readily determinable fair values during the three months ended March 31, 2018 that would require us to adjust the carrying value of these investments held as of March 31, 2018 . Beginning January 1, 2018, unrealized and realized gains and losses on equity investments without readily determinable fair values are recorded in "Noninterest income - other." Our equity investments with readily determinable fair values include investments in public companies and publicly-traded mutual funds. The Company reclassified $5.9 million of equity securities with readily determinable fair values previously included in securities available-for-sale to other assets on our condensed consolidated balance sheet in the first quarter of 2018. The reclassification was applied prospectively without prior period amounts being restated. Beginning January 1, 2018, unrealized and realized gains and losses on equity investments with readily determinable fair values are recorded in "Noninterest income - other." The remaining other assets balance of $54.2 million at March 31, 2018 consists of, among other things, prepaid expenses, other receivables, equity warrants, and derivative assets.

Borrowings and Subordinated Deb

Borrowings and Subordinated Debentures	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Borrowings and Subordinated Debentures	BORROWINGS AND SUBORDINATED DEBENTURES Borrowings The following table summarizes our borrowings as of the dates indicated: March 31, 2018 December 31, 2017 Weighted Weighted Average Average Amount Rate Amount Rate (Dollars in thousands) Non‑recourse debt $ 284 6.94 % $ 342 6.87 % FHLB secured advances 340,000 1.87 % 332,000 1.41 % FHLB unsecured overnight advance 135,000 1.85 % 135,000 1.34 % AFX borrowings 100,000 1.82 % — — % Total borrowings $ 575,284 $ 467,342 The non‑recourse debt represents the payment stream of certain equipment leases sold to third parties. The debt is secured by the leased equipment and all interest rates are fixed. As of March 31, 2018 , this debt had a weighted average remaining maturity of 1.7 years. The Bank has established secured and unsecured lines of credit under which it may borrow funds from time to time on a term or overnight basis from the FHLB, the FRBSF, and other financial institutions. FHLB Secured Line of Credit. The Bank had secured financing capacity with the FHLB as of March 31, 2018 of $3.9 billion , collateralized by a blanket lien on $5.7 billion of certain qualifying loans. As of March 31, 2018 , the balance outstanding was a $340.0 million overnight advance. As of December 31, 2017 , the balance outstanding was a $332.0 million overnight advance. FRBSF Secured Line of Credit. The Bank has a secured line of credit with the FRBSF. As of March 31, 2018 , the Bank had secured borrowing capacity of $1.7 billion collateralized by liens covering $2.1 billion of certain qualifying loans. As of March 31, 2018 and December 31, 2017 , there were no balances outstanding. FHLB Unsecured Line of Credit. The Bank has a $135.0 million unsecured line of credit with the FHLB for the purchase of overnight funds, of which $135.0 million was outstanding at March 31, 2018 . At December 31, 2017 , the balance outstanding was $135.0 million . Federal Funds Arrangements with Commercial Banks. As of March 31, 2018 , the Bank had unsecured lines of credit of $75.0 million with correspondent banks for the purchase of overnight funds, subject to availability of funds. These lines are renewable annually and have no unused commitment fees. As of March 31, 2018 and December 31, 2017 , there were no balances outstanding. The Bank is a member of the AFX, through which it may either borrow or lend funds on an overnight or short-term basis with a group of pre-approved commercial banks. The availability of funds changes daily. As of March 31, 2018 the balance outstanding was $100.0 million in overnight borrowings. As of December 31, 2017 , there were no balances outstanding. Subordinated Debentures The following table summarizes the terms of each issuance of subordinated debentures outstanding as of the dates indicated: March 31, 2018 December 31, 2017 Date Maturity Rate Index Series Amount Rate Amount Rate Issued Date (Quarterly Reset) (Dollars in thousands) Trust V $ 10,310 5.28 % $ 10,310 4.70 % 8/15/2003 9/17/2033 3 month LIBOR + 3.10 Trust VI 10,310 5.17 % 10,310 4.64 % 9/3/2003 9/15/2033 3 month LIBOR + 3.05 Trust CII 5,155 5.13 % 5,155 4.55 % 9/17/2003 9/17/2033 3 month LIBOR + 2.95 Trust VII 61,856 4.52 % 61,856 4.13 % 2/5/2004 4/23/2034 3 month LIBOR + 2.75 Trust CIII 20,619 3.81 % 20,619 3.28 % 8/15/2005 9/15/2035 3 month LIBOR + 1.69 Trust FCCI 16,495 3.72 % 16,495 3.19 % 1/25/2007 3/15/2037 3 month LIBOR + 1.60 Trust FCBI 10,310 3.67 % 10,310 3.14 % 9/30/2005 12/15/2035 3 month LIBOR + 1.55 Trust CS 2005-1 82,475 4.07 % 82,475 3.54 % 11/21/2005 12/15/2035 3 month LIBOR + 1.95 Trust CS 2005-2 128,866 3.72 % 128,866 3.33 % 12/14/2005 1/30/2036 3 month LIBOR + 1.95 Trust CS 2006-1 51,545 3.72 % 51,545 3.33 % 2/22/2006 4/30/2036 3 month LIBOR + 1.95 Trust CS 2006-2 51,550 3.72 % 51,550 3.33 % 9/27/2006 10/30/2036 3 month LIBOR + 1.95 Trust CS 2006-3 (1) 31,773 1.72 % 30,986 1.72 % 9/29/2006 10/30/2036 3 month EURIBOR + 2.05 Trust CS 2006-4 16,470 3.72 % 16,470 3.33 % 12/5/2006 1/30/2037 3 month LIBOR + 1.95 Trust CS 2006-5 6,650 3.72 % 6,650 3.33 % 12/19/2006 1/30/2037 3 month LIBOR + 1.95 Trust CS 2007-2 39,177 3.72 % 39,177 3.33 % 6/13/2007 7/30/2037 3 month LIBOR + 1.95 Trust I (2) — — % 6,186 3.64 % 12/10/2004 3/15/2035 3 month LIBOR + 2.05 Trust II (2) — — % 3,093 3.34 % 12/23/2005 3/15/2036 3 month LIBOR + 1.75 Trust III (2) — — % 3,093 3.44 % 6/30/2006 9/18/2036 3 month LIBOR + 1.85 Gross subordinated debentures 543,561 555,146 Unamortized discount (3) (91,338 ) (92,709 ) Net subordinated debentures $ 452,223 $ 462,437 ___________________ (1) Denomination is in Euros with a value of €25.8 million . (2) Acquired in the CUB acquisition on October 20, 2017 and redeemed in the first quarter of 2018. (3) Amount represents the fair value adjustment on trust preferred securities assumed in acquisitions. Interest payments made by the Company on subordinated debentures are considered dividend payments under FRB regulations. Bank holding companies, such as PacWest, are required to notify the FRB prior to declaring and paying a dividend during any period in which quarterly and/or cumulative twelve‑month net earnings are insufficient to fund the dividend amount, among other requirements.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Lending Commitments The Company is a party to financial instruments with off‑balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. Those instruments involve, to varying degrees, elements of credit risk in excess of the amount recognized in the condensed consolidated balance sheets. The contract or notional amounts of those instruments reflect the extent of involvement the Company has in particular classes of financial instruments. The following table presents a summary of the financial instruments described above as of the dates indicated: March 31, December 31, 2018 2017 (In thousands) Loan commitments to extend credit $ 6,352,803 $ 6,234,061 Standby letters of credit 337,678 320,063 Total $ 6,690,481 $ 6,554,124 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. 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 increase in loan commitments to extend credit is primarily a result of the continued growth of our construction and venture capital portfolios. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. We provide standby letters of credit in conjunction with several of our lending arrangements and property lease obligations. Most guarantees expire within one year from the date of issuance. If a borrower defaults on its commitments subject to any letter of credit issued under these arrangements, we would be required to meet the borrower's financial obligation but would seek repayment of that financial obligation from the borrower. In some cases, borrowers have pledged cash and investment securities as collateral with us under these arrangements. In addition, the Company invests in low income housing project partnerships, which provide income tax credits, and in small business investment companies that call for capital contributions up to an amount specified in the partnership agreements. As of March 31, 2018 and December 31, 2017 , we had commitments to contribute capital to these entities totaling $79.4 million and $62.6 million . We also had commitments to contribute up to an additional $2.5 million to private equity funds at March 31, 2018 and December 31, 2017 . Legal Matters In the ordinary course of our business, the Company is party to various legal actions, which we believe are incidental to the operation of our business. The outcome of such legal actions and the timing of ultimate resolution are inherently difficult to predict. In the opinion of management, based upon currently available information, any resulting liability, in addition to amounts already accrued, and taking into consideration insurance which may be applicable, would not have a material adverse effect on the Company’s financial statements or operations.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS ASC Topic 820, “ Fair Value Measurement ,” defines fair value, establishes a framework for measuring fair value including a three‑level valuation hierarchy, and expands disclosures about fair value measurements. Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date reflecting assumptions that a market participant would use when pricing an asset or liability. The hierarchy uses three levels of inputs to measure the fair value of assets and liabilities as follows: • Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2: Observable inputs other than Level 1, including quoted prices for similar assets and liabilities in active markets, quoted prices in less active markets, or other observable inputs that can be corroborated by observable market data, either directly or indirectly, for substantially the full term of the financial instrument. This category generally includes municipal securities, agency residential and commercial MBS, collateralized loan obligations, registered publicly rated private label CMOs, and asset-backed securitizations. • Level 3: Inputs to a valuation methodology that are unobservable, supported by little or no market activity, and significant to the fair value measurement. These valuation methodologies generally include pricing models, discounted cash flow models, or a determination of fair value that requires significant management judgment or estimation. This category also includes observable inputs from a pricing service not corroborated by observable market data, and includes our non-rated private label CMOs, non-rated private label asset-backed securities, and equity warrants. The Company uses fair value to measure certain assets and liabilities on a recurring basis, primarily securities available‑for‑sale and derivatives. For assets measured at the lower of cost or fair value, the fair value measurement criteria may or may not be met during a reporting period and such measurements are therefore considered “nonrecurring” for purposes of disclosing our fair value measurements. Fair value is used on a nonrecurring basis to adjust carrying values for impaired loans and other real estate owned and also to record impairment on certain assets, such as goodwill, CDI, and other long‑lived assets. The following tables present information on the assets and liabilities measured and recorded at fair value on a recurring basis as of the dates indicated: Fair Value Measurements as of March 31, 2018 Measured on a Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Securities available‑for‑sale: Residential MBS and CMOs: Agency MBS $ 251,776 $ — $ 251,776 $ — Agency CMOs 545,945 — 545,945 — Private label CMOs 116,245 — 94,164 22,081 Municipal securities 1,403,586 — 1,403,586 — Agency commercial MBS 1,089,494 — 1,089,494 — U.S. Treasury securities 148,582 148,582 — — SBA securities 148,264 — 148,264 — Asset-backed securities 79,734 — 43,316 36,418 Corporate debt securities 18,360 — 18,360 — Total securities available-for-sale 3,801,986 148,582 3,594,905 58,499 Equity warrants 5,284 — — 5,284 Other derivative assets 3,327 — 3,327 — Equity investments with readily determinable fair values 5,028 5,028 — — Total recurring assets $ 3,815,625 $ 153,610 $ 3,598,232 $ 63,783 Derivative liabilities $ 642 $ — $ 642 $ — Fair Value Measurements as of December 31, 2017 Measured on a Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Securities available‑for‑sale: Residential MBS and CMOs: Agency MBS $ 246,274 $ — $ 246,274 $ — Agency CMOs 275,709 — 275,709 — Private label CMOs 125,987 — 103,113 22,874 Municipal securities 1,680,068 — 1,680,068 — Agency commercial MBS 1,163,969 — 1,163,969 — SBA securities 160,334 — 160,334 — Asset-backed securities 88,710 — 46,601 42,109 Corporate debt securities 19,295 — 19,295 — Collateralized loan obligations 7,015 — 7,015 — Equity investments 7,070 5,922 1,148 — Total securities available-for-sale 3,774,431 5,922 3,703,526 64,983 Equity warrants 5,161 — — 5,161 Other derivative assets 1,873 — 1,873 — Total recurring assets $ 3,781,465 $ 5,922 $ 3,705,399 $ 70,144 Derivative liabilities $ 1,379 $ — $ 1,379 $ — During the three months ended March 31, 2018 , there were no transfers of assets between Level 1 and Level 2, and there was a $13,000 transfer of private label CMOs from Level 3 to Level 2 of the fair value hierarchy for assets measured on a recurring basis. The following table presents information about quantitative inputs and assumptions used to determine the fair values provided by our third party pricing service for our Level 3 private label CMOs and asset-backed securities available-for-sale measured at fair value on a recurring basis as of the date indicated: March 31, 2018 Private Label CMOs Asset-Backed Securities Weighted Weighted Range Average Range Average Unobservable Inputs of Inputs Input of Inputs Input Voluntary annual prepayment speeds 3.8% - 52.7% 8.3% 5% - 15% 14.0% Annual default rates 0.1% - 16.5% 2.5% 1% - 2% 1.9% Loss severity rates 3.2% - 105.7% 46.3% 10% - 60% 55.2% Discount rates 2.0% - 10.3% 5.3% 3.2% - 4.3% 3.6% The following table presents information about quantitative inputs and assumptions used in the modified Black-Scholes option pricing model to determine the fair value for our Level 3 equity warrants measured at fair value on a recurring basis as of the date indicated: March 31, 2018 Equity Warrants Weighted Average Unobservable Inputs Input Volatility 16.8% Risk-free interest rate 2.4% Remaining life assumption (in years) 3.7 The following table summarizes activity for our Level 3 private label CMOs available-for-sale, asset-backed securities available-for-sale, and equity warrants measured at fair value on a recurring basis for the period indicated: Private Asset-Backed Equity Label CMOs Securities Warrants (In thousands) Balance, December 31, 2017 $ 22,874 $ 42,109 $ 5,161 Total included in earnings 165 (10 ) 248 Total included in other comprehensive income (141 ) (228 ) — Issuances — — 206 Sales — — (331 ) Transfer to Level 2 (13 ) — — Net settlements (804 ) (5,453 ) — Balance, March 31, 2018 $ 22,081 $ 36,418 $ 5,284 The following tables present assets measured at fair value on a non‑recurring basis as of the dates indicated: Fair Value Measurement as of March 31, 2018 Measured on a Non‑Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Impaired loans $ 45,557 $ — $ 1,128 $ 44,429 OREO 953 — 953 — Total non-recurring $ 46,510 $ — $ 2,081 $ 44,429 Fair Value Measurement as of December 31, 2017 Measured on a Non‑Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Impaired Non‑PCI loans $ 61,095 $ — $ 5,143 $ 55,952 Loans held for sale 483,563 — 483,563 — Total non-recurring $ 544,658 $ — $ 488,706 $ 55,952 The following table presents losses recognized on assets measured on a nonrecurring basis for the periods indicated: Three Months Ended Losses on Assets March 31, Measured on a Non‑Recurring Basis 2018 2017 (In thousands) Impaired loans (1) $ 7,816 $ 13,617 OREO 65 — Total losses $ 7,881 $ 13,617 __________________________ (1) Loss for 2018 period relates to total loans. Loss for 2017 period relates to Non-PCI loans. The following table presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a nonrecurring basis as of the date indicated: March 31, 2018 Valuation Unobservable Weighted Asset Fair Value Technique Inputs Range Average (In thousands) Impaired loans $ 32,638 Discounted cash flows Discount rates 2.00% - 10.20% 7.33% Impaired loans 11,791 Third party appraisals No discounts Total non-recurring Level 3 $ 44,429 ASC Topic 825, “ Financial Instruments, ” (as amended by ASU 2016-01 and ASU 2018-03) requires disclosure of the estimated fair value of certain financial instruments and the methods and significant assumptions used to estimate such fair values. Additionally, certain financial instruments and all nonfinancial instruments are excluded from the applicable disclosure requirements. On January 1, 2018, we adopted ASU 2016-01 and ASU 2018-03 which requires the use of the exit price notion when measuring the fair values of financial instruments for disclosure purposes. Starting in the first quarter of 2018, we updated our methodology used to estimate fair values for our loan portfolios to conform to the new requirements. The following tables present carrying amounts and estimated fair values of certain financial instruments as of the dates indicated: March 31, 2018 Carrying Estimated Fair Value Amount Total Level 1 Level 2 Level 3 ( In thousands ) Financial Assets: Cash and due from banks $ 235,061 $ 235,061 $ 235,061 $ — $ — Interest‑earning deposits in financial institutions 312,735 312,735 312,735 — — Securities available‑for‑sale 3,801,986 3,801,986 148,582 3,594,905 58,499 Investment in FHLB stock 17,250 17,250 — 17,250 — Loans and leases held for investment, net 16,321,010 16,247,325 — 1,128 16,246,197 Equity warrants 5,284 5,284 — — 5,284 Other derivative assets 3,327 3,327 — 3,327 — Equity investments with readily determinable fair values 5,028 5,028 5,028 — — Financial Liabilities: Core deposits 15,661,529 15,661,529 — 15,661,529 — Non-core non-maturity deposits 585,399 585,399 — 585,399 — Time deposits 1,831,860 1,820,330 — 1,820,330 — Borrowings 575,284 575,285 575,000 285 — Subordinated debentures 452,223 435,985 — 435,985 — Derivative liabilities 642 642 — 642 — December 31, 2017 Carrying Estimated Fair Value Amount Total Level 1 Level 2 Level 3 ( In thousands ) Financial Assets: Cash and due from banks $ 233,215 $ 233,215 $ 233,215 $ — $ — Interest‑earning deposits in financial institutions 165,222 165,222 165,222 — — Securities available‑for‑sale 3,774,431 3,774,431 5,922 3,703,526 64,983 Investment in FHLB stock 20,790 20,790 — 20,790 — Loans held for sale 481,100 483,563 — 483,563 — Loans and leases held for investment, net 16,833,287 17,023,098 — 5,143 17,017,955 Equity warrants 5,161 5,161 — — 5,161 Other derivative assets 1,873 1,873 — 1,873 — Financial Liabilities: Core deposits 15,937,012 15,937,012 — 15,937,012 — Non-core non-maturity deposits 863,202 863,202 — 863,202 — Time deposits 2,065,322 2,055,104 — 2,055,104 — Borrowings 467,342 467,342 467,000 342 — Subordinated debentures 462,437 444,383 — 444,383 — Derivative liabilities 1,379 1,379 — 1,379 — For information regarding the valuation methodologies used to measure our assets recorded at fair value (under ASC Topic 820), and for estimating fair value for financial instruments not recorded at fair value (under ASC Topic 825, as amended by ASU 2016-01 and ASU 2018-03), see Note 1. Nature of Operations and Summary of Significant Accounting Policies, and Note 12. Fair Value Measurements, to the Consolidated Financial Statements of the Company's 2017 Annual Report on Form 10-K. Limitations Fair value estimates are made at a specific point in time and are based on relevant market information and information about the financial instrument. These estimates do not reflect income taxes or any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no market exists for a portion of the Company’s financial instruments, fair value estimates are based on what management believes to be reasonable judgments regarding expected future cash flows, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimated fair values are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Since the fair values have been estimated as of March 31, 2018 , the amounts that will actually be realized or paid at settlement or maturity of the instruments could be significantly different.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table presents the computations of basic and diluted net earnings per share for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (Dollars in thousands, except per share data) Basic Earnings Per Share: Net earnings $ 118,276 $ 84,037 $ 78,668 Less: Earnings allocated to unvested restricted stock (1) (1,115 ) (951 ) (999 ) Net earnings allocated to common shares $ 117,161 $ 83,086 $ 77,669 Weighted-average basic shares and unvested restricted stock outstanding 127,487 127,971 121,346 Less: Weighted-average unvested restricted stock outstanding (1,413 ) (1,440 ) (1,503 ) Weighted-average basic shares outstanding 126,074 126,531 119,843 Basic earnings per share $ 0.93 $ 0.66 $ 0.65 Diluted Earnings Per Share: Net earnings allocated to common shares $ 117,161 $ 83,086 $ 77,669 Weighted-average basic shares outstanding 126,074 126,531 119,843 Diluted earnings per share $ 0.93 $ 0.66 $ 0.65 ________________________ (1) Represents cash dividends paid to holders of unvested restricted stock, net of forfeitures, plus undistributed earnings amounts available to holders of unvested restricted stock, if any.

Revenue From Contracts With Cus

Revenue From Contracts With Customers	3 Months Ended
	Mar. 31, 2018
Revenue From Contracts With Customers [Abstract]
Revenue from Contract with Customer	REVENUE FROM CONTRACTS WITH CUSTOMERS The Company adopted Topic 606 Revenue from Contracts with Customers effective as of January 1, 2018 and has applied the guidance to all contracts within the scope of Topic 606 as of that date. Revenue from contracts with customers in the scope of Topic 606 is measured based on the consideration specified in the contract with a customer, and excludes amounts collected on behalf of third parties. The Company recognizes revenue from contracts with customers when it satisfies its performance obligations. The Company's performance obligations are typically satisfied as services are rendered and payment is generally collected at the time services are rendered, or on a monthly, quarterly or annual basis. The Company had no material unsatisfied performance obligations as of March 31, 2018. In certain cases, other parties are involved with providing products and services to our customers. If the Company is a principal in the transaction (providing goods or services itself), revenues are reported based on the gross consideration received from the customer and any related expenses are reported gross in noninterest expense. If the Company is an agent in the transaction (arranging for another party to provide goods or services), the Company reports its net fee or commission retained as revenue. Rebates, waivers, and reversals are recorded as a reduction of revenue either when the revenue is recognized by the Company or at the time the rebate, waiver, or reversal is earned by the customer. The Company has elected the following practical expedients: (1) we do not disclose information about remaining performance obligations that have original expected durations of one year or less; and (2) we do not adjust the consideration from customers for the effects of a significant financing component if at contract inception the period between when the Company transfers the goods or services and when the customer pays for that good or service will be one year or less. Nature of Goods and Service s Substantially all of the Company's revenue, such as interest income on loans, investment securities, and interest-earning deposits in financial institutions, is specifically out-of-scope of Topic 606. For the revenue that is in-scope, the following is a description of principal activities, separated by the timing of revenue recognition, from which the Company generates its revenue from contracts with customers: • Revenue earned at a point in time. Examples of revenue earned at a point in time are ATM transaction fees, wire transfer fees, NSF fees, and credit and debit card interchange fees. Revenue is generally derived from transactional information accumulated by our systems and is recognized as revenue immediately as the transactions occur or upon providing the service to complete the customer's transaction. The Company is the principal in each of these contracts with the exception of credit and debit card interchange fees, in which case the Company is acting as the agent and records revenue net of expenses paid to the principal. • Revenue earned over time. The Company earns certain revenue from contracts with customers monthly. Examples of this type of revenue are deposit account service fees, investment management fees, merchant referral services, MasterCard marketing incentives and safe deposit box fees. Account service charges, management fees and referral fees are recognized on a monthly basis while any transaction-based revenue is recorded as the activity occurs. Revenue is primarily based on the number and type of transactions and is generally derived from transactional information accumulated by our systems. Revenue is recorded in the same period as the related transactions occur or services are rendered to the customer. Disaggregation of Revenue The following table presents interest income and noninterest income, the components of total revenue, as disclosed in the condensed consolidated statements of earnings and the related amounts which are from contracts with customers within the scope of Topic 606. As illustrated here, substantially all of our revenue is specifically excluded from the scope of Topic 606. Three Months Ended March 31, 2018 Total Revenue from Recorded Contracts With Revenue Customers (In thousands) Total interest income $ 277,775 $ — Noninterest income: Service charges on deposit accounts 4,174 4,174 Other commissions and fees 10,265 4,651 Leased equipment income 9,587 — Gain on sale of loans 4,569 — Gain on sale of securities 6,311 — Other income 3,653 461 Total noninterest income 38,559 9,286 Total revenue $ 316,334 $ 9,286 The following table presents revenue from contracts with customers based on the timing of revenue recognition for the period indicated: Three Months Ended March 31, 2018 (In thousands) Products and services transferred at a point in time $ 4,661 Products and services transferred over time 4,625 Total revenue from contracts with customers $ 9,286 Contract Balances The following table provides information about receivables, contract assets and contract liabilities from contracts with customers: March 31, 2018 (In thousands) Receivables, which are included in "Other assets" $ 1,438 Contract assets, which are included in "Other assets" $ — Contract liabilities, which are included in "Interest payable and other liabilities" $ 719 Contract liabilities relate to advance consideration received from customers for which revenue is recognized over the life of the contract. The change in contract liabilities for the three months ended March 31, 2018 due to revenue recognized that was included in the contract liability balance at the beginning of the period was $33,000 . As illustrated here, substantially all of our revenue is specifically excluded from the scope of Topic 606. Three Months Ended March 31, 2018 Total Revenue from Recorded Contracts With Revenue Customers (In thousands) Total interest income $ 277,775 $ — Noninterest income: Service charges on deposit accounts 4,174 4,174 Other commissions and fees 10,265 4,651 Leased equipment income 9,587 — Gain on sale of loans 4,569 — Gain on sale of securities 6,311 — Other income 3,653 461 Total noninterest income 38,559 9,286 Total revenue $ 316,334 $ 9,286

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Based Compensation	STOCK-BASED COMPENSATION The Company’s 2017 Stock Incentive Plan, or the 2017 Plan, permits stock-based compensation awards to officers, directors, employees, and consultants. As of March 31, 2018 , the 2017 Plan authorized grants of stock‑based compensation instruments to purchase or issue up to 4,000,000 shares of Company common stock. As of March 31, 2018 , there were 3,537,972 shares available for grant under the 2017 Plan. Though frozen for new issuances, certain awards issued under the 2003 Stock Incentive Plan, or the 2003 Plan, remain outstanding. Restricted Stock Restricted stock amortization totaled $7.2 million , $5.4 million , and $6.5 million for the three months ended March 31, 2018 , December 31, 2017 and March 31, 2017 . Such amounts are included in "Compensation expense" on the condensed consolidated statements of earnings. The amount of unrecognized compensation expense related to unvested TRSAs and PRSUs as of March 31, 2018 totaled $52.1 million . Time-Based Restricted Stock Awards At March 31, 2018 , there were 1,383,914 shares of unvested TRSAs outstanding pursuant to the Company's 2003 and 2017 Stock Incentive Plans (the "Plans"). The TRSAs generally vest ratably over a service period of three or four years from the date of the grant or immediately upon death of an employee. Compensation expense related to TRSAs is based on the fair value of the underlying stock on the award date and is recognized over the vesting period using the straight‑line method. Performance-Based Restricted Stock Units At March 31, 2018 , there were 325,741 unvested PRSUs granted. The PRSUs will vest only if performance goals with respect to certain financial metrics are met over a three -year performance period. The PRSUs are not considered issued and outstanding under either the 2017 Plan or the 2003 Plan until they vest. PRSUs are granted and initially expensed based on a target number. The number of shares that will ultimately vest based on actual performance will range from zero to a maximum of either 150% or 200% of target. Compensation expense related to PRSUs is based on the fair value of the underlying stock on the award date and is amortized over the vesting period using the straight-line method unless it is determined that: (1) attainment of the financial metrics is less than probable, in which case a portion of the amortization is suspended, or (2) attainment of the financial metrics is improbable, in which case a portion of the previously recognized amortization is reversed and also suspended. If it is determined that attainment of a financial measure higher than target is probable, the amortization will increase to up to 150% or 200% of the target amortization amount. Annual PRSU expense may vary during the three -year performance period based upon changes in management's estimate of the number of shares that may ultimately vest. In the case where the performance target for the PRSU is based on a market condition (such as total shareholder return), the amortization is neither reversed nor suspended if it is subsequently determined that the attainment of the performance target is less than probable or improbable.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	3 Months Ended
	Mar. 31, 2018
Recently Issued Accounting Standards [Abstract]
Recently Issued Accounting Standards	RECENTLY ISSUED ACCOUNTING STANDARDS In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842) ," which, among other things, requires lessees to recognize most leases on-balance sheet, which will result in an increase in their reported assets and liabilities. Lessor accounting remains substantially similar to current U.S. GAAP. ASU 2016-02 supersedes Topic 840, Leases, and is effective for annual and interim periods in fiscal years beginning after December 15, 2018. There have been further amendments, including practical expedients, with the issuance of ASU 2018-01, “ Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842” in January 2018. The FASB has also approved an optional transition method when adopting Topic 842, which would allow companies to elect not to adjust their comparative period financial information, and effectively apply the requirements of the new standard prospectively. The Company will adopt the standard effective January 1, 2019. The Company has reviewed its current lessee portfolio and is assessing the impact of the new standard on its financial statements, related disclosures, systems, and internal controls. The accounting changes are expected to relate primarily to its leased branches and office space which are currently accounted for as operating leases. The Company is on track with its implementation plan which includes a new software solution and procedures. The Company has not yet determined the quantitative effect ASU 2016-02 will have on its consolidated financial position and results of operations. For information on the Company's future minimum lease payments refer to Note 8. Premises and Equipment, Net in our Annual Report on Form 10-K for the year ended December 31, 2017 . In June 2016, the FASB issued ASU 2016-13, " Measurement of Credit Losses on Financial Instruments," which significantly changes the way entities recognize credit losses and impairment of financial assets recorded at amortized cost. Currently, the credit loss and impairment model for loans and leases is based on incurred losses, and investments are recognized as impaired when there is no longer an assumption that future cash flows will be collected in full under the originally contracted terms. Under the new current expected credit loss ("CECL") model, the standard requires immediate recognition of estimated credit losses expected to occur over the remaining life of the asset. The forward-looking concept of CECL to estimate future credit losses will broaden the range of data to consider including, but not limited to, past and current events and conditions along with reasonable and supportable forecasts that affect expected collectability. The new standard will also add new disclosure requirements. The Company has established a multidisciplinary project team, developed an implementation plan, selected a software solution, completed the readiness assessment, and is engaged in the implementation phase of the project. The Company, with the assistance of a third party adviser, is working on: (1) developing a new expected loss model with supportable assumptions, (2) identifying data, reporting, and disclosure gaps, (3) assessing updates to accounting policies, and (4) documenting new processes and controls. ASU 2016-13 is effective for interim and annual periods in fiscal years beginning after December 15, 2019, with earlier adoption permitted. The Company plans to adopt this standard on January 1, 2020. Entities are required to use a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted (modified-retrospective approach). A prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the adoption date. The new standard will be significant to the policies, processes, and methodology used to determine credit losses, however the Company has not yet determined the quantitative effect ASU 2016-13 will have on its consolidated financial position and results of operations. In January 2017, the FASB issued ASU 2017-04, " Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment," which intends to simplify goodwill impairment testing by eliminating the second step of the analysis under which the implied fair value of goodwill is determined as if the reporting unit were being acquired in a business combination. ASU 2017-04 instead requires entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit's fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. ASU 2017-04 must be applied prospectively and is effective for the Company on January 1, 2020. Early adoption is permitted. The Company does not expect ASU 2017-04 to have a material impact on its consolidated financial position or results of operations.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Common Stock Dividends On April 24, 2018 , the Company announced that the Board of Directors had declared a quarterly cash dividend of $0.60 per common share. The cash dividend is payable on May 31, 2018 to stockholders of record at the close of business on May 21, 2018 . The Company has evaluated events that have occurred subsequent to March 31, 2018 and have concluded there are no other subsequent events that would require recognition in the accompanying consolidated financial statements.

Organization Organization (Poli

Organization Organization (Policies)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recently Issued Accounting Standards	ORGANIZATION PacWest Bancorp, a Delaware corporation, is a bank holding company registered under the BHCA, with our corporate headquarters located in Beverly Hills, California. Our principal business is to serve as the holding company for our wholly-owned subsidiary, Pacific Western Bank. References to "Pacific Western" or the "Bank" refer to Pacific Western Bank together with its wholly-owned subsidiaries. References to "we," "us," or the "Company" refer to PacWest Bancorp together with its subsidiaries on a consolidated basis. When we refer to "PacWest" or to the "holding company," we are referring to PacWest Bancorp, the parent company, on a stand-alone basis. We are focused on relationship-based business banking to small, middle-market and venture-backed businesses nationwide. At March 31, 2018 , the Bank offers a broad range of loan and lease and deposit products and services through 75 full-service branches located throughout the State of California, one branch located in Durham, North Carolina, and several loan production offices located in cities across the country. We provide commercial banking services, including real estate, construction, and commercial loans, and comprehensive deposit and treasury management services to small and middle-market businesses. We offer additional products and services through our CapitalSource and Square 1 Bank Divisions. Our CapitalSource Division provides asset-based, equipment, real estate, security cash flow loans and treasury management services to established middle-market businesses on a national basis. Our Square 1 Bank Division offers a comprehensive suite of financial services focused on entrepreneurial businesses and their venture capital and private equity investors, with offices located in key innovation hubs across the United States. In addition, we provide investment advisory and asset management services to select clients through Square 1 Asset Management, Inc., a wholly-owned subsidiary of the Bank and a SEC-registered investment adviser. We generate our revenue primarily from interest received on loans and leases and, to a lesser extent, from interest received on investment securities, and fees received in connection with deposit services, extending credit and other services offered, including foreign exchange services. Our major operating expenses are compensation, occupancy, general operating expenses, and the interest paid by the Bank on deposits and borrowings. We have completed 29 acquisitions from May 1, 2000 through March 31, 2018 . Our acquisitions have been accounted for using the acquisition method of accounting and, accordingly, the operating results of the acquired entities have been included in the consolidated financial statements from their respective acquisition dates. See Note 3. Acquisitions, for more information about the CUB acquisition. Significant Accounting Policies Our accounting policies are described in Note 1. Nature of Operations and Summary of Significant Accounting Policies , of our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017 as filed with the Securities and Exchange Commission ("Form 10-K"). Updates to our significant accounting policies described below reflect the impact of the adoption of ASU 2016-01, " Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities " and ASU 2018-03, “ Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” Investment Securities Our significant accounting policy for investment securities applied to both debt and equity securities in prior periods. Effective January 1, 2018, upon the adoption of ASUs 2016-01 and 2018-03, our significant accounting policy for investment securities applies only to debt securities. Equity Investments Investments in common or preferred stock that are not publicly traded and certain investments in limited partnerships are considered equity investments that do not have a readily determinable fair value. If we have the ability to significantly influence the operating and financial policies of the investee, the investment is accounted for pursuant to the equity method of accounting. This is generally presumed to exist when we own between 20% and 50% of a corporation, or when we own greater than 5% of a limited partnership or similarly structured entity. Our equity investment carrying values are included in other assets and our share of earnings and losses in equity method investees is included in "Noninterest income - other" on the condensed consolidated statements of earnings. Prior to January 1, 2018, if we did not have significant influence over the investee, the cost method was used to account for the equity interest. Effective January 1, 2018 with the adoption of ASU 2016-01, our accounting treatment for equity investments differs for those with and without readily determinable fair values. Equity investments with readily determinable fair values are recorded at fair value with changes in fair value recorded in “Noninterest income - other.” For equity investments without readily determinable fair values we have elected the “measurement alternative,” and therefore carry these investments at cost, less impairment (if any), plus or minus changes in observable prices. On a quarterly basis, we review our equity investments without readily determinable fair values for impairment. We consider a number of qualitative factors such as whether there is a significant deterioration in earnings performance, credit rating, asset quality, or business prospects of the investee in determining if impairment exists. If the investment is considered impaired, an impairment loss equal to the amount by which the carrying value exceeds its fair value is recorded through a charge to earnings. The impairment loss may be reversed in a subsequent period if there are observable transactions for the identical or similar investment of the same issuer at a higher amount than the carrying amount that was established when the impairment was recognized. Realized gains or losses resulting from the sale of equity investments are calculated using the specific identification method and are included in "Noninterest income - other." Comprehensive Income Comprehensive income consists of net earnings and net unrealized gains (losses) on debt securities available‑for‑sale, net, and is presented in the consolidated statements of comprehensive income. Accounting Standards Adopted in 2018 Effective January 1, 2018, the Company adopted ASU 2014-09, " Revenue Recognition (Topic 606): Revenue from Contracts with Customers ." ASU 2014-09 supersedes Topic 605, " Revenue Recognition " and requires an entity to recognize revenue at an amount that reflects the consideration to which it expects to be entitled to in exchange for the transfer of promised goods or services to customers. Substantially all of the Company's revenue is interest income on loans, investment securities, and deposits at other financial institutions which are specifically outside the scope of ASU 2014-09. ASU 2014-09 applies primarily to certain noninterest income items in the Company's condensed consolidated statement of earnings. The Company adopted ASU 2014-09 as of January 1, 2018 using the cumulative effect transition method, which resulted in no adjustment to retained earnings and no material impact on the Company's consolidated financial position, results of operations, or cash flows. The Company did make minor changes to accounting operations and internal controls as part of adopting this new standard. See Note 13. Revenue From Contracts With Customers for further details. Effective January 1, 2018, the Company adopted ASU 2016-01, " Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities " and ASU 2018-03, “ Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-01 contained a number of changes which are applicable to the Company including the following: (1) requires equity investments to be measured at fair value with changes in fair value recognized in net income; (2) allows equity investments without readily determinable fair values to be measured at cost less impairment, if any, plus or minus changes in observable prices (referred to as the "measurement alternative"); and (3) changes certain presentation and disclosure requirements for financial instruments, including using the exit price notion when measuring the fair value of financial instruments (see Note 11. Fair Value Measurements) . ASU 2018-03 also clarified certain aspects of the guidance issued in ASU 2016-01, including requiring a prospective transition approach for equity investments without readily determinable fair value in which the measurement alternative is applied. ASU 2016-01 does not apply to investments accounted for using the equity method, investments in consolidated subsidiaries, FHLB stock, and investments in low income housing tax credit projects. Upon adoption of ASU 2016-01, the Company recorded a transition adjustment to reclassify $529,000 in net unrealized gains from accumulated other comprehensive income ("AOCI") to retained earnings. The ASU also eliminated the requirement to classify equity investments into different categories such as “Available-for-Sale.” The adoption of this ASU may result in more earnings volatility as changes in fair value of certain equity investments will now be recorded in the statement of earnings as opposed to AOCI. Effective January 1, 2018, the Company adopted ASU 2016-15, " Classification of Certain Cash Receipts and Cash Payments." Upon adoption , the Company applied the retrospective transition method to each period presented. ASU 2016-15 addressed eight issues related to the statement of cash flows, the most relevant to the Company being the classification of proceeds from the settlement of BOLI policies. As the Company classified proceeds from the settlement of BOLI policies in the manner required by ASU 2016-15 in the prior periods presented, there was no change to the Company's consolidated financial position, results of operations, or cash flows for both current and prior periods upon adoption. Effective January 1, 2018, the Company adopted ASU 2016-18, " Statement of Cash Flows (Topic 230): Restricted Cash ." Upon adoption, the Company applied the retrospective transition method to each period presented. As the Company does not present restricted cash as a separate line in the statement of financial position, there is no change to the presentation of cash on the statement of cash flows. The nature and amount of our restricted cash is shown in Note 2. Restricted Cash Balances . Effective January 1, 2018, the Company adopted ASU 2017-01, " Business Combinations (Topic 805): Clarifying the Definition of a Business." ASU 2017-01 provides a new framework for determining whether transactions should be accounted for as acquisitions of assets or businesses. The Company had no acquisitions or purchases of components of a business in the first quarter of 2018, thus, the impact of adopting the new standard had no impact on the Company's consolidated financial position, results of operations, or cash flows. Effective January 1, 2018, the Company adopted ASU 2017-09, " Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting." ASU 2017-09 provided clarification of what constitutes a modification of a share-based payment award. The Company did not modify any share-based payment awards in the first quarter of 2018, thus, the impact of adopting the new standard had no impact on the Company's consolidated financial position, results of operations, or cash flows. Effective January 1, 2018, the Company early-adopted ASU 2018-02, " Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The TCJA required deferred tax assets and liabilities to be re-measured at its enactment date for the effect of the change in the federal corporate tax rate. This process resulted in "stranded tax effects" in AOCI for deferred tax asset or liabilities which were established with an offsetting amount in AOCI. ASU 2018-02 allows for a reclassification of the stranded tax effects resulting from the enactment of the TCJA from AOCI to retained earnings. The Company elected to reclassify its stranded tax effects of $6.665 million from AOCI to retained earnings effective January 1, 2018, while no other income tax effects related to the application of the TCJA were reclassified. RECENTLY ISSUED ACCOUNTING STANDARDS In February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842) ," which, among other things, requires lessees to recognize most leases on-balance sheet, which will result in an increase in their reported assets and liabilities. Lessor accounting remains substantially similar to current U.S. GAAP. ASU 2016-02 supersedes Topic 840, Leases, and is effective for annual and interim periods in fiscal years beginning after December 15, 2018. There have been further amendments, including practical expedients, with the issuance of ASU 2018-01, “ Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842” in January 2018. The FASB has also approved an optional transition method when adopting Topic 842, which would allow companies to elect not to adjust their comparative period financial information, and effectively apply the requirements of the new standard prospectively. The Company will adopt the standard effective January 1, 2019. The Company has reviewed its current lessee portfolio and is assessing the impact of the new standard on its financial statements, related disclosures, systems, and internal controls. The accounting changes are expected to relate primarily to its leased branches and office space which are currently accounted for as operating leases. The Company is on track with its implementation plan which includes a new software solution and procedures. The Company has not yet determined the quantitative effect ASU 2016-02 will have on its consolidated financial position and results of operations. For information on the Company's future minimum lease payments refer to Note 8. Premises and Equipment, Net in our Annual Report on Form 10-K for the year ended December 31, 2017 . In June 2016, the FASB issued ASU 2016-13, " Measurement of Credit Losses on Financial Instruments," which significantly changes the way entities recognize credit losses and impairment of financial assets recorded at amortized cost. Currently, the credit loss and impairment model for loans and leases is based on incurred losses, and investments are recognized as impaired when there is no longer an assumption that future cash flows will be collected in full under the originally contracted terms. Under the new current expected credit loss ("CECL") model, the standard requires immediate recognition of estimated credit losses expected to occur over the remaining life of the asset. The forward-looking concept of CECL to estimate future credit losses will broaden the range of data to consider including, but not limited to, past and current events and conditions along with reasonable and supportable forecasts that affect expected collectability. The new standard will also add new disclosure requirements. The Company has established a multidisciplinary project team, developed an implementation plan, selected a software solution, completed the readiness assessment, and is engaged in the implementation phase of the project. The Company, with the assistance of a third party adviser, is working on: (1) developing a new expected loss model with supportable assumptions, (2) identifying data, reporting, and disclosure gaps, (3) assessing updates to accounting policies, and (4) documenting new processes and controls. ASU 2016-13 is effective for interim and annual periods in fiscal years beginning after December 15, 2019, with earlier adoption permitted. The Company plans to adopt this standard on January 1, 2020. Entities are required to use a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted (modified-retrospective approach). A prospective transition approach is required for debt securities for which an other-than-temporary impairment had been recognized before the adoption date. The new standard will be significant to the policies, processes, and methodology used to determine credit losses, however the Company has not yet determined the quantitative effect ASU 2016-13 will have on its consolidated financial position and results of operations. In January 2017, the FASB issued ASU 2017-04, " Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment," which intends to simplify goodwill impairment testing by eliminating the second step of the analysis under which the implied fair value of goodwill is determined as if the reporting unit were being acquired in a business combination. ASU 2017-04 instead requires entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit's fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. ASU 2017-04 must be applied prospectively and is effective for the Company on January 1, 2020. Early adoption is permitted. The Company does not expect ASU 2017-04 to have a material impact on its consolidated financial position or results of operations.
Basis of Presentation	Basis of Presentation Our interim condensed consolidated financial statements are prepared in accordance with U.S. GAAP for interim financial information and pursuant to the requirements for reporting on Form 10-Q and Article 10 of Regulation S-X of the Securities Exchange Act of 1934. Accordingly, certain disclosures accompanying annual consolidated financial statements are omitted. In the opinion of management, all significant intercompany accounts and transactions have been eliminated and adjustments, consisting solely of normal recurring accruals and considered necessary for the fair presentation of financial statements for the interim periods, have been included. The current period's results of operations are not necessarily indicative of the results that ultimately may be achieved for the year. The interim condensed consolidated financial statements and notes thereto should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Form 10-K.
Use of Estimates	Use of Estimates We have made a number of estimates and assumptions related to the reporting of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period to prepare these condensed consolidated financial statements in conformity with U.S. GAAP. Actual results could differ from those estimates. Material estimates subject to change in the near term include, among other items, the allowance for credit losses, the carrying value of intangible assets, the realization of deferred tax assets, and the fair value estimates of assets acquired and liabilities assumed in acquisitions. These estimates may be adjusted as more current information becomes available, and any adjustment may be significant.
Reclassifications	Reclassifications Certain prior period amounts have been reclassified to conform to the current period’s presentation format.
Fair Value Measurement	FAIR VALUE MEASUREMENTS ASC Topic 820, “ Fair Value Measurement ,” defines fair value, establishes a framework for measuring fair value including a three‑level valuation hierarchy, and expands disclosures about fair value measurements. Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date reflecting assumptions that a market participant would use when pricing an asset or liability. The hierarchy uses three levels of inputs to measure the fair value of assets and liabilities as follows: • Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2: Observable inputs other than Level 1, including quoted prices for similar assets and liabilities in active markets, quoted prices in less active markets, or other observable inputs that can be corroborated by observable market data, either directly or indirectly, for substantially the full term of the financial instrument. This category generally includes municipal securities, agency residential and commercial MBS, collateralized loan obligations, registered publicly rated private label CMOs, and asset-backed securitizations. • Level 3: Inputs to a valuation methodology that are unobservable, supported by little or no market activity, and significant to the fair value measurement. These valuation methodologies generally include pricing models, discounted cash flow models, or a determination of fair value that requires significant management judgment or estimation. This category also includes observable inputs from a pricing service not corroborated by observable market data, and includes our non-rated private label CMOs, non-rated private label asset-backed securities, and equity warrants. The Company uses fair value to measure certain assets and liabilities on a recurring basis, primarily securities available‑for‑sale and derivatives. For assets measured at the lower of cost or fair value, the fair value measurement criteria may or may not be met during a reporting period and such measurements are therefore considered “nonrecurring” for purposes of disclosing our fair value measurements. Fair value is used on a nonrecurring basis to adjust carrying values for impaired loans and other real estate owned and also to record impairment on certain assets, such as goodwill, CDI, and other long‑lived assets.

Other Assets (Policies)

Other Assets (Policies)	3 Months Ended
	Mar. 31, 2018
Other Assets [Abstract]
Life Settlement Contracts, Disclosure	The Company has purchased life insurance policies on certain employees and has also acquired life insurance policies through acquisitions. BOLI is recorded at the amount that can be realized under the insurance contract, which is the cash surrender value. The increase in the cash surrender value each period is recorded to " Noninterest income - other."

Goodwill and Other Intangible26

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets disclosure	The following table presents the changes in CDI and CRI and the related accumulated amortization for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (In thousands) Gross Amount of CDI and CRI: Balance, beginning of period $ 119,497 $ 61,997 $ 64,187 Addition from CUB acquisition — 57,500 — Balance, end of period 119,497 119,497 64,187 Accumulated Amortization: Balance, beginning of period (39,871 ) (34,809 ) (27,821 ) Amortization (6,346 ) (5,062 ) (3,064 ) Balance, end of period (46,217 ) (39,871 ) (30,885 ) Net CDI and CRI, end of period $ 73,280 $ 79,626 $ 33,302

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of available-for-sale securities reconciliation	The following table presents amortized cost, gross unrealized gains and losses, and fair values of securities available-for-sale as of the dates indicated: March 31, 2018 December 31, 2017 Gross Gross Gross Gross Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair Security Type Cost Gains Losses Value Cost Gains Losses Value (In thousands) Residential MBS and CMOs: Agency MBS $ 251,585 $ 2,748 $ (2,557 ) $ 251,776 $ 243,375 $ 3,743 $ (844 ) $ 246,274 Agency CMOs 551,021 840 (5,916 ) 545,945 277,638 968 (2,897 ) 275,709 Private label CMOs 114,386 3,071 (1,212 ) 116,245 122,816 3,813 (642 ) 125,987 Municipal securities 1,392,261 19,389 (8,064 ) 1,403,586 1,627,707 53,700 (1,339 ) 1,680,068 Agency commercial MBS 1,114,430 121 (25,057 ) 1,089,494 1,169,969 2,758 (8,758 ) 1,163,969 U.S. Treasury securities 148,217 365 — 148,582 — — — — SBA securities 148,787 706 (1,229 ) 148,264 160,214 695 (575 ) 160,334 Asset-backed securities 81,022 11 (1,299 ) 79,734 89,425 159 (874 ) 88,710 Corporate debt securities 17,000 1,360 — 18,360 17,000 2,295 — 19,295 Collateralized loan obligations — — — — 6,960 55 — 7,015 Equity investments — — — — 6,421 779 (130 ) 7,070 Total $ 3,818,709 $ 28,611 $ (45,334 ) $ 3,801,986 $ 3,721,525 $ 68,965 $ (16,059 ) $ 3,774,431
Unrealized losses on investment securities	The following tables present the gross unrealized losses and fair values of securities available-for-sale that were in unrealized loss positions, for which other-than-temporary impairments have not been recognized in earnings, as of the dates indicated: March 31, 2018 Less Than 12 Months 12 Months or More Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized Security Type Value Losses Value Losses Value Losses (In thousands) Residential MBS and CMOs: Agency MBS $ 104,277 $ (1,649 ) $ 24,518 $ (908 ) $ 128,795 $ (2,557 ) Agency CMOs 251,805 (5,359 ) 18,377 (557 ) 270,182 (5,916 ) Private label CMOs 92,396 (1,105 ) 4,446 (107 ) 96,842 (1,212 ) Municipal securities 364,270 (6,320 ) 30,973 (1,744 ) 395,243 (8,064 ) Agency commercial MBS 1,006,897 (21,302 ) 67,387 (3,755 ) 1,074,284 (25,057 ) SBA securities 87,303 (1,229 ) — — 87,303 (1,229 ) Asset-backed securities 64,382 (1,199 ) 7,630 (100 ) 72,012 (1,299 ) Total $ 1,971,330 $ (38,163 ) $ 153,331 $ (7,171 ) $ 2,124,661 $ (45,334 ) December 31, 2017 Less Than 12 Months 12 Months or More Total Gross Gross Gross Fair Unrealized Fair Unrealized Fair Unrealized Security Type Value Losses Value Losses Value Losses (In thousands) Residential MBS and CMOs: Agency MBS $ 44,795 $ (311 ) $ 26,010 $ (533 ) $ 70,805 $ (844 ) Agency CMOs 163,014 (2,452 ) 20,928 (445 ) 183,942 (2,897 ) Private label CMOs 50,521 (500 ) 5,035 (142 ) 55,556 (642 ) Municipal securities 67,936 (365 ) 32,326 (974 ) 100,262 (1,339 ) Agency commercial MBS 579,373 (3,777 ) 129,060 (4,981 ) 708,433 (8,758 ) SBA securities 74,904 (575 ) — — 74,904 (575 ) Asset-backed securities 45,198 (818 ) 10,473 (56 ) 55,671 (874 ) Equity investments 1,039 (130 ) — — 1,039 (130 ) Total $ 1,026,780 $ (8,928 ) $ 223,832 $ (7,131 ) $ 1,250,612 $ (16,059 )
Investments classified by contractual maturity date	The following table presents the contractual maturities of our securities available-for-sale portfolio based on amortized cost and carrying value as of the date indicated: March 31, 2018 Amortized Fair Maturity Cost Value (In thousands) Due in one year or less $ 10,384 $ 10,517 Due after one year through five years 486,326 483,913 Due after five years through ten years 1,053,610 1,035,714 Due after ten years 2,268,389 2,271,842 Total securities available-for-sale $ 3,818,709 $ 3,801,986
Investment income	The following table presents the composition of our interest income on investment securities for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (In thousands) Taxable interest $ 14,599 $ 13,724 $ 12,166 Non-taxable interest 11,107 11,429 10,381 Dividend income 432 559 492 Total interest income on investment securities $ 26,138 $ 25,712 $ 23,039

Loans and Leases (Tables)

Loans and Leases (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Schedule of composition of loans portfolio	The following table summarizes the composition of our loans and leases held for investment as of the dates indicated: March 31, 2018 December 31, 2017 Total Non-PCI Total Loans Loans PCI Loans and Leases and Leases Loans and Leases (In thousands) Real estate mortgage $ 7,570,526 $ 7,815,355 $ 53,658 $ 7,869,013 Real estate construction and land 1,699,630 1,611,287 — 1,611,287 Commercial 6,848,576 7,137,978 4,158 7,142,136 Consumer 397,895 409,551 234 409,785 Gross loans and leases held for investment 16,516,627 16,974,171 58,050 17,032,221 Deferred fees, net (61,342 ) (59,464 ) (14 ) (59,478 ) Loans and leases held for investment, net of deferred fees 16,455,285 16,914,707 58,036 16,972,743 Allowance for loan and lease losses (134,275 ) (133,012 ) (6,444 ) (139,456 ) Total loans and leases held for investment, net $ 16,321,010 $ 16,781,695 $ 51,592 $ 16,833,287
Delinquent loans in loan portfolio	The following tables present an aging analysis of our loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated: March 31, 2018 30 - 89 90 or More Days Days Total Past Due Past Due Past Due Current Total (In thousands) Real estate mortgage: Commercial $ 26,262 $ 6,849 $ 33,111 $ 4,999,895 $ 5,033,006 Residential 1,512 1,976 3,488 2,517,749 2,521,237 Total real estate mortgage 27,774 8,825 36,599 7,517,644 7,554,243 Real estate construction and land: Commercial — — — 789,892 789,892 Residential 2,605 — 2,605 884,505 887,110 Total real estate construction and land 2,605 — 2,605 1,674,397 1,677,002 Commercial: Asset-based — 680 680 2,957,210 2,957,890 Venture capital 737 1,492 2,229 1,918,414 1,920,643 Other commercial 5,133 1,388 6,521 1,941,069 1,947,590 Total commercial 5,870 3,560 9,430 6,816,693 6,826,123 Consumer 1,000 — 1,000 396,917 397,917 Total $ 37,249 $ 12,385 $ 49,634 $ 16,405,651 $ 16,455,285 December 31, 2017 30 - 89 90 or More Days Days Total Past Due Past Due Past Due Current Total (In thousands) Real estate mortgage: Commercial $ 29,070 $ 9,107 $ 38,177 $ 5,323,310 $ 5,361,487 Residential 6,999 2,022 9,021 2,428,483 2,437,504 Total real estate mortgage 36,069 11,129 47,198 7,751,793 7,798,991 Real estate construction and land: Commercial — — — 769,075 769,075 Residential 2,081 — 2,081 820,073 822,154 Total real estate construction and land 2,081 — 2,081 1,589,148 1,591,229 Commercial: Asset-based 344 690 1,034 2,923,837 2,924,871 Venture capital 6,533 760 7,293 2,115,418 2,122,711 Other commercial 2,846 1,586 4,432 2,062,906 2,067,338 Total commercial 9,723 3,036 12,759 7,102,161 7,114,920 Consumer 562 — 562 409,005 409,567 Total (1) $ 48,435 $ 14,165 $ 62,600 $ 16,852,107 $ 16,914,707
Schedule of non accrual and performing restructured impaired financing receivables	The following table presents the composition of our impaired loans and leases held for investment, net of deferred fees, by portfolio segment as of the dates indicated: March 31, 2018 December 31, 2017 (1) Performing Total Performing Total Nonaccrual Troubled Impaired Nonaccrual Troubled Impaired Loans Debt Loans Loans Debt Loans and Restructured and and Restructured and Leases Loans Leases Leases Loans Leases (In thousands) Real estate mortgage $ 24,341 $ 51,031 $ 75,372 $ 68,913 $ 47,560 $ 116,473 Real estate construction and land — 5,670 5,670 — 5,690 5,690 Commercial 79,133 3,349 82,482 86,851 3,488 90,339 Consumer 251 123 374 20 100 120 Total $ 103,725 $ 60,173 $ 163,898 $ 155,784 $ 56,838 $ 212,622 The following table presents our nonaccrual and performing loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated: March 31, 2018 December 31, 2017 (1) Nonaccrual Performing Total Nonaccrual Performing Total (In thousands) Real estate mortgage: Commercial $ 19,116 $ 5,013,890 $ 5,033,006 $ 65,563 $ 5,295,924 $ 5,361,487 Residential 5,225 2,516,012 2,521,237 3,350 2,434,154 2,437,504 Total real estate mortgage 24,341 7,529,902 7,554,243 68,913 7,730,078 7,798,991 Real estate construction and land: Commercial — 789,892 789,892 — 769,075 769,075 Residential — 887,110 887,110 — 822,154 822,154 Total real estate construction and land — 1,677,002 1,677,002 — 1,591,229 1,591,229 Commercial: Asset-based 32,838 2,925,052 2,957,890 33,553 2,891,318 2,924,871 Venture capital 21,861 1,898,782 1,920,643 29,424 2,093,287 2,122,711 Other commercial 24,434 1,923,156 1,947,590 23,874 2,043,464 2,067,338 Total commercial 79,133 6,746,990 6,826,123 86,851 7,028,069 7,114,920 Consumer 251 397,666 397,917 20 409,547 409,567 Total $ 103,725 $ 16,351,560 $ 16,455,285 $ 155,784 $ 16,758,923 $ 16,914,707
CV of loans held for investment by class by performing and nonperforming	The following table presents the credit risk rating categories for loans and leases held for investment, net of deferred fees, by portfolio segment and class as of the dates indicated. Classified loans and leases are those with a credit risk rating of either substandard or doubtful. March 31, 2018 Classified Special Mention Pass Total (In thousands) Real estate mortgage: Commercial $ 44,635 $ 158,496 $ 4,829,875 $ 5,033,006 Residential 12,436 1,672 2,507,129 2,521,237 Total real estate mortgage 57,071 160,168 7,337,004 7,554,243 Real estate construction and land: Commercial 453 — 789,439 789,892 Residential — 30,626 856,484 887,110 Total real estate construction and land 453 30,626 1,645,923 1,677,002 Commercial: Asset-based 49,913 54,882 2,853,095 2,957,890 Venture capital 31,364 124,303 1,764,976 1,920,643 Other commercial 68,813 43,681 1,835,096 1,947,590 Total commercial 150,090 222,866 6,453,167 6,826,123 Consumer 428 1,456 396,033 397,917 Total $ 208,042 $ 415,116 $ 15,832,127 $ 16,455,285 December 31, 2017 (1) Classified Special Mention Pass Total (In thousands) Real estate mortgage: Commercial $ 93,795 $ 122,488 $ 5,145,204 $ 5,361,487 Residential 8,425 4,582 2,424,497 2,437,504 Total real estate mortgage 102,220 127,070 7,569,701 7,798,991 Real estate construction and land: Commercial — — 769,075 769,075 Residential — 619 821,535 822,154 Total real estate construction and land — 619 1,590,610 1,591,229 Commercial: Asset-based 51,000 37,256 2,836,615 2,924,871 Venture capital 49,671 114,210 1,958,830 2,122,711 Other commercial 75,251 21,883 1,970,204 2,067,338 Total commercial 175,922 173,349 6,765,649 7,114,920 Consumer 263 1,130 408,174 409,567 Total $ 278,405 $ 302,168 $ 16,334,134 $ 16,914,707 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
Impaired financing receivables, average balances and interest income recognized	The following tables present information regarding our impaired loans and leases held for investment, net of deferred fees, by portfolio segment and class as of and for the dates indicated: March 31, 2018 December 31, 2017 (1) Unpaid Unpaid Recorded Principal Related Recorded Principal Related Impaired Loans and Leases Investment Balance Allowance Investment Balance Allowance (In thousands) With An Allowance Recorded: Real estate mortgage: Commercial $ 13,884 $ 14,690 $ 576 $ 15,750 $ 16,548 $ 628 Residential 4,295 4,926 512 2,787 2,957 342 Commercial: Venture capital 17,367 18,312 4,970 16,565 17,203 4,267 Other commercial 18,048 31,672 8,171 20,404 29,951 8,368 Consumer 295 355 16 100 100 16 With No Related Allowance Recorded: Real estate mortgage: Commercial $ 48,729 $ 63,283 $ 93,827 $ 105,923 Residential 8,464 10,674 4,109 4,481 Real estate construction and land: Commercial 5,670 5,670 5,690 5,689 Commercial: Asset-based 32,838 55,890 33,553 54,911 Venture capital 6,129 29,786 14,534 40,029 Other commercial 8,100 27,819 5,283 9,351 Consumer 79 179 20 93 Total Loans and Leases With and Without an Allowance Recorded: Real estate mortgage $ 75,372 $ 93,573 $ 1,088 $ 116,473 $ 129,909 $ 970 Real estate construction and land 5,670 5,670 — 5,690 5,689 — Commercial 82,482 163,479 13,141 90,339 151,445 12,635 Consumer 374 534 16 120 193 16 Total $ 163,898 $ 263,256 $ 14,245 $ 212,622 $ 287,236 $ 13,621 ________________________ (1) Excludes loans held for sale carried at lower of cost or fair value and PCI loans. Three Months Ended March 31, 2018 2017 Weighted Interest Weighted Interest Average Income Average Income Impaired Loans and Leases Balance (1) Recognized Balance (1) Recognized (In thousands) With An Allowance Recorded: Real estate mortgage: Commercial $ 13,884 $ 201 $ 14,350 $ 206 Residential 4,295 23 3,501 12 Commercial: Venture capital 14,598 — 4,693 — Other commercial 16,851 15 44,333 15 Consumer 295 2 187 — With No Related Allowance Recorded: Real estate mortgage: Commercial $ 46,782 $ 765 $ 92,753 $ 560 Residential 8,464 45 5,216 15 Real estate construction and land: Commercial 5,670 89 6,111 67 Residential — — 572 2 Commercial: Asset-based 32,838 — 30,739 — Venture capital 4,474 — 2,429 — Other commercial 7,859 1,147 4,750 30 Consumer 79 — 127 2 Total Loans and Leases With and Without an Allowance Recorded: Real estate mortgage $ 73,425 $ 1,034 $ 115,820 $ 793 Real estate construction and land 5,670 89 6,683 69 Commercial 76,620 1,162 86,944 45 Consumer 374 2 314 2 Total $ 156,089 $ 2,287 $ 209,761 $ 909 _________________________ (1) For loans and leases reported as impaired at March 31, 2018 and 2017 , amounts were calculated based on the period of time such loans and leases were impaired during the reported period.
Troubled debt restructurings on financing receivables	The following table presents our troubled debt restructurings of loans held for investment by portfolio segment and class for the periods indicated: Three Months Ended March 31, 2018 2017 Pre- Post- Pre- Post- Modification Modification Modification Modification Outstanding Outstanding Outstanding Outstanding Number Recorded Recorded Number Recorded Recorded Troubled Debt Restructurings of Loans Investment Investment of Loans Investment Investment (Dollars in thousands) Real estate mortgage: Commercial — $ — $ — 1 $ 64 $ — Residential — — — 2 42 42 Commercial: Venture capital — — — 3 13,065 13,065 Other commercial 2 11,783 11,783 4 719 719 Consumer — — — 1 97 97 Total 2 $ 11,783 $ 11,783 11 $ 13,987 $ 13,923
Subsequently defaulted trouble debt restructurings	The following table presents troubled debt restructurings of loans held for investment by portfolio segment and class that subsequently defaulted for the periods indicated: Three Months Ended March 31, 2018 2017 Troubled Debt Restructurings Number Recorded Number Recorded That Subsequently Defaulted of Loans Investment (1) of Loans Investment (1) (Dollars in thousands) Commercial: Other commercial 1 $ 2,250 — $ — Consumer — — 1 28 Total 1 $ 2,250 (2) 1 $ 28 (3) _________________________ (1) The population of defaulted restructured loans for the period indicated includes only those loans restructured during the preceding 12-month period. For example, for the 12-month period ended March 31, 2018 , the population of defaulted restructured loans includes only those loans restructured after March 31, 2017 . The table excludes defaulted troubled debt restructurings in those classes for which the recorded investment was zero at the end of the period. (2) Represents the balance at March 31, 2018 , and there were no charge-offs. (3) Represents the balance at March 31, 2017 , and there were no charge-offs.
Allowance for credit losses on financing receivables	The following tables present a summary of the activity in the allowance for loan and lease losses on loans and leases held for investment by portfolio segment for the periods indicated: Three Months Ended March 31, 2018 Real Estate Real Estate Construction Mortgage and Land Commercial Consumer Total (In thousands) Allowance for Loan and Lease Losses: Balance, beginning of period $ 40,051 $ 13,055 $ 84,022 $ 2,328 $ 139,456 Charge-offs (2,598 ) — (9,524 ) (31 ) (12,153 ) Recoveries 1,657 9 5,487 45 7,198 Provision (negative provision) 1,048 5,126 (6,205 ) (195 ) (226 ) Balance, end of period $ 40,158 $ 18,190 $ 73,780 $ 2,147 $ 134,275 Ending Allowance by Impairment Methodology: Individually evaluated for impairment $ 1,088 $ — $ 13,141 $ 16 $ 14,245 Collectively evaluated for impairment $ 39,070 $ 18,190 $ 60,639 $ 2,131 $ 120,030 Ending Loans and Leases by Impairment Methodology: Individually evaluated for impairment $ 74,390 $ 5,670 $ 82,434 $ 324 $ 162,818 Collectively evaluated for impairment 7,479,853 1,671,332 6,743,689 397,593 16,292,467 Ending balance $ 7,554,243 $ 1,677,002 $ 6,826,123 $ 397,917 $ 16,455,285 Three Months Ended March 31, 2017 Real Estate Real Estate Construction Total Total Mortgage and Land Commercial Consumer Non-PCI PCI Total (In thousands) Allowance for Loan and Lease Losses: Balance, beginning of period $ 37,765 $ 10,045 $ 93,853 $ 2,092 $ 143,755 $ 13,483 $ 157,238 Charge-offs (1,544 ) — (19,285 ) (99 ) (20,928 ) (2,230 ) (23,158 ) Recoveries 230 8 2,448 53 2,739 — 2,739 Provision (negative provision) (1,083 ) 423 25,118 (198 ) 24,260 228 24,488 Balance, end of period $ 35,368 $ 10,476 $ 102,134 $ 1,848 $ 149,826 $ 11,481 $ 161,307 Ending Allowance by Impairment Methodology: Individually evaluated for impairment $ 1,070 $ — $ 12,267 $ 90 $ 13,427 Collectively evaluated for impairment $ 34,298 $ 10,476 $ 89,867 $ 1,758 $ 136,399 Acquired loans with deteriorated credit quality $ 11,481 Ending Loans and Leases by Impairment Methodology: Individually evaluated for impairment $ 118,275 $ 6,683 $ 103,221 $ 281 $ 228,460 Collectively evaluated for impairment 5,768,694 1,101,553 7,979,457 382,190 15,231,894 Acquired loans with deteriorated credit quality $ 96,335 Ending balance $ 5,886,969 $ 1,108,236 $ 8,082,678 $ 382,471 $ 15,460,354 $ 96,335 $ 15,556,689

Foreclosed Assets (Tables)

Foreclosed Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Other Real Estate Owned Net Covered and NonCovered Including Foreclosed Assets [Abstract]
Other real estate and foreclosed assets	The following table summarizes foreclosed assets as of the dates indicated: March 31, December 31, Property Type 2018 2017 (In thousands) Construction and land development $ 219 $ 219 Commercial real estate 64 64 Single family residence 953 1,019 Total other real estate owned, net 1,236 1,302 Other foreclosed assets — 27 Total foreclosed assets, net $ 1,236 $ 1,329
Other foreclosed assets rollforward	The following table presents the changes in foreclosed assets, net of the valuation allowance, for the period indicated: Foreclosed Assets (In thousands) Balance, December 31, 2017 $ 1,329 Provision for losses (65 ) Reductions related to sales (28 ) Balance, March 31, 2018 $ 1,236

Other Assets (Tables)

Other Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Other Assets [Abstract]
Schedule of Other Assets	The following table presents the detail of our other assets as of the dates indicated: March 31, December 31, Other Assets 2018 2017 (In thousands) Cash surrender value of BOLI $ 195,163 $ 193,917 Interest receivable 78,822 82,935 Taxes receivable 64,739 98,998 CRA investments 53,838 49,432 Low income housing tax credit ("LIHTC") investments 43,793 39,235 Equity investments without readily determinable fair values 15,642 14,856 Equity investments with readily determinable fair values 5,028 — Other assets 54,159 61,350 Total other assets $ 511,184 $ 540,723

Borrowings and Subordinated D31

Borrowings and Subordinated Debentures (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of debt	The following table summarizes our borrowings as of the dates indicated: March 31, 2018 December 31, 2017 Weighted Weighted Average Average Amount Rate Amount Rate (Dollars in thousands) Non‑recourse debt $ 284 6.94 % $ 342 6.87 % FHLB secured advances 340,000 1.87 % 332,000 1.41 % FHLB unsecured overnight advance 135,000 1.85 % 135,000 1.34 % AFX borrowings 100,000 1.82 % — — % Total borrowings $ 575,284 $ 467,342
Borrowings subordinated debentures and brokered deposits disclosure	The following table summarizes the terms of each issuance of subordinated debentures outstanding as of the dates indicated: March 31, 2018 December 31, 2017 Date Maturity Rate Index Series Amount Rate Amount Rate Issued Date (Quarterly Reset) (Dollars in thousands) Trust V $ 10,310 5.28 % $ 10,310 4.70 % 8/15/2003 9/17/2033 3 month LIBOR + 3.10 Trust VI 10,310 5.17 % 10,310 4.64 % 9/3/2003 9/15/2033 3 month LIBOR + 3.05 Trust CII 5,155 5.13 % 5,155 4.55 % 9/17/2003 9/17/2033 3 month LIBOR + 2.95 Trust VII 61,856 4.52 % 61,856 4.13 % 2/5/2004 4/23/2034 3 month LIBOR + 2.75 Trust CIII 20,619 3.81 % 20,619 3.28 % 8/15/2005 9/15/2035 3 month LIBOR + 1.69 Trust FCCI 16,495 3.72 % 16,495 3.19 % 1/25/2007 3/15/2037 3 month LIBOR + 1.60 Trust FCBI 10,310 3.67 % 10,310 3.14 % 9/30/2005 12/15/2035 3 month LIBOR + 1.55 Trust CS 2005-1 82,475 4.07 % 82,475 3.54 % 11/21/2005 12/15/2035 3 month LIBOR + 1.95 Trust CS 2005-2 128,866 3.72 % 128,866 3.33 % 12/14/2005 1/30/2036 3 month LIBOR + 1.95 Trust CS 2006-1 51,545 3.72 % 51,545 3.33 % 2/22/2006 4/30/2036 3 month LIBOR + 1.95 Trust CS 2006-2 51,550 3.72 % 51,550 3.33 % 9/27/2006 10/30/2036 3 month LIBOR + 1.95 Trust CS 2006-3 (1) 31,773 1.72 % 30,986 1.72 % 9/29/2006 10/30/2036 3 month EURIBOR + 2.05 Trust CS 2006-4 16,470 3.72 % 16,470 3.33 % 12/5/2006 1/30/2037 3 month LIBOR + 1.95 Trust CS 2006-5 6,650 3.72 % 6,650 3.33 % 12/19/2006 1/30/2037 3 month LIBOR + 1.95 Trust CS 2007-2 39,177 3.72 % 39,177 3.33 % 6/13/2007 7/30/2037 3 month LIBOR + 1.95 Trust I (2) — — % 6,186 3.64 % 12/10/2004 3/15/2035 3 month LIBOR + 2.05 Trust II (2) — — % 3,093 3.34 % 12/23/2005 3/15/2036 3 month LIBOR + 1.75 Trust III (2) — — % 3,093 3.44 % 6/30/2006 9/18/2036 3 month LIBOR + 1.85 Gross subordinated debentures 543,561 555,146 Unamortized discount (3) (91,338 ) (92,709 ) Net subordinated debentures $ 452,223 $ 462,437 ___________________ (1) Denomination is in Euros with a value of €25.8 million .

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments disclosure	The following table presents a summary of the financial instruments described above as of the dates indicated: March 31, December 31, 2018 2017 (In thousands) Loan commitments to extend credit $ 6,352,803 $ 6,234,061 Standby letters of credit 337,678 320,063 Total $ 6,690,481 $ 6,554,124

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair value, assets measured on recurring basis	The following tables present information on the assets and liabilities measured and recorded at fair value on a recurring basis as of the dates indicated: Fair Value Measurements as of March 31, 2018 Measured on a Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Securities available‑for‑sale: Residential MBS and CMOs: Agency MBS $ 251,776 $ — $ 251,776 $ — Agency CMOs 545,945 — 545,945 — Private label CMOs 116,245 — 94,164 22,081 Municipal securities 1,403,586 — 1,403,586 — Agency commercial MBS 1,089,494 — 1,089,494 — U.S. Treasury securities 148,582 148,582 — — SBA securities 148,264 — 148,264 — Asset-backed securities 79,734 — 43,316 36,418 Corporate debt securities 18,360 — 18,360 — Total securities available-for-sale 3,801,986 148,582 3,594,905 58,499 Equity warrants 5,284 — — 5,284 Other derivative assets 3,327 — 3,327 — Equity investments with readily determinable fair values 5,028 5,028 — — Total recurring assets $ 3,815,625 $ 153,610 $ 3,598,232 $ 63,783 Derivative liabilities $ 642 $ — $ 642 $ — Fair Value Measurements as of December 31, 2017 Measured on a Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Securities available‑for‑sale: Residential MBS and CMOs: Agency MBS $ 246,274 $ — $ 246,274 $ — Agency CMOs 275,709 — 275,709 — Private label CMOs 125,987 — 103,113 22,874 Municipal securities 1,680,068 — 1,680,068 — Agency commercial MBS 1,163,969 — 1,163,969 — SBA securities 160,334 — 160,334 — Asset-backed securities 88,710 — 46,601 42,109 Corporate debt securities 19,295 — 19,295 — Collateralized loan obligations 7,015 — 7,015 — Equity investments 7,070 5,922 1,148 — Total securities available-for-sale 3,774,431 5,922 3,703,526 64,983 Equity warrants 5,161 — — 5,161 Other derivative assets 1,873 — 1,873 — Total recurring assets $ 3,781,465 $ 5,922 $ 3,705,399 $ 70,144 Derivative liabilities $ 1,379 $ — $ 1,379 $ —
Fair value, assets and liabilities measured on nonrecurring basis, valuation techniques	The following table presents information about quantitative inputs and assumptions used to determine the fair values provided by our third party pricing service for our Level 3 private label CMOs and asset-backed securities available-for-sale measured at fair value on a recurring basis as of the date indicated: March 31, 2018 Private Label CMOs Asset-Backed Securities Weighted Weighted Range Average Range Average Unobservable Inputs of Inputs Input of Inputs Input Voluntary annual prepayment speeds 3.8% - 52.7% 8.3% 5% - 15% 14.0% Annual default rates 0.1% - 16.5% 2.5% 1% - 2% 1.9% Loss severity rates 3.2% - 105.7% 46.3% 10% - 60% 55.2% Discount rates 2.0% - 10.3% 5.3% 3.2% - 4.3% 3.6%
Fair value, quantitative inputs and assumptions used to determine fair value	The following table presents information about quantitative inputs and assumptions used in the modified Black-Scholes option pricing model to determine the fair value for our Level 3 equity warrants measured at fair value on a recurring basis as of the date indicated: March 31, 2018 Equity Warrants Weighted Average Unobservable Inputs Input Volatility 16.8% Risk-free interest rate 2.4% Remaining life assumption (in years) 3.7
Fair value, assets measured on recurring basis, significant unobservable inputs (level 3) reconciliation	The following table summarizes activity for our Level 3 private label CMOs available-for-sale, asset-backed securities available-for-sale, and equity warrants measured at fair value on a recurring basis for the period indicated: Private Asset-Backed Equity Label CMOs Securities Warrants (In thousands) Balance, December 31, 2017 $ 22,874 $ 42,109 $ 5,161 Total included in earnings 165 (10 ) 248 Total included in other comprehensive income (141 ) (228 ) — Issuances — — 206 Sales — — (331 ) Transfer to Level 2 (13 ) — — Net settlements (804 ) (5,453 ) — Balance, March 31, 2018 $ 22,081 $ 36,418 $ 5,284
Assets carried at fair value on a nonrecurring basis	The following tables present assets measured at fair value on a non‑recurring basis as of the dates indicated: Fair Value Measurement as of March 31, 2018 Measured on a Non‑Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Impaired loans $ 45,557 $ — $ 1,128 $ 44,429 OREO 953 — 953 — Total non-recurring $ 46,510 $ — $ 2,081 $ 44,429 Fair Value Measurement as of December 31, 2017 Measured on a Non‑Recurring Basis Total Level 1 Level 2 Level 3 (In thousands) Impaired Non‑PCI loans $ 61,095 $ — $ 5,143 $ 55,952 Loans held for sale 483,563 — 483,563 — Total non-recurring $ 544,658 $ — $ 488,706 $ 55,952
Net losses (gains) on nonrecurring assets	The following table presents losses recognized on assets measured on a nonrecurring basis for the periods indicated: Three Months Ended Losses on Assets March 31, Measured on a Non‑Recurring Basis 2018 2017 (In thousands) Impaired loans (1) $ 7,816 $ 13,617 OREO 65 — Total losses $ 7,881 $ 13,617
Fair value inputs, assets, quantitative information	The following table presents the valuation methodology and unobservable inputs for Level 3 assets measured at fair value on a nonrecurring basis as of the date indicated: March 31, 2018 Valuation Unobservable Weighted Asset Fair Value Technique Inputs Range Average (In thousands) Impaired loans $ 32,638 Discounted cash flows Discount rates 2.00% - 10.20% 7.33% Impaired loans 11,791 Third party appraisals No discounts Total non-recurring Level 3 $ 44,429
Fair value, by balance sheet grouping	The following tables present carrying amounts and estimated fair values of certain financial instruments as of the dates indicated: March 31, 2018 Carrying Estimated Fair Value Amount Total Level 1 Level 2 Level 3 ( In thousands ) Financial Assets: Cash and due from banks $ 235,061 $ 235,061 $ 235,061 $ — $ — Interest‑earning deposits in financial institutions 312,735 312,735 312,735 — — Securities available‑for‑sale 3,801,986 3,801,986 148,582 3,594,905 58,499 Investment in FHLB stock 17,250 17,250 — 17,250 — Loans and leases held for investment, net 16,321,010 16,247,325 — 1,128 16,246,197 Equity warrants 5,284 5,284 — — 5,284 Other derivative assets 3,327 3,327 — 3,327 — Equity investments with readily determinable fair values 5,028 5,028 5,028 — — Financial Liabilities: Core deposits 15,661,529 15,661,529 — 15,661,529 — Non-core non-maturity deposits 585,399 585,399 — 585,399 — Time deposits 1,831,860 1,820,330 — 1,820,330 — Borrowings 575,284 575,285 575,000 285 — Subordinated debentures 452,223 435,985 — 435,985 — Derivative liabilities 642 642 — 642 — December 31, 2017 Carrying Estimated Fair Value Amount Total Level 1 Level 2 Level 3 ( In thousands ) Financial Assets: Cash and due from banks $ 233,215 $ 233,215 $ 233,215 $ — $ — Interest‑earning deposits in financial institutions 165,222 165,222 165,222 — — Securities available‑for‑sale 3,774,431 3,774,431 5,922 3,703,526 64,983 Investment in FHLB stock 20,790 20,790 — 20,790 — Loans held for sale 481,100 483,563 — 483,563 — Loans and leases held for investment, net 16,833,287 17,023,098 — 5,143 17,017,955 Equity warrants 5,161 5,161 — — 5,161 Other derivative assets 1,873 1,873 — 1,873 — Financial Liabilities: Core deposits 15,937,012 15,937,012 — 15,937,012 — Non-core non-maturity deposits 863,202 863,202 — 863,202 — Time deposits 2,065,322 2,055,104 — 2,055,104 — Borrowings 467,342 467,342 467,000 342 — Subordinated debentures 462,437 444,383 — 444,383 — Derivative liabilities 1,379 1,379 — 1,379 —

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Net income per share	The following table presents the computations of basic and diluted net earnings per share for the periods indicated: Three Months Ended March 31, December 31, March 31, 2018 2017 2017 (Dollars in thousands, except per share data) Basic Earnings Per Share: Net earnings $ 118,276 $ 84,037 $ 78,668 Less: Earnings allocated to unvested restricted stock (1) (1,115 ) (951 ) (999 ) Net earnings allocated to common shares $ 117,161 $ 83,086 $ 77,669 Weighted-average basic shares and unvested restricted stock outstanding 127,487 127,971 121,346 Less: Weighted-average unvested restricted stock outstanding (1,413 ) (1,440 ) (1,503 ) Weighted-average basic shares outstanding 126,074 126,531 119,843 Basic earnings per share $ 0.93 $ 0.66 $ 0.65 Diluted Earnings Per Share: Net earnings allocated to common shares $ 117,161 $ 83,086 $ 77,669 Weighted-average basic shares outstanding 126,074 126,531 119,843 Diluted earnings per share $ 0.93 $ 0.66 $ 0.65 ________________________ (1) Represents cash dividends paid to holders of unvested restricted stock, net of forfeitures, plus undistributed earnings amounts available to holders of unvested restricted stock, if any.

Revenue From Contracts With C35

Revenue From Contracts With Customers (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue From Contracts With Customers [Abstract]
Revenue from Contract with Customer	REVENUE FROM CONTRACTS WITH CUSTOMERS The Company adopted Topic 606 Revenue from Contracts with Customers effective as of January 1, 2018 and has applied the guidance to all contracts within the scope of Topic 606 as of that date. Revenue from contracts with customers in the scope of Topic 606 is measured based on the consideration specified in the contract with a customer, and excludes amounts collected on behalf of third parties. The Company recognizes revenue from contracts with customers when it satisfies its performance obligations. The Company's performance obligations are typically satisfied as services are rendered and payment is generally collected at the time services are rendered, or on a monthly, quarterly or annual basis. The Company had no material unsatisfied performance obligations as of March 31, 2018. In certain cases, other parties are involved with providing products and services to our customers. If the Company is a principal in the transaction (providing goods or services itself), revenues are reported based on the gross consideration received from the customer and any related expenses are reported gross in noninterest expense. If the Company is an agent in the transaction (arranging for another party to provide goods or services), the Company reports its net fee or commission retained as revenue. Rebates, waivers, and reversals are recorded as a reduction of revenue either when the revenue is recognized by the Company or at the time the rebate, waiver, or reversal is earned by the customer. The Company has elected the following practical expedients: (1) we do not disclose information about remaining performance obligations that have original expected durations of one year or less; and (2) we do not adjust the consideration from customers for the effects of a significant financing component if at contract inception the period between when the Company transfers the goods or services and when the customer pays for that good or service will be one year or less. Nature of Goods and Service s Substantially all of the Company's revenue, such as interest income on loans, investment securities, and interest-earning deposits in financial institutions, is specifically out-of-scope of Topic 606. For the revenue that is in-scope, the following is a description of principal activities, separated by the timing of revenue recognition, from which the Company generates its revenue from contracts with customers: • Revenue earned at a point in time. Examples of revenue earned at a point in time are ATM transaction fees, wire transfer fees, NSF fees, and credit and debit card interchange fees. Revenue is generally derived from transactional information accumulated by our systems and is recognized as revenue immediately as the transactions occur or upon providing the service to complete the customer's transaction. The Company is the principal in each of these contracts with the exception of credit and debit card interchange fees, in which case the Company is acting as the agent and records revenue net of expenses paid to the principal. • Revenue earned over time. The Company earns certain revenue from contracts with customers monthly. Examples of this type of revenue are deposit account service fees, investment management fees, merchant referral services, MasterCard marketing incentives and safe deposit box fees. Account service charges, management fees and referral fees are recognized on a monthly basis while any transaction-based revenue is recorded as the activity occurs. Revenue is primarily based on the number and type of transactions and is generally derived from transactional information accumulated by our systems. Revenue is recorded in the same period as the related transactions occur or services are rendered to the customer. Disaggregation of Revenue The following table presents interest income and noninterest income, the components of total revenue, as disclosed in the condensed consolidated statements of earnings and the related amounts which are from contracts with customers within the scope of Topic 606. As illustrated here, substantially all of our revenue is specifically excluded from the scope of Topic 606. Three Months Ended March 31, 2018 Total Revenue from Recorded Contracts With Revenue Customers (In thousands) Total interest income $ 277,775 $ — Noninterest income: Service charges on deposit accounts 4,174 4,174 Other commissions and fees 10,265 4,651 Leased equipment income 9,587 — Gain on sale of loans 4,569 — Gain on sale of securities 6,311 — Other income 3,653 461 Total noninterest income 38,559 9,286 Total revenue $ 316,334 $ 9,286 The following table presents revenue from contracts with customers based on the timing of revenue recognition for the period indicated: Three Months Ended March 31, 2018 (In thousands) Products and services transferred at a point in time $ 4,661 Products and services transferred over time 4,625 Total revenue from contracts with customers $ 9,286 Contract Balances The following table provides information about receivables, contract assets and contract liabilities from contracts with customers: March 31, 2018 (In thousands) Receivables, which are included in "Other assets" $ 1,438 Contract assets, which are included in "Other assets" $ — Contract liabilities, which are included in "Interest payable and other liabilities" $ 719 Contract liabilities relate to advance consideration received from customers for which revenue is recognized over the life of the contract. The change in contract liabilities for the three months ended March 31, 2018 due to revenue recognized that was included in the contract liability balance at the beginning of the period was $33,000 . As illustrated here, substantially all of our revenue is specifically excluded from the scope of Topic 606. Three Months Ended March 31, 2018 Total Revenue from Recorded Contracts With Revenue Customers (In thousands) Total interest income $ 277,775 $ — Noninterest income: Service charges on deposit accounts 4,174 4,174 Other commissions and fees 10,265 4,651 Leased equipment income 9,587 — Gain on sale of loans 4,569 — Gain on sale of securities 6,311 — Other income 3,653 461 Total noninterest income 38,559 9,286 Total revenue $ 316,334 $ 9,286
Revenue Recognition of Contracts With Customers	The following table presents revenue from contracts with customers based on the timing of revenue recognition for the period indicated: Three Months Ended March 31, 2018 (In thousands) Products and services transferred at a point in time $ 4,661 Products and services transferred over time 4,625 Total revenue from contracts with customers $ 9,286
Contract with Customer, Asset and Liability	The following table provides information about receivables, contract assets and contract liabilities from contracts with customers: March 31, 2018 (In thousands) Receivables, which are included in "Other assets" $ 1,438 Contract assets, which are included in "Other assets" $ — Contract liabilities, which are included in "Interest payable and other liabilities" $ 719

Organization (Details Textual)

Organization (Details Textual)	3 Months Ended
	Mar. 31, 2018USD ($)bank_branchacquisition
Business Acquisition [Line Items]
Number of Businesses Acquired | acquisition	29
CALIFORNIA
Business Acquisition [Line Items]
Retail Branch Locations | bank_branch	75
NORTH CAROLINA
Business Acquisition [Line Items]
Retail Branch Locations | bank_branch	1
Accounting Standards Update 2016-01 [Member]
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption | $	$ (529,000)
Accounting Standards Update 2018-02 [Member]
Business Acquisition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption | $	$ 6,665,000

Restricted Cash (Details Textua

Restricted Cash (Details Textual) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Restricted Cash [Abstract]
Restricted Cash and Cash Equivalents	$ 80.7	$ 77.6

Acquisitions (Details Textual)

Acquisitions (Details Textual) - CU Bancorp [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Oct. 20, 2017
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loans And Leases Receivable Net Reported Amount Covered And Not Covered		$ 2,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		2,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		3,500
CU Bancorp [Member]
Goodwill, Acquired During Period	$ 374.7
Core Deposits [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ 2,700

Goodwill and Other Intangible39

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 0	$ 57,500	$ 0
Finite-lived Intangible Assets [Roll Forward]
CDI and CRI Balance, beginning of period	119,497	61,997	64,187
Accumulated Amortization, beginning of period	(39,871)	(34,809)	(27,821)
Amortization	(6,346)	(5,062)	(3,064)
CDI and CRI Balance, end of period	119,497	119,497	64,187
Accumulated Amortization, end of period	(46,217)	(39,871)	(30,885)
Net CDI and CRI, end of period	$ 73,280	$ 79,626	$ 33,302

Goodwill and Other Intangible40

Goodwill and Other Intangible Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization	$ 6,346	$ 5,062	$ 3,064
Aggregate amortization expense 2019	18,700
Aggregate amortization expense 2020	14,600
Aggregate amortization expense 2021	10,800
Aggregate amortization expense 2022	7,500
Aggregate amortization expense 2023	$ 1,400
Scenario, Forecast
Finite-Lived Intangible Assets [Line Items]
Intangible asset amortization				$ 22,500

Investment Securities (Details)

Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	$ 3,818,709	$ 3,721,525
Available-for-sale Securities, Gross Unrealized Gain	28,611	68,965
Available-for-sale Securities, Gross Unrealized Loss	(45,334)	(16,059)
Securities available‑for‑sale	3,801,986	3,774,431
Government agency and government-sponsored enterprise pass through securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	251,585	243,375
Available-for-sale Securities, Gross Unrealized Gain	2,748	3,743
Available-for-sale Securities, Gross Unrealized Loss	(2,557)	(844)
Securities available‑for‑sale	251,776	246,274
Government agency and government-sponsored enterprise collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	551,021	277,638
Available-for-sale Securities, Gross Unrealized Gain	840	968
Available-for-sale Securities, Gross Unrealized Loss	(5,916)	(2,897)
Securities available‑for‑sale	545,945	275,709
Private label collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	114,386	122,816
Available-for-sale Securities, Gross Unrealized Gain	3,071	3,813
Available-for-sale Securities, Gross Unrealized Loss	(1,212)	(642)
Securities available‑for‑sale	116,245	125,987
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	1,392,261	1,627,707
Available-for-sale Securities, Gross Unrealized Gain	19,389	53,700
Available-for-sale Securities, Gross Unrealized Loss	(8,064)	(1,339)
Securities available‑for‑sale	1,403,586	1,680,068
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	1,114,430	1,169,969
Available-for-sale Securities, Gross Unrealized Gain	121	2,758
Available-for-sale Securities, Gross Unrealized Loss	(25,057)	(8,758)
Securities available‑for‑sale	1,089,494	1,163,969
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	148,217	0
Available-for-sale Securities, Gross Unrealized Gain	365	0
Available-for-sale Securities, Gross Unrealized Loss	0	0
Securities available‑for‑sale	148,582	0
SBA asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	148,787	160,214
Available-for-sale Securities, Gross Unrealized Gain	706	695
Available-for-sale Securities, Gross Unrealized Loss	(1,229)	(575)
Securities available‑for‑sale	148,264	160,334
Asset-backed
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	81,022	89,425
Available-for-sale Securities, Gross Unrealized Gain	11	159
Available-for-sale Securities, Gross Unrealized Loss	(1,299)	(874)
Securities available‑for‑sale	79,734	88,710
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	17,000	17,000
Available-for-sale Securities, Gross Unrealized Gain	1,360	2,295
Available-for-sale Securities, Gross Unrealized Loss	0	0
Securities available‑for‑sale	18,360	19,295
Collateralized loan obligations
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	0	6,960
Available-for-sale Securities, Gross Unrealized Gain	0	55
Available-for-sale Securities, Gross Unrealized Loss	0	0
Securities available‑for‑sale	0	7,015
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Total securities available-for-sale	0	6,421
Available-for-sale Securities, Gross Unrealized Gain	0	779
Available-for-sale Securities, Gross Unrealized Loss	0	(130)
Securities available‑for‑sale	$ 0	$ 7,070

Investment Securities (Details

Investment Securities (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	$ 1,971,330	$ 1,026,780
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(38,163)	(8,928)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	153,331	223,832
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(7,171)	(7,131)
Unrealized Losses on Securities Available-for-Sale, Fair Value	2,124,661	1,250,612
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(45,334)	(16,059)
Government agency and government-sponsored enterprise pass through securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	104,277	44,795
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,649)	(311)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	24,518	26,010
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(908)	(533)
Unrealized Losses on Securities Available-for-Sale, Fair Value	128,795	70,805
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(2,557)	(844)
Government agency and government-sponsored enterprise collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	251,805	163,014
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(5,359)	(2,452)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	18,377	20,928
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(557)	(445)
Unrealized Losses on Securities Available-for-Sale, Fair Value	270,182	183,942
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(5,916)	(2,897)
Private label collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	92,396	50,521
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,105)	(500)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	4,446	5,035
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(107)	(142)
Unrealized Losses on Securities Available-for-Sale, Fair Value	96,842	55,556
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,212)	(642)
Municipal securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	364,270	67,936
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(6,320)	(365)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	30,973	32,326
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1,744)	(974)
Unrealized Losses on Securities Available-for-Sale, Fair Value	395,243	100,262
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(8,064)	(1,339)
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	1,006,897	579,373
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(21,302)	(3,777)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	67,387	129,060
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(3,755)	(4,981)
Unrealized Losses on Securities Available-for-Sale, Fair Value	1,074,284	708,433
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(25,057)	(8,758)
SBA asset-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	87,303	74,904
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,229)	(575)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	87,303	74,904
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,229)	(575)
Asset-backed
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	64,382	45,198
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,199)	(818)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	7,630	10,473
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(100)	(56)
Unrealized Losses on Securities Available-for-Sale, Fair Value	72,012	55,671
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	$ (1,299)	(874)
Equity Securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value		1,039
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses		(130)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value		0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses		0
Unrealized Losses on Securities Available-for-Sale, Fair Value		1,039
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses		$ (130)

Investment Securities (Detail43

Investment Securities (Details 2) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less	$ 10,384
Due after one year through five years	486,326
Due after five years through ten years	1,053,610
Due after ten years	2,268,389
Total securities available-for-sale	3,818,709	$ 3,721,525
Fair Value
Due in one year or less	10,517
Due after one year through five years	483,913
Due after five years through ten years	1,035,714
Due after ten years	2,271,842
Total securities available-for-sale	$ 3,801,986	$ 3,774,431

Investment Securities (Detail44

Investment Securities (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Taxable interest	$ 14,599	$ 13,724	$ 12,166
Non-taxable interest	11,107	11,429	10,381
Dividend income	432	559	492
Total interest income on investment securities	$ 26,138	$ 25,712	$ 23,039

Investment Securities (Detail45

Investment Securities (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
AFS securities pledged as collateral	$ 433,300,000
Proceeds from sales of securities available-for-sale	306,253,000	$ 42,996,000
Gross realized gains on sale of securities	6,800,000	204,000
Gross realized losses on sale of securities	(515,000)	(303,000)
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of securities available-for-sale	299,900,000	$ 43,100,000
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 7,100,000

Loans and Leases (Details)

Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment	$ 16,516,627	$ 17,032,221
Deferred fees, net	(61,342)	(59,478)
Loans held for investment, net	16,455,285	16,972,743
Allowance for loan and lease losses	(134,275)	(139,456)
Total loans and leases held for investment, net	16,321,010	16,833,287
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		16,974,171
Deferred fees, net		(59,464)
Loans held for investment, net		16,914,707	[1],[2],[3]	$ 15,460,354
Allowance for loan and lease losses		(133,012)		(149,826)	$ (143,755)
Total loans and leases held for investment, net		16,781,695
Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		58,050
Deferred fees, net		(14)
Loans held for investment, net		58,036		96,335
Allowance for loan and lease losses		(6,444)
Total loans and leases held for investment, net		51,592
NonPCI and PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases held for investment, net		16,833,287
Real Estate Mortgage
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment	7,570,526
Loans held for investment, net	7,554,243
Allowance for loan and lease losses	(40,158)	(40,051)
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		7,815,355
Loans held for investment, net		7,798,991	[1],[2]	5,886,969
Allowance for loan and lease losses				(35,368)	(37,765)
Real Estate Mortgage | Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		53,658
Real Estate Mortgage | NonPCI and PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		7,869,013
Real Estate Construction and Land
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment	1,699,630
Loans held for investment, net	1,677,002
Allowance for loan and lease losses	(18,190)	(13,055)
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		1,611,287
Loans held for investment, net		1,591,229	[1],[2]	1,108,236
Allowance for loan and lease losses				(10,476)	(10,045)
Real Estate Construction and Land | Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		0
Real Estate Construction and Land | NonPCI and PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		1,611,287
Commercial
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment	6,848,576
Loans held for investment, net	6,826,123
Allowance for loan and lease losses	(73,780)	(84,022)
Commercial | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		7,137,978
Loans held for investment, net		7,114,920	[1],[2]	8,082,678
Allowance for loan and lease losses				(102,134)	(93,853)
Commercial | Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		4,158
Commercial | NonPCI and PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		7,142,136
Consumer
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment	397,895
Loans held for investment, net	397,917
Allowance for loan and lease losses	$ (2,147)	(2,328)
Consumer | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		409,551
Loans held for investment, net		409,567	[1],[2]	382,471
Allowance for loan and lease losses				$ (1,848)	$ (2,092)
Consumer | Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		234
Consumer | NonPCI and PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Gross loans and leases held for investment		$ 409,785
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 1)

Loans and Leases (Details 1) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017
Delinquent loans in loan portfolio
30-89 Days Past Due		$ 37,249	$ 3,200
90 or More Days Past Due		12,385	14,200
Total Past Due		49,634
Current		16,405,651
Loans held for investment, net		16,455,285	16,972,743
Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due	[1]		48,435
90 or More Days Past Due	[1]		14,165
Total Past Due	[1]		62,600
Current	[1]		16,852,107
Loans held for investment, net			16,914,707	[1],[2],[3]	$ 15,460,354
Real Estate Mortgage
Delinquent loans in loan portfolio
30-89 Days Past Due		27,774
90 or More Days Past Due		8,825
Total Past Due		36,599
Current		7,517,644
Loans held for investment, net		7,554,243
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			36,069
90 or More Days Past Due			11,129
Total Past Due			47,198
Current			7,751,793
Loans held for investment, net			7,798,991	[2],[3]	5,886,969
Real Estate Mortgage | Commercial real estate
Delinquent loans in loan portfolio
30-89 Days Past Due		26,262
90 or More Days Past Due		6,849
Total Past Due		33,111
Current		4,999,895
Loans held for investment, net		5,033,006
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			29,070
90 or More Days Past Due			9,107
Total Past Due			38,177
Current			5,323,310
Loans held for investment, net	[2],[3]		5,361,487
Real Estate Mortgage | Residential Real Estate
Delinquent loans in loan portfolio
30-89 Days Past Due		1,512
90 or More Days Past Due		1,976
Total Past Due		3,488
Current		2,517,749
Loans held for investment, net		2,521,237
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			6,999
90 or More Days Past Due			2,022
Total Past Due			9,021
Current			2,428,483
Loans held for investment, net	[2],[3]		2,437,504
Real Estate Construction and Land
Delinquent loans in loan portfolio
30-89 Days Past Due		2,605
90 or More Days Past Due		0
Total Past Due		2,605
Current		1,674,397
Loans held for investment, net		1,677,002
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			2,081
90 or More Days Past Due			0
Total Past Due			2,081
Current			1,589,148
Loans held for investment, net			1,591,229	[2],[3]	1,108,236
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable
Delinquent loans in loan portfolio
30-89 Days Past Due		0
90 or More Days Past Due		0
Total Past Due		0
Current		789,892
Loans held for investment, net		789,892
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			0
90 or More Days Past Due			0
Total Past Due			0
Current			769,075
Loans held for investment, net	[2],[3]		769,075
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable
Delinquent loans in loan portfolio
30-89 Days Past Due		2,605
90 or More Days Past Due		0
Total Past Due		2,605
Current		884,505
Loans held for investment, net		887,110
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			2,081
90 or More Days Past Due			0
Total Past Due			2,081
Current			820,073
Loans held for investment, net	[2],[3]		822,154
Commercial
Delinquent loans in loan portfolio
30-89 Days Past Due		5,870
90 or More Days Past Due		3,560
Total Past Due		9,430
Current		6,816,693
Loans held for investment, net		6,826,123
Commercial | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			9,723
90 or More Days Past Due			3,036
Total Past Due			12,759
Current			7,102,161
Loans held for investment, net			7,114,920	[2],[3]	8,082,678
Commercial | Asset Based
Delinquent loans in loan portfolio
30-89 Days Past Due		0
90 or More Days Past Due		680
Total Past Due		680
Current		2,957,210
Loans held for investment, net		2,957,890
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			344
90 or More Days Past Due			690
Total Past Due			1,034
Current			2,923,837
Loans held for investment, net	[2],[3]		2,924,871
Commercial | Venture Capital Loans
Delinquent loans in loan portfolio
30-89 Days Past Due		737
90 or More Days Past Due		1,492
Total Past Due		2,229
Current		1,918,414
Loans held for investment, net		1,920,643
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			6,533
90 or More Days Past Due			760
Total Past Due			7,293
Current			2,115,418
Loans held for investment, net	[2],[3]		2,122,711
Commercial | Other Commercial
Delinquent loans in loan portfolio
30-89 Days Past Due		5,133
90 or More Days Past Due		1,388
Total Past Due		6,521
Current		1,941,069
Loans held for investment, net		1,947,590
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			2,846
90 or More Days Past Due			1,586
Total Past Due			4,432
Current			2,062,906
Loans held for investment, net	[2],[3]		2,067,338
Consumer
Delinquent loans in loan portfolio
30-89 Days Past Due		1,000
90 or More Days Past Due		0
Total Past Due		1,000
Current		396,917
Loans held for investment, net		$ 397,917
Consumer | Non Purchased Credit Impaired Loans and Leases
Delinquent loans in loan portfolio
30-89 Days Past Due			562
90 or More Days Past Due			0
Total Past Due			562
Current			409,005
Loans held for investment, net			$ 409,567	[2],[3]	$ 382,471
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 2)

Loans and Leases (Details 2) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017
Financing Receivable, Impaired [Line Items]
Nonaccrual		$ 103,725	$ 155,784	[1]
Loans held for investment		16,455,285	16,972,743
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		155,784
Loans held for investment			16,914,707	[2],[3],[4]	$ 15,460,354
Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		16,351,560
Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		16,758,923
Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Nonaccrual		24,341
Loans held for investment		7,554,243
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[1],[2]		68,913
Loans held for investment			7,798,991	[2],[3]	5,886,969
Real Estate Mortgage | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		7,529,902
Real Estate Mortgage | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		7,730,078
Real Estate Mortgage | Commercial real estate
Financing Receivable, Impaired [Line Items]
Nonaccrual		19,116
Loans held for investment		5,033,006
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		65,563
Loans held for investment	[2],[3]		5,361,487
Real Estate Mortgage | Commercial real estate | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		5,013,890
Real Estate Mortgage | Commercial real estate | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		5,295,924
Real Estate Mortgage | Residential Real Estate
Financing Receivable, Impaired [Line Items]
Nonaccrual		5,225
Loans held for investment		2,521,237
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		3,350
Loans held for investment	[2],[3]		2,437,504
Real Estate Mortgage | Residential Real Estate | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		2,516,012
Real Estate Mortgage | Residential Real Estate | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		2,434,154
Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Nonaccrual		0
Loans held for investment		1,677,002
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[1],[2]		0
Loans held for investment			1,591,229	[2],[3]	1,108,236
Real Estate Construction and Land | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		1,677,002
Real Estate Construction and Land | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		1,591,229
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable
Financing Receivable, Impaired [Line Items]
Nonaccrual		0
Loans held for investment		789,892
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		0
Loans held for investment	[2],[3]		769,075
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		789,892
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		769,075
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable
Financing Receivable, Impaired [Line Items]
Nonaccrual		0
Loans held for investment		887,110
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		0
Loans held for investment	[2],[3]		822,154
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		887,110
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		822,154
Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual		79,133
Loans held for investment		6,826,123
Commercial | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[1],[2]		86,851
Loans held for investment			7,114,920	[2],[3]	8,082,678
Commercial | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		6,746,990
Commercial | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		7,028,069
Commercial | Asset Based
Financing Receivable, Impaired [Line Items]
Nonaccrual		32,838
Loans held for investment		2,957,890
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		33,553
Loans held for investment	[2],[3]		2,924,871
Commercial | Asset Based | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		2,925,052
Commercial | Asset Based | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		2,891,318
Commercial | Venture Capital Loans
Financing Receivable, Impaired [Line Items]
Nonaccrual		21,861
Loans held for investment		1,920,643
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		29,424
Loans held for investment	[2],[3]		2,122,711
Commercial | Venture Capital Loans | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		1,898,782
Commercial | Venture Capital Loans | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		2,093,287
Commercial | Other Commercial
Financing Receivable, Impaired [Line Items]
Nonaccrual		24,434
Loans held for investment		1,947,590
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[2]		23,874
Loans held for investment	[2],[3]		2,067,338
Commercial | Other Commercial | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		1,923,156
Commercial | Other Commercial | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		2,043,464
Consumer
Financing Receivable, Impaired [Line Items]
Nonaccrual		251
Loans held for investment		397,917
Consumer | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Nonaccrual	[1],[2]		20
Loans held for investment			409,567	[2],[3]	$ 382,471
Consumer | Performing
Financing Receivable, Impaired [Line Items]
Loans held for investment		$ 397,666
Consumer | Performing | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Loans held for investment	[2]		$ 409,547
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[4]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 3)

Loans and Leases (Details 3) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		$ 16,455,285	$ 16,972,743
Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		208,042
Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		415,116
Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		15,832,127
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment			16,914,707	[1],[2],[3]	$ 15,460,354
Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		278,405
Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		302,168
Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		16,334,134
Real Estate Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		7,554,243
Real Estate Mortgage | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		57,071
Real Estate Mortgage | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		160,168
Real Estate Mortgage | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		7,337,004
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment			7,798,991	[1],[2]	5,886,969
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		102,220
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		127,070
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		7,569,701
Real Estate Mortgage | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		5,033,006
Real Estate Mortgage | Commercial real estate | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		44,635
Real Estate Mortgage | Commercial real estate | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		158,496
Real Estate Mortgage | Commercial real estate | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		4,829,875
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		5,361,487
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		93,795
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		122,488
Real Estate Mortgage | Commercial real estate | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		5,145,204
Real Estate Mortgage | Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		2,521,237
Real Estate Mortgage | Residential Real Estate | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		12,436
Real Estate Mortgage | Residential Real Estate | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,672
Real Estate Mortgage | Residential Real Estate | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		2,507,129
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		2,437,504
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		8,425
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		4,582
Real Estate Mortgage | Residential Real Estate | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		2,424,497
Real Estate Construction and Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,677,002
Real Estate Construction and Land | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		453
Real Estate Construction and Land | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		30,626
Real Estate Construction and Land | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,645,923
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment			1,591,229	[1],[2]	1,108,236
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		0
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		619
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		1,590,610
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		789,892
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		453
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		0
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		789,439
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		769,075
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		0
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		0
Real Estate Construction and Land | Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		769,075
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		887,110
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		0
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		30,626
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		856,484
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		822,154
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		0
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		619
Real Estate Construction and Land | Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		821,535
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		6,826,123
Commercial | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		150,090
Commercial | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		222,866
Commercial | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		6,453,167
Commercial | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment			7,114,920	[1],[2]	8,082,678
Commercial | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		175,922
Commercial | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		173,349
Commercial | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		6,765,649
Commercial | Asset Based
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		2,957,890
Commercial | Asset Based | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		49,913
Commercial | Asset Based | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		54,882
Commercial | Asset Based | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		2,853,095
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		2,924,871
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		51,000
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		37,256
Commercial | Asset Based | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		2,836,615
Commercial | Venture Capital Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,920,643
Commercial | Venture Capital Loans | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		31,364
Commercial | Venture Capital Loans | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		124,303
Commercial | Venture Capital Loans | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,764,976
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		2,122,711
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		49,671
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		114,210
Commercial | Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		1,958,830
Commercial | Other Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,947,590
Commercial | Other Commercial | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		68,813
Commercial | Other Commercial | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		43,681
Commercial | Other Commercial | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,835,096
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1],[2]		2,067,338
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		75,251
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		21,883
Commercial | Other Commercial | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		1,970,204
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		397,917
Consumer | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		428
Consumer | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		1,456
Consumer | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment		$ 396,033
Consumer | Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment			409,567	[1],[2]	$ 382,471
Consumer | Non Purchased Credit Impaired Loans and Leases | Classified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		263
Consumer | Non Purchased Credit Impaired Loans and Leases | Nonclassified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		1,130
Consumer | Non Purchased Credit Impaired Loans and Leases | Pass [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held for investment	[1]		$ 408,174
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 4)

Loans and Leases (Details 4) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases		$ 103,725	$ 155,784	[1]
Performing Restructured Loans		60,173	56,838	[1]
Total Impaired Loans and Leases		163,898	212,622	[1]
Non Purchased Credit Impaired Loans and Leases
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases	[2]		155,784
Total Impaired Loans and Leases	[3]		212,622
Real Estate Mortgage
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases		24,341
Performing Restructured Loans		51,031
Total Impaired Loans and Leases		75,372
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases	[1],[2]		68,913
Performing Restructured Loans	[1]		47,560
Total Impaired Loans and Leases	[1],[3]		116,473
Real Estate Construction and Land
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases		0
Performing Restructured Loans		5,670
Total Impaired Loans and Leases		5,670
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases	[1],[2]		0
Performing Restructured Loans	[1]		5,690
Total Impaired Loans and Leases	[1],[3]		5,690
Commercial
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases		79,133
Performing Restructured Loans		3,349
Total Impaired Loans and Leases		82,482
Commercial | Non Purchased Credit Impaired Loans and Leases
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases	[1],[2]		86,851
Performing Restructured Loans	[1]		3,488
Total Impaired Loans and Leases	[1],[3]		90,339
Consumer
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases		251
Performing Restructured Loans		123
Total Impaired Loans and Leases		$ 374
Consumer | Non Purchased Credit Impaired Loans and Leases
Schedule Of Non Accrual and Performing Restructured Impaired Financing Receivables [Line Items]
Nonaccrual loans and leases	[1],[2]		20
Performing Restructured Loans	[1]		100
Total Impaired Loans and Leases	[1],[3]		$ 120
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 5)

Loans and Leases (Details 5) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance		$ 14,245
Total Impaired Loans and Leases		163,898		$ 212,622	[1]
Impaired Financing Receivable, Unpaid Principal Balance		263,256
Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance		1,088
Total Impaired Loans and Leases		75,372
Impaired Financing Receivable, Unpaid Principal Balance		93,573
Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance		0
Total Impaired Loans and Leases		5,670
Impaired Financing Receivable, Unpaid Principal Balance		5,670
Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance		13,141
Total Impaired Loans and Leases		82,482
Impaired Financing Receivable, Unpaid Principal Balance		163,479
Consumer
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		295
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		355
Impaired Financing Receivable, with Related Allowance, Related Allowance		16
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		79
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		179
Total Impaired Loans and Leases		374
Impaired Financing Receivable, Unpaid Principal Balance		534
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			13,621
Total Impaired Loans and Leases	[2]			212,622
Impaired Financing Receivable, Unpaid Principal Balance	[2]			287,236
Impaired Financing Receivable, Average Recorded Investment	[3]	156,089	$ 209,761
Impaired Financing Receivable, Interest Income, Accrual Method		2,287	909
Non Purchased Credit Impaired Loans and Leases | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			970
Total Impaired Loans and Leases	[1],[2]			116,473
Impaired Financing Receivable, Unpaid Principal Balance	[2]			129,909
Impaired Financing Receivable, Average Recorded Investment	[3]	73,425	115,820
Impaired Financing Receivable, Interest Income, Accrual Method		1,034	793
Non Purchased Credit Impaired Loans and Leases | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			0
Total Impaired Loans and Leases	[1],[2]			5,690
Impaired Financing Receivable, Unpaid Principal Balance	[2]			5,689
Impaired Financing Receivable, Average Recorded Investment	[3]	5,670	6,683
Impaired Financing Receivable, Interest Income, Accrual Method		89	69
Non Purchased Credit Impaired Loans and Leases | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			12,635
Total Impaired Loans and Leases	[1],[2]			90,339
Impaired Financing Receivable, Unpaid Principal Balance	[2]			151,445
Impaired Financing Receivable, Average Recorded Investment	[3]	76,620	86,944
Impaired Financing Receivable, Interest Income, Accrual Method		1,162	45
Non Purchased Credit Impaired Loans and Leases | Consumer
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[2]			100
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]			100
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			16
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			20
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			93
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	[3]	295	187
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		2	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	79	127
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	2
Total Impaired Loans and Leases	[1],[2]			120
Impaired Financing Receivable, Unpaid Principal Balance	[2]			193
Impaired Financing Receivable, Average Recorded Investment	[3]	374	314
Impaired Financing Receivable, Interest Income, Accrual Method		2	2
Asset Based | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		32,838
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		55,890
Asset Based | Non Purchased Credit Impaired Loans and Leases | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			33,553
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			54,911
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	32,838	30,739
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	0
Venture Capital Loans | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		17,367
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		18,312
Impaired Financing Receivable, with Related Allowance, Related Allowance		4,970
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		6,129
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		29,786
Venture Capital Loans | Non Purchased Credit Impaired Loans and Leases | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[2]			16,565
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]			17,203
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			4,267
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			14,534
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			40,029
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	[3]	14,598	4,693
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	4,474	2,429
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	0
Other Commercial | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		18,048
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		31,672
Impaired Financing Receivable, with Related Allowance, Related Allowance		8,171
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		8,100
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		27,819
Other Commercial | Non Purchased Credit Impaired Loans and Leases | Commercial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[2]			20,404
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]			29,951
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			8,368
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			5,283
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			9,351
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	[3]	16,851	44,333
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		15	15
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	7,859	4,750
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		1,147	30
Commercial Real Estate Construction Loan Receivable | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		5,670
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		5,670
Commercial Real Estate Construction Loan Receivable | Non Purchased Credit Impaired Loans and Leases | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			5,690
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			5,689
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	5,670	6,111
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		89	67
Residential Real Estate Construction Financing Receivable | Non Purchased Credit Impaired Loans and Leases | Real Estate Construction and Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	572
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		0	2
Commercial real estate | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		13,884
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		14,690
Impaired Financing Receivable, with Related Allowance, Related Allowance		576
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		48,729
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		63,283
Commercial real estate | Non Purchased Credit Impaired Loans and Leases | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[2]			15,750
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]			16,548
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			628
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			93,827
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			105,923
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	[3]	13,884	14,350
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		201	206
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	46,782	92,753
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		765	560
Residential Real Estate | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		4,295
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		4,926
Impaired Financing Receivable, with Related Allowance, Related Allowance		512
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		8,464
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		10,674
Residential Real Estate | Non Purchased Credit Impaired Loans and Leases | Real Estate Mortgage
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[2]			2,787
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]			2,957
Impaired Financing Receivable, with Related Allowance, Related Allowance	[2]			342
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[2]			4,109
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]			$ 4,481
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	[3]	4,295	3,501
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method		23	12
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	[3]	8,464	5,216
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method		$ 45	$ 15
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	For loans and leases reported as impaired at March 31, 2018 and 2017, amounts were calculated based on the period of time such loans and leases were impaired during the reported period.

Loans and Leases (Details 6)

Loans and Leases (Details 6)		3 Months Ended
		Mar. 31, 2018USD ($)contractContract		Mar. 31, 2017USD ($)contractContract
Financing Receivable, Modifications [Line Items]
Number of loans | contract		2		11
Pre-Modification Outstanding Recorded Investment		$ 11,783,000		$ 13,987,000
Post-Modification Outstanding Recorded Investment		$ 11,783,000		$ 13,923,000
Number of Loans | contract		1		1
Recorded Investment		$ 2,250,000	[1],[2]	$ 28,000	[3]
Charge-offs				$ 0
Other Commercial
Financing Receivable, Modifications [Line Items]
Number of Loans		1		0
Recorded Investment	[2]	$ 2,250,000		$ 0
Consumer
Financing Receivable, Modifications [Line Items]
Number of Loans		0		1
Recorded Investment	[2]	$ 0		$ 28,000
Real Estate Mortgage | Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of loans | contract		0		1
Pre-Modification Outstanding Recorded Investment		$ 0		$ 64,000
Post-Modification Outstanding Recorded Investment		$ 0		$ 0
Real Estate Mortgage | Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of loans | contract		0		2
Pre-Modification Outstanding Recorded Investment		$ 0		$ 42,000
Post-Modification Outstanding Recorded Investment		$ 0		$ 42,000
Commercial | Venture Capital Loans
Financing Receivable, Modifications [Line Items]
Number of loans		0		3
Pre-Modification Outstanding Recorded Investment		$ 0		$ 13,065,000
Post-Modification Outstanding Recorded Investment		$ 0		$ 13,065,000
Commercial | Other Commercial
Financing Receivable, Modifications [Line Items]
Number of loans		2		4
Pre-Modification Outstanding Recorded Investment		$ 11,783,000		$ 719,000
Post-Modification Outstanding Recorded Investment		$ 11,783,000		$ 719,000
Consumer
Financing Receivable, Modifications [Line Items]
Number of loans | contract		0		1
Pre-Modification Outstanding Recorded Investment		$ 0		$ 97,000
Post-Modification Outstanding Recorded Investment		$ 0		$ 97,000
[1]	Represents the balance at March 31, 2018, and there were no charge-offs.
[2]	The population of defaulted restructured loans for the period indicated includes only those loans restructured during the preceding 12-month period. For example, for the 12-month period ended March 31, 2018, the population of defaulted restructured loans includes only those loans restructured after March 31, 2017. The table excludes defaulted troubled debt restructurings in those classes for which the recorded investment was zero at the end of the period.
[3]	Represents the balance at March 31, 2017, and there were no charge-offs.

Loans and Leases (Details 7)

Loans and Leases (Details 7) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 139,456
Charge-offs	(12,153)
Recoveries	7,198
Provision	(226)
Balance, end of period	134,275
Amount of the allowance applicable to loans and leases:
impairment	14,245
impairment	120,030
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	162,818
impairment	16,292,467
Ending balance of loans and leases	16,455,285		$ 16,972,743
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	133,012	$ 143,755
Charge-offs		(20,928)
Recoveries		2,739
Provision		24,260
Balance, end of period		149,826
Amount of the allowance applicable to loans and leases:
impairment		13,427
impairment		136,399
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		228,460
impairment		15,231,894
Ending balance of loans and leases		15,460,354	16,914,707	[1],[2],[3]
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	6,444
Balance, beginning of period		13,483
Charge-offs		(2,230)
Recoveries		0
Provision		228
Balance, end of period		11,481
Amount of the allowance applicable to loans and leases:
deteriorated credit quality		11,481
The ending balance of the loan and lease portfolio is composed of loans and leases:
deteriorated credit quality		96,335
Ending balance of loans and leases		96,335	58,036
NonPCI and PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		157,238
Charge-offs		(23,158)
Recoveries		2,739
Provision		24,488
Balance, end of period		161,307
The ending balance of the loan and lease portfolio is composed of loans and leases:
Total loans and leases		15,556,689
Real Estate Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	40,051
Charge-offs	(2,598)
Recoveries	1,657
Provision	1,048
Balance, end of period	40,158
Amount of the allowance applicable to loans and leases:
impairment	1,088
impairment	39,070
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	74,390
impairment	7,479,853
Ending balance of loans and leases	7,554,243
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		37,765
Charge-offs		(1,544)
Recoveries		230
Provision		(1,083)
Balance, end of period		35,368
Amount of the allowance applicable to loans and leases:
impairment		1,070
impairment		34,298
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		118,275
impairment		5,768,694
Ending balance of loans and leases		5,886,969	7,798,991	[1],[2]
Real Estate Construction and Land
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	13,055
Charge-offs	0
Recoveries	9
Provision	5,126
Balance, end of period	18,190
Amount of the allowance applicable to loans and leases:
impairment	0
impairment	18,190
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	5,670
impairment	1,671,332
Ending balance of loans and leases	1,677,002
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		10,045
Charge-offs		0
Recoveries		8
Provision		423
Balance, end of period		10,476
Amount of the allowance applicable to loans and leases:
impairment		0
impairment		10,476
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		6,683
impairment		1,101,553
Ending balance of loans and leases		1,108,236	1,591,229	[1],[2]
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	84,022
Charge-offs	(9,524)
Recoveries	5,487
Provision	(6,205)
Balance, end of period	73,780
Amount of the allowance applicable to loans and leases:
impairment	13,141
impairment	60,639
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	82,434
impairment	6,743,689
Ending balance of loans and leases	6,826,123
Commercial | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		93,853
Charge-offs		(19,285)
Recoveries		2,448
Provision		25,118
Balance, end of period		102,134
Amount of the allowance applicable to loans and leases:
impairment		12,267
impairment		89,867
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		103,221
impairment		7,979,457
Ending balance of loans and leases		8,082,678	7,114,920	[1],[2]
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	2,328
Charge-offs	(31)
Recoveries	45
Provision	(195)
Balance, end of period	2,147
Amount of the allowance applicable to loans and leases:
impairment	16
impairment	2,131
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	324
impairment	397,593
Ending balance of loans and leases	$ 397,917
Consumer | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		2,092
Charge-offs		(99)
Recoveries		53
Provision		(198)
Balance, end of period		1,848
Amount of the allowance applicable to loans and leases:
impairment		90
impairment		1,758
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		281
impairment		382,190
Ending balance of loans and leases		$ 382,471	$ 409,567	[1],[2]
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Loans and Leases (Details 8)

Loans and Leases (Details 8) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period	$ 139,456
Reserve for Unfunded Loan Commitments, Balance, beginning of period	28,635		$ 17,523
Allowance for Credit Losses, Balance, beginning of period	168,091		174,761
Allowance for Loan and Lease Losses, Charge-offs	12,153
Reserve for Unfunded Loan Commitments, Charge-offs	0		0
Allowance for Credit Losses, Charge-offs	(12,153)		(23,158)
Allowance for Loan and Lease Loss, Recoveries	7,198
Reserve for Unfunded Loan Commitments, Recoveries	0		0
Allowance for Credit Losses, Recoveries	7,198		2,739
Allowance for Loan and Lease Losses, Net charge-offs	(4,955)
Reserve for Unfunded Loan Commitments, Net charge-offs	0		0
Allowance For Credit Losses, Net charge-offs	(4,955)		(20,419)
Allowance for Loan and Lease Losses, Provision (negative provision)	(226)
Reserve for Unfunded Commitments, Provision (negative provision)	(4,226)		(240)
Allowance for Credit Losses, Provision (negative provision)	4,000	$ 6,406	24,728
Balance, end of period	134,275	139,456
Reserve for Unfunded Loan Commitments, Balance, end of period	32,861	28,635	17,763
Allowance for Credit Losses, Balance, end of period	167,136	168,091	179,070
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period	133,012		143,755
Allowance for Credit Losses, Balance, beginning of period			161,278
Allowance for Loan and Lease Losses, Charge-offs			20,928
Allowance for Credit Losses, Charge-offs			(20,928)
Allowance for Loan and Lease Loss, Recoveries			2,739
Allowance for Credit Losses, Recoveries			2,739
Allowance for Loan and Lease Losses, Net charge-offs			(18,189)
Allowance For Credit Losses, Net charge-offs			(18,189)
Allowance for Loan and Lease Losses, Provision (negative provision)			24,260
Allowance for Credit Losses, Provision (negative provision)			24,500
Balance, end of period		133,012	149,826
Allowance for Credit Losses, Balance, end of period			167,589
Purchased Credit Impaired Loans and Leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of period	$ 6,444
Balance, beginning of period			13,483
Allowance for Loan and Lease Losses, Charge-offs			2,230
Allowance for Loan and Lease Loss, Recoveries			0
Allowance for Loan and Lease Losses, Net charge-offs			(2,230)
Allowance for Loan and Lease Losses, Provision (negative provision)			228
Balance, end of period		$ 6,444
Balance, end of period			$ 11,481

Loans and Leases (Details Textu

Loans and Leases (Details Textual) - USD ($)		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at lower of cost or fair value		$ 1,500,000,000
Loan receivable held-for-sale, charge-offs		0
Nonaccrual loans and leases		103,725,000	$ 155,784,000	[1]
Receivable, 90 or more days past due		12,385,000	14,200,000
Receivable, 30-89 days past due		37,249,000	3,200,000
Financing receivable, nonaccrual status, current			138,400,000
Charge-offs					$ 0
Proceeds from Sale of Loans Held-for-sale		1,000,000,000
Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group		0	481,100,000
Gain on sale of loans and leases		4,569,000	1,988,000		$ 712,000
Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases		$ 68,800,000
Percentage of nonaccrual loans and leases		66.30%
Available For Sale Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gain on sale of loans and leases		$ 1,300,000
Non Purchased Credit Impaired Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans and leases	[2]		155,784,000
Receivable, 90 or more days past due	[3]		14,165,000
Receivable, 30-89 days past due	[3]		$ 48,435,000
Nonaccrual [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable, 90 or more days past due		11,900,000
Receivable, 30-89 days past due		8,700,000
Financing receivable, nonaccrual status, current		$ 83,100,000
[1]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[2]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.
[3]	Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

Foreclosed Assets (Details)

Foreclosed Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Total other real estate owned, net	$ 1,236	$ 1,302
Other foreclosed assets	0	27
Foreclosed assets, net	1,236	1,329
Construction and land development
Total other real estate owned, net	219	219
Commercial real estate
Total other real estate owned, net	64	64
Single family residence
Total other real estate owned, net	$ 953	$ 1,019

Foreclosed Assets (Details 1)

Foreclosed Assets (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Real Estate Owned Net Covered and NonCovered Including Foreclosed Assets [Abstract]
Balance, beginning of period	$ 1,329
Loans transferred to foreclosed assets	0	$ 78
Provision for losses	(65)
Reductions related to sales	(28)
Balance, end of period	$ 1,236

Other Assets (Details)

Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other Assets [Abstract]
Cash Surrender Value of Life Insurance	$ 195,163	$ 193,917
Interest and fees receivable income	78,822	82,935
Income Taxes Receivable	64,739	98,998
Equity Method Investments, Other Asset Investments	53,838	49,432
Low Income Housing Tax Credit - LIHTC	43,793	39,235
Equity Investments Without Readily Determinable Fair Value	15,642	14,856
Equity Investments With Readily Determinable Fair Value	5,028	0
Other Assets, Miscellaneous	54,159	61,350
Other Assets	$ 511,184	$ 540,723

Other Assets (Details Textual)

Other Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Other Investment Not Readily Marketable [Line Items]
Equity Method Investment, Other than Temporary Impairment	$ 5,900
Other Assets, Miscellaneous	$ 54,159	$ 61,350

Borrowings and Subordinated D60

Borrowings and Subordinated Debentures (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Borrowings	$ 575,284	$ 467,342
Non‑recourse debt
Debt Instrument [Line Items]
Amount	$ 284	$ 342
Rate	6.94%	6.87%
AFX borrowings
Debt Instrument [Line Items]
Amount	$ 100,000	$ 0
Rate	1.82%	0.00%
Federal Home Loan Bank of San Francisco | FHLB secured advances
Debt Instrument [Line Items]
Amount	$ 340,000	$ 332,000
Rate	1.87%	1.41%
Federal Home Loan Bank of San Francisco | FHLB unsecured overnight advance
Debt Instrument [Line Items]
Amount	$ 135,000	$ 135,000
Rate	1.85%	1.34%

Borrowings and Subordinated D61

Borrowings and Subordinated Debentures (Details 1) $ in Thousands, € in Millions		3 Months Ended
		Mar. 31, 2018USD ($)	Mar. 31, 2018EUR (€)	Dec. 31, 2017USD ($)
Subordinated Borrowing [Line Items]
Amount		$ 543,561		$ 555,146
Date Issued		Jun. 30, 2006
Maturity Date		Sep. 18, 2036
Unamortized discount	[1]	$ (91,338)		(92,709)
Net subordinated debentures		$ 452,223		462,437
Description of variable rate basis		3 month LIBOR + 1.85
Subordinated Debt Trust V Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		5.28%	5.28%	4.70%
Date Issued		Aug. 15, 2003
Maturity Date		Sep. 17, 2033
Description of variable rate basis		3 month LIBOR + 3.10
Subordinated Debt Trust VI Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		5.17%	5.17%	4.64%
Date Issued		Sep. 3, 2003
Maturity Date		Sep. 15, 2033
Description of variable rate basis		3 month LIBOR + 3.05
Subordinated Debt Trust CII Due September 2033
Subordinated Borrowing [Line Items]
Amount		$ 5,155		$ 5,155
Rate		5.13%	5.13%	4.55%
Date Issued		Sep. 17, 2003
Maturity Date		Sep. 17, 2033
Description of variable rate basis		3 month LIBOR + 2.95
Subordinated Debt Trust VII Due April 2034
Subordinated Borrowing [Line Items]
Amount		$ 61,856		$ 61,856
Rate		4.52%	4.52%	4.13%
Date Issued		Feb. 5, 2004
Maturity Date		Apr. 23, 2034
Description of variable rate basis		3 month LIBOR + 2.75
Subordinated Debt Trust CIII Due September 2035
Subordinated Borrowing [Line Items]
Amount		$ 20,619		$ 20,619
Rate		3.81%	3.81%	3.28%
Date Issued		Aug. 15, 2005
Maturity Date		Sep. 15, 2035
Description of variable rate basis		3 month LIBOR + 1.69
Subordinated Debt Trust FCCI Due March 2037
Subordinated Borrowing [Line Items]
Amount		$ 16,495		$ 16,495
Rate		3.72%	3.72%	3.19%
Date Issued		Jan. 25, 2007
Maturity Date		Mar. 15, 2037
Description of variable rate basis		3 month LIBOR + 1.60
Subordinated Debt Trust FCBI Due December 2035
Subordinated Borrowing [Line Items]
Amount		$ 10,310		$ 10,310
Rate		3.67%	3.67%	3.14%
Date Issued		Sep. 30, 2005
Maturity Date		Dec. 15, 2035
Description of variable rate basis		3 month LIBOR + 1.55
Trust Preferred Securities Two Thousand Five Series One
Subordinated Borrowing [Line Items]
Amount		$ 82,475		$ 82,475
Rate		4.07%	4.07%	3.54%
Date Issued		Nov. 21, 2005
Maturity Date		Dec. 15, 2035
Description of variable rate basis		3 month LIBOR + 1.95
Trust Preferred Securities Two Thousand Five Series Two
Subordinated Borrowing [Line Items]
Amount		$ 128,866		$ 128,866
Rate		3.72%	3.72%	3.33%
Date Issued		Dec. 14, 2005
Maturity Date		Jan. 30, 2036
Description of variable rate basis		3 month LIBOR + 1.95
Two Thousand Six One Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 51,545		$ 51,545
Rate		3.72%	3.72%	3.33%
Date Issued		Feb. 22, 2006
Maturity Date		Apr. 30, 2036
Description of variable rate basis		3 month LIBOR + 1.95
Two Thousand Six Two Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 51,550		$ 51,550
Rate		3.72%	3.72%	3.33%
Date Issued		Sep. 27, 2006
Maturity Date		Oct. 30, 2036
Description of variable rate basis		3 month LIBOR + 1.95
Trust Preferred Securities Two Thousand Six Series Three
Subordinated Borrowing [Line Items]
Amount	[2]	$ 31,773		$ 30,986
Rate		1.72%	1.72%	1.72%
Date Issued		Sep. 29, 2006
Maturity Date		Oct. 30, 2036
Denomination value | €			€ 25.8
Description of variable rate basis		3 month EURIBOR + 2.05
Trust Preferred Securities Two Thousand Six Series Four
Subordinated Borrowing [Line Items]
Amount		$ 16,470		$ 16,470
Rate		3.72%	3.72%	3.33%
Date Issued		Dec. 5, 2006
Maturity Date		Jan. 30, 2037
Description of variable rate basis		3 month LIBOR + 1.95
Trust Preferred Securities Two Thousand Six Series Five
Subordinated Borrowing [Line Items]
Amount		$ 6,650		$ 6,650
Rate		3.72%	3.72%	3.33%
Date Issued		Dec. 19, 2006
Maturity Date		Jan. 30, 2037
Description of variable rate basis		3 month LIBOR + 1.95
Two Thousand Seven One Term Debt Securitization
Subordinated Borrowing [Line Items]
Amount		$ 39,177		$ 39,177
Rate		3.72%	3.72%	3.33%
Date Issued		Jun. 13, 2007
Maturity Date		Jul. 30, 2037
Description of variable rate basis		3 month LIBOR + 1.95
Subordinated Debentures Trust I Due March 2035 [Domain]
Subordinated Borrowing [Line Items]
Amount	[3]	$ 0		$ 6,186
Rate				3.64%
Date Issued		Dec. 10, 2004
Maturity Date		Mar. 15, 2035
Description of variable rate basis		3 month LIBOR + 2.05
Subordinated Debentures Trust II Due March 2036 [Member]
Subordinated Borrowing [Line Items]
Amount	[3]	$ 0		$ 3,093
Rate				3.34%
Date Issued		Dec. 23, 2005
Maturity Date		Mar. 15, 2036
Description of variable rate basis		3 month LIBOR + 1.75
Subordinated Debentures Trust III Due September 2036 [Member]
Subordinated Borrowing [Line Items]
Amount	[3]	$ 0		$ 3,093
Rate				3.44%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust V Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.10%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VI Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		3.05%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CII Due September 2033
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.95%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust VII Due April 2034
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.75%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust CIII Due September 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.69%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCCI Due March 2037
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.60%
London Interbank Offered Rate (LIBOR) | Subordinated Debt Trust FCBI Due December 2035
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.55%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series One
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Five Series Two
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Six One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Six Two Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Four
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Trust Preferred Securities Two Thousand Six Series Five
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Two Thousand Seven One Term Debt Securitization
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		1.95%
London Interbank Offered Rate (LIBOR) | Subordinated Debentures Trust I Due March 2035 [Domain]
Subordinated Borrowing [Line Items]
Rate		0.00%	0.00%
London Interbank Offered Rate (LIBOR) | Subordinated Debentures Trust II Due March 2036 [Member]
Subordinated Borrowing [Line Items]
Rate		0.00%	0.00%
London Interbank Offered Rate (LIBOR) | Subordinated Debentures Trust III Due September 2036 [Member]
Subordinated Borrowing [Line Items]
Rate		0.00%	0.00%
Euribor Rate | Trust Preferred Securities Two Thousand Six Series Three
Subordinated Borrowing [Line Items]
Rate Index (Quarterly Reset)		2.05%
[1]	Amount represents the fair value adjustment on trust preferred securities assumed in acquisitions.
[2]	Denomination is in Euros with a value of €25.8 million.
[3]	Acquired in the CUB acquisition on October 20, 2017 and redeemed in the first quarter of 2018.

Borrowings and Subordinated D62

Borrowings and Subordinated Debentures (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Early Repayment of Subordinated Debt	$ 12,372,000	$ 0
Non‑recourse debt
Debt Instrument [Line Items]
Weighted average remaining maturity period	20 months
Unused Lines of Credit
Debt Instrument [Line Items]
Amount outstanding	$ 0		$ 0
Current borrowing capacity	75,000,000
Unused commitment fees	0
AFX borrowings
Debt Instrument [Line Items]
Amount outstanding	100,000,000		0
Federal Reserve Bank Advances
Debt Instrument [Line Items]
Loans pledged as collateral	2,100,000,000
Amount outstanding	0		0
Federal Reserve Bank Advances | FHLB secured advances
Debt Instrument [Line Items]
Borrowing capacity description	1,670,180,000
Federal Home Loan Bank of San Francisco
Debt Instrument [Line Items]
Loans pledged as collateral	5,700,000,000
Federal Home Loan Bank of San Francisco | FHLB secured advances
Debt Instrument [Line Items]
Borrowing capacity description	3,919,613,000
Current outstanding	340,000,000		332,000,000
Federal Home Loan Bank of San Francisco | FHLB unsecured overnight advance
Debt Instrument [Line Items]
Current outstanding	135,000,000		135,000,000
Federal Home Loan Bank of San Francisco | Unused Lines of Credit
Debt Instrument [Line Items]
Borrowing capacity description	$ 135,000,000
Amount outstanding			$ 135,000,000

Commitments and Contingencies63

Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Loan commitments to extend credit	$ 6,352,803	$ 6,234,061
Standby letters of credit	337,678		$ 320,063
Total	$ 6,690,481		$ 6,554,124

Commitments and Contingencies64

Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Long-term Purchase Commitment [Line Items]
Commitment to contribute capital	$ 79,400	$ 62,600
Private Equity Funds
Long-term Purchase Commitment [Line Items]
Remaining minimum amount committed	$ 2,500	$ 2,541

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	$ 3,801,986	$ 3,774,431
Equity warrants		5,161
Fair Value, Estimate Not Practicable, Equity Method Investments	5,028
Derivative Liability	642	1,379
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		5,922
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		3,703,526
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		64,983
Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	251,776	246,274
Government agency and government-sponsored enterprise collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	545,945	275,709
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,403,586	1,680,068
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,089,494	1,163,969
US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,582	0
SBA asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,264	160,334
Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	79,734	88,710
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	18,360	19,295
Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	7,015
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	7,070
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	3,801,986	3,774,431
Equity warrants	5,284	5,161
Other derivative assets	3,327	1,873
Total recurring assets	3,815,625	3,781,465
Derivative liabilities	642	1,379
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,582	5,922
Equity warrants	0	0
Other derivative assets	0	0
Fair Value, Estimate Not Practicable, Equity Method Investments	5,028
Total recurring assets	153,610	5,922
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	3,594,905	3,703,526
Equity warrants	0	0
Other derivative assets	3,327	1,873
Fair Value, Estimate Not Practicable, Equity Method Investments	0
Total recurring assets	3,598,232	3,705,399
Derivative liabilities	642	1,379
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	58,499	64,983
Equity warrants	5,284	5,161
Other derivative assets	0	0
Fair Value, Estimate Not Practicable, Equity Method Investments	0
Total recurring assets	63,783	70,144
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise pass through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	251,776	246,274
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise pass through securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise pass through securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	251,776	246,274
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise pass through securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	545,945	275,709
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise collateralized mortgage obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise collateralized mortgage obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	545,945	275,709
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise collateralized mortgage obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Private Label Collateralized Mortgage Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	116,245	125,987
Fair Value, Measurements, Recurring | Private Label Collateralized Mortgage Obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Private Label Collateralized Mortgage Obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	94,164	103,113
Fair Value, Measurements, Recurring | Private Label Collateralized Mortgage Obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	22,081	22,874
Fair Value, Measurements, Recurring | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,403,586	1,680,068
Fair Value, Measurements, Recurring | Municipal securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Municipal securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,403,586	1,680,068
Fair Value, Measurements, Recurring | Municipal securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,089,494	1,163,969
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise commercial mortgage-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise commercial mortgage-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	1,089,494	1,163,969
Fair Value, Measurements, Recurring | Government agency and government-sponsored enterprise commercial mortgage-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | US Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,582
Fair Value, Measurements, Recurring | US Treasury Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,582
Fair Value, Measurements, Recurring | US Treasury Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0
Fair Value, Measurements, Recurring | US Treasury Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0
Fair Value, Measurements, Recurring | SBA asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,264	160,334
Fair Value, Measurements, Recurring | SBA asset-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | SBA asset-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	148,264	160,334
Fair Value, Measurements, Recurring | SBA asset-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	79,734	88,710
Fair Value, Measurements, Recurring | Asset-backed | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Asset-backed | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	43,316	46,601
Fair Value, Measurements, Recurring | Asset-backed | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	36,418
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	18,360	19,295
Fair Value, Measurements, Recurring | Corporate debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	0	0
Fair Value, Measurements, Recurring | Corporate debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	18,360	19,295
Fair Value, Measurements, Recurring | Corporate debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale	$ 0	0
Fair Value, Measurements, Recurring | Collateralized loan obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		7,015
Fair Value, Measurements, Recurring | Collateralized loan obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		0
Fair Value, Measurements, Recurring | Collateralized loan obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		7,015
Fair Value, Measurements, Recurring | Collateralized loan obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		0
Fair Value, Measurements, Recurring | Equity Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		5,922
Fair Value, Measurements, Recurring | Equity Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		1,148
Fair Value, Measurements, Recurring | Equity Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		0
Square 1 Financial, Inc. | Fair Value, Measurements, Recurring | Asset-backed | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available‑for‑sale		$ 42,109

Fair Value Measurements (Deta66

Fair Value Measurements (Details 1) - Level 3 - Fair Value, Measurements, Recurring	3 Months Ended
	Mar. 31, 2018
Minimum | Private label collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Voluntary annual prepayment speeds	3.80%
Annual default rates	0.10%
Loss severity rates	3.20%
Discount rates	2.00%
Maximum | Private label collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Voluntary annual prepayment speeds	52.70%
Annual default rates	16.50%
Loss severity rates	105.70%
Discount rates	10.30%
Weighted Average | Private Label CMOs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Voluntary annual prepayment speeds	8.30%
Annual default rates	2.50%
Loss severity rates	46.30%
Discount rates	5.30%
Weighted Average | Private label collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Voluntary annual prepayment speeds	8.30%
Annual default rates	2.50%
Loss severity rates	46.30%
Discount rates	5.30%
Weighted Average | SBA securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Voluntary annual prepayment speeds	14.00%
Annual default rates	1.90%
Loss severity rates	55.20%
Discount rates	3.60%

Fair Value Measurements (Deta67

Fair Value Measurements (Details 2) - Weighted Average - Warrant - Fair Value, Measurements, Recurring - Level 3	3 Months Ended
	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Volatility	16.80%
Risk-free interest rate	2.40%
Remaining life assumption (in years)	3 years 8 months

Fair Value Measurements (Deta68

Fair Value Measurements (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period	$ 5,161
Level 3
Level 3 CMO [Roll Forward]
Total included in earnings, Equity Warrants	248
Total included in other comprehensive income	0
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants	206
Sales, Equity Warrants	(331)
Net settlements, Equity Warrants	0
Fair Value, Measurements, Recurring
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period	5,161
Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Equity warrants, Balance, beginning of period	5,161
Private Label CMOs | Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	22,081	$ 22,874
Total included in earnings	165
Total included in other comprehensive income	(141)
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0
Net settlements	(804)
Fair value transfers of assets measured on a recurring basis	(13)
Asset-backed | Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	36,418	$ 42,109
Total included in earnings	(10)
Total included in other comprehensive income	(228)
Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0
Net settlements	(5,453)
Private label collateralized mortgage obligations
Level 3 CMO [Roll Forward]
Fair value transfers of assets measured on a recurring basis	(13)
SBA securities | Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Fair value transfers of assets measured on a recurring basis	0
Warrant | Fair Value, Measurements, Recurring | Level 3
Level 3 CMO [Roll Forward]
Fair value transfers of assets measured on a recurring basis	$ 0

Fair Value Measurements (Deta69

Fair Value Measurements (Details 4) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 46,510	$ 544,658
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	2,081	488,706
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	44,429	55,952
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	45,557	61,095
Non Purchased Credit Impaired Loans and Leases | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Non Purchased Credit Impaired Loans and Leases | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,128	5,143
Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	44,429	55,952
Other real estate and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	953	483,563
Other real estate and foreclosed assets | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate and foreclosed assets | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	953	483,563
Third party appraisals | Other real estate and foreclosed assets | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 0	$ 0

Fair Value Measurements (Deta70

Fair Value Measurements (Details 5) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	$ 7,881	$ 13,617
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	7,816	13,617
Other real estate and foreclosed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total losses	$ 65	$ 0

Fair Value Measurements (Deta71

Fair Value Measurements (Details 6) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 46,510	$ 544,658
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	44,429	55,952
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	45,557	61,095
Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	44,429	$ 55,952
Discount Rates | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	32,638
No Discounts | Third party appraisals | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 11,791
Minimum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	2.00%
Maximum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	10.20%
Weighted Average | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	7.33%
Weighted Average | Discount Rates | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates	7.33%

Fair Value Measurements (Deta72

Fair Value Measurements (Details 7) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 46,510	$ 544,658
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	44,429	55,952
Non Purchased Credit Impaired Loans and Leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	45,557	61,095
Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 44,429	$ 55,952
Minimum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	2.00%
Maximum | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	10.20%
Weighted Average | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	7.33%
Discount Rates | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 32,638
Discount Rates | Weighted Average | Discounted Cash Flow | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates, Weighted Average	7.33%
No Discounts | Third party appraisals | Non Purchased Credit Impaired Loans and Leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 11,791

Fair Value Measurements (Deta73

Fair Value Measurements (Details 8) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 235,061	$ 233,215
Interest-earning deposits in financial institutions	312,735	165,222
Securities available-for-sale, Carrying Amount		3,774,431
Securities available-for-sale, at fair value	3,801,986	3,774,431
Investment in FHLB stock, Carrying Amount	17,250	20,790
Investment in FHLB stock, Fair Value	17,250	20,790
Trade and Loans Receivables Held-for-sale, Net, Not Part of Disposal Group	0	481,100
Loans Held-for-sale, Fair Value Disclosure		483,563
Loans and leases, net	16,321,010	16,833,287
Loans and leases held for investment, net	16,247,325
Warrants and Rights Outstanding		5,161
Equity warrants		5,161
Other derivative assets, Carrying Amount	3,327	1,873
Fair Value, Estimate Not Practicable, Equity Method Investments	5,028
Demand, interest checking, money market, and savings deposits	15,661,529	15,937,012
Interest-bearing Domestic Deposit, Brokered	585,399	863,202
Time deposits	1,831,860	2,065,322
Time deposits	1,820,330	2,055,104
Borrowings	575,284	467,342
Borrowings	575,285	467,342
Subordinated debentures	452,223	462,437
Subordinated debentures	435,985	444,383
Derivative Liability	642	1,379
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	235,061	233,215
Interest-earning deposits in financial institutions	312,735	165,222
Securities available-for-sale, at fair value		5,922
Investment in FHLB stock, Fair Value	0	0
Demand, interest checking, money market, and savings deposits	0	0
Interest-bearing Domestic Deposit, Brokered	0	0
Time deposits	0	0
Borrowings	575,000	467,000
Subordinated debentures	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-earning deposits in financial institutions	0	0
Securities available-for-sale, at fair value		3,703,526
Investment in FHLB stock, Fair Value	17,250	20,790
Demand, interest checking, money market, and savings deposits	15,661,529	15,937,012
Interest-bearing Domestic Deposit, Brokered	585,399	863,202
Time deposits	1,820,330	2,055,104
Borrowings	285	342
Subordinated debentures	435,985	444,383
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	0	0
Interest-earning deposits in financial institutions	0	0
Securities available-for-sale, at fair value		64,983
Investment in FHLB stock, Fair Value	0	0
Loans and leases held for investment, net	16,246,197
Demand, interest checking, money market, and savings deposits	0	0
Interest-bearing Domestic Deposit, Brokered	0	0
Time deposits	0	0
Borrowings	0	0
Subordinated debentures	0	0
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	3,801,986	3,774,431
Equity warrants	5,284	5,161
Other derivative assets, Fair Value	3,327	1,873
Derivative liabilities	642	1,379
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	148,582	5,922
Equity warrants	0	0
Other derivative assets, Fair Value	0	0
Fair Value, Estimate Not Practicable, Equity Method Investments	5,028
Derivative liabilities	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	3,594,905	3,703,526
Equity warrants	0	0
Other derivative assets, Fair Value	3,327	1,873
Fair Value, Estimate Not Practicable, Equity Method Investments	0
Derivative liabilities	642	1,379
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities available-for-sale, at fair value	58,499	64,983
Equity warrants	5,284	5,161
Other derivative assets, Fair Value	0	0
Fair Value, Estimate Not Practicable, Equity Method Investments	0
Derivative liabilities	0	0
Non Purchased Credit Impaired Loans and Leases | Fair Value, Measurements, Nonrecurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Held-for-sale, Fair Value Disclosure		0
Non Purchased Credit Impaired Loans and Leases | Fair Value, Measurements, Nonrecurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Held-for-sale, Fair Value Disclosure		483,563
Non Purchased Credit Impaired Loans and Leases | Fair Value, Measurements, Nonrecurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans Held-for-sale, Fair Value Disclosure		0
NonPCI and PCI Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases, net		16,833,287
Loans and leases held for investment, net		17,023,098
NonPCI and PCI Loans | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases held for investment, net	0	0
NonPCI and PCI Loans | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases held for investment, net	$ 1,128	5,143
NonPCI and PCI Loans | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases held for investment, net		$ 17,017,955

Fair Value Measurements (Deta74

Fair Value Measurements (Details Textual)	3 Months Ended
	Mar. 31, 2018USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers of assets	$ 0
Private label collateralized mortgage obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value transfers of assets measured on a recurring basis	$ 13,000

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Earnings Per Share [Abstract]
Net earnings from continuing operations		$ 118,276	$ 84,037	$ 78,668
Less: Earnings allocated to unvested restricted stock	[1]	(1,115)	(951)	(999)
Net earnings allocated to common shares		$ 117,161	$ 83,086	$ 77,669
Weighted-average basic shares and unvested restricted stock outstanding (shares)		127,487	127,971	121,346
Weighted-average unvested restricted stock outstanding (shares)		(1,413)	(1,440)	(1,503)
Weighted-average basic shares outstanding (shares)		126,074	126,531	119,843
Basic net income per share (usd per share)		$ 0.93	$ 0.66	$ 0.65
Net earnings from continuing operations allocated to common shares		$ 117,161	$ 83,086	$ 77,669
Diluted net income per share (usd per share)		$ 0.93	$ 0.66	$ 0.65
[1]	Represents cash dividends paid to holders of unvested restricted stock, net of forfeitures, plus undistributed earnings amounts available to holders of unvested restricted stock, if any.

Revenue From Contracts With C76

Revenue From Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Interest Income, Operating	$ 277,775
Service charges on deposit accounts	4,174	$ 4,574	$ 3,758
Other commissions and fees	10,265	10,505	10,390
Operating Leases, Income Statement, Lease Revenue	9,587	8,258	9,475
Gain on sale of loans and leases	4,569	1,988	712
Gain (Loss) on Sale of Investments	6,311
Other income	3,653	4,799	10,878
Total noninterest income	38,559	$ 26,795	$ 35,114
Revenues	316,334
Revenue from Contract with Customer, Excluding Assessed Tax	9,286
Interest Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Service Charges On Deposit Accounts [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,174
Other Commissions And Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,651
Lease Equipment Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Gain On Sale Of Loans [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Gain On Sale Of Securities [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0
Other Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	461
Noninterest Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 9,286

Revenue From Contracts With C77

Revenue From Contracts With Customers (Details 1) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Revenue From Contracts With Customers [Abstract]
Revenue, Performance Obligation Satisfied At Point In Time	$ 4,661
Product and Services Transferred Over Time	4,625
Revenue from Contract with Customer, Excluding Assessed Tax	$ 9,286

Revenue From Contracts With C78

Revenue From Contracts With Customers (Details 2) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Revenue From Contracts With Customers [Abstract]
Contract With Customer, Receivable Reclassified to Other Assets	$ 1,438
Contract with Customer, Asset, Net	0
Contract With Customer, Liabilities Reclassified to Other Assets	$ 719

Revenue From Contracts With C79

Revenue From Contracts With Customers (Details Textual)	3 Months Ended
	Mar. 31, 2018USD ($)
Revenue From Contracts With Customers [Abstract]
Contract with Customer, Liability, Revenue Recognized	$ 33,000

Stock Based Compensation (Detai

Stock Based Compensation (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	1,383,914				1,436,120
Vesting period of time-based restricted stock, lower limit		3 years
Vesting period of time-based restricted stock, higher limit		4 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	0.00%
Performance Target 1 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	150.00%
Performance Target 2 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	200.00%
Restricted Stock | Vesting Based On Service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense		$ 7.2	$ 5.4	$ 6.5
Restricted Stock Awards And Performance Based Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share based compensation expense	$ 52.1
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	325,741
Performance period	3 years
PacWest 2003 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)	4,000,000
Number of shares available for grant (shares)	3,537,972
PacWest 2003 Stock Incentive Plan | Time-Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	1,383,914

Subsequent Events (Details Text

Subsequent Events (Details Textuals) - $ / shares	May 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Subsequent Event [Line Items]
Dividends declared per share (usd per share)		$ 0.50	$ 0.5	$ 0.5
Subsequent Event [Member] | Dividend Declared
Subsequent Event [Line Items]
Dividends declared per share (usd per share)	$ 0.60