First Citizens BancShares (FCNCO) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 06, 2019
Entity Registrant Name	FIRST CITIZENS BANCSHARES INC /DE/
Entity Central Index Key	0000798941
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A Common Stock
Entity Common Stock, Shares Outstanding		10,373,120
Class B Common Stock
Entity Common Stock, Shares Outstanding		1,005,185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and due from banks	$ 268,599	$ 327,440
Overnight investments	1,386,525	797,406
Investment in marketable equity securities	109,884	92,599
Investment securities available for sale	4,589,800	4,557,110
Investment securities held to maturity	2,214,829	2,184,653
Loans held for sale	53,232	45,505
Loans and leases	25,463,785	25,523,276
Allowance for loan and lease losses	(228,775)	(223,712)
Net loans and leases	25,235,010	25,299,564
Premises and equipment	1,203,674	1,204,179
Other real estate owned	43,306	48,030
Income earned not collected	113,812	109,903
Goodwill	236,347	236,347
Other intangible assets	67,053	72,298
Other assets	439,599	433,595
Total assets	35,961,670	35,408,629
Deposits [Abstract]
Noninterest-bearing deposits	12,376,913	11,882,670
Interest-bearing deposits	18,821,180	18,789,790
Total deposits	31,198,093	30,672,460
Securities sold under customer repurchase agreements	508,508	543,936
Debt, Long-term and Short-term, Combined Amount	189,594	193,556
Subordinated Debt	136,544	140,741
Long-term obligations	14,970	13,921
FDIC shared-loss payable	107,256	105,618
Other liabilities	283,396	249,443
Total liabilities	32,438,361	31,919,675
Shareholders' Equity
Preferred stock	0	0
Surplus	393,449	493,962
Retained earnings	3,325,335	3,218,551
Accumulated other comprehensive loss	(206,860)	(235,187)
Total shareholders' equity	3,523,309	3,488,954
Total liabilities and shareholders' equity	35,961,670	35,408,629
Class A Common Stock
Shareholders' Equity
Common stock	10,380	10,623
Class B Common Stock
Shareholders' Equity
Common stock	$ 1,005	$ 1,005

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Class A Common Stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shared authorized	16,000,000	16,000,000
Common stock, shares issued	10,380,220	10,623,220
Common stock, shares outstanding	10,380,220	10,623,220
Class B Common Stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shared authorized	2,000,000	2,000,000
Common stock, shares issued	1,005,185	1,005,185
Common stock, shares outstanding	1,005,185	1,005,185

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income
Loans and leases	$ 290,922	$ 251,982
Investment securities and dividend income	39,605	35,020
Overnight investments	6,397	5,599
Total interest income	336,924	292,601
Interest expense
Deposits	12,926	3,756
Short-term borrowings	459	404
Federal home loan bank borrowings	1,285	2,384
Subordinated debentures	1,672	1,441
Long-term obligations	110	179
Total interest expense	16,452	8,164
Net interest income	320,472	284,437
Provision (credit) for loan and lease losses	11,750	7,605
Net interest income after provision for loan and lease losses	308,722	276,832
Noninterest income
Marketable equity securities gains, net	11,328	971
Gain on extinguishment of debt	0	25,814
Other	3,919	7,164
Total noninterest income	103,663	122,684
Noninterest expense
Salaries and wages	132,421	129,203
Employee benefits	32,535	32,091
Occupancy expense	27,761	27,954
Equipment expense	26,740	24,974
FDIC insurance expense	2,660	5,733
Collection and foreclosure-related expenses	3,022	4,146
Merger-related expenses	1,719	598
Processing fees paid to third parties	7,089	8,196
Other	33,710	35,168
Total noninterest expense	267,657	268,063
Income before income taxes	144,728	131,453
Income taxes	33,369	31,222
Net income	$ 111,359	$ 100,231
Average shares outstanding (in shares)	11,519,008	12,010,405
Net income per share	$ 9.67	$ 8.35
Cardholder services, net
Noninterest income
Revenue from contract with customers	$ 16,633	$ 14,782
Merchant services, net
Noninterest income
Revenue from contract with customers	5,835	6,177
Service charges on deposit accounts
Noninterest income
Revenue from contract with customers	25,065	26,543
Wealth management services
Noninterest income
Revenue from contract with customers	25,001	23,569
Other service charges and fees
Noninterest income
Revenue from contract with customers	7,422	7,480
Mortgage income
Noninterest income
Revenue from contract with customers	3,658	4,237
Insurance commissions
Noninterest income
Revenue from contract with customers	3,291	3,776
ATM income
Noninterest income
Revenue from contract with customers	$ 1,511	$ 2,171

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 111,359	$ 100,231
Unrealized (losses) gains on securities available for sale:
Change in unrealized (losses) gains on securities available for sale arising during period	28,071	(78,635)
Tax effect	(6,456)	18,088
Total change in unrealized (losses) gains on securities available for sale, net of tax	21,615	(60,547)
Unrealized losses on securities available for sale transferred to held to maturity:
Reclassification adjustment for accretion of unrealized losses on securities available for sale transferred to held to maturity	5,962	0
Tax effect	(1,371)	0
Total change in unrealized losses on securities available for sale transferred to held to maturity, net of tax	4,591	0
Change in pension obligation:
Amortization of actuarial losses and prior service cost	2,755	3,337
Tax effect	(634)	(768)
Total change in pension obligation, net of tax	2,121	2,569
Net current period other comprehensive income	28,327	(57,978)
Total comprehensive income	$ 139,686	$ 42,253

Consolidated Statements of Chan

Consolidated Statements of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common StockClass A Common Stock	Common StockClass B Common Stock	Surplus	SurplusClass A Common Stock	Retained Earnings	Retained EarningsClass A Common Stock	Retained EarningsClass B Common Stock	Accumulated Other Comprehensive (Loss) Income	Financial Instruments ASU cumulative effect adjustmentRetained Earnings	Financial Instruments ASU cumulative effect adjustmentAccumulated Other Comprehensive (Loss) Income	Income tax ASU cumulative effect adjustmentRetained Earnings	Income tax ASU cumulative effect adjustmentAccumulated Other Comprehensive (Loss) Income
Shareholders' equity	$ 3,334,064			$ 11,005	$ 1,005	$ 658,918		$ 2,785,430			$ (122,294)
Net income	100,231							100,231
Other comprehensive income (loss), net of tax	(57,978)										(57,978)
Cash dividends		$ (3,851)	$ (352)						$ (3,851)	$ (352)
Cumulative effect of new accounting principle in period of adoption												$ 18,715	$ (18,715)	$ 31,336	$ (31,336)
Shareholders' equity	3,372,114			11,005	1,005	658,918		2,931,509			(230,323)
Shareholders' equity	3,488,954			10,623	1,005	493,962		3,218,551			(235,187)
Net income	111,359							111,359
Other comprehensive income (loss), net of tax	28,327
Stock repurchased during period	(100,700)	(100,756)		(243)			$ (100,513)
Cash dividends		$ (4,173)	$ (402)						$ (4,173)	$ (402)
Shareholders' equity	$ 3,523,309			$ 10,380	$ 1,005	$ 393,449		$ 3,325,335			$ (206,860)

Consolidated Statements of Ch_2

Consolidated Statements of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock repurchased during period (in shares)	243,000
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.40	$ 0.35
Common Stock | Class A Common Stock
Stock repurchased during period (in shares)	243,000	0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
Net income	$ 111,359	$ 100,231
Adjustments to reconcile net income to cash provided by operating activities:
Provision (credit) for loan and lease losses	11,750	7,605
Deferred tax expense (benefit)	(7,316)	(5,573)
Net change in current taxes	37,898	33,128
Depreciation	28,195	23,179
Net (decrease) increase in accrued interest payable	3,457	(2,454)
Net (increase) decrease in income earned not collected	(3,909)	(1,358)
Marketable equity securities gain (loss), net	(11,328)	(971)
Gain on extinguishment of debt	0	(25,814)
Origination of loans held for sale	(128,949)	(131,353)
Proceeds from sale of loans held for sale	123,047	138,538
Gain on sale of loans held for sale	(2,181)	(2,666)
Net writedowns/losses on other real estate	427	1,210
(Gain) loss on sales of premises and equipment	358	0
Net accretion of premiums and discounts	(8,737)	(10,323)
Amortization of intangible assets	5,943	6,049
Net change in FDIC payable for shared-loss agreements	1,638	1,124
Net change in mortgage servicing rights	(698)	(1,200)
Net change in other assets	31,072	341,678
Net change in other liabilities	(51,985)	(12,642)
Net cash provided by operating activities	140,041	458,388
INVESTING ACTIVITIES
Net increase in loans outstanding	68,052	(7,283)
Purchases of investment securities available for sale	(593,952)	(374,850)
Purchases of investment securities held to maturity	(116,028)	0
Purchases of marketable equity securities	(6,076)	(2,272)
Proceeds from maturities/calls of investment securities held to maturity	88,400	2
Proceeds from maturities/calls of investment securities available for sale	587,023	503,717
Proceeds from sales of marketable equity securities	119	664
Net decrease (increase) in overnight investments	(589,119)	(558,955)
Cash paid to the FDIC for shared-loss agreements	(8)	0
Proceeds from sales of other real estate	7,430	8,380
Proceeds from sales of premises and equipment	54	13
Purchases of premises and equipment	(23,875)	(24,081)
Net cash used in investing activities	(577,980)	(454,665)
FINANCING ACTIVITIES
Net decrease in time deposits	138,640	(92,064)
Net increase in demand and other interest-bearing deposits	387,319	795,034
Net decrease in short-term borrowings	(35,428)	(139,049)
Repayment of long-term obligations	(8,688)	(651,451)
Repurchase of common stock	(98,077)	0
Cash dividends paid	(4,668)	(4,204)
Net cash (used in) provided by financing activities	379,098	(91,734)
Change in cash and due from banks	(58,841)	(88,011)
Cash and due from banks at beginning of period	327,440	336,150
Cash and due from banks at end of period	268,599	248,139
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Transfers of loans to other real estate	2,613	6,582
Dividends declared but not paid	4,575	4,204
Transfer of Portfolio Loans (From) To Loans Held-for-sale	605	0
Transfers of premises and equipment to other real estate	520	0
Unsettled common stock repurchases	(2,679)	0
Initial recognition of operating lease assets	70,652	0
Initial recognition of operating lease liabilities	$ 71,793	$ 0

Accounting Policies and Basis o

Accounting Policies and Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Accounting Policies and Basis of Presentation	ACCOUNTING POLICIES AND BASIS OF PRESENTATION First Citizens BancShares, Inc. (BancShares) is a financial holding company organized under the laws of Delaware and conducts operations through its banking subsidiary, First-Citizens Bank & Trust Company (FCB), which is headquartered in Raleigh, North Carolina. General These consolidated financial statements and notes thereto are presented in accordance with instructions for Form 10-Q and Article 10 of Regulation S-X and, therefore, do not include all information and notes necessary for a complete presentation of financial position, results of operations and cash flow activity required in accordance with accounting principles generally accepted in the United States of America (GAAP). In the opinion of management, all normal recurring adjustments necessary for a fair presentation of the consolidated financial position and consolidated results of operations have been made. The unaudited interim consolidated financial statements included in this Form 10-Q should be read in conjunction with the consolidated financial statements and notes to consolidated financial statements included in BancShares' Annual Report on Form 10-K for the year ended December 31, 2018 . Reclassifications In certain instances, amounts reported in prior years' consolidated financial statements have been reclassified to conform to the current financial statement presentation. Such reclassifications had no effect on previously reported cash flows, shareholders' equity or net income. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported. Actual results could differ from those estimates. The estimates that BancShares considers significant are the allowance for loan and lease losses, fair value measurements, Federal Deposit Insurance Corporation (FDIC) shared-loss payable, pension plan assumptions, goodwill and other intangible assets and income taxes. Share Repurchases In October 2018, BancShares' Board of Directors (Board) authorized the purchase of up to 800,000 of BancShares' Class A common stock for the period November 1, 2018 through October 31, 2019. The authorization does not obligate Bancshares to purchase any particular amount of shares, and purchases may be suspended or discontinued at any time. During the first quarter of 2019, BancShares repurchased 243,000 shares of Class A common stock for approximately $100.7 million at an average cost per share of $414.58 . There were no share repurchases made during the first quarter of 2018. As of March 31, 2019, a total of 425,000 shares have been repurchased under the current Board authority. Subsequent to quarter-end and through May 6, 2019 , BancShares repurchased an additional 63,400 shares of Class A common stock for approximately $27.4 million at an average cost per share of $432.78 . Recently Adopted Accounting Pronouncements Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) 2016-02, Leases (Topic 842) This ASU increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The key difference between prior standards and this ASU is the requirement for lessees to recognize all lease contracts on their balance sheet. This ASU requires lessees to classify leases as either operating or finance leases, which are substantially similar to the previous operating and capital leases classifications. The distinction between these two classifications under the new standard does not relate to balance sheet treatment, but relates to treatment in the statements of income and cash flows. Lessor guidance remains largely unchanged with the exception of how a lessor determines the appropriate lease classification for each lease to better align the lessor guidance with revised lessee classification guidance. We adopted this standard, as of January 1, 2019, using the effective date method that allows for entities to initially apply the new leases standard at the adoption date. In addition, we made several policy elections permitted under the transition guidance, which among other things, allowed us to carry forward the historical lease classification. We determined that most renewal options would not be reasonably determinable in estimating the expected lease term. We made the policy election available under Topic 842 to combine lease and non-lease components and applied this practical expedient to leases in effect prior to the date of adoption. We will continue to apply the practical expedient to all leases entered into going forward. The adoption of the new standard had an impact on our Consolidated Balance Sheet, with the recording of operating Right-of-Use (ROU) assets and operating lease liabilities of $70.7 million and $71.8 million , respectively. The operating lease liability includes a $1.1 million fair value adjustment for leases assumed in the acquisition of HomeBancorp, Inc. (HomeBancorp). In addition, at the adoption date we had finance lease ROU assets and finance lease liabilities, previously classified as capital leases, of $9.1 million and $8.3 million , respectively. The Company did not have a cumulative-effect adjustment to the opening balance of retained earnings at commencement. The Company has no related party lease agreements. This ASU did not have a material impact on our Consolidated Statements of Income. See Note N in the Consolidated Financial Statements for additional disclosures. FASB ASU 2019-01, Leases (Topic 842): Codification Improvements This ASU reinstated the exception in Topic 842 for lessors that are not manufacturers or dealers for determining the fair value of leased property as the underlying asset's cost, reflecting any volume or trade discounts that may apply, allows lessors that are depository and lending institutions within the scope of ASU Topic 942 to present "principal payments received under leases" within investing activities on the Statement of Cash Flows, and provides an exemption to the ASC 250-10-50-3 interim disclosure requirements in the Topic 842 transition disclosure requirements. We early adopted this standard with ASU 2016-02 as of January 1, 2019 and the impact was not material to our Consolidated Financial Statements. Recently Issued Accounting Pronouncements FASB ASU 2018-15 - Intangibles - Goodwill and Other - Internal Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract This ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include internal-use software license). This ASU requires entities to use the guidance in FASB ASC 350-40, Intangibles - Goodwill and Other - Internal Use Software, to determine whether to capitalize or expense implementation costs related to the service contract. This ASU also requires entities to (1) expense capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement (2) present the expense related to the capitalized implementation costs in the same line item on the income statement as fees associated with the hosting element of the arrangement (3) classify payments for capitalized implementation costs in the statement of cash flows in the same manner as payments made for fees associated with the hosting element (4) present the capitalized implementation costs in the same balance sheet line item that a prepayment for the fees associated with the hosting arrangement would be presented. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. BancShares is currently evaluating the impact this new standard will have on its Consolidated Financial Statements and whether we will early adopt prior to the first quarter of 2020. FASB ASU 2018-14 - Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans This ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans by eliminating the requirement to disclose the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year and adding a requirement to disclose an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The amendments in this ASU are effective for public entities for fiscal years ending after December 15, 2020. Early adoption is permitted for all entities. BancShares will adopt all applicable amendments and update the disclosures as appropriate during the first quarter of 2021. FASB ASU 2018-13 - Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement This ASU modifies the disclosure requirements on fair value measurements by eliminating the requirements to disclose (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy (2) the policy for timing of transfers between levels and (3) the valuation processes for Level 3 fair value measurements. This ASU also added specific disclosure requirements for fair value measurements for public business entities including the requirement to disclose the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendments in this ASU are effective for all entities for fiscal years beginning after December 15, 2019, and all interim periods within those fiscal years. Early adoption is permitted upon issuance of the ASU. Entities are permitted to early adopt amendments that remove or modify disclosures and delay the adoption of the additional disclosures until their effective date. BancShares will adopt all applicable amendments and update the disclosures as appropriate during the first quarter of 2020. FASB ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment This ASU eliminates Step 2 from the goodwill impairment test. Under Step 2, an entity had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, under the amendments in this ASU, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This ASU eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative test. This ASU will be effective for BancShares' annual or interim goodwill impairment tests for fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We expect to adopt the guidance for our annual impairment test in fiscal year 2020. BancShares does not anticipate any impact to our consolidated financial position or consolidated results of operations as a result of the adoption. FASB ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This ASU introduces a new credit loss methodology which requires earlier recognition of credit losses, replacing multiple existing impairment methods in current GAAP, which generally require that a loss be incurred before it is recognized. The amendments in this ASU require loss estimates be determined over the lifetime of the asset and broaden the information that an entity must consider in developing its expected credit losses. The ASU does not specify a method for measuring expected credit losses and allows an entity to apply methods that reasonably reflect its expectations of the credit loss estimate based on the entity's size, complexity and risk profile. In addition, the disclosures of credit quality indicators in relation to the amortized cost of financing receivables, a current disclosure requirement, are further disaggregated by year of origination. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018. BancShares will adopt the guidance in the first quarter of 2020 with a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. For BancShares, the standard will apply to loans, unfunded loan commitments and debt securities. A cross-functional team co-led by Corporate Finance and Risk Management is in place to implement the new standard. We have completed preliminary current expected credit losses (CECL) accounting interpretations, and continue to refine and test our models, estimation techniques, data, operational processes and controls to be used in preparing CECL loss estimates. During 2019, we expect to address any gaps in our interpretations, methodology, data and operational processes based upon our reviews and tests. BancShares continues to evaluate the impact of this standard on its consolidated financial statements but the magnitude of this impact has not been determined. The final impact will be dependent on, among other items, loan portfolio composition and credit quality at the adoption date, as well as economic conditions, financial models used and forecasts in place at that time.

Business Combinations

Business Combinations	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS First South Bancorp, Inc. On May 1, 2019, FCB completed the merger of Spartanburg, South Carolina-based First South Bancorp and its bank subsidiary, First South Bank. Under the terms of the agreement, cash consideration of $1.15 per share was paid to the shareholders of First South Bancorp for each share of common stock totaling approximately $37.5 million . The total consideration assumes the conversion of all First South Bancorp's Series A preferred shares into common stock. The merger will allow FCB to expand its presence and enhance banking efforts in South Carolina. As of March 31, 2019 , First South Bancorp reported $236.0 million in consolidated assets, $206.1 million in deposits and $183.3 million in loans. Entegra Financial Corp. On April 23, 2019, FCB and Entegra Financial Corp. (Entegra) entered into a definitive merger agreement for the acquisition by FCB of Franklin, North Carolina-based Entegra and its bank subsidiary, Entegra Bank. Under the terms of the agreement, cash consideration of $30.18 per share will be paid to the shareholders of Entegra for each share of common stock and for each restricted stock unit after conversion to common stock, and each option to purchase Entegra common stock will be canceled and each option holder will receive a cash payment equal to $30.18 for each share underlying the option minus the applicable exercise price of the option. The total transaction value, including termination fee, is anticipated to be approximately $219.8 million . The transaction is anticipated to close during the second half of 2019, subject to the receipt of regulatory approvals and the approval of Entegra's shareholders. As of March 31, 2019 , Entegra reported $1.67 billion in consolidated assets, $1.25 billion in deposits and $1.08 billion in loans. Biscayne Bancshares, Inc. On April 2, 2019 , FCB completed the merger of Coconut Grove, Florida-based Biscayne Bancshares, Inc. (Biscayne Bancshares) and its bank subsidiary, Biscayne Bank. Under the terms of the agreement, cash consideration of $25.05 per share was paid to the shareholders of Biscayne Bancshares for each share of common stock, totaling approximately $118.9 million . The merger will allow FCB to expand its presence in Florida and enhance banking efforts in South Florida. As of March 31, 2019 , Biscayne Bancshares reported $1.02 billion in consolidated assets, $879.9 million in loans and $788.2 million in deposits.

Loans and Leases

Loans and Leases	3 Months Ended
	Mar. 31, 2019
Loans and Leases Receivable Disclosure [Abstract]
Loans and Leases	LOANS AND LEASES BancShares' accounting methods for loans and leases differ depending on whether they are non-purchased credit impaired (Non-PCI) or purchased credit impaired (PCI). Loans that are originated by FCB, as well as loans that are performing under their contractual obligations at acquisition, are classified as Non-PCI. Loans that reflect credit deterioration since origination, such that it is probable at acquisition that FCB will be unable to collect all contractually required payments, are classified as PCI. Additionally, at the date of acquisition, all acquired loans are recorded at fair value with no corresponding allowance for loan and lease losses. Loans and leases outstanding included the following at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 Non-PCI loans and leases: Commercial: Construction and land development $ 804,463 $ 757,854 Commercial mortgage 10,747,715 10,717,234 Other commercial real estate 427,419 426,985 Commercial and industrial and leases 3,879,575 3,938,730 Other 280,848 296,424 Total commercial loans 16,140,020 16,137,227 Noncommercial: Residential mortgage 4,303,137 4,265,687 Revolving mortgage 2,469,898 2,542,975 Construction and land development 258,959 257,030 Consumer 1,734,415 1,713,781 Total noncommercial loans 8,766,409 8,779,473 Total non-PCI loans and leases 24,906,429 24,916,700 PCI loans: Total PCI loans 557,356 606,576 Total loans and leases $ 25,463,785 $ 25,523,276 At March 31, 2019 , $9.08 billion in non-PCI loans with a lendable collateral value of $6.36 billion were used to secure $175.2 million in Federal Home Loan Bank (FHLB) of Atlanta advances and $14.5 million in FHLB of Chicago advances, resulting in additional borrowing capacity of $6.17 billion . At December 31, 2018 , $9.12 billion in non-PCI loans with a lendable collateral value of $6.36 billion were used to secure $175.2 million in FHLB of Atlanta advances, resulting in additional borrowing capacity of $6.18 billion . At March 31, 2019 , $2.93 billion in non-PCI loans with a lendable collateral value of $2.23 billion were used to secure additional borrowing capacity at the Federal Reserve Bank (FRB). At December 31, 2018 , $2.94 billion in non-PCI loans with a lendable collateral value of $2.19 billion were used to secure additional borrowing capacity at the FRB. Certain residential real estate loans are originated to be sold to investors and are recorded in loans held for sale at fair value. In addition, we may change our strategy for certain portfolio loans and decide to sell them in the secondary market. At that time, portfolio loans are transferred to loans held for sale at fair value. Loans held for sale totaled $53.2 million and $45.5 million at March 31, 2019 and December 31, 2018 , respectively. During the three months ended March 31, 2019 , total proceeds from sales of loans held for sale were $123.0 million and there were no transfers to loans held for sale from the residential mortgage portfolio. For the three months ended March 31, 2018 , total proceeds from sales of loans held for sale were $138.5 million and there were no transfers to loans held for sale from the residential mortgage portfolio. Net deferred fees on non-PCI loans and leases, including unearned income as well as unamortized costs and fees, were $130 thousand and $79 thousand at March 31, 2019 and December 31, 2018 , respectively. The net unamortized discount related to purchased non-PCI loans and leases was $30.1 million at March 31, 2019 and $33.3 million at December 31, 2018. During the three months ended March 31, 2019 and March 31, 2018 , accretion income on purchased non-PCI loans and leases was $3.2 million and $2.9 million , respectively. Credit quality indicators Loans and leases are monitored for credit quality on a recurring basis. Commercial and noncommercial loans and leases have different credit quality indicators as a result of the unique characteristics of the loan segments being evaluated. The credit quality indicators for non-PCI and PCI commercial loans and leases are developed through a review of individual borrowers on an ongoing basis. Commercial loans are evaluated periodically with more frequent evaluations done on criticized loans. Commercial credit cards are included in the Commercial and industrial and leases segment, but are not specifically graded as with other commercial loans. The indicators as of the date presented are based on the most recent assessment performed and are defined below: Pass – A pass rated asset is not adversely classified because it does not display any of the characteristics for adverse classification. Special mention – A special mention asset has potential weaknesses that deserve management’s close attention. If left uncorrected, such potential weaknesses may result in deterioration of the repayment prospects or collateral position at some future date. Special mention assets are not adversely classified and do not warrant adverse classification. Substandard – A substandard asset is inadequately protected by the current net worth and paying capacity of the borrower or of the collateral pledged, if any. Assets classified as substandard generally have a well-defined weakness, or weaknesses, that jeopardize the liquidation of the debt. These assets are characterized by the distinct possibility of loss if the deficiencies are not corrected. Doubtful – An asset classified as doubtful has all the weaknesses inherent in an asset classified substandard with the added characteristic that the weaknesses make collection or liquidation in full highly questionable and improbable on the basis of currently existing facts, conditions and values. Loss – Assets classified as loss are considered uncollectible and of such little value that it is inappropriate to be carried as an asset. This classification is not necessarily equivalent to any potential for recovery or salvage value, but rather that it is not appropriate to defer a full charge-off even though partial recovery may be affected in the future. Ungraded – Ungraded loans represent loans that are not included in the individual credit grading process due to their relatively small balances or borrower type. The majority of ungraded loans at March 31, 2019 and December 31, 2018 relate to business credit cards. Business credit card loans are subject to automatic charge-off when they become 120 days past due in the same manner as unsecured consumer lines of credit. The remaining balance is comprised of a small amount of commercial mortgage, lease financing and other commercial real estate loans. The credit quality indicators for non-PCI and PCI noncommercial loans are based on delinquency status of the borrower as of the date presented. As the borrower becomes more delinquent, the likelihood of loss increases. The composition of the loans and leases outstanding at March 31, 2019 and December 31, 2018 by credit quality indicator are provided below: March 31, 2019 (Dollars in thousands) Non-PCI commercial loans and leases Grade: Construction and Commercial mortgage Other commercial real estate Commercial and industrial and leases Other Total non-PCI commercial loans and leases Pass $ 800,703 $ 10,528,026 $ 423,288 $ 3,717,237 $ 279,899 $ 15,749,153 Special mention 1,345 110,413 3,244 46,928 350 162,280 Substandard 2,415 109,276 887 37,443 599 150,620 Doubtful — — — 354 — 354 Ungraded — — — 77,613 — 77,613 Total $ 804,463 $ 10,747,715 $ 427,419 $ 3,879,575 $ 280,848 $ 16,140,020 December 31, 2018 (Dollars in thousands) Non-PCI commercial loans and leases Grade: Construction and Commercial mortgage Other commercial real estate Commercial and industrial and leases Other Total non-PCI commercial loans and leases Pass $ 753,985 $ 10,507,687 $ 422,500 $ 3,778,797 $ 294,700 $ 15,757,669 Special mention 1,369 114,219 3,193 54,814 1,105 174,700 Substandard 2,500 92,743 1,292 30,688 619 127,842 Doubtful — — — 354 — 354 Ungraded — 2,585 — 74,077 — 76,662 Total $ 757,854 $ 10,717,234 $ 426,985 $ 3,938,730 $ 296,424 $ 16,137,227 March 31, 2019 Non-PCI noncommercial loans and leases (Dollars in thousands) Residential Revolving Construction Consumer Total non-PCI noncommercial loans and leases Current $ 4,248,823 $ 2,444,150 $ 256,801 $ 1,720,142 $ 8,669,916 30-59 days past due 33,623 10,734 581 7,966 52,904 60-89 days past due 7,760 4,227 28 3,001 15,016 90 days or greater past due 12,931 10,787 1,549 3,306 28,573 Total $ 4,303,137 $ 2,469,898 $ 258,959 $ 1,734,415 $ 8,766,409 December 31, 2018 Non-PCI noncommercial loans and leases (Dollars in thousands) Residential Revolving Construction Consumer Total non-PCI noncommercial loans and leases Current $ 4,214,783 $ 2,514,269 $ 254,837 $ 1,696,321 $ 8,680,210 30-59 days past due 28,239 12,585 581 10,035 51,440 60-89 days past due 7,357 4,490 21 3,904 15,772 90 days or greater past due 15,308 11,631 1,591 3,521 32,051 Total $ 4,265,687 $ 2,542,975 $ 257,030 $ 1,713,781 $ 8,779,473 PCI loans outstanding at March 31, 2019 and December 31, 2018 by credit quality indicator are provided below: March 31, 2019 December 31, 2018 (Dollars in thousands) PCI commercial loans Grade: Pass $ 131,018 $ 141,922 Special mention 43,068 48,475 Substandard 91,940 101,447 Doubtful 3,887 4,828 Total $ 269,913 $ 296,672 March 31, 2019 December 31, 2018 (Dollars in thousands) PCI noncommercial loans Current $ 255,145 $ 268,280 30-59 days past due 8,565 11,155 60-89 days past due 3,449 7,708 90 days or greater past due 20,284 22,761 Total $ 287,443 $ 309,904 The aging of the outstanding non-PCI loans and leases, by class, at March 31, 2019 and December 31, 2018 are provided in the tables below. Loans and leases 30 days or less past due are considered current as various grace periods allow borrowers to make payments within a stated period after the due date and still remain in compliance with the loan agreement. March 31, 2019 (Dollars in thousands) 30-59 days 60-89 days 90 days or greater Total past Current Total loans Non-PCI loans and leases: Commercial: Construction and land development - commercial $ 617 $ 262 $ 206 $ 1,085 $ 803,378 $ 804,463 Commercial mortgage 16,120 8,818 2,802 27,740 10,719,975 10,747,715 Other commercial real estate 1,198 517 — 1,715 425,704 427,419 Commercial and industrial and leases 9,706 2,403 3,389 15,498 3,864,077 3,879,575 Other 113 24 — 137 280,711 280,848 Total commercial loans 27,754 12,024 6,397 46,175 16,093,845 16,140,020 Noncommercial: Residential mortgage 33,623 7,760 12,931 54,314 4,248,823 4,303,137 Revolving mortgage 10,734 4,227 10,787 25,748 2,444,150 2,469,898 Construction and land development - non-commercial 581 28 1,549 2,158 256,801 258,959 Consumer 7,966 3,001 3,306 14,273 1,720,142 1,734,415 Total noncommercial loans 52,904 15,016 28,573 96,493 8,669,916 8,766,409 Total non-PCI loans and leases $ 80,658 $ 27,040 $ 34,970 $ 142,668 $ 24,763,761 $ 24,906,429 December 31, 2018 (Dollars in thousands) 30-59 days 60-89 days 90 days or greater Total past Current Total loans Non-PCI loans and leases: Commercial: Construction and land development - commercial $ 516 $ 9 $ 444 $ 969 $ 756,885 $ 757,854 Commercial mortgage 14,200 2,066 3,237 19,503 10,697,731 10,717,234 Other commercial real estate 91 76 300 467 426,518 426,985 Commercial and industrial and leases 9,655 1,759 2,892 14,306 3,924,424 3,938,730 Other 285 — 89 374 296,050 296,424 Total commercial loans 24,747 3,910 6,962 35,619 16,101,608 16,137,227 Noncommercial: Residential mortgage 28,239 7,357 15,308 50,904 4,214,783 4,265,687 Revolving mortgage 12,585 4,490 11,631 28,706 2,514,269 2,542,975 Construction and land development - non-commercial 581 21 1,591 2,193 254,837 257,030 Consumer 10,035 3,904 3,521 17,460 1,696,321 1,713,781 Total noncommercial loans 51,440 15,772 32,051 99,263 8,680,210 8,779,473 Total non-PCI loans and leases $ 76,187 $ 19,682 $ 39,013 $ 134,882 $ 24,781,818 $ 24,916,700 The recorded investment, by class, in loans and leases on nonaccrual status, and loans and leases greater than 90 days past due and still accruing at March 31, 2019 and December 31, 2018 for non-PCI loans and leases, were as follows: March 31, 2019 December 31, 2018 (Dollars in thousands) Nonaccrual loans and leases Loans and leases > 90 days and accruing Nonaccrual loans and leases Loans and leases > 90 days and accruing Non-PCI loans and leases: Construction and land development - commercial $ 407 $ — $ 666 $ — Commercial mortgage 15,744 — 12,594 — Other commercial real estate 19 — 366 — Commercial and industrial and leases 5,482 667 4,624 808 Residential mortgage 36,573 614 35,662 — Revolving mortgage 25,723 — 25,563 — Construction and land development - noncommercial 1,699 — 1,823 — Consumer 3,054 2,212 2,969 2,080 Other 257 — 279 — Total non-PCI loans and leases $ 88,958 $ 3,493 $ 84,546 $ 2,888 The following table provides changes in the carrying value of all PCI loans during the three months ended March 31, 2019 and March 31, 2018 : (Dollars in thousands) 2019 2018 Balance at January 1 $ 606,576 $ 762,998 Fair value of acquired loans — — Accretion 17,755 17,973 Payments received and other changes, net (66,975 ) (77,134 ) Balance at March 31 $ 557,356 $ 703,837 Unpaid principal balance at March 31 $ 810,683 $ 1,108,379 The carrying value of PCI loans on the cost recovery method was $3.3 million at both March 31, 2019 and December 31, 2018 . The cost recovery method is applied to loans when the timing of future cash flows cannot be reasonably estimated due to borrower nonperformance or uncertainty in the ultimate disposition of the asset. The recorded investment of PCI loans on nonaccrual status was $1.7 million and $1.3 million at March 31, 2019 and December 31, 2018 , respectively. The remaining discount on PCI loans was $89.4 million and $95.5 million at March 31, 2019 and December 31, 2018, respectively. During the three months ended March 31, 2019 and March 31, 2018 , accretion income on PCI loans was $17.8 million and $18.0 million , respectively. For PCI loans, improved credit loss expectations generally result in the reclassification of nonaccretable difference to accretable yield. Changes in expected cash flow not related to credit improvements or deterioration do not affect the nonaccretable difference. The following table documents changes to the amount of accretable yield for the first three months of 2019 and 2018 . (Dollars in thousands) 2019 2018 Balance at January 1 $ 312,894 $ 316,679 Additions from acquisitions — — Accretion (17,755 ) (17,973 ) Reclassifications from (to) nonaccretable difference 600 (929 ) Changes in expected cash flows that do not affect nonaccretable difference (9,547 ) 11,568 Balance at March 31 $ 286,192 $ 309,345

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Allowance	NOTE E - ALLOWANCE FOR LOAN AND LEASE LOSSES (ALLL) Activity in the allowance for non-PCI loan and lease losses by class of loans is summarized as follows: Three months ended March 31, 2019 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: Balance at January 1 $ 35,270 $ 43,451 $ 2,481 $ 55,620 $ 2,221 $ 15,472 $ 21,862 $ 2,350 $ 35,841 $ 214,568 Provision (credits) 2,119 2,371 (83 ) 2,725 (498 ) 1,508 209 123 3,440 11,914 Charge-offs (44 ) (761 ) — (1,858 ) — (166 ) (963 ) — (6,362 ) (10,154 ) Recoveries 131 220 1 538 444 173 387 — 1,573 3,467 Balance at March 31 $ 37,476 $ 45,281 $ 2,399 $ 57,025 $ 2,167 $ 16,987 $ 21,495 $ 2,473 $ 34,492 $ 219,795 Three months ended March 31, 2018 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Balance at January 1 $ 24,470 $ 45,005 $ 4,571 $ 59,824 $ 4,689 $ 15,706 $ 22,436 $ 3,962 $ 31,204 $ 211,867 Provision (credits) 2,225 (1,365 ) (1,293 ) 562 114 1,512 466 107 2,923 5,251 Charge-offs — (46 ) — (2,329 ) (3 ) (806 ) (992 ) (182 ) (5,255 ) (9,613 ) Recoveries 23 239 145 1,260 42 77 194 26 1,309 3,315 Balance at March 31 $ 26,718 $ 43,833 $ 3,423 $ 59,317 $ 4,842 $ 16,489 $ 22,104 $ 3,913 $ 30,181 $ 210,820 The following tables present the allowance and recorded investment in loans and leases by class of loans, as well as the associated impairment method at March 31, 2019 and December 31, 2018 : March 31, 2019 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: ALLL for loans and leases individually evaluated for impairment $ 533 $ 2,949 $ 16 $ 1,420 $ 151 $ 3,149 $ 2,742 $ 99 $ 906 $ 11,965 ALLL for loans and leases collectively evaluated for impairment 36,943 42,332 2,383 55,605 2,016 13,838 18,753 2,374 33,586 207,830 Total allowance for loan and lease losses $ 37,476 $ 45,281 $ 2,399 $ 57,025 $ 2,167 $ 16,987 $ 21,495 $ 2,473 $ 34,492 $ 219,795 Loans and leases: Loans and leases individually evaluated for impairment $ 2,123 $ 56,157 $ 541 $ 9,987 $ 337 $ 44,944 $ 29,216 $ 3,742 $ 2,954 $ 150,001 Loans and leases collectively evaluated for impairment 802,340 10,691,558 426,878 3,869,588 280,511 4,258,193 2,440,682 255,217 1,731,461 24,756,428 Total loan and leases $ 804,463 $ 10,747,715 $ 427,419 $ 3,879,575 $ 280,848 $ 4,303,137 $ 2,469,898 $ 258,959 $ 1,734,415 $ 24,906,429 December 31, 2018 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: ALLL for loans and leases individually evaluated for impairment $ 490 $ 2,671 $ 42 $ 1,137 $ 105 $ 1,901 $ 2,515 $ 81 $ 885 $ 9,827 ALLL for loans and leases collectively evaluated for impairment 34,780 40,780 2,439 54,483 2,116 13,571 19,347 2,269 34,956 204,741 Total allowance for loan and lease losses $ 35,270 $ 43,451 $ 2,481 $ 55,620 $ 2,221 $ 15,472 $ 21,862 $ 2,350 $ 35,841 $ 214,568 Loans and leases: Loans and leases individually evaluated for impairment $ 2,175 $ 55,447 $ 860 $ 9,868 $ 291 $ 42,168 $ 28,852 $ 3,749 $ 3,020 $ 146,430 Loans and leases collectively evaluated for impairment 755,679 10,661,787 426,125 3,928,862 296,133 4,223,519 2,514,123 253,281 1,710,761 24,770,270 Total loan and leases $ 757,854 $ 10,717,234 $ 426,985 $ 3,938,730 $ 296,424 $ 4,265,687 $ 2,542,975 $ 257,030 $ 1,713,781 $ 24,916,700 Activity in the PCI allowance activity and balances for the three months ended March 31, 2019 and March 31, 2018 is summarized as follows: (Dollars in thousands) Three months ended March 31, 2019 Three months ended March 31, 2018 Allowance for loan losses: Balance at January 1 $ 9,144 $ 10,026 Provision (164 ) 2,354 Charge-offs — (84 ) Recoveries — — Balance at March 31 $ 8,980 $ 12,296 The following table presents the PCI allowance and recorded investment in loans at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 ALLL for loans acquired with deteriorated credit quality $ 8,980 $ 9,144 Loans acquired with deteriorated credit quality 557,356 606,576 At March 31, 2019 and December 31, 2018 , $160.4 million and $186.6 million , respectively, in PCI loans experienced an adverse change in expected cash flows since the date of acquisition. The following tables provide information on non-PCI impaired loans and leases, exclusive of loans and leases evaluated collectively as a homogeneous group, including interest income recognized in the period during which the loans and leases were considered impaired. March 31, 2019 (Dollars in thousands) With a With no Total Unpaid Related Non-PCI impaired loans and leases: Construction and land development - commercial $ 1,932 $ 191 $ 2,123 $ 2,538 $ 533 Commercial mortgage 37,575 18,582 56,157 61,845 2,949 Other commercial real estate 222 319 541 629 16 Commercial and industrial and leases 7,613 2,374 9,987 14,002 1,420 Other 262 75 337 353 151 Residential mortgage 43,553 1,391 44,944 48,216 3,149 Revolving mortgage 26,017 3,199 29,216 32,074 2,742 Construction and land development - noncommercial 2,330 1,412 3,742 4,045 99 Consumer 2,872 82 2,954 3,378 906 Total non-PCI impaired loans and leases $ 122,376 $ 27,625 $ 150,001 $ 167,080 $ 11,965 December 31, 2018 (Dollars in thousands) With a With no Total Unpaid Related Non-PCI impaired loans and leases: Construction and land development - commercial $ 1,897 $ 278 $ 2,175 $ 2,606 $ 490 Commercial mortgage 34,177 21,270 55,447 61,317 2,671 Other commercial real estate 243 617 860 946 42 Commercial and industrial and leases 7,153 2,715 9,868 14,695 1,137 Other 216 75 291 301 105 Residential mortgage 40,359 1,809 42,168 45,226 1,901 Revolving mortgage 25,751 3,101 28,852 31,371 2,515 Construction and land development - noncommercial 2,337 1,412 3,749 4,035 81 Consumer 2,940 80 3,020 3,405 885 Total non-PCI impaired loans and leases $ 115,073 $ 31,357 $ 146,430 $ 163,902 $ 9,827 Non-PCI impaired loans less than $500,000 that were collectively evaluated for impairment totaled $44.8 million and $47.1 million at March 31, 2019 and December 31, 2018 , respectively. The following tables show the average non-PCI impaired loan balance and the interest income recognized by loan class for the three months ended March 31, 2019 and March 31, 2018 : Three months ended March 31, 2019 Three months ended March 31, 2018 (Dollars in thousands) Average Interest income recognized Average Interest income recognized Non-PCI impaired loans and leases: Construction and land development - commercial $ 2,147 $ 28 $ 1,155 $ 11 Commercial mortgage 56,629 564 72,267 711 Other commercial real estate 685 8 1,713 11 Commercial and industrial and leases 10,000 100 9,762 87 Other 315 2 — — Residential mortgage 42,626 325 38,724 275 Revolving mortgage 28,742 247 24,792 201 Construction and land development - noncommercial 3,747 36 4,104 48 Consumer 3,000 29 2,508 28 Total non-PCI impaired loans and leases $ 147,891 $ 1,339 $ 155,025 $ 1,372 Troubled Debt Restructurings BancShares accounts for certain loan modifications or restructurings as troubled debt restructurings (TDRs). In general, the modification or restructuring of a loan is considered a TDR if, for economic reasons or legal reasons related to a borrower's financial difficulties, a concession is granted to the borrower that creditors would not otherwise consider. Concessions may relate to the contractual interest rate, maturity date, payment structure or other actions. The majority of TDRs are included in the special mention, substandard or doubtful credit quality indicators, which results in more elevated loss expectations when projecting the expected cash flows that are used to determine the allowance for loan losses associated with these loans. The lower the credit quality indicator, the lower the estimated expected cash flows and the greater the allowance recorded. All TDRs are individually evaluated for impairment through review of collateral values or analysis of cash flows at least annually. The following table provides a summary of total TDRs by accrual status. Total TDRs included $17.9 million and $18.2 million of PCI TDRs at March 31, 2019 and December 31, 2018 , respectively. March 31, 2019 December 31, 2018 (Dollars in thousands) Accruing Nonaccruing Total Accruing Nonaccruing Total Commercial loans Construction and land development - $ 1,914 $ 329 $ 2,243 $ 1,946 $ 352 $ 2,298 Commercial mortgage 51,202 6,653 57,855 53,270 7,795 61,065 Other commercial real estate 536 5 541 851 9 860 Commercial and industrial and leases 8,253 1,792 10,045 7,986 2,060 10,046 Other 119 218 337 118 173 291 Total commercial loans 62,024 8,997 71,021 64,171 10,389 74,560 Noncommercial Residential mortgage 37,111 10,582 47,693 37,903 9,621 47,524 Revolving mortgage 20,320 9,200 29,520 20,492 8,196 28,688 Construction and land development - 2,150 180 2,330 2,227 110 2,337 Consumer and other 2,106 847 2,953 2,300 721 3,021 Total noncommercial loans 61,687 20,809 82,496 62,922 18,648 81,570 Total loans $ 123,711 $ 29,806 $ 153,517 $ 127,093 $ 29,037 $ 156,130 The following table provides the types of TDRs made during the three months ended March 31, 2019 and March 31, 2018 , as well as a summary of loans that were modified as a TDR during the twelve month periods ended March 31, 2019 and March 31, 2018 that subsequently defaulted during the three months ended March 31, 2019 and March 31, 2018 . BancShares defines payment default as movement of the TDR to nonaccrual status, which is generally 90 days past due for TDRs, foreclosure or charge-off, whichever occurs first. Three months ended March 31, 2019 Three months ended March 31, 2018 All restructurings Restructurings with payment default All restructurings Restructurings with payment default (Dollars in thousands) Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Loans and leases Interest only — $ — — $ — 1 $ 644 — $ — Loan term extension 3 420 3 541 6 932 1 305 Below market interest rate 46 2,953 33 2,123 66 5,660 30 1,814 Discharged from bankruptcy 42 1,868 25 1,144 48 3,813 43 3,172 Total restructurings 91 $ 5,241 61 $ 3,808 121 $ 11,049 74 $ 5,291 For the three months ended March 31, 2019 and March 31, 2018 , the pre-modification and post-modification outstanding recorded investments of loans modified as TDRs were not materially different.

Other Real Estate Owned

Other Real Estate Owned	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
Real Estate Owned [Text Block]	NOTE F - OTHER REAL ESTATE OWNED (OREO) The following table explains changes in other real estate owned during the three months ended March 31, 2019 and March 31, 2018 . (Dollars in thousands) Total Balance at December 31, 2018 $ 48,030 Additions 3,133 Sales (6,934 ) Write-downs (923 ) Balance at March 31, 2019 $ 43,306 Balance at December 31, 2017 $ 51,097 Additions 6,582 Sales (7,997 ) Write-downs (1,593 ) Balance at March 31, 2018 $ 48,089 At March 31, 2019 and December 31, 2018 , BancShares had $15.4 million and $17.2 million , respectively, of foreclosed residential real estate property in OREO. The recorded investment in consumer mortgage loans collateralized by residential real estate property in the process of foreclosure was $23.9 million and $22.0 million at March 31, 2019 and December 31, 2018 , respectively.

FDIC Shared-Loss Receivable

FDIC Shared-Loss Receivable	3 Months Ended
	Mar. 31, 2019
FDIC Shared-Loss Receivable [Abstract]
FDIC Shared-Loss Receivable	FDIC SHARED-LOSS PAYABLE As of March 31, 2019 , shared-loss protection remains for single family residential loans acquired in the amount of $53.9 million . The shared-loss agreements for two FDIC-assisted transactions include provisions related to payments that may be owed to the FDIC at the termination of the agreements (clawback liability) . The clawback liability represents a payment by BancShares to the FDIC if actual cumulative losses on acquired covered assets are lower than the cumulative losses originally estimated by the FDIC at the time of acquisition and is recorded in the Consolidated Balance Sheets as a payable to the FDIC under the relevant shared-loss agreements. The clawback liability payment dates are March 2020 and March 2021. The following table provides changes in the FDIC shared-loss payable since December 31, 2018 : (Dollars in thousands) Total Balance at December 31, 2018 $ 105,618 Accretion 1,638 Balance at March 31, 2019 $ 107,256

Mortgage Servicing Rights

Mortgage Servicing Rights	3 Months Ended
	Mar. 31, 2019
Mortgage Servicing Rights [Abstract]
Transfers and Servicing of Financial Assets [Text Block]	Our portfolio of residential mortgage loans serviced for third parties was $2.97 billion and $2.95 billion as of March 31, 2019 and December 31, 2018 , respectively. These loans were originated by BancShares and sold to third parties on a non-recourse basis with servicing rights retained. The retained servicing rights are recorded as a servicing asset and reported in other intangible assets on the Consolidated Balance Sheets, while the associated amortization expense and any valuation allowance recognized is included as a reduction of mortgage income in the Consolidated Statements of Income. The mortgage servicing rights are initially recorded at fair value and then carried at the lower of amortized cost or fair value. Contractually specified mortgage servicing fees, late fees, and ancillary fees earned for the three months ended March 31, 2019 and 2018 were $1.9 million and reported in mortgage income in the Consolidated Statements of Income. The following table explains changes in the servicing asset during the three months ended March 31 , 2019 and 2018 . (Dollars in thousands) Total Balance at December 31, 2018 $ 21,396 Servicing rights originated 859 Amortization (1,447 ) Valuation allowance provision (161 ) Balance at March 31, 2019 $ 20,647 Balance at December 31, 2017 $ 21,945 Servicing rights originated 1,200 Amortization (1,486 ) Balance at March 31, 2018 $ 21,659 BancShares recorded a valuation allowance of $161.0 thousand compared to no valuation allowance for the three months ended March 31, 2019 and March 31, 2018, respectively. Valuation of mortgage servicing rights is performed using a pooling methodology. Similar loans are pooled together and evaluated on a discounted earnings basis to determine the present value of future earnings. Key economic assumptions used to value mortgage servicing rights were as follows: March 31, 2019 December 31, 2018 Discount rate - conventional fixed loans 9.41 % 9.69 % Discount rate - all loans excluding conventional fixed loans 10.41 % 10.69 % Weighted average constant prepayment rate 11.28 % 9.26 % Weighted average cost to service a loan $ 88.07 $ 87.52 The fair value of mortgage servicing rights is sensitive to changes in assumptions and is determined by estimating the present value of the asset's future cash flows by utilizing discount rates, prepayment rates, and other inputs. The discount rate is based on the 10-year U.S. Treasury rate plus 700 basis points for conventional fixed loans and 800 basis points for all other loans. The 700 and 800 basis points are used as a risk premium when calculating the discount rate. The prepayment rate is derived from the Public Securities Association Standard Prepayment model. Generally, as interest rates decline, mortgage loan prepayments accelerate due to increased refinance activity. This results in a decrease in fair value. The average cost to service a loan is based on the number of loans serviced and the total costs to service the loans. Other Servicing Rights Other servicing rights were acquired as part of a business combination and relate to the sale of the guaranteed portion of government guaranteed loans with servicing retained. The amount of the other servicing rights were $2.4 million and $2.7 million at March 31, 2019 and December 31, 2018 , respectively.

Repurchase Agreements

Repurchase Agreements	3 Months Ended
	Mar. 31, 2019
Repurchase Agreements [Abstract]
Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block]	REPURCHASE AGREEMENTS BancShares, through FCB, utilizes securities sold under customer repurchase agreements to facilitate the needs of customers and secure wholesale funding needs. Repurchase agreements are transactions whereby FCB offers to sell to a counterparty an undivided interest in an eligible security, and which obligates FCB to repurchase the security, with interest, at an agreed upon date, repurchase price, and interest rate. These agreements are recorded at the amount of cash received in connection with the transaction and are reflected as securities sold under customer repurchase agreements on the Consolidated Balance Sheets. Repurchase agreements require FCB to maintain collateral to support the outstanding obligations. BancShares monitors collateral levels on a continuous basis and maintains records of each transaction specifically describing the applicable security and the counterparty’s fractional interest in that security, and segregates the security from general assets in accordance with regulations governing custodial holdings of securities. The primary risk with repurchase agreements is market risk associated with the investments securing the transactions, as additional collateral may be required based on fair value changes of the underlying investments. Securities pledged as collateral under repurchase agreements are maintained with safekeeping agents. The carrying value of investment securities pledged as collateral under repurchase agreements was $571.6 million and $598.6 million at March 31, 2019 and December 31, 2018 , respectively. The remaining contractual maturity of the $508.5 million and $543.9 million securities sold under repurchase agreements at March 31, 2019 and December 31, 2018 , respectively, is overnight and continuous and are pledged by U.S. Treasury securities.

Estimated Fair Values

Estimated Fair Values	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Estimated Fair Values	ESTIMATED FAIR VALUES Fair value estimates are intended to represent the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. Where there is no active market for a financial instrument, BancShares has made estimates using discounted cash flows or other valuation techniques. Inputs used in these valuation techniques are subjective in nature, involve uncertainties and require significant judgment and therefore can only be derived within a range of precision. Accordingly, the derived fair value estimates presented below are not necessarily indicative of the amounts BancShares would realize in a current market exchange. ASC 820, Fair Value Measurements and Disclosures , indicates that assets and liabilities are recorded at fair value according to a fair value hierarchy comprised of three levels. The levels are based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. The level within the fair value hierarchy for an asset or liability is based on the highest level of input that is significant to the fair value measurement (with Level 1 considered highest and Level 3 considered lowest). A brief description of each level follows: • Level 1 values are based on quoted prices for identical instruments in active markets. • Level 2 values are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market. • Level 3 values are derived from valuation techniques in which one or more significant inputs or assumptions are not observable in the market. These unobservable inputs and assumptions reflect estimates that market participants would use in pricing the asset or liability. Valuation techniques include the use of discounted cash flow models and similar techniques. BancShares' management reviews any changes to its valuation methodologies to ensure they are appropriate and supportable, and refines valuation methodologies as more market-based data becomes available. Transfers between levels of the fair value hierarchy are recognized at the end of the reporting period. The methodologies used to estimate the fair value of financial assets and financial liabilities are discussed below: Investment securities available for sale . Investment securities available for sale are carried at fair value. U.S. Treasury, government agency and mortgage-backed securities are generally measured at fair value using a third party pricing service. The third party provider evaluates securities based on comparable investments with trades and market data and will utilize pricing models that use a variety of inputs, such as benchmark yields, reported trades, broker-dealer quotes, issuer spreads, benchmark securities, bids and offers as needed. These securities are generally classified as Level 2. Corporate bonds and trust preferred securities are generally measured at fair value based on indicative bids from broker-dealers and are not directly observable. These securities are considered Level 3. Investment in marketable equity securities. Equity securities are measured at fair value using observable closing prices and the valuation also considers the amount of market activity by examining the trade volume of each security. Equity securities are classified as Level 1 if they are traded in an active market and as Level 2 if the observable closing price is from a less than active market. Loans held for sale. Certain residential real estate loans that are originated to be sold to investors are carried at fair value based on quoted market prices for similar types of loans. Accordingly, the inputs used to calculate fair value of originated residential real estate loans held for sale are classified as Level 2 inputs. Portfolio loans that are subsequently transferred to held for sale to be sold in the secondary market are carried at the lower of amortized cost or fair value. The fair value of the transferred portfolio loans is based on the quoted prices and is considered a Level 1 input. Net loans and leases (PCI and Non-PCI). Fair value is estimated based on discounted future cash flows using the current interest rates at which loans with similar terms would be made to borrowers of similar credit quality. The inputs used in the fair value measurements for loans and leases are considered Level 3 inputs. FHLB stock . The carrying amount of FHLB stock is a reasonable estimate of fair value as these securities are not readily marketable and are evaluated for impairment based on the ultimate recoverability of the par value. BancShares considers positive and negative evidence, including the profitability and asset quality of the issuer, dividend payment history and recent redemption experience, when determining the ultimate recoverability of the par value. BancShares believes its investment in FHLB stock is ultimately recoverable at par. The inputs used in the fair value measurement for the FHLB stock are considered Level 2 inputs. Mortgage and other servicing rights. Mortgage and other servicing rights are carried at the lower of amortized cost or market and are, therefore, carried at fair value only when fair value is less than the amortized cost. The fair value of mortgage and other servicing rights is performed using a pooling methodology. Similar loans are pooled together and a model that relies on discount rates, estimates of prepayment rates and the weighted average cost to service the loans is used to determine the fair value. The inputs used in the fair value measurement for mortgage and other servicing rights are considered Level 3 inputs. Deposits. For non-time deposits, carrying value is a reasonable estimate of fair value. The fair value of time deposits is estimated by discounting future cash flows using the interest rates currently offered for deposits of similar remaining maturities. The inputs used in the fair value measurement for deposits are considered Level 2 inputs. Borrowings. For borrowings, the fair values are determined based on recent trades or sales of the actual security if available, otherwise, fair values are estimated by discounting future cash flows using current interest rates for similar financial instruments. The inputs used in the fair value measurement for long-term borrowings are considered Level 2 inputs. Payable to the FDIC for shared-loss agreements. The fair value of the payable to the FDIC for shared-loss agreements is determined by the projected cash flows based on expected payments to the FDIC in accordance with the shared-loss agreements. Cash flows are discounted using current discount rates to reflect the timing of the estimated amounts due to the FDIC. The inputs used in the fair value measurement for the payable to the FDIC are considered Level 3 inputs. Off-balance-sheet commitments and contingencies. Carrying amounts are reasonable estimates of the fair values for such financial instruments. Carrying amounts include unamortized fee income and, in some cases, reserves for any credit losses from those financial instruments. These amounts are not material to BancShares' financial position. For all other financial assets and financial liabilities, the carrying value is a reasonable estimate of the fair value as of March 31, 2019 and December 31, 2018. The carrying value and fair value for these assets and liabilities are equivalent because they are relatively short term in nature and there is no interest rate or credit risk that would cause the fair value to differ from the carrying value. Cash and due from banks is classified on the fair value hierarchy as Level 1. Overnight investments, income earned not collected, securities sold under customer repurchase agreements, and accrued interest payable are considered Level 2. The table presents the carrying values and estimated fair values for financial instruments as of March 31, 2019 and December 31, 2018 . (Dollars in thousands) March 31, 2019 December 31, 2018 Carrying value Fair value Carrying value Fair value Cash and due from banks $ 268,599 $ 268,599 $ 327,440 $ 327,440 Overnight investments 1,386,525 1,386,525 797,406 797,406 Investment securities available for sale 4,589,800 4,589,800 4,557,110 4,557,110 Investment securities held to maturity 2,214,829 2,254,924 2,184,653 2,201,502 Investment in marketable equity securities 109,884 109,884 92,599 92,599 Loans held for sale 53,232 53,232 45,505 45,505 Net loans and leases 25,235,010 25,187,938 25,299,564 24,845,060 Income earned not collected 113,812 113,812 109,903 109,903 Federal Home Loan Bank stock 25,174 25,174 25,304 25,304 Mortgage and other servicing rights 24,080 25,769 24,615 27,435 Deposits 31,198,093 31,174,142 30,672,460 30,623,214 Securities sold under customer repurchase agreements 508,508 508,508 543,936 543,936 Federal Home Loan Bank borrowings 189,594 192,779 193,556 195,374 Subordinated debentures 136,544 140,676 140,741 151,670 Other borrowings 14,970 14,833 13,921 13,985 FDIC shared-loss payable 107,256 109,947 105,618 105,846 Accrued interest payable 7,169 7,169 3,712 3,712 Among BancShares' assets and liabilities, investment securities available for sale, marketable equity securities and loans held for sale are reported at their fair values on a recurring basis. For assets and liabilities carried at fair value on a recurring basis, the following table provides fair value information as of March 31, 2019 and December 31, 2018 . March 31, 2019 Fair value measurements using: (Dollars in thousands) Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets measured at fair value Investment securities available for sale U.S. Treasury $ 1,197,042 $ — $ 1,197,042 $ — Government agency 350,527 — 350,527 — Mortgage-backed securities 2,895,944 — 2,895,944 — Corporate bonds 142,162 — — 142,162 Other 4,125 — — 4,125 Total investment securities available for sale $ 4,589,800 $ — $ 4,443,513 $ 146,287 Marketable equity securities $ 109,884 $ 18,250 $ 91,634 $ — Loans held for sale $ 53,232 $ — $ 53,232 $ — December 31, 2018 Fair value measurements using: Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets measured at fair value Investment securities available for sale U.S. Treasury $ 1,247,710 $ — $ 1,247,710 $ — Government agency 256,835 — 256,835 — Mortgage-backed securities 2,909,339 — 2,909,339 — Corporate bonds 139,101 — — 139,101 Other 4,125 — — 4,125 Total investment securities available for sale $ 4,557,110 $ — $ 4,413,884 $ 143,226 Marketable equity securities $ 92,599 $ 17,887 $ 74,712 $ — Loans held for sale $ 45,505 $ — $ 45,505 $ — During the three months ended March 31, 2019 , there were no transfers between levels. For the three months ended March 31, 2018 there were transfers from Level 2 to Level 3 of $59.7 million and $5.6 million for corporate bonds and other investment securities available for sale, respectively. The transfers were due to a lack of observable inputs and trade activity for those securities. The following tables summarize activity for Level 3 assets: Three months ended March 31, 2019 (Dollars in thousands) Corporate bonds Other Balance at January 1, 2019 $ 139,101 $ 4,125 Transfers in — — Amounts included in net income 39 6 Unrealized net gains (losses) included in other comprehensive income 22 (6 ) Purchases 3,000 — Sales / Calls — — Balance at March 31, 2019 $ 142,162 $ 4,125 The following table presents quantitative information about Level 3 fair value measurements for fair value on a recurring basis at March 31, 2019 . (Dollars in thousands) March 31, 2019 Level 3 assets Valuation technique Significant unobservable input Fair Value Corporate bonds Indicative bid provided by broker Multiple factors, including but not limited to, current operations, financial condition, cash flows, and recently executed financing transactions related to the company $ 142,162 Other Indicative bid provided by broker Multiple factors, including but not limited to, current operations, financial condition, cash flows, and recently executed financing transactions related to the company 4,125 Fair Value Option BancShares has elected the fair value option for residential real estate loans originated to be sold. This election reduces certain timing differences in the Consolidated Statement of Income and better aligns with the management of the portfolio from a business perspective. The changes in fair value are recorded as a component of mortgage income and included a gain of $249 thousand and a loss of $455 thousand for the three months ended March 31, 2019 and March 31, 2018 , respectively. The following table summarizes the difference between the aggregate fair value and the aggregate unpaid principal balance for residential real estate originated for sale measured at fair value as of March 31, 2019 and December 31, 2018 . March 31, 2019 (Dollars in thousands) Fair Value Aggregate Unpaid Principal Balance Difference Originated loans held for sale $ 53,232 $ 51,550 $ 1,682 December 31, 2018 Fair Value Aggregate Unpaid Principal Balance Difference Originated loans held for sale $ 45,505 $ 44,073 $ 1,432 No originated loans held for sale were 90 or more days past due or on nonaccrual status as of March 31, 2019 or December 31, 2018 . We may be required to measure certain financial assets at fair value on a nonrecurring basis. These adjustments to fair value usually result from the application of lower of amortized cost or fair value accounting or write-downs of individual assets due to impairment. Impaired loans are deemed to be at fair value if an associated allowance or current period charge-off has been recorded. The value of impaired loans is determined by either collateral valuations or discounted present value of the expected cash flow calculations. Collateral values are determined using appraisals or other third-party value estimates of the subject property with discounts generally between 6% and 11% applied for estimated selling costs and other external factors that may impact the marketability of the property. Expected cash flows are determined using expected payment information at the individual loan level, discounted using the effective interest rate. The effective interest rate generally ranges between 2% and 18% . OREO acquired or written down within the previous 12 months is deemed to be at fair value. Asset valuations are determined by using appraisals or other third-party value estimates of the subject property with discounts generally between 6% and 11% applied for estimated selling costs and other external factors that may impact the marketability of the property. Changes to the value of the assets between scheduled valuation dates are monitored through continued communication with brokers and monthly reviews by the asset manager assigned to each asset. If there are any significant changes in the market or the subject property, valuations are adjusted or new appraisals ordered to ensure the reported values reflect the most current information. For financial assets and liabilities carried at fair value on a nonrecurring basis, the following table provides fair value information as of March 31, 2019 and December 31, 2018 . March 31, 2019 Fair value measurements using: (Dollars in thousands) Fair value Level 1 inputs Level 2 inputs Level 3 inputs Impaired loans $ 110,411 $ — $ — $ 110,411 Other real estate remeasured during the previous 12 months 32,620 — — 32,620 December 31, 2018 Fair value measurements using: Fair value Level 1 inputs Level 2 inputs Level 3 inputs Impaired loans $ 105,994 $ — $ — $ 105,994 Other real estate remeasured during the previous 12 months 35,344 — — 35,344 No financial liabilities were carried at fair value on a nonrecurring basis as of March 31, 2019 and December 31, 2018 .

Employee Benefit Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2019
Retirement Benefits, Description [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS BancShares sponsors noncontributory defined benefit pension plans for its qualifying employees (BancShares Plan) and former First Citizens Bancorporation, Inc. employees (Bancorporation Plan). The service cost component of net periodic benefit cost is included in salaries and wages while all other non-service cost components are included in other noninterest expense. BancShares Plan For the three months ended March 31, 2019 and 2018 , the components of net periodic benefit cost are as follows: Three months ended March 31 (Dollars in thousands) 2019 2018 Service cost $ 2,568 $ 3,429 Interest cost 7,531 7,057 Expected return on assets (12,867 ) (11,957 ) Amortization of prior service cost 14 20 Amortization of net actuarial loss 2,114 3,246 Net periodic (benefit) cost $ (640 ) $ 1,795 Bancorporation Plan For the three months ended March 31, 2019 and 2018 , the components of net periodic benefit cost are as follows: Three months ended March 31 (Dollars in thousands) 2019 2018 Service cost $ 545 $ 662 Interest cost 1,760 1,587 Expected return on assets (2,768 ) (3,106 ) Amortization of net actuarial loss 627 71 Net periodic cost (benefit) $ 164 $ (786 ) No discretionary contributions were made during the three months ended March 31, 2019 to the BancShares or Bancorporation pension plans. Management evaluates the need for its pension plan contributions on a periodic basis based upon numerous factors including, but not limited to, the funded status of and returns on the pension plans, discount rates and the current economic environment.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES To meet the financing needs of its customers, BancShares and its subsidiaries have financial instruments with off-balance sheet risk. These financial instruments include commitments to extend credit, standby letters of credit and recourse obligations on mortgage loans sold. These instruments involve elements of credit, interest rate or liquidity risk. Commitments to extend credit are legally binding agreements to lend to customers. Commitments generally have fixed expiration dates or other termination clauses and may require payment of fees. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future liquidity requirements. Established credit standards control the credit risk exposure associated with these commitments. In some cases, BancShares requires that collateral be pledged to secure the commitment, including cash deposits, securities and other assets. Standby letters of credit are commitments guaranteeing performance of a customer to a third party. Those commitments are primarily issued to support public and private borrowing arrangements, and the fair value of those commitments is not material. To mitigate its risk, BancShares’ credit policies govern the issuance of standby letters of credit. The credit risk related to the issuance of these letters of credit is essentially the same as that involved in extending loans to clients and, therefore, these letters of credit are collateralized when necessary. The following table presents the commitments to extend credit and unfunded commitments as of March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 Unused commitments to extend credit $ 10,187,550 $ 10,054,712 Standby letters of credit 91,719 96,467 Unfunded commitments for investments in affordable housing projects 72,002 67,952 Affordable housing project investments were $152.9 million and $147.3 million as of March 31, 2019 and December 31, 2018 , respectively, and are included in other assets on the Consolidated Balance Sheets. BancShares and various subsidiaries have been named as defendants in legal actions arising from their normal business activities in which damages in various amounts are claimed. BancShares is also exposed to litigation risk relating to the prior business activities of banks from which assets were acquired and liabilities assumed in the various merger transactions. Although the amount of any ultimate liability with respect to such matters cannot be determined, in the opinion of management, any such liability will not have a material effect on BancShares’ consolidated financial statements.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss	ACCUMULATED OTHER COMPREHENSIVE LOSS Accumulated other comprehensive loss included the following as of March 31, 2019 and December 31, 2018 : March 31, 2019 December 31, 2018 (Dollars in thousands) Accumulated other comprehensive loss Deferred tax benefit Accumulated other comprehensive loss, net of tax Accumulated other comprehensive loss Deferred tax benefit Accumulated other comprehensive loss, net of tax Unrealized losses on securities available for sale $ (21,936 ) $ (5,046 ) $ (16,890 ) $ (50,007 ) $ (11,502 ) $ (38,505 ) Unrealized losses on securities available for sale transferred to held to maturity (86,439 ) (19,881 ) (66,558 ) (92,401 ) (21,252 ) (71,149 ) Defined benefit pension items (160,275 ) (36,863 ) (123,412 ) (163,030 ) (37,497 ) (125,533 ) Total $ (268,650 ) $ (61,790 ) $ (206,860 ) $ (305,438 ) $ (70,251 ) $ (235,187 ) The following table highlights changes in accumulated other comprehensive (loss) income by component for the three months ended March 31, 2019 and March 31, 2018 : Three months ended March 31, 2019 (Dollars in thousands) Unrealized (losses) gains on securities available for sale (1) Unrealized losses on securities available for sale transferred to held to maturity (1) Defined benefit pension items (1) Total Beginning balance $ (38,505 ) $ (71,149 ) $ (125,533 ) $ (235,187 ) Cumulative effect adjustments — — — — Net unrealized gains arising during period 21,615 — — 21,615 Amounts reclassified from accumulated other comprehensive loss — 4,591 2,121 6,712 Net current period other comprehensive income 21,615 4,591 2,121 28,327 Ending balance $ (16,890 ) $ (66,558 ) $ (123,412 ) $ (206,860 ) Three months ended March 31, 2018 Unrealized (losses) gains on securities available for sale (1) Unrealized losses on securities available for sale transferred to held to maturity (1) Defined benefit pension items (1) Total Beginning balance $ (30,945 ) $ — $ (91,349 ) $ (122,294 ) Cumulative effect adjustments (29,751 ) — (20,300 ) (50,051 ) Net unrealized (losses) arising during period (60,547 ) — — (60,547 ) Amounts reclassified from accumulated other comprehensive loss — — 2,569 2,569 Net current period other comprehensive (loss) income (60,547 ) — 2,569 (57,978 ) Ending balance $ (121,243 ) $ — $ (109,080 ) $ (230,323 ) (1) All amounts are net of tax. Amounts in parentheses indicate debits. The following table presents the amounts reclassified from accumulated other comprehensive (loss) income and the line item affected in the statement where net income is presented for the three months ended March 31, 2019 and March 31, 2018 . Three months ended March 31, 2019 (Dollars in thousands) Details about accumulated other comprehensive (loss) income Amounts reclassified from accumulated other comprehensive (loss) income (1) Affected line item in the statement where net income is presented Amortization of unrealized losses on securities available for sale transferred to held to maturity $ (5,962 ) Net interest income 1,371 Income taxes $ (4,591 ) Net Income Amortization of defined benefit pension items Prior service costs $ (14 ) Salaries and wages Actuarial losses (2,741 ) Other (2,755 ) Income before income taxes 634 Income taxes $ (2,121 ) Net income Total reclassifications for the period $ (6,712 ) Three months ended March 31, 2018 Details about accumulated other comprehensive (loss) income Amounts reclassified from accumulated other comprehensive (loss) income (1) Affected line item in the statement where net income is presented Amortization of defined benefit pension items Prior service costs $ (20 ) Salaries and wages Actuarial losses (3,317 ) Other (3,337 ) Income before income taxes 768 Income taxes $ (2,569 ) Net income Total reclassifications for the period $ (2,569 ) (1) Amounts in parentheses indicate debits to profit/loss.

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	LEASES BancShares leases certain branch locations, administrative offices and equipment. Operating leases are included in other assets and other liabilities on the Consolidated Balance Sheets. Finance leases are included in premises and equipment and other borrowings on the Consolidated Balance Sheets. Leases with an initial term of 12 months or less are not recorded on the Consolidated Balance Sheets; we instead recognize lease expense for these leases on a straight-line basis over the lease term. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our corresponding obligation to make lease payments arising from the lease. Operating and finance lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The operating and finance lease ROU asset also includes initial direct costs and pre-paid lease payments made, excluding lease incentives. As most of our leases do not provide an implicit rate, BancShares uses its incremental borrowing rate, based on the information available at commencement date in determining the present value of lease payments. BancShares determines the incremental borrowing rate using secured rates for FHLB new advances under similar terms as the lease at inception. BancShares used the incremental borrowing rate on January 1, 2019, for operating leases that commenced prior to that date. Most leases include one or more options to renew, with renewal terms that can extend the lease term from 1 to 25 years . The exercise of lease renewal options is at our sole discretion. When it is reasonably certain that we will exercise our option to renew or extend the lease term, that option is included in determining the value of the ROU and lease liability. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. We determine if an arrangement is a lease at inception and our lease agreements do not contain any material residual value guarantees or material restrictive covenants. We have no related party lease agreements. As of March 31, 2019, there are no leases that have not yet commenced that would have a material impact on our Consolidated Financial Statements. We rent or sublease certain real estate to third parties to manage occupancy costs and provide flexibility to expand and contract occupancy space to meet our business needs. The following table presents lease assets and liabilities as of March 31, 2019 . (Dollars in thousands) Classification March 31, 2019 Assets: Operating Other assets $ 70,815 Finance Premises and equipment 8,763 Total leased assets $ 79,578 Liabilities: Operating Other liabilities 72,315 Finance Other borrowings 7,828 Total lease liabilities $ 80,143 The following table presents lease costs for the three months ended March 31, 2019 . Variable lease cost primarily represents variable payments such as common area maintenance and utilities that are recognized in the period in which the expense is incurred. Certain of our lease agreements also include rental payments that are adjusted periodically for inflation. While lease liabilities are not remeasured as a result of these changes, these adjustments are treated as a variable lease cost and recognized in the period in which the expense is incurred. (Dollars in thousands) Classification Three months ended March 31, 2019 Lease cost: Operating lease cost (1) Occupancy expense $ 3,204 Finance lease cost: Amortization of leased assets Equipment expense 447 Interest on lease liabilities Interest Expense - Other borrowings 65 Variable lease cost Occupancy expense 528 Sublease income Occupancy expense (130 ) Net lease cost $ 4,114 (1) Operating lease cost includes short-term lease cost, which is immaterial. The following table presents lease liability maturities in the next five years and thereafter. (Dollars in thousands) Operating Leases Finance Leases Total 2019 (1) $ 10,310 $ 1,301 $ 11,611 2020 12,475 1,748 14,223 2021 10,947 1,764 12,711 2022 9,575 1,481 11,056 2023 7,772 599 8,371 Thereafter 35,343 1,683 37,026 Total lease payments $ 86,422 $ 8,576 $ 94,998 Less: Interest 14,107 748 14,855 Present value of lease liabilities $ 72,315 $ 7,828 $ 80,143 (1) Represents the lease liability payments that will be made for the period April 1, 2019 through December 31, 2019. The following table presents the remaining weighted average lease terms and discount rates as of March 31, 2019 . Weighted average remaining lease term (years): March 31, 2019 Operating 9.7 Finance 5.4 Weighted average discount rate: Operating 3.36 % Finance 3.22 The following table presents supplemental cash flow information related to leases for the three months ended March 31, 2019 . (Dollars in thousands) March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,550 Operating cash flows from finance leases 65 Financing cash flows from finance leases 366 Right-of-use assets obtained in exchange for new operating lease liabilities 3,591 Right-of-use assets obtained in exchange for new finance lease liabilities —
Leases	LEASES BancShares leases certain branch locations, administrative offices and equipment. Operating leases are included in other assets and other liabilities on the Consolidated Balance Sheets. Finance leases are included in premises and equipment and other borrowings on the Consolidated Balance Sheets. Leases with an initial term of 12 months or less are not recorded on the Consolidated Balance Sheets; we instead recognize lease expense for these leases on a straight-line basis over the lease term. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our corresponding obligation to make lease payments arising from the lease. Operating and finance lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The operating and finance lease ROU asset also includes initial direct costs and pre-paid lease payments made, excluding lease incentives. As most of our leases do not provide an implicit rate, BancShares uses its incremental borrowing rate, based on the information available at commencement date in determining the present value of lease payments. BancShares determines the incremental borrowing rate using secured rates for FHLB new advances under similar terms as the lease at inception. BancShares used the incremental borrowing rate on January 1, 2019, for operating leases that commenced prior to that date. Most leases include one or more options to renew, with renewal terms that can extend the lease term from 1 to 25 years . The exercise of lease renewal options is at our sole discretion. When it is reasonably certain that we will exercise our option to renew or extend the lease term, that option is included in determining the value of the ROU and lease liability. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. We determine if an arrangement is a lease at inception and our lease agreements do not contain any material residual value guarantees or material restrictive covenants. We have no related party lease agreements. As of March 31, 2019, there are no leases that have not yet commenced that would have a material impact on our Consolidated Financial Statements. We rent or sublease certain real estate to third parties to manage occupancy costs and provide flexibility to expand and contract occupancy space to meet our business needs. The following table presents lease assets and liabilities as of March 31, 2019 . (Dollars in thousands) Classification March 31, 2019 Assets: Operating Other assets $ 70,815 Finance Premises and equipment 8,763 Total leased assets $ 79,578 Liabilities: Operating Other liabilities 72,315 Finance Other borrowings 7,828 Total lease liabilities $ 80,143 The following table presents lease costs for the three months ended March 31, 2019 . Variable lease cost primarily represents variable payments such as common area maintenance and utilities that are recognized in the period in which the expense is incurred. Certain of our lease agreements also include rental payments that are adjusted periodically for inflation. While lease liabilities are not remeasured as a result of these changes, these adjustments are treated as a variable lease cost and recognized in the period in which the expense is incurred. (Dollars in thousands) Classification Three months ended March 31, 2019 Lease cost: Operating lease cost (1) Occupancy expense $ 3,204 Finance lease cost: Amortization of leased assets Equipment expense 447 Interest on lease liabilities Interest Expense - Other borrowings 65 Variable lease cost Occupancy expense 528 Sublease income Occupancy expense (130 ) Net lease cost $ 4,114 (1) Operating lease cost includes short-term lease cost, which is immaterial. The following table presents lease liability maturities in the next five years and thereafter. (Dollars in thousands) Operating Leases Finance Leases Total 2019 (1) $ 10,310 $ 1,301 $ 11,611 2020 12,475 1,748 14,223 2021 10,947 1,764 12,711 2022 9,575 1,481 11,056 2023 7,772 599 8,371 Thereafter 35,343 1,683 37,026 Total lease payments $ 86,422 $ 8,576 $ 94,998 Less: Interest 14,107 748 14,855 Present value of lease liabilities $ 72,315 $ 7,828 $ 80,143 (1) Represents the lease liability payments that will be made for the period April 1, 2019 through December 31, 2019. The following table presents the remaining weighted average lease terms and discount rates as of March 31, 2019 . Weighted average remaining lease term (years): March 31, 2019 Operating 9.7 Finance 5.4 Weighted average discount rate: Operating 3.36 % Finance 3.22 The following table presents supplemental cash flow information related to leases for the three months ended March 31, 2019 . (Dollars in thousands) March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,550 Operating cash flows from finance leases 65 Financing cash flows from finance leases 366 Right-of-use assets obtained in exchange for new operating lease liabilities 3,591 Right-of-use assets obtained in exchange for new finance lease liabilities —

Accounting Policies and Basis_2

Accounting Policies and Basis of Presentation Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Reclassifications	Reclassifications In certain instances, amounts reported in prior years' consolidated financial statements have been reclassified to conform to the current financial statement presentation. Such reclassifications had no effect on previously reported cash flows, shareholders' equity or net income.
Use of Estimates	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported. Actual results could differ from those estimates. The estimates that BancShares considers significant are the allowance for loan and lease losses, fair value measurements, Federal Deposit Insurance Corporation (FDIC) shared-loss payable, pension plan assumptions, goodwill and other intangible assets and income taxes.
New Accounting Pronouncements	Recently Adopted Accounting Pronouncements Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) 2016-02, Leases (Topic 842) This ASU increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The key difference between prior standards and this ASU is the requirement for lessees to recognize all lease contracts on their balance sheet. This ASU requires lessees to classify leases as either operating or finance leases, which are substantially similar to the previous operating and capital leases classifications. The distinction between these two classifications under the new standard does not relate to balance sheet treatment, but relates to treatment in the statements of income and cash flows. Lessor guidance remains largely unchanged with the exception of how a lessor determines the appropriate lease classification for each lease to better align the lessor guidance with revised lessee classification guidance. We adopted this standard, as of January 1, 2019, using the effective date method that allows for entities to initially apply the new leases standard at the adoption date. In addition, we made several policy elections permitted under the transition guidance, which among other things, allowed us to carry forward the historical lease classification. We determined that most renewal options would not be reasonably determinable in estimating the expected lease term. We made the policy election available under Topic 842 to combine lease and non-lease components and applied this practical expedient to leases in effect prior to the date of adoption. We will continue to apply the practical expedient to all leases entered into going forward. The adoption of the new standard had an impact on our Consolidated Balance Sheet, with the recording of operating Right-of-Use (ROU) assets and operating lease liabilities of $70.7 million and $71.8 million , respectively. The operating lease liability includes a $1.1 million fair value adjustment for leases assumed in the acquisition of HomeBancorp, Inc. (HomeBancorp). In addition, at the adoption date we had finance lease ROU assets and finance lease liabilities, previously classified as capital leases, of $9.1 million and $8.3 million , respectively. The Company did not have a cumulative-effect adjustment to the opening balance of retained earnings at commencement. The Company has no related party lease agreements. This ASU did not have a material impact on our Consolidated Statements of Income. See Note N in the Consolidated Financial Statements for additional disclosures. FASB ASU 2019-01, Leases (Topic 842): Codification Improvements This ASU reinstated the exception in Topic 842 for lessors that are not manufacturers or dealers for determining the fair value of leased property as the underlying asset's cost, reflecting any volume or trade discounts that may apply, allows lessors that are depository and lending institutions within the scope of ASU Topic 942 to present "principal payments received under leases" within investing activities on the Statement of Cash Flows, and provides an exemption to the ASC 250-10-50-3 interim disclosure requirements in the Topic 842 transition disclosure requirements. We early adopted this standard with ASU 2016-02 as of January 1, 2019 and the impact was not material to our Consolidated Financial Statements. Recently Issued Accounting Pronouncements FASB ASU 2018-15 - Intangibles - Goodwill and Other - Internal Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract This ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include internal-use software license). This ASU requires entities to use the guidance in FASB ASC 350-40, Intangibles - Goodwill and Other - Internal Use Software, to determine whether to capitalize or expense implementation costs related to the service contract. This ASU also requires entities to (1) expense capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement (2) present the expense related to the capitalized implementation costs in the same line item on the income statement as fees associated with the hosting element of the arrangement (3) classify payments for capitalized implementation costs in the statement of cash flows in the same manner as payments made for fees associated with the hosting element (4) present the capitalized implementation costs in the same balance sheet line item that a prepayment for the fees associated with the hosting arrangement would be presented. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. BancShares is currently evaluating the impact this new standard will have on its Consolidated Financial Statements and whether we will early adopt prior to the first quarter of 2020. FASB ASU 2018-14 - Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans This ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans by eliminating the requirement to disclose the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year and adding a requirement to disclose an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The amendments in this ASU are effective for public entities for fiscal years ending after December 15, 2020. Early adoption is permitted for all entities. BancShares will adopt all applicable amendments and update the disclosures as appropriate during the first quarter of 2021. FASB ASU 2018-13 - Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement This ASU modifies the disclosure requirements on fair value measurements by eliminating the requirements to disclose (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy (2) the policy for timing of transfers between levels and (3) the valuation processes for Level 3 fair value measurements. This ASU also added specific disclosure requirements for fair value measurements for public business entities including the requirement to disclose the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendments in this ASU are effective for all entities for fiscal years beginning after December 15, 2019, and all interim periods within those fiscal years. Early adoption is permitted upon issuance of the ASU. Entities are permitted to early adopt amendments that remove or modify disclosures and delay the adoption of the additional disclosures until their effective date. BancShares will adopt all applicable amendments and update the disclosures as appropriate during the first quarter of 2020. FASB ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment This ASU eliminates Step 2 from the goodwill impairment test. Under Step 2, an entity had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, under the amendments in this ASU, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This ASU eliminates the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative test. This ASU will be effective for BancShares' annual or interim goodwill impairment tests for fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We expect to adopt the guidance for our annual impairment test in fiscal year 2020. BancShares does not anticipate any impact to our consolidated financial position or consolidated results of operations as a result of the adoption. FASB ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This ASU introduces a new credit loss methodology which requires earlier recognition of credit losses, replacing multiple existing impairment methods in current GAAP, which generally require that a loss be incurred before it is recognized. The amendments in this ASU require loss estimates be determined over the lifetime of the asset and broaden the information that an entity must consider in developing its expected credit losses. The ASU does not specify a method for measuring expected credit losses and allows an entity to apply methods that reasonably reflect its expectations of the credit loss estimate based on the entity's size, complexity and risk profile. In addition, the disclosures of credit quality indicators in relation to the amortized cost of financing receivables, a current disclosure requirement, are further disaggregated by year of origination. The amendments in this ASU are effective for public business entities for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for fiscal years beginning after December 15, 2018. BancShares will adopt the guidance in the first quarter of 2020 with a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. For BancShares, the standard will apply to loans, unfunded loan commitments and debt securities. A cross-functional team co-led by Corporate Finance and Risk Management is in place to implement the new standard. We have completed preliminary current expected credit losses (CECL) accounting interpretations, and continue to refine and test our models, estimation techniques, data, operational processes and controls to be used in preparing CECL loss estimates. During 2019, we expect to address any gaps in our interpretations, methodology, data and operational processes based upon our reviews and tests. BancShares continues to evaluate the impact of this standard on its consolidated financial statements but the magnitude of this impact has not been determined. The final impact will be dependent on, among other items, loan portfolio composition and credit quality at the adoption date, as well as economic conditions, financial models used and forecasts in place at that time.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2019
Investments [Abstract]
Aggregate Values And Unrealized Gains And Losses Of Investment Securities	The amortized cost and fair value of investment securities at March 31, 2019 and December 31, 2018 , were as follows: March 31, 2019 (Dollars in thousands) Cost Gross Gross unrealized Fair Investment securities available for sale U.S. Treasury $ 1,196,584 $ 1,305 $ 847 $ 1,197,042 Government agency 351,284 330 1,087 350,527 Mortgage-backed securities 2,917,000 7,373 28,429 2,895,944 Corporate bonds 142,939 183 960 142,162 Other 3,929 196 — 4,125 Total investment securities available for sale 4,611,736 9,387 31,323 4,589,800 Investment in marketable equity securities 79,809 30,252 177 109,884 Investment securities held to maturity Mortgage-backed securities 2,214,829 40,545 450 2,254,924 Total investment securities $ 6,906,374 $ 80,184 $ 31,950 $ 6,954,608 December 31, 2018 (Dollars in thousands) Cost Gross Gross unrealized Fair Investment securities available for sale U.S. Treasury $ 1,249,243 $ 633 $ 2,166 $ 1,247,710 Government agency 257,252 222 639 256,835 Mortgage-backed securities 2,956,793 5,309 52,763 2,909,339 Corporate bonds 139,906 59 864 139,101 Other 3,923 202 — 4,125 Total investment securities available for sale 4,607,117 6,425 56,432 4,557,110 Investment in marketable equity securities 73,809 19,010 220 92,599 Investment securities held to maturity Mortgage-backed securities 2,184,653 17,339 490 2,201,502 Total investment securities $ 6,865,579 $ 42,774 $ 57,142 $ 6,851,211
Investment Securities Maturity Information	The following table provides the amortized cost and fair value by contractual maturity for investment securities available for sale and held to maturity. Expected maturities will differ from contractual maturities on certain securities because borrowers and issuers may have the right to call or prepay obligations with or without prepayment penalties. Repayments of mortgage-backed securities are dependent on the repayments of the underlying loan balances, while repayments of certain corporate bonds are subject to call provisions that can be exercised by the issuer at their discretion. March 31, 2019 December 31, 2018 (Dollars in thousands) Cost Fair value Cost Fair value Investment securities available for sale Non-amortizing securities maturing in: One year or less $ 1,046,796 $ 1,046,362 $ 1,049,253 $ 1,047,380 One through five years 155,297 155,680 205,526 205,805 Five through 10 years 137,430 137,162 134,370 133,626 Over 10 years 3,929 4,125 3,923 4,125 Government agency 351,284 350,527 257,252 256,835 Mortgage-backed securities 2,917,000 2,895,944 2,956,793 2,909,339 Total investment securities available for sale $ 4,611,736 $ 4,589,800 $ 4,607,117 $ 4,557,110 Investment securities held to maturity Total investment securities held to maturity $ 2,214,829 $ 2,254,924 $ 2,184,653 $ 2,201,502
Marketable Securities Gains (Losses)	The following table provides the realized and unrealized gains on marketable equity securities for the three months ended March 31, 2019 . Three months ended March 31 (Dollars in thousands) 2019 2018 Marketable equity securities gains, net $ 11,328 $ 971 Less net gains recognized on marketable equity securities sold 44 96 Unrealized gains recognized on marketable equity securities held $ 11,284 $ 875
Investment Securities With Unrealized Losses	The following table provides information regarding securities with unrealized losses as of March 31, 2019 and December 31, 2018 . March 31, 2019 Less than 12 months 12 months or more Total (Dollars in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Investment securities available for sale U.S. Treasury $ — $ — $ 599,883 $ 847 $ 599,883 $ 847 Government agency 219,395 901 12,590 186 231,985 1,087 Mortgage-backed securities 114,863 314 1,956,003 28,115 2,070,866 28,429 Corporate bonds 56,393 891 9,950 69 66,343 960 Total $ 390,651 $ 2,106 $ 2,578,426 $ 29,217 $ 2,969,077 $ 31,323 Investment securities held to maturity Mortgage-backed securities $ 40,142 $ 291 $ 9,988 $ 159 $ 50,130 $ 450 December 31, 2018 Less than 12 months 12 months or more Total (Dollars in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Investment securities available for sale U.S. Treasury $ 248,983 $ 113 $ 848,622 $ 2,053 $ 1,097,605 $ 2,166 Government agency 115,273 601 2,310 38 117,583 639 Mortgage-backed securities 262,204 2,387 1,940,695 50,376 2,202,899 52,763 Corporate bonds 79,066 842 5,000 22 84,066 864 Total $ 705,526 $ 3,943 $ 2,796,627 $ 52,489 $ 3,502,153 $ 56,432 Investment securities held to maturity Mortgage-backed securities $ 5,111 $ 181 $ 10,131 $ 309 $ 15,242 $ 490
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	INVESTMENTS The amortized cost and fair value of investment securities at March 31, 2019 and December 31, 2018 , were as follows: March 31, 2019 (Dollars in thousands) Cost Gross Gross unrealized Fair Investment securities available for sale U.S. Treasury $ 1,196,584 $ 1,305 $ 847 $ 1,197,042 Government agency 351,284 330 1,087 350,527 Mortgage-backed securities 2,917,000 7,373 28,429 2,895,944 Corporate bonds 142,939 183 960 142,162 Other 3,929 196 — 4,125 Total investment securities available for sale 4,611,736 9,387 31,323 4,589,800 Investment in marketable equity securities 79,809 30,252 177 109,884 Investment securities held to maturity Mortgage-backed securities 2,214,829 40,545 450 2,254,924 Total investment securities $ 6,906,374 $ 80,184 $ 31,950 $ 6,954,608 December 31, 2018 (Dollars in thousands) Cost Gross Gross unrealized Fair Investment securities available for sale U.S. Treasury $ 1,249,243 $ 633 $ 2,166 $ 1,247,710 Government agency 257,252 222 639 256,835 Mortgage-backed securities 2,956,793 5,309 52,763 2,909,339 Corporate bonds 139,906 59 864 139,101 Other 3,923 202 — 4,125 Total investment securities available for sale 4,607,117 6,425 56,432 4,557,110 Investment in marketable equity securities 73,809 19,010 220 92,599 Investment securities held to maturity Mortgage-backed securities 2,184,653 17,339 490 2,201,502 Total investment securities $ 6,865,579 $ 42,774 $ 57,142 $ 6,851,211 Investments in mortgage-backed securities represent securities issued by the Government National Mortgage Association, Federal National Mortgage Association and Federal Home Loan Mortgage Corporation. Investments in government agency securities represent securities issued by the United States Small Business Administration. Investments in corporate bonds and marketable equity securities represent positions in securities of other financial institutions. Other investments include trust preferred securities of financial institutions. BancShares holds approximately 298,000 shares of Visa Class B common stock. BancShares' Visa Class B shares are not considered to have a readily determinable fair value and are included in the Consolidated Balance Sheet with no fair value. The following table provides the amortized cost and fair value by contractual maturity for investment securities available for sale and held to maturity. Expected maturities will differ from contractual maturities on certain securities because borrowers and issuers may have the right to call or prepay obligations with or without prepayment penalties. Repayments of mortgage-backed securities are dependent on the repayments of the underlying loan balances, while repayments of certain corporate bonds are subject to call provisions that can be exercised by the issuer at their discretion. March 31, 2019 December 31, 2018 (Dollars in thousands) Cost Fair value Cost Fair value Investment securities available for sale Non-amortizing securities maturing in: One year or less $ 1,046,796 $ 1,046,362 $ 1,049,253 $ 1,047,380 One through five years 155,297 155,680 205,526 205,805 Five through 10 years 137,430 137,162 134,370 133,626 Over 10 years 3,929 4,125 3,923 4,125 Government agency 351,284 350,527 257,252 256,835 Mortgage-backed securities 2,917,000 2,895,944 2,956,793 2,909,339 Total investment securities available for sale $ 4,611,736 $ 4,589,800 $ 4,607,117 $ 4,557,110 Investment securities held to maturity Total investment securities held to maturity $ 2,214,829 $ 2,254,924 $ 2,184,653 $ 2,201,502 There were no gross gains or losses on sales of investment securities available for sale for the three months ended March 31, 2019 and March 31, 2018 . The following table provides the realized and unrealized gains on marketable equity securities for the three months ended March 31, 2019 . Three months ended March 31 (Dollars in thousands) 2019 2018 Marketable equity securities gains, net $ 11,328 $ 971 Less net gains recognized on marketable equity securities sold 44 96 Unrealized gains recognized on marketable equity securities held $ 11,284 $ 875 The following table provides information regarding securities with unrealized losses as of March 31, 2019 and December 31, 2018 . March 31, 2019 Less than 12 months 12 months or more Total (Dollars in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Investment securities available for sale U.S. Treasury $ — $ — $ 599,883 $ 847 $ 599,883 $ 847 Government agency 219,395 901 12,590 186 231,985 1,087 Mortgage-backed securities 114,863 314 1,956,003 28,115 2,070,866 28,429 Corporate bonds 56,393 891 9,950 69 66,343 960 Total $ 390,651 $ 2,106 $ 2,578,426 $ 29,217 $ 2,969,077 $ 31,323 Investment securities held to maturity Mortgage-backed securities $ 40,142 $ 291 $ 9,988 $ 159 $ 50,130 $ 450 December 31, 2018 Less than 12 months 12 months or more Total (Dollars in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Investment securities available for sale U.S. Treasury $ 248,983 $ 113 $ 848,622 $ 2,053 $ 1,097,605 $ 2,166 Government agency 115,273 601 2,310 38 117,583 639 Mortgage-backed securities 262,204 2,387 1,940,695 50,376 2,202,899 52,763 Corporate bonds 79,066 842 5,000 22 84,066 864 Total $ 705,526 $ 3,943 $ 2,796,627 $ 52,489 $ 3,502,153 $ 56,432 Investment securities held to maturity Mortgage-backed securities $ 5,111 $ 181 $ 10,131 $ 309 $ 15,242 $ 490 As of March 31, 2019 , there were 230 investment securities available for sale that had continuous losses for more than 12 months of which 223 were government sponsored enterprise-issued mortgage-backed securities or government agency securities, five were U.S. Treasury securities and two were corporate bonds. There were two investment securities held to maturity, which were government sponsored enterprise-issued mortgage-backed securities, which had continuous losses for more than 12 months at March 31, 2019 . None of the unrealized losses identified as of March 31, 2019 or December 31, 2018 relate to the marketability of the securities or the issuers' ability to honor redemption obligations. Rather, the unrealized losses relate to changes in interest rates relative to when the debt securities were purchased. BancShares has the ability and intent to retain these securities for a period of time sufficient to recover all unrealized losses. Therefore, none of the securities were deemed to be other than temporarily impaired. Debt securities having an aggregate carrying value of $3.68 billion at March 31, 2019 and $4.03 billion at December 31, 2018 were pledged as collateral to secure public funds on deposit and certain short-term borrowings, and for other purposes as required by law.

Loans and Leases (Tables)

Loans and Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Loans And Leases Outstanding	Loans and leases outstanding included the following at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 Non-PCI loans and leases: Commercial: Construction and land development $ 804,463 $ 757,854 Commercial mortgage 10,747,715 10,717,234 Other commercial real estate 427,419 426,985 Commercial and industrial and leases 3,879,575 3,938,730 Other 280,848 296,424 Total commercial loans 16,140,020 16,137,227 Noncommercial: Residential mortgage 4,303,137 4,265,687 Revolving mortgage 2,469,898 2,542,975 Construction and land development 258,959 257,030 Consumer 1,734,415 1,713,781 Total noncommercial loans 8,766,409 8,779,473 Total non-PCI loans and leases 24,906,429 24,916,700 PCI loans: Total PCI loans 557,356 606,576 Total loans and leases $ 25,463,785 $ 25,523,276
Composition Of The Loans And Leases Outstanding By Credit Quality Indicator	March 31, 2019 and December 31, 2018 by credit quality indicator are provided below: March 31, 2019 (Dollars in thousands) Non-PCI commercial loans and leases Grade: Construction and Commercial mortgage Other commercial real estate Commercial and industrial and leases Other Total non-PCI commercial loans and leases Pass $ 800,703 $ 10,528,026 $ 423,288 $ 3,717,237 $ 279,899 $ 15,749,153 Special mention 1,345 110,413 3,244 46,928 350 162,280 Substandard 2,415 109,276 887 37,443 599 150,620 Doubtful — — — 354 — 354 Ungraded — — — 77,613 — 77,613 Total $ 804,463 $ 10,747,715 $ 427,419 $ 3,879,575 $ 280,848 $ 16,140,020 December 31, 2018 (Dollars in thousands) Non-PCI commercial loans and leases Grade: Construction and Commercial mortgage Other commercial real estate Commercial and industrial and leases Other Total non-PCI commercial loans and leases Pass $ 753,985 $ 10,507,687 $ 422,500 $ 3,778,797 $ 294,700 $ 15,757,669 Special mention 1,369 114,219 3,193 54,814 1,105 174,700 Substandard 2,500 92,743 1,292 30,688 619 127,842 Doubtful — — — 354 — 354 Ungraded — 2,585 — 74,077 — 76,662 Total $ 757,854 $ 10,717,234 $ 426,985 $ 3,938,730 $ 296,424 $ 16,137,227 March 31, 2019 Non-PCI noncommercial loans and leases (Dollars in thousands) Residential Revolving Construction Consumer Total non-PCI noncommercial loans and leases Current $ 4,248,823 $ 2,444,150 $ 256,801 $ 1,720,142 $ 8,669,916 30-59 days past due 33,623 10,734 581 7,966 52,904 60-89 days past due 7,760 4,227 28 3,001 15,016 90 days or greater past due 12,931 10,787 1,549 3,306 28,573 Total $ 4,303,137 $ 2,469,898 $ 258,959 $ 1,734,415 $ 8,766,409 December 31, 2018 Non-PCI noncommercial loans and leases (Dollars in thousands) Residential Revolving Construction Consumer Total non-PCI noncommercial loans and leases Current $ 4,214,783 $ 2,514,269 $ 254,837 $ 1,696,321 $ 8,680,210 30-59 days past due 28,239 12,585 581 10,035 51,440 60-89 days past due 7,357 4,490 21 3,904 15,772 90 days or greater past due 15,308 11,631 1,591 3,521 32,051 Total $ 4,265,687 $ 2,542,975 $ 257,030 $ 1,713,781 $ 8,779,473 PCI loans outstanding at March 31, 2019 and December 31, 2018 by credit quality indicator are provided below: March 31, 2019 December 31, 2018 (Dollars in thousands) PCI commercial loans Grade: Pass $ 131,018 $ 141,922 Special mention 43,068 48,475 Substandard 91,940 101,447 Doubtful 3,887 4,828 Total $ 269,913 $ 296,672 March 31, 2019 December 31, 2018 (Dollars in thousands) PCI noncommercial loans Current $ 255,145 $ 268,280 30-59 days past due 8,565 11,155 60-89 days past due 3,449 7,708 90 days or greater past due 20,284 22,761 Total $ 287,443 $ 309,904
Aging Of The Outstanding Loans And Leases By Class Excluding Loans Impaired At Acquisition Date	The aging of the outstanding non-PCI loans and leases, by class, at March 31, 2019 and December 31, 2018 are provided in the tables below. Loans and leases 30 days or less past due are considered current as various grace periods allow borrowers to make payments within a stated period after the due date and still remain in compliance with the loan agreement. March 31, 2019 (Dollars in thousands) 30-59 days 60-89 days 90 days or greater Total past Current Total loans Non-PCI loans and leases: Commercial: Construction and land development - commercial $ 617 $ 262 $ 206 $ 1,085 $ 803,378 $ 804,463 Commercial mortgage 16,120 8,818 2,802 27,740 10,719,975 10,747,715 Other commercial real estate 1,198 517 — 1,715 425,704 427,419 Commercial and industrial and leases 9,706 2,403 3,389 15,498 3,864,077 3,879,575 Other 113 24 — 137 280,711 280,848 Total commercial loans 27,754 12,024 6,397 46,175 16,093,845 16,140,020 Noncommercial: Residential mortgage 33,623 7,760 12,931 54,314 4,248,823 4,303,137 Revolving mortgage 10,734 4,227 10,787 25,748 2,444,150 2,469,898 Construction and land development - non-commercial 581 28 1,549 2,158 256,801 258,959 Consumer 7,966 3,001 3,306 14,273 1,720,142 1,734,415 Total noncommercial loans 52,904 15,016 28,573 96,493 8,669,916 8,766,409 Total non-PCI loans and leases $ 80,658 $ 27,040 $ 34,970 $ 142,668 $ 24,763,761 $ 24,906,429 December 31, 2018 (Dollars in thousands) 30-59 days 60-89 days 90 days or greater Total past Current Total loans Non-PCI loans and leases: Commercial: Construction and land development - commercial $ 516 $ 9 $ 444 $ 969 $ 756,885 $ 757,854 Commercial mortgage 14,200 2,066 3,237 19,503 10,697,731 10,717,234 Other commercial real estate 91 76 300 467 426,518 426,985 Commercial and industrial and leases 9,655 1,759 2,892 14,306 3,924,424 3,938,730 Other 285 — 89 374 296,050 296,424 Total commercial loans 24,747 3,910 6,962 35,619 16,101,608 16,137,227 Noncommercial: Residential mortgage 28,239 7,357 15,308 50,904 4,214,783 4,265,687 Revolving mortgage 12,585 4,490 11,631 28,706 2,514,269 2,542,975 Construction and land development - non-commercial 581 21 1,591 2,193 254,837 257,030 Consumer 10,035 3,904 3,521 17,460 1,696,321 1,713,781 Total noncommercial loans 51,440 15,772 32,051 99,263 8,680,210 8,779,473 Total non-PCI loans and leases $ 76,187 $ 19,682 $ 39,013 $ 134,882 $ 24,781,818 $ 24,916,700
Recorded Investment, By Class, In Loans And Leases On Nonaccrual Status And Loans And Leases Greater Than 90 Days Past Due And Still Accruing	The recorded investment, by class, in loans and leases on nonaccrual status, and loans and leases greater than 90 days past due and still accruing at March 31, 2019 and December 31, 2018 for non-PCI loans and leases, were as follows: March 31, 2019 December 31, 2018 (Dollars in thousands) Nonaccrual loans and leases Loans and leases > 90 days and accruing Nonaccrual loans and leases Loans and leases > 90 days and accruing Non-PCI loans and leases: Construction and land development - commercial $ 407 $ — $ 666 $ — Commercial mortgage 15,744 — 12,594 — Other commercial real estate 19 — 366 — Commercial and industrial and leases 5,482 667 4,624 808 Residential mortgage 36,573 614 35,662 — Revolving mortgage 25,723 — 25,563 — Construction and land development - noncommercial 1,699 — 1,823 — Consumer 3,054 2,212 2,969 2,080 Other 257 — 279 — Total non-PCI loans and leases $ 88,958 $ 3,493 $ 84,546 $ 2,888
Changes In Carrying Value Of PCI Loans	The following table provides changes in the carrying value of all PCI loans during the three months ended March 31, 2019 and March 31, 2018 : (Dollars in thousands) 2019 2018 Balance at January 1 $ 606,576 $ 762,998 Fair value of acquired loans — — Accretion 17,755 17,973 Payments received and other changes, net (66,975 ) (77,134 ) Balance at March 31 $ 557,356 $ 703,837 Unpaid principal balance at March 31 $ 810,683 $ 1,108,379
Changes in Carrying Value of Accretable Yield for PCI Loans	The following table documents changes to the amount of accretable yield for the first three months of 2019 and 2018 . (Dollars in thousands) 2019 2018 Balance at January 1 $ 312,894 $ 316,679 Additions from acquisitions — — Accretion (17,755 ) (17,973 ) Reclassifications from (to) nonaccretable difference 600 (929 ) Changes in expected cash flows that do not affect nonaccretable difference (9,547 ) 11,568 Balance at March 31 $ 286,192 $ 309,345

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses	for the three months ended March 31, 2019 and March 31, 2018 is summarized as follows: (Dollars in thousands) Three months ended March 31, 2019 Three months ended March 31, 2018 Allowance for loan losses: Balance at January 1 $ 9,144 $ 10,026 Provision (164 ) 2,354 Charge-offs — (84 ) Recoveries — — Balance at March 31 $ 8,980 $ 12,296 Three months ended March 31, 2019 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: Balance at January 1 $ 35,270 $ 43,451 $ 2,481 $ 55,620 $ 2,221 $ 15,472 $ 21,862 $ 2,350 $ 35,841 $ 214,568 Provision (credits) 2,119 2,371 (83 ) 2,725 (498 ) 1,508 209 123 3,440 11,914 Charge-offs (44 ) (761 ) — (1,858 ) — (166 ) (963 ) — (6,362 ) (10,154 ) Recoveries 131 220 1 538 444 173 387 — 1,573 3,467 Balance at March 31 $ 37,476 $ 45,281 $ 2,399 $ 57,025 $ 2,167 $ 16,987 $ 21,495 $ 2,473 $ 34,492 $ 219,795 Three months ended March 31, 2018 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Balance at January 1 $ 24,470 $ 45,005 $ 4,571 $ 59,824 $ 4,689 $ 15,706 $ 22,436 $ 3,962 $ 31,204 $ 211,867 Provision (credits) 2,225 (1,365 ) (1,293 ) 562 114 1,512 466 107 2,923 5,251 Charge-offs — (46 ) — (2,329 ) (3 ) (806 ) (992 ) (182 ) (5,255 ) (9,613 ) Recoveries 23 239 145 1,260 42 77 194 26 1,309 3,315 Balance at March 31 $ 26,718 $ 43,833 $ 3,423 $ 59,317 $ 4,842 $ 16,489 $ 22,104 $ 3,913 $ 30,181 $ 210,820 The following tables provide information on non-PCI impaired loans and leases, exclusive of loans and leases evaluated collectively as a homogeneous group, including interest income recognized in the period during which the loans and leases were considered impaired. March 31, 2019 (Dollars in thousands) With a With no Total Unpaid Related Non-PCI impaired loans and leases: Construction and land development - commercial $ 1,932 $ 191 $ 2,123 $ 2,538 $ 533 Commercial mortgage 37,575 18,582 56,157 61,845 2,949 Other commercial real estate 222 319 541 629 16 Commercial and industrial and leases 7,613 2,374 9,987 14,002 1,420 Other 262 75 337 353 151 Residential mortgage 43,553 1,391 44,944 48,216 3,149 Revolving mortgage 26,017 3,199 29,216 32,074 2,742 Construction and land development - noncommercial 2,330 1,412 3,742 4,045 99 Consumer 2,872 82 2,954 3,378 906 Total non-PCI impaired loans and leases $ 122,376 $ 27,625 $ 150,001 $ 167,080 $ 11,965 December 31, 2018 (Dollars in thousands) With a With no Total Unpaid Related Non-PCI impaired loans and leases: Construction and land development - commercial $ 1,897 $ 278 $ 2,175 $ 2,606 $ 490 Commercial mortgage 34,177 21,270 55,447 61,317 2,671 Other commercial real estate 243 617 860 946 42 Commercial and industrial and leases 7,153 2,715 9,868 14,695 1,137 Other 216 75 291 301 105 Residential mortgage 40,359 1,809 42,168 45,226 1,901 Revolving mortgage 25,751 3,101 28,852 31,371 2,515 Construction and land development - noncommercial 2,337 1,412 3,749 4,035 81 Consumer 2,940 80 3,020 3,405 885 Total non-PCI impaired loans and leases $ 115,073 $ 31,357 $ 146,430 $ 163,902 $ 9,827 Non-PCI impaired loans less than $500,000 that were collectively evaluated for impairment totaled $44.8 million and $47.1 million at March 31, 2019 and December 31, 2018 , respectively. The following tables show the average non-PCI impaired loan balance and the interest income recognized by loan class for the three months ended March 31, 2019 and March 31, 2018 : Three months ended March 31, 2019 Three months ended March 31, 2018 (Dollars in thousands) Average Interest income recognized Average Interest income recognized Non-PCI impaired loans and leases: Construction and land development - commercial $ 2,147 $ 28 $ 1,155 $ 11 Commercial mortgage 56,629 564 72,267 711 Other commercial real estate 685 8 1,713 11 Commercial and industrial and leases 10,000 100 9,762 87 Other 315 2 — — Residential mortgage 42,626 325 38,724 275 Revolving mortgage 28,742 247 24,792 201 Construction and land development - noncommercial 3,747 36 4,104 48 Consumer 3,000 29 2,508 28 Total non-PCI impaired loans and leases $ 147,891 $ 1,339 $ 155,025 $ 1,372
Allocation of Allowance for Loan and Lease Losses	The following table presents the PCI allowance and recorded investment in loans at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 ALLL for loans acquired with deteriorated credit quality $ 8,980 $ 9,144 Loans acquired with deteriorated credit quality 557,356 606,576 The following tables present the allowance and recorded investment in loans and leases by class of loans, as well as the associated impairment method at March 31, 2019 and December 31, 2018 : March 31, 2019 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: ALLL for loans and leases individually evaluated for impairment $ 533 $ 2,949 $ 16 $ 1,420 $ 151 $ 3,149 $ 2,742 $ 99 $ 906 $ 11,965 ALLL for loans and leases collectively evaluated for impairment 36,943 42,332 2,383 55,605 2,016 13,838 18,753 2,374 33,586 207,830 Total allowance for loan and lease losses $ 37,476 $ 45,281 $ 2,399 $ 57,025 $ 2,167 $ 16,987 $ 21,495 $ 2,473 $ 34,492 $ 219,795 Loans and leases: Loans and leases individually evaluated for impairment $ 2,123 $ 56,157 $ 541 $ 9,987 $ 337 $ 44,944 $ 29,216 $ 3,742 $ 2,954 $ 150,001 Loans and leases collectively evaluated for impairment 802,340 10,691,558 426,878 3,869,588 280,511 4,258,193 2,440,682 255,217 1,731,461 24,756,428 Total loan and leases $ 804,463 $ 10,747,715 $ 427,419 $ 3,879,575 $ 280,848 $ 4,303,137 $ 2,469,898 $ 258,959 $ 1,734,415 $ 24,906,429 December 31, 2018 (Dollars in thousands) Construction Commercial Other Commercial Other Residential Revolving Construction Consumer Total Non-PCI Loans Allowance for loan and lease losses: ALLL for loans and leases individually evaluated for impairment $ 490 $ 2,671 $ 42 $ 1,137 $ 105 $ 1,901 $ 2,515 $ 81 $ 885 $ 9,827 ALLL for loans and leases collectively evaluated for impairment 34,780 40,780 2,439 54,483 2,116 13,571 19,347 2,269 34,956 204,741 Total allowance for loan and lease losses $ 35,270 $ 43,451 $ 2,481 $ 55,620 $ 2,221 $ 15,472 $ 21,862 $ 2,350 $ 35,841 $ 214,568 Loans and leases: Loans and leases individually evaluated for impairment $ 2,175 $ 55,447 $ 860 $ 9,868 $ 291 $ 42,168 $ 28,852 $ 3,749 $ 3,020 $ 146,430 Loans and leases collectively evaluated for impairment 755,679 10,661,787 426,125 3,928,862 296,133 4,223,519 2,514,123 253,281 1,710,761 24,770,270 Total loan and leases $ 757,854 $ 10,717,234 $ 426,985 $ 3,938,730 $ 296,424 $ 4,265,687 $ 2,542,975 $ 257,030 $ 1,713,781 $ 24,916,700
Troubled Debt Restructurings on Financing Receivables	The following table provides the types of TDRs made during the three months ended March 31, 2019 and March 31, 2018 , as well as a summary of loans that were modified as a TDR during the twelve month periods ended March 31, 2019 and March 31, 2018 that subsequently defaulted during the three months ended March 31, 2019 and March 31, 2018 . BancShares defines payment default as movement of the TDR to nonaccrual status, which is generally 90 days past due for TDRs, foreclosure or charge-off, whichever occurs first. Three months ended March 31, 2019 Three months ended March 31, 2018 All restructurings Restructurings with payment default All restructurings Restructurings with payment default (Dollars in thousands) Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Number of Loans Recorded investment at period end Loans and leases Interest only — $ — — $ — 1 $ 644 — $ — Loan term extension 3 420 3 541 6 932 1 305 Below market interest rate 46 2,953 33 2,123 66 5,660 30 1,814 Discharged from bankruptcy 42 1,868 25 1,144 48 3,813 43 3,172 Total restructurings 91 $ 5,241 61 $ 3,808 121 $ 11,049 74 $ 5,291 For the three months ended March 31, 2019 and March 31, 2018 , the pre-modification and post-modification outstanding recorded investments of loans modified as TDRs were not materially different. The following table provides a summary of total TDRs by accrual status. Total TDRs included $17.9 million and $18.2 million of PCI TDRs at March 31, 2019 and December 31, 2018 , respectively. March 31, 2019 December 31, 2018 (Dollars in thousands) Accruing Nonaccruing Total Accruing Nonaccruing Total Commercial loans Construction and land development - $ 1,914 $ 329 $ 2,243 $ 1,946 $ 352 $ 2,298 Commercial mortgage 51,202 6,653 57,855 53,270 7,795 61,065 Other commercial real estate 536 5 541 851 9 860 Commercial and industrial and leases 8,253 1,792 10,045 7,986 2,060 10,046 Other 119 218 337 118 173 291 Total commercial loans 62,024 8,997 71,021 64,171 10,389 74,560 Noncommercial Residential mortgage 37,111 10,582 47,693 37,903 9,621 47,524 Revolving mortgage 20,320 9,200 29,520 20,492 8,196 28,688 Construction and land development - 2,150 180 2,330 2,227 110 2,337 Consumer and other 2,106 847 2,953 2,300 721 3,021 Total noncommercial loans 61,687 20,809 82,496 62,922 18,648 81,570 Total loans $ 123,711 $ 29,806 $ 153,517 $ 127,093 $ 29,037 $ 156,130

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
Changes in other real estate owned	The following table explains changes in other real estate owned during the three months ended March 31, 2019 and March 31, 2018 . (Dollars in thousands) Total Balance at December 31, 2018 $ 48,030 Additions 3,133 Sales (6,934 ) Write-downs (923 ) Balance at March 31, 2019 $ 43,306 Balance at December 31, 2017 $ 51,097 Additions 6,582 Sales (7,997 ) Write-downs (1,593 ) Balance at March 31, 2018 $ 48,089

FDIC Shared-Loss Receivable (Ta

FDIC Shared-Loss Receivable (Tables)	3 Months Ended
	Mar. 31, 2019
FDIC Shared-Loss Receivable [Abstract]
Changes In Payable to FDIC	The following table provides changes in the FDIC shared-loss payable since December 31, 2018 : (Dollars in thousands) Total Balance at December 31, 2018 $ 105,618 Accretion 1,638 Balance at March 31, 2019 $ 107,256

Mortgage Servicing Rights (Tabl

Mortgage Servicing Rights (Tables)	3 Months Ended
	Mar. 31, 2019
Mortgage Servicing Rights [Abstract]
Mortgage servicing rights	The following table explains changes in the servicing asset during the three months ended March 31 , 2019 and 2018 . (Dollars in thousands) Total Balance at December 31, 2018 $ 21,396 Servicing rights originated 859 Amortization (1,447 ) Valuation allowance provision (161 ) Balance at March 31, 2019 $ 20,647 Balance at December 31, 2017 $ 21,945 Servicing rights originated 1,200 Amortization (1,486 ) Balance at March 31, 2018 $ 21,659
Mortgage servicing rights economic assumptions	Valuation of mortgage servicing rights is performed using a pooling methodology. Similar loans are pooled together and evaluated on a discounted earnings basis to determine the present value of future earnings. Key economic assumptions used to value mortgage servicing rights were as follows: March 31, 2019 December 31, 2018 Discount rate - conventional fixed loans 9.41 % 9.69 % Discount rate - all loans excluding conventional fixed loans 10.41 % 10.69 % Weighted average constant prepayment rate 11.28 % 9.26 % Weighted average cost to service a loan $ 88.07 $ 87.52

Estimated Fair Values (Tables)

Estimated Fair Values (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Estimated Fair Values For Certain Financial Assets And Financial Liabilities	The table presents the carrying values and estimated fair values for financial instruments as of March 31, 2019 and December 31, 2018 . (Dollars in thousands) March 31, 2019 December 31, 2018 Carrying value Fair value Carrying value Fair value Cash and due from banks $ 268,599 $ 268,599 $ 327,440 $ 327,440 Overnight investments 1,386,525 1,386,525 797,406 797,406 Investment securities available for sale 4,589,800 4,589,800 4,557,110 4,557,110 Investment securities held to maturity 2,214,829 2,254,924 2,184,653 2,201,502 Investment in marketable equity securities 109,884 109,884 92,599 92,599 Loans held for sale 53,232 53,232 45,505 45,505 Net loans and leases 25,235,010 25,187,938 25,299,564 24,845,060 Income earned not collected 113,812 113,812 109,903 109,903 Federal Home Loan Bank stock 25,174 25,174 25,304 25,304 Mortgage and other servicing rights 24,080 25,769 24,615 27,435 Deposits 31,198,093 31,174,142 30,672,460 30,623,214 Securities sold under customer repurchase agreements 508,508 508,508 543,936 543,936 Federal Home Loan Bank borrowings 189,594 192,779 193,556 195,374 Subordinated debentures 136,544 140,676 140,741 151,670 Other borrowings 14,970 14,833 13,921 13,985 FDIC shared-loss payable 107,256 109,947 105,618 105,846 Accrued interest payable 7,169 7,169 3,712 3,712
Assets And Liabilities Carried At Fair Value On A Recurring Basis	For assets and liabilities carried at fair value on a recurring basis, the following table provides fair value information as of March 31, 2019 and December 31, 2018 . March 31, 2019 Fair value measurements using: (Dollars in thousands) Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets measured at fair value Investment securities available for sale U.S. Treasury $ 1,197,042 $ — $ 1,197,042 $ — Government agency 350,527 — 350,527 — Mortgage-backed securities 2,895,944 — 2,895,944 — Corporate bonds 142,162 — — 142,162 Other 4,125 — — 4,125 Total investment securities available for sale $ 4,589,800 $ — $ 4,443,513 $ 146,287 Marketable equity securities $ 109,884 $ 18,250 $ 91,634 $ — Loans held for sale $ 53,232 $ — $ 53,232 $ — December 31, 2018 Fair value measurements using: Fair value Level 1 inputs Level 2 inputs Level 3 inputs Assets measured at fair value Investment securities available for sale U.S. Treasury $ 1,247,710 $ — $ 1,247,710 $ — Government agency 256,835 — 256,835 — Mortgage-backed securities 2,909,339 — 2,909,339 — Corporate bonds 139,101 — — 139,101 Other 4,125 — — 4,125 Total investment securities available for sale $ 4,557,110 $ — $ 4,413,884 $ 143,226 Marketable equity securities $ 92,599 $ 17,887 $ 74,712 $ — Loans held for sale $ 45,505 $ — $ 45,505 $ —
Fair Value of Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following tables summarize activity for Level 3 assets: Three months ended March 31, 2019 (Dollars in thousands) Corporate bonds Other Balance at January 1, 2019 $ 139,101 $ 4,125 Transfers in — — Amounts included in net income 39 6 Unrealized net gains (losses) included in other comprehensive income 22 (6 ) Purchases 3,000 — Sales / Calls — — Balance at March 31, 2019 $ 142,162 $ 4,125
Fair Value Level 3 Significant Unobservable Input Assumptions	(Dollars in thousands) March 31, 2019 Level 3 assets Valuation technique Significant unobservable input Fair Value Corporate bonds Indicative bid provided by broker Multiple factors, including but not limited to, current operations, financial condition, cash flows, and recently executed financing transactions related to the company $ 142,162 Other Indicative bid provided by broker Multiple factors, including but not limited to, current operations, financial condition, cash flows, and recently executed financing transactions related to the company 4,125
Fair Value Option	The following table summarizes the difference between the aggregate fair value and the aggregate unpaid principal balance for residential real estate originated for sale measured at fair value as of March 31, 2019 and December 31, 2018 . March 31, 2019 (Dollars in thousands) Fair Value Aggregate Unpaid Principal Balance Difference Originated loans held for sale $ 53,232 $ 51,550 $ 1,682 December 31, 2018 Fair Value Aggregate Unpaid Principal Balance Difference Originated loans held for sale $ 45,505 $ 44,073 $ 1,432 No originated loans held for sale were 90 or more days past due or on nonaccrual status as of March 31, 2019 or December 31, 2018 . We may be required to measure certain financial assets at fair value on a nonrecurring basis. These adjustments to fair value usually result from the application of lower of amortized cost or fair value accounting or write-downs of individual assets due to impairment. Impaired loans are deemed to be at fair value if an associated allowance or current period charge-off has been recorded. The value of impaired loans is determined by either collateral valuations or discounted present value of the expected cash flow calculations. Collateral values are determined using appraisals or other third-party value estimates of the subject property with discounts generally between 6% and 11% applied for estimated selling costs and other external factors that may impact the marketability of the property. Expected cash flows are determined using expected payment information at the individual loan level, discounted using the effective interest rate. The effective interest rate generally ranges between 2% and 18% . OREO acquired or written down within the previous 12 months is deemed to be at fair value. Asset valuations are determined by using appraisals or other third-party value estimates of the subject property with discounts generally between 6% and 11% applied for estimated selling costs and other external factors that may impact the marketability of the property. Changes to the value of the assets between scheduled valuation dates are monitored through continued communication with brokers and monthly reviews by the asset manager assigned to each asset. If there are any significant changes in the market or the subject property, valuations are adjusted or new appraisals ordered to ensure the reported values reflect the most current information.
Assets And Liabilities Carried At Fair Value On A Nonrecurring Basis	For financial assets and liabilities carried at fair value on a nonrecurring basis, the following table provides fair value information as of March 31, 2019 and December 31, 2018 . March 31, 2019 Fair value measurements using: (Dollars in thousands) Fair value Level 1 inputs Level 2 inputs Level 3 inputs Impaired loans $ 110,411 $ — $ — $ 110,411 Other real estate remeasured during the previous 12 months 32,620 — — 32,620 December 31, 2018 Fair value measurements using: Fair value Level 1 inputs Level 2 inputs Level 3 inputs Impaired loans $ 105,994 $ — $ — $ 105,994 Other real estate remeasured during the previous 12 months 35,344 — — 35,344

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2019
BancShares Plan
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs	BancShares Plan For the three months ended March 31, 2019 and 2018 , the components of net periodic benefit cost are as follows: Three months ended March 31 (Dollars in thousands) 2019 2018 Service cost $ 2,568 $ 3,429 Interest cost 7,531 7,057 Expected return on assets (12,867 ) (11,957 ) Amortization of prior service cost 14 20 Amortization of net actuarial loss 2,114 3,246 Net periodic (benefit) cost $ (640 ) $ 1,795
Bancorporation Plan
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs	Bancorporation Plan For the three months ended March 31, 2019 and 2018 , the components of net periodic benefit cost are as follows: Three months ended March 31 (Dollars in thousands) 2019 2018 Service cost $ 545 $ 662 Interest cost 1,760 1,587 Expected return on assets (2,768 ) (3,106 ) Amortization of net actuarial loss 627 71 Net periodic cost (benefit) $ 164 $ (786 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Schedule of fair falue for off-balance sheet risks	The following table presents the commitments to extend credit and unfunded commitments as of March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, 2019 December 31, 2018 Unused commitments to extend credit $ 10,187,550 $ 10,054,712 Standby letters of credit 91,719 96,467 Unfunded commitments for investments in affordable housing projects 72,002 67,952

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule Of Accumulated Other Comprehensive Income (Loss)	Accumulated other comprehensive loss included the following as of March 31, 2019 and December 31, 2018 : March 31, 2019 December 31, 2018 (Dollars in thousands) Accumulated other comprehensive loss Deferred tax benefit Accumulated other comprehensive loss, net of tax Accumulated other comprehensive loss Deferred tax benefit Accumulated other comprehensive loss, net of tax Unrealized losses on securities available for sale $ (21,936 ) $ (5,046 ) $ (16,890 ) $ (50,007 ) $ (11,502 ) $ (38,505 ) Unrealized losses on securities available for sale transferred to held to maturity (86,439 ) (19,881 ) (66,558 ) (92,401 ) (21,252 ) (71,149 ) Defined benefit pension items (160,275 ) (36,863 ) (123,412 ) (163,030 ) (37,497 ) (125,533 ) Total $ (268,650 ) $ (61,790 ) $ (206,860 ) $ (305,438 ) $ (70,251 ) $ (235,187 ) The following table highlights changes in accumulated other comprehensive (loss) income by component for the three months ended March 31, 2019 and March 31, 2018 : Three months ended March 31, 2019 (Dollars in thousands) Unrealized (losses) gains on securities available for sale (1) Unrealized losses on securities available for sale transferred to held to maturity (1) Defined benefit pension items (1) Total Beginning balance $ (38,505 ) $ (71,149 ) $ (125,533 ) $ (235,187 ) Cumulative effect adjustments — — — — Net unrealized gains arising during period 21,615 — — 21,615 Amounts reclassified from accumulated other comprehensive loss — 4,591 2,121 6,712 Net current period other comprehensive income 21,615 4,591 2,121 28,327 Ending balance $ (16,890 ) $ (66,558 ) $ (123,412 ) $ (206,860 ) Three months ended March 31, 2018 Unrealized (losses) gains on securities available for sale (1) Unrealized losses on securities available for sale transferred to held to maturity (1) Defined benefit pension items (1) Total Beginning balance $ (30,945 ) $ — $ (91,349 ) $ (122,294 ) Cumulative effect adjustments (29,751 ) — (20,300 ) (50,051 ) Net unrealized (losses) arising during period (60,547 ) — — (60,547 ) Amounts reclassified from accumulated other comprehensive loss — — 2,569 2,569 Net current period other comprehensive (loss) income (60,547 ) — 2,569 (57,978 ) Ending balance $ (121,243 ) $ — $ (109,080 ) $ (230,323 ) (1) All amounts are net of tax.
Reclassification out of Accumulated Other Comprehensive Income	The following table presents the amounts reclassified from accumulated other comprehensive (loss) income and the line item affected in the statement where net income is presented for the three months ended March 31, 2019 and March 31, 2018 . Three months ended March 31, 2019 (Dollars in thousands) Details about accumulated other comprehensive (loss) income Amounts reclassified from accumulated other comprehensive (loss) income (1) Affected line item in the statement where net income is presented Amortization of unrealized losses on securities available for sale transferred to held to maturity $ (5,962 ) Net interest income 1,371 Income taxes $ (4,591 ) Net Income Amortization of defined benefit pension items Prior service costs $ (14 ) Salaries and wages Actuarial losses (2,741 ) Other (2,755 ) Income before income taxes 634 Income taxes $ (2,121 ) Net income Total reclassifications for the period $ (6,712 ) Three months ended March 31, 2018 Details about accumulated other comprehensive (loss) income Amounts reclassified from accumulated other comprehensive (loss) income (1) Affected line item in the statement where net income is presented Amortization of defined benefit pension items Prior service costs $ (20 ) Salaries and wages Actuarial losses (3,317 ) Other (3,337 ) Income before income taxes 768 Income taxes $ (2,569 ) Net income Total reclassifications for the period $ (2,569 ) (1) Amounts in parentheses indicate debits to profit/loss.

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of Operating and Finance Lease Assets and Liabilities	The following table presents lease assets and liabilities as of March 31, 2019 . (Dollars in thousands) Classification March 31, 2019 Assets: Operating Other assets $ 70,815 Finance Premises and equipment 8,763 Total leased assets $ 79,578 Liabilities: Operating Other liabilities 72,315 Finance Other borrowings 7,828 Total lease liabilities $ 80,143
Schedule of Net Lease Cost	(Dollars in thousands) Classification Three months ended March 31, 2019 Lease cost: Operating lease cost (1) Occupancy expense $ 3,204 Finance lease cost: Amortization of leased assets Equipment expense 447 Interest on lease liabilities Interest Expense - Other borrowings 65 Variable lease cost Occupancy expense 528 Sublease income Occupancy expense (130 ) Net lease cost $ 4,114 (1) Operating lease cost includes short-term lease cost, which is immaterial.
Schedule of Lease Liability Maturities	The following table presents lease liability maturities in the next five years and thereafter. (Dollars in thousands) Operating Leases Finance Leases Total 2019 (1) $ 10,310 $ 1,301 $ 11,611 2020 12,475 1,748 14,223 2021 10,947 1,764 12,711 2022 9,575 1,481 11,056 2023 7,772 599 8,371 Thereafter 35,343 1,683 37,026 Total lease payments $ 86,422 $ 8,576 $ 94,998 Less: Interest 14,107 748 14,855 Present value of lease liabilities $ 72,315 $ 7,828 $ 80,143 (1) Represents the lease liability payments that will be made for the period April 1, 2019 through December 31, 2019.
Schedule of Lease Liability Maturities	The following table presents lease liability maturities in the next five years and thereafter. (Dollars in thousands) Operating Leases Finance Leases Total 2019 (1) $ 10,310 $ 1,301 $ 11,611 2020 12,475 1,748 14,223 2021 10,947 1,764 12,711 2022 9,575 1,481 11,056 2023 7,772 599 8,371 Thereafter 35,343 1,683 37,026 Total lease payments $ 86,422 $ 8,576 $ 94,998 Less: Interest 14,107 748 14,855 Present value of lease liabilities $ 72,315 $ 7,828 $ 80,143 (1) Represents the lease liability payments that will be made for the period April 1, 2019 through December 31, 2019.
Schedule of Remaining Weighted Average Lease Terms and Discount Rates	The following table presents the remaining weighted average lease terms and discount rates as of March 31, 2019 . Weighted average remaining lease term (years): March 31, 2019 Operating 9.7 Finance 5.4 Weighted average discount rate: Operating 3.36 % Finance 3.22
Schedule of Supplemental Cash Flow Information	The following table presents supplemental cash flow information related to leases for the three months ended March 31, 2019 . (Dollars in thousands) March 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 3,550 Operating cash flows from finance leases 65 Financing cash flows from finance leases 366 Right-of-use assets obtained in exchange for new operating lease liabilities 3,591 Right-of-use assets obtained in exchange for new finance lease liabilities —

Accounting Policies and Basis_3

Accounting Policies and Basis of Presentation Accounting Policies and Basis of Presentation (Recently Adopted Accounting Standards) (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 30, 2019	Mar. 31, 2019	Jan. 01, 2019	Oct. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of shares authorized to be repurchased (in shares)				800,000
Stock repurchased during period (in shares)		243,000
Stock repurchased during period		$ 100,700
Stock repurchased during period (in USD per share)		$ 414.58
Total number of shares repurchase (in shares)		425,000
Operating lease assets		$ 70,815
Present value of lease liabilities		$ 72,315
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease assets			$ 70,700
Present value of lease liabilities			71,800
Right-of-use asset previously classified as capital lease			9,100
Liability previously classified as capital lease			8,300
Accounting Standards Update 2016-02 | HomeBancorp Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Present value of lease liabilities			$ 1,100
Subsequent Event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in shares)	63,400
Stock repurchased during period	$ 27,400
Stock repurchased during period (in USD per share)	$ 432.78

Business Combinations (Details)

Business Combinations (Details) - USD ($) $ / shares in Units, $ in Millions	May 01, 2019	Apr. 23, 2019	Apr. 02, 2019	Mar. 31, 2019	Dec. 31, 2018
First South Bancorp
Business Acquisition [Line Items]
Assets				$ 236
Deposits				206.1
Loans				183.3
First South Bancorp | Subsequent Event
Business Acquisition [Line Items]
Share price (usd per share)	$ 1.15
Consideration	$ 37.5
Entegra Financial
Business Acquisition [Line Items]
Assets					$ 1,700
Deposits					1,300
Loans					$ 1,100
Entegra Financial | Subsequent Event
Business Acquisition [Line Items]
Share price (usd per share)		$ 30.18
Consideration		$ 219.8
Biscayne Bancshares
Business Acquisition [Line Items]
Assets				1,020
Deposits				788.2
Loans				$ 879.9
Biscayne Bancshares | Subsequent Event
Business Acquisition [Line Items]
Share price (usd per share)			$ 25.05
Consideration			$ 118.9

Investments (Aggregate Values a

Investments (Aggregate Values and Unrealized Gains and Losses) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Investment securities available for sale
Cost	$ 4,611,736	$ 4,607,117
Gross Unrealized Gains	9,387	6,425
Gross Unrealized Losses	31,323	56,432
Fair Value	4,589,800	4,557,110
Cost	79,809	73,809
Gross unrealized gains	30,252	19,010
Gross unrealized losses	177	220
Fair value	109,884	92,599
Investment securities held to maturity
Cost	2,214,829	2,184,653
Cost	6,906,374	6,865,579
Gross unrealized gains	80,184	42,774
Gross unrealized losses	31,950	57,142
Fair value	6,954,608	6,851,211
U. S. Treasury
Investment securities available for sale
Cost	1,196,584	1,249,243
Gross Unrealized Gains	1,305	633
Gross Unrealized Losses	847	2,166
Fair Value	1,197,042	1,247,710
Agency Securities
Investment securities available for sale
Cost	351,284	257,252
Gross Unrealized Gains	330	222
Gross Unrealized Losses	1,087	639
Fair Value	350,527	256,835
Mortgage Backed Securities
Investment securities available for sale
Cost	2,917,000	2,956,793
Gross Unrealized Gains	7,373	5,309
Gross Unrealized Losses	28,429	52,763
Fair Value	2,895,944	2,909,339
Investment securities held to maturity
Cost	2,214,829	2,184,653
Held To Maturity Securities Accumulated Unrecognized Holding Gain	40,545	17,339
Held To Maturity Securities Accumulated Unrecognized Holding Loss	450	490
Fair Value	2,254,924	2,201,502
Corporate Bonds
Investment securities available for sale
Cost	142,939	139,906
Gross Unrealized Gains	183	59
Gross Unrealized Losses	960	864
Fair Value	142,162	139,101
Other
Investment securities available for sale
Cost	3,929	3,923
Gross Unrealized Gains	196	202
Gross Unrealized Losses	0	0
Fair Value	$ 4,125	$ 4,125

Investments (Maturity Informati

Investments (Maturity Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Investment securities available for sale
Total investment securities available for sale, cost	$ 4,611,736	$ 4,607,117
Total investment securities available for sale, fair value	4,589,800	4,557,110
Investment securities held to maturity
Investment securities held to maturity	2,214,829	2,184,653
Debt Securities
Investment securities available for sale
Maturing in one year or less, cost	1,046,796	1,049,253
Maturing in one through five years, cost	155,297	205,526
Maturing in five through ten years, cost	137,430	134,370
Maturing in over ten years, cost	3,929	3,923
Maturing in one year or less, fair value	1,046,362	1,047,380
Maturing in one through five years, fair value	155,680	205,805
Maturing in five through ten yeas, fair value	137,162	133,626
Maturing in over ten years, fair value	4,125	4,125
Agency Securities
Investment securities available for sale
Total investment securities available for sale, cost	351,284	257,252
Total investment securities available for sale, fair value	350,527	256,835
Mortgage Backed Securities
Investment securities available for sale
Total investment securities available for sale, cost	2,917,000	2,956,793
Total investment securities available for sale, fair value	2,895,944	2,909,339
Investment securities held to maturity
Investment securities held to maturity	2,214,829	2,184,653
Fair Value	$ 2,254,924	$ 2,201,502

Investments (Unrealized Losses)

Investments (Unrealized Losses) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Unrealized losses related to marketability of securities or issuer's ability to honor redemption obligations	$ 0
Investment securities available for sale:
Fair Value, Less than 12 months	390,651,000	705,526,000
Unrealized Losses, Less than 12 months	2,106,000	3,943,000
Fair Value, 12 months or more	2,578,426,000	2,796,627,000
Unrealized Losses, Greater than 12 months	29,217,000	52,489,000
Fair Value, Total	2,969,077,000	3,502,153,000
Unrealized Losses, Total	31,323,000	56,432,000
U. S. Treasury
Investment securities available for sale:
Fair Value, Less than 12 months	0	248,983,000
Unrealized Losses, Less than 12 months	0	113,000
Fair Value, 12 months or more	599,883,000	848,622,000
Unrealized Losses, Greater than 12 months	847,000	2,053,000
Fair Value, Total	599,883,000	1,097,605,000
Unrealized Losses, Total	847,000	2,166,000
Agency Securities
Investment securities available for sale:
Fair Value, Less than 12 months	219,395,000	115,273,000
Unrealized Losses, Less than 12 months	901,000	601,000
Fair Value, 12 months or more	12,590,000	2,310,000
Unrealized Losses, Greater than 12 months	186,000	38,000
Fair Value, Total	231,985,000	117,583,000
Unrealized Losses, Total	1,087,000	639,000
Mortgage Backed Securities
Investment securities available for sale:
Fair Value, Less than 12 months	114,863,000	262,204,000
Unrealized Losses, Less than 12 months	314,000	2,387,000
Fair Value, 12 months or more	1,956,003,000	1,940,695,000
Unrealized Losses, Greater than 12 months	28,115,000	50,376,000
Fair Value, Total	2,070,866,000	2,202,899,000
Unrealized Losses, Total	28,429,000	52,763,000
Investment securities held to maturity
Fair Value, Less than 12 months	40,142,000	5,111,000
Unrealized Losses, Less than 12 months	291,000	181,000
Fair Value, 12 months or more	9,988,000	10,131,000
Unrealized Losses, 12 months or more	159,000	309,000
Fair Value, Total	50,130,000	15,242,000
Unrealized Losses, Total	450,000	490,000
Corporate bonds
Investment securities available for sale:
Fair Value, Less than 12 months		79,066,000
Unrealized Losses, Less than 12 months		842,000
Fair Value, 12 months or more		5,000,000
Unrealized Losses, Greater than 12 months		22,000
Fair Value, Total		84,066,000
Unrealized Losses, Total		864,000
Corporate Bonds
Investment securities available for sale:
Fair Value, Less than 12 months	56,393,000
Unrealized Losses, Less than 12 months	891,000
Fair Value, 12 months or more	9,950,000
Unrealized Losses, Greater than 12 months	69,000
Fair Value, Total	66,343,000
Unrealized Losses, Total	960,000	864,000
Other
Investment securities available for sale:
Unrealized Losses, Total	$ 0	$ 0

Investments Marketable Equity S

Investments Marketable Equity Securities Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Marketable Equity Securities Gains (Losses) [Abstract]
Marketable equity securities gain (loss), net	$ 11,328	$ 971
Net gains (losses) recognized on marketable equity securities sold	44	96
Unrealized gains (losses) recognized on marketable equity securities held	$ 11,284	$ 875

Investments (Narrative) (Detail

Investments (Narrative) (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)investmentinvestmentsshares	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2018USD ($)
Schedule of Investments [Line Items]
Investment in marketable equity securities	$ 109,884,000		$ 92,599,000
Investment securities available for sale	$ 4,589,800,000		4,557,110,000
Cumulative effect of new accounting principle in period of adoption				$ (50,051,000)
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | investment	230
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions | investment	2
Unrealized losses related to marketability of securities or issuer's ability to honor redemption obligations	$ 0
Investment value deemed to be OTTI	0
Investment securities, aggregate carrying value, pledged as collateral	3,680,000,000		4,030,000,000
Mortgage Backed Securities
Schedule of Investments [Line Items]
Investment securities available for sale	$ 2,895,944,000		2,909,339,000
Available-for-sale, securities in unrealized loss positions, number of positions, greater than or equal to one year | investments	223
U. S. Treasury
Schedule of Investments [Line Items]
Investment securities available for sale	$ 1,197,042,000		1,247,710,000
Corporate Bonds
Schedule of Investments [Line Items]
Investment securities available for sale	$ 142,162,000		$ 139,101,000
Available-for-sale, securities in unrealized loss positions, number of positions, greater than or equal to one year | investments	2
Visa Class B Common Stock
Schedule of Investments [Line Items]
Investment owned (in shares) | shares	298
Investment owned, fair value	$ 0
U. S. Treasury
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | investment	5

Loans and Leases (Narrative) (D

Loans and Leases (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Purchase Discount Remaining	$ 30,100		$ 33,300
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	6,360,000		6,360,000
Advances from Federal Home Loan Banks			175,200
Federal Home Loan Bank Advances, Current Borrowing Capacity	6,170,000		6,180,000
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	100		100
Loans and Leases Receivable, Gross, Carrying Amount, Covered	53,900
Federal Reserve Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	2,230,000		2,190,000
Loans held for sale	53,232		45,505
Proceeds From Sales of Loans	123,047	$ 138,538
Proceeds from sales of portfolio loans	0	0
Non-PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Nonaccruing	88,958		84,546
Remaining discount	89,400		95,500
Accretion Income	3,200	2,900
PCI Loans
Financing Receivable, Recorded Investment [Line Items]
Nonaccruing	1,700		1,300
Accretion Income	17,800	$ 18,000
Federal Home Loan Bank of Atlanta
Financing Receivable, Recorded Investment [Line Items]
Advances from Federal Home Loan Banks	175,200
Loans Pledged as Collateral	9,080,000		9,120,000
Federal Home Loan Bank of Chicago
Financing Receivable, Recorded Investment [Line Items]
Advances from Federal Home Loan Banks	14,500
Federal Reserve Bank
Financing Receivable, Recorded Investment [Line Items]
Loans Pledged as Collateral	$ 2,930,000		$ 2,940,000

Loans and Leases (Loans and Lea

Loans and Leases (Loans and Leases Outstanding) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 24,906,429	$ 24,916,700
PCI loans	557,356	606,576	$ 703,837	$ 762,998
Total loans and leases	25,463,785	25,523,276
Commercial
Loans and leases, not acquired in a transfer accounted for as debt securities	16,140,020	16,137,227
PCI loans	269,913	296,672
Commercial | Construction and land development
Loans and leases, not acquired in a transfer accounted for as debt securities	804,463	757,854
Commercial | Mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	10,747,715	10,717,234
Commercial | Other commercial real estate
Loans and leases, not acquired in a transfer accounted for as debt securities	427,419	426,985
Commercial | Commercial and industrial
Loans and leases, not acquired in a transfer accounted for as debt securities	3,879,575	3,938,730
Commercial | Other
Loans and leases, not acquired in a transfer accounted for as debt securities	280,848	296,424
Noncommercial
Loans and leases, not acquired in a transfer accounted for as debt securities	8,766,409	8,779,473
PCI loans	287,443
Noncommercial | Construction and land development
Loans and leases, not acquired in a transfer accounted for as debt securities	258,959	257,030
Noncommercial | Mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	4,303,137	4,265,687
PCI loans		309,904
Noncommercial | Revolving mortgage
Loans and leases, not acquired in a transfer accounted for as debt securities	2,469,898	2,542,975
Noncommercial | Consumer
Loans and leases, not acquired in a transfer accounted for as debt securities	$ 1,734,415	$ 1,713,781

Loans and Leases (Composition o

Loans and Leases (Composition of the Loans and Leases Outstanding By Credit Quality Indicator) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	$ 24,906,429	$ 24,916,700
PCI loans	557,356	606,576	$ 703,837	$ 762,998
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	16,140,020	16,137,227
PCI loans	269,913	296,672
Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	10,747,715	10,717,234
Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	427,419	426,985
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	3,879,575	3,938,730
Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	280,848	296,424
Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	804,463	757,854
Commercial | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	15,749,153	15,757,669
PCI loans	131,018	141,922
Commercial | Pass | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	10,528,026	10,507,687
Commercial | Pass | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	423,288	422,500
Commercial | Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	3,717,237	3,778,797
Commercial | Pass | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	279,899	294,700
Commercial | Pass | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	800,703	753,985
Commercial | Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	162,280	174,700
PCI loans	43,068	48,475
Commercial | Special Mention | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	110,413	114,219
Commercial | Special Mention | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	3,244	3,193
Commercial | Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	46,928	54,814
Commercial | Special Mention | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	350	1,105
Commercial | Special Mention | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	1,345	1,369
Commercial | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	150,620	127,842
PCI loans	91,940	101,447
Commercial | Substandard | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	109,276	92,743
Commercial | Substandard | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	887	1,292
Commercial | Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	37,443	30,688
Commercial | Substandard | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	599	619
Commercial | Substandard | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	2,415	2,500
Commercial | Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	354	354
PCI loans	3,887	4,828
Commercial | Doubtful | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Doubtful | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	354	354
Commercial | Doubtful | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Doubtful | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Ungraded
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	77,613	76,662
Commercial | Ungraded | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	2,585
Commercial | Ungraded | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Ungraded | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	77,613	74,077
Commercial | Ungraded | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Commercial | Ungraded | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	0	0
Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	8,766,409	8,779,473
PCI loans	287,443
Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	4,303,137	4,265,687
PCI loans		309,904
Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	258,959	257,030
Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	2,469,898	2,542,975
Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	1,734,415	1,713,781
Non-PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	24,906,429	24,916,700
Past due loans	142,668	134,882
Current loans	24,763,761	24,781,818
Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	16,140,020	16,137,227
Past due loans	46,175	35,619
Current loans	16,093,845	16,101,608
Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	10,747,715	10,717,234
Past due loans	27,740	19,503
Current loans	10,719,975	10,697,731
Non-PCI Loans | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	427,419	426,985
Past due loans	1,715	467
Current loans	425,704	426,518
Non-PCI Loans | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	3,879,575	3,938,730
Past due loans	15,498	14,306
Current loans	3,864,077	3,924,424
Non-PCI Loans | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	280,848	296,424
Past due loans	137	374
Current loans	280,711	296,050
Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	804,463	757,854
Past due loans	1,085	969
Current loans	803,378	756,885
Non-PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	8,766,409	8,779,473
Past due loans	96,493	99,263
Current loans	8,669,916	8,680,210
Non-PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	4,303,137	4,265,687
Past due loans	54,314	50,904
Current loans	4,248,823	4,214,783
Non-PCI Loans | Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	258,959	257,030
Past due loans	2,158	2,193
Current loans	256,801	254,837
Non-PCI Loans | Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	2,469,898	2,542,975
Past due loans	25,748	28,706
Current loans	2,444,150	2,514,269
Non-PCI Loans | Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-PCI loans	1,734,415	1,713,781
Past due loans	14,273	17,460
Current loans	1,720,142	1,696,321
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans	557,356
PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	255,145
PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans		268,280
30 to 59 Days past due | Non-PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	80,658	76,187
30 to 59 Days past due | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	27,754	24,747
30 to 59 Days past due | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	16,120	14,200
30 to 59 Days past due | Non-PCI Loans | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	1,198	91
30 to 59 Days past due | Non-PCI Loans | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	9,706	9,655
30 to 59 Days past due | Non-PCI Loans | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	113	285
30 to 59 Days past due | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	617	516
30 to 59 Days past due | Non-PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	52,904	51,440
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	33,623	28,239
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	581	581
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	10,734	12,585
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	7,966	10,035
30 to 59 Days past due | PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	8,565
30 to 59 Days past due | PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		11,155
60 to 89 Days past due | Non-PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	27,040	19,682
60 to 89 Days past due | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	12,024	3,910
60 to 89 Days past due | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	8,818	2,066
60 to 89 Days past due | Non-PCI Loans | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	517	76
60 to 89 Days past due | Non-PCI Loans | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	2,403	1,759
60 to 89 Days past due | Non-PCI Loans | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	24	0
60 to 89 Days past due | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	262	9
60 to 89 Days past due | Non-PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	15,016	15,772
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	7,760	7,357
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	28	21
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	4,227	4,490
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,001	3,904
60 to 89 Days past due | PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,449
60 to 89 Days past due | PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		7,708
90 Days or greater | Non-PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	34,970	39,013
90 Days or greater | Non-PCI Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	6,397	6,962
90 Days or greater | Non-PCI Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	2,802	3,237
90 Days or greater | Non-PCI Loans | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	0	300
90 Days or greater | Non-PCI Loans | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,389	2,892
90 Days or greater | Non-PCI Loans | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	0	89
90 Days or greater | Non-PCI Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	206	444
90 Days or greater | Non-PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	28,573	32,051
90 Days or greater | Non-PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	12,931	15,308
90 Days or greater | Non-PCI Loans | Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	1,549	1,591
90 Days or greater | Non-PCI Loans | Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	10,787	11,631
90 Days or greater | Non-PCI Loans | Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	3,306	3,521
90 Days or greater | PCI Loans | Noncommercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans	$ 20,284
90 Days or greater | PCI Loans | Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due loans		$ 22,761

Loans and Leases (Aging Of The

Loans and Leases (Aging Of The Outstanding Loans and Leases By Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI loans	$ 557,356	$ 606,576	$ 703,837	$ 762,998
Non-PCI loans	24,906,429	24,916,700
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI loans	269,913	296,672
Non-PCI loans	16,140,020	16,137,227
Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	804,463	757,854
Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	10,747,715	10,717,234
Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	427,419	426,985
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	3,879,575	3,938,730
Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	280,848	296,424
Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI loans	287,443
Non-PCI loans	8,766,409	8,779,473
Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	258,959	257,030
Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI loans		309,904
Non-PCI loans	4,303,137	4,265,687
Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	2,469,898	2,542,975
Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-PCI loans	1,734,415	1,713,781
PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI loans	557,356
PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current loans	255,145
PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current loans		268,280
Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	142,668	134,882
Current loans	24,763,761	24,781,818
Non-PCI loans	24,906,429	24,916,700
Non-PCI Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	46,175	35,619
Current loans	16,093,845	16,101,608
Non-PCI loans	16,140,020	16,137,227
Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	1,085	969
Current loans	803,378	756,885
Non-PCI loans	804,463	757,854
Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	27,740	19,503
Current loans	10,719,975	10,697,731
Non-PCI loans	10,747,715	10,717,234
Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	1,715	467
Current loans	425,704	426,518
Non-PCI loans	427,419	426,985
Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	15,498	14,306
Current loans	3,864,077	3,924,424
Non-PCI loans	3,879,575	3,938,730
Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	137	374
Current loans	280,711	296,050
Non-PCI loans	280,848	296,424
Non-PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	96,493	99,263
Current loans	8,669,916	8,680,210
Non-PCI loans	8,766,409	8,779,473
Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	2,158	2,193
Current loans	256,801	254,837
Non-PCI loans	258,959	257,030
Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	54,314	50,904
Current loans	4,248,823	4,214,783
Non-PCI loans	4,303,137	4,265,687
Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	25,748	28,706
Current loans	2,444,150	2,514,269
Non-PCI loans	2,469,898	2,542,975
Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	14,273	17,460
Current loans	1,720,142	1,696,321
Non-PCI loans	1,734,415	1,713,781
30 to 59 Days past due | PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	8,565
30 to 59 Days past due | PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans		11,155
30 to 59 Days past due | Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	80,658	76,187
30 to 59 Days past due | Non-PCI Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	27,754	24,747
30 to 59 Days past due | Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	617	516
30 to 59 Days past due | Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	16,120	14,200
30 to 59 Days past due | Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	1,198	91
30 to 59 Days past due | Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	9,706	9,655
30 to 59 Days past due | Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	113	285
30 to 59 Days past due | Non-PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	52,904	51,440
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	581	581
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	33,623	28,239
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	10,734	12,585
30 to 59 Days past due | Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	7,966	10,035
60 to 89 Days past due | PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	3,449
60 to 89 Days past due | PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans		7,708
60 to 89 Days past due | Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	27,040	19,682
60 to 89 Days past due | Non-PCI Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	12,024	3,910
60 to 89 Days past due | Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	262	9
60 to 89 Days past due | Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	8,818	2,066
60 to 89 Days past due | Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	517	76
60 to 89 Days past due | Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	2,403	1,759
60 to 89 Days past due | Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	24	0
60 to 89 Days past due | Non-PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	15,016	15,772
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	28	21
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	7,760	7,357
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	4,227	4,490
60 to 89 Days past due | Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	3,001	3,904
90 Days or greater | PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	20,284
90 Days or greater | PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans		22,761
90 Days or greater | Non-PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	34,970	39,013
90 Days or greater | Non-PCI Loans | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	6,397	6,962
90 Days or greater | Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	206	444
90 Days or greater | Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	2,802	3,237
90 Days or greater | Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	0	300
90 Days or greater | Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	3,389	2,892
90 Days or greater | Non-PCI Loans | Commercial | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	0	89
90 Days or greater | Non-PCI Loans | Noncommercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	28,573	32,051
90 Days or greater | Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	1,549	1,591
90 Days or greater | Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	12,931	15,308
90 Days or greater | Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	10,787	11,631
90 Days or greater | Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due loans	$ 3,306	$ 3,521

Loans and Leases (Recorded Inve

Loans and Leases (Recorded Investment, By Class, In Loans And Leases On Nonaccrual Status And Loans And Leases Greater Than 90 Days Past Due And Still Accruing) (Details) - Non-PCI Loans - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	$ 88,958	$ 84,546
Loans and leases greater than 90 days and accruing	3,493	2,888
Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	407	666
Loans and leases greater than 90 days and accruing	0	0
Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	15,744	12,594
Loans and leases greater than 90 days and accruing	0	0
Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	19	366
Loans and leases greater than 90 days and accruing	0	0
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	5,482	4,624
Loans and leases greater than 90 days and accruing	667	808
Noncommercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	1,699	1,823
Loans and leases greater than 90 days and accruing	0	0
Noncommercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	36,573	35,662
Loans and leases greater than 90 days and accruing	614	0
Noncommercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	257	279
Loans and leases greater than 90 days and accruing	0	0
Noncommercial | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	25,723	25,563
Loans and leases greater than 90 days and accruing	0	0
Noncommercial | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccruing	3,054	2,969
Loans and leases greater than 90 days and accruing	$ 2,212	$ 2,080

Loans and Leases (Changes In Ca

Loans and Leases (Changes In Carrying Value Of Acquired Impaired Loans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Jan. 13, 2017	Mar. 11, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 810,683	$ 1,108,379
Carrying Value of Acquired Impaired Loans [Roll Forward]
Beginning balance	606,576	762,998
Fair value of acquired loans				$ 0	$ 0
Accretion	17,755	17,973
Payments received and other changes, net	(66,975)	(77,134)
Ending balance	557,356	703,837
Loans on the Cost Recovery Method
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans on cost recovery method	3,333		$ 3,348
Commercial
Carrying Value of Acquired Impaired Loans [Roll Forward]
Beginning balance	296,672
Ending balance	269,913
Noncommercial
Carrying Value of Acquired Impaired Loans [Roll Forward]
Ending balance	287,443
Mortgage | Noncommercial
Carrying Value of Acquired Impaired Loans [Roll Forward]
Beginning balance	309,904
PCI Loans
Carrying Value of Acquired Impaired Loans [Roll Forward]
Accretion Income	17,800	$ 18,000
Ending balance	557,356
Nonaccruing	$ 1,700		$ 1,300

Loans and Leases (Changes In _2

Loans and Leases (Changes In Carrying Amount Of Accretable Yield) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Abstract]
Accretable yield	$ 286,192	$ 309,345	$ 312,894	$ 316,679
Additions from acquisitions	0	0
Accretion	(17,755)	(17,973)
Reclassifications from nonaccretable difference	600	(929)
Changes in expected cash flows that do not affect nonaccretable difference	$ (9,547)	$ 11,568

Loans and Leases Loans and Leas

Loans and Leases Loans and Leases (Schedule of Contractually Required Payments Including Principal and Interest, Expected Cash Flows to be Collected and Fair Values) (Details) - USD ($) $ in Thousands	Jan. 13, 2017	Mar. 11, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
PCI loans and leases	$ 0	$ 0

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Net loans and leases			$ 25,235,010	$ 25,299,564
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality			557,356	606,576	$ 703,837	$ 762,998
Commercial
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality			269,913	296,672
Noncommercial
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality			287,443
Noncommercial | Mortgage
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality				309,904
Non-PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 214,568	$ 211,867
Provision for Loan, Lease, and Other Losses	11,914	5,251
Charge-offs	(10,154)	(9,613)
Recoveries	3,467	3,315
Ending balance	219,795	210,820
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			150,001	146,430
Loans and leases collectively evaluated for impairment			24,756,428	24,770,270
Net loans and leases			24,906,429	24,916,700
ALLL for loans and leases individually evaluated for impairment			11,965	9,827
ALLL for loans and leases collectively evaluated for impairment			207,830	204,741
Total allowance for loan and lease losses	214,568	211,867	219,795	214,568	210,820	211,867
Non-PCI Loans | Commercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	35,270	24,470
Provision for Loan, Lease, and Other Losses	2,119	2,225
Charge-offs	(44)	0
Recoveries	131	23
Ending balance	37,476	26,718
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			2,123	2,175
Loans and leases collectively evaluated for impairment			802,340	755,679
Net loans and leases			804,463	757,854
ALLL for loans and leases individually evaluated for impairment			533	490
ALLL for loans and leases collectively evaluated for impairment			36,943	34,780
Total allowance for loan and lease losses	35,270	24,470	37,476	35,270	26,718	24,470
Non-PCI Loans | Commercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	43,451	45,005
Provision for Loan, Lease, and Other Losses	2,371	(1,365)
Charge-offs	(761)	(46)
Recoveries	220	239
Ending balance	45,281	43,833
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			56,157	55,447
Loans and leases collectively evaluated for impairment			10,691,558	10,661,787
Net loans and leases			10,747,715	10,717,234
ALLL for loans and leases individually evaluated for impairment			2,949	2,671
ALLL for loans and leases collectively evaluated for impairment			42,332	40,780
Total allowance for loan and lease losses	43,451	45,005	45,281	43,451	43,833	45,005
Non-PCI Loans | Commercial | Other commercial real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,481	4,571
Provision for Loan, Lease, and Other Losses	(83)	(1,293)
Charge-offs	0	0
Recoveries	1	145
Ending balance	2,399	3,423
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			541	860
Loans and leases collectively evaluated for impairment			426,878	426,125
Net loans and leases			427,419	426,985
ALLL for loans and leases individually evaluated for impairment			16	42
ALLL for loans and leases collectively evaluated for impairment			2,383	2,439
Total allowance for loan and lease losses	2,481	4,571	2,399	2,481	3,423	4,571
Non-PCI Loans | Commercial | Commercial and industrial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	55,620	59,824
Provision for Loan, Lease, and Other Losses	2,725	562
Charge-offs	(1,858)	(2,329)
Recoveries	538	1,260
Ending balance	57,025	59,317
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			9,987	9,868
Loans and leases collectively evaluated for impairment			3,869,588	3,928,862
Net loans and leases			3,879,575	3,938,730
ALLL for loans and leases individually evaluated for impairment			1,420	1,137
ALLL for loans and leases collectively evaluated for impairment			55,605	54,483
Total allowance for loan and lease losses	55,620	59,824	57,025	55,620	59,317	59,824
Non-PCI Loans | Commercial | Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,221	4,689
Provision for Loan, Lease, and Other Losses	(498)	114
Charge-offs	0	(3)
Recoveries	444	42
Ending balance	2,167	4,842
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			337	291
Loans and leases collectively evaluated for impairment			280,511	296,133
Net loans and leases			280,848	296,424
ALLL for loans and leases individually evaluated for impairment			151	105
ALLL for loans and leases collectively evaluated for impairment			2,016	2,116
Total allowance for loan and lease losses	2,221	4,689	2,167	2,221	4,842	4,689
Non-PCI Loans | Noncommercial | Construction and land development
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,350	3,962
Provision for Loan, Lease, and Other Losses	123	107
Charge-offs	0	(182)
Recoveries	0	26
Ending balance	2,473	3,913
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			3,742	3,749
Loans and leases collectively evaluated for impairment			255,217	253,281
Net loans and leases			258,959	257,030
ALLL for loans and leases individually evaluated for impairment			99	81
ALLL for loans and leases collectively evaluated for impairment			2,374	2,269
Total allowance for loan and lease losses	2,350	3,962	2,473	2,350	3,913	3,962
Non-PCI Loans | Noncommercial | Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	15,472	15,706
Provision for Loan, Lease, and Other Losses	1,508	1,512
Charge-offs	(166)	(806)
Recoveries	173	77
Ending balance	16,987	16,489
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			44,944	42,168
Loans and leases collectively evaluated for impairment			4,258,193	4,223,519
Net loans and leases			4,303,137	4,265,687
ALLL for loans and leases individually evaluated for impairment			3,149	1,901
ALLL for loans and leases collectively evaluated for impairment			13,838	13,571
Total allowance for loan and lease losses	15,472	15,706	16,987	15,472	16,489	15,706
Non-PCI Loans | Noncommercial | Revolving mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	21,862	22,436
Provision for Loan, Lease, and Other Losses	209	466
Charge-offs	(963)	(992)
Recoveries	387	194
Ending balance	21,495	22,104
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			29,216	28,852
Loans and leases collectively evaluated for impairment			2,440,682	2,514,123
Net loans and leases			2,469,898	2,542,975
ALLL for loans and leases individually evaluated for impairment			2,742	2,515
ALLL for loans and leases collectively evaluated for impairment			18,753	19,347
Total allowance for loan and lease losses	21,862	22,436	21,495	21,862	22,104	22,436
Non-PCI Loans | Noncommercial | Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	35,841	31,204
Provision for Loan, Lease, and Other Losses	3,440	2,923
Charge-offs	(6,362)	(5,255)
Recoveries	1,573	1,309
Ending balance	34,492	30,181
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Loans and leases individually evaluated for impairment			2,954	3,020
Loans and leases collectively evaluated for impairment			1,731,461	1,710,761
Net loans and leases			1,734,415	1,713,781
ALLL for loans and leases individually evaluated for impairment			906	885
ALLL for loans and leases collectively evaluated for impairment			33,586	34,956
Total allowance for loan and lease losses	35,841	31,204	34,492	35,841	30,181	31,204
PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,144	10,026
Provision for Loan, Lease, and Other Losses	(164)	2,354
Charge-offs	0	(84)
Recoveries	0	0
Ending balance	8,980	12,296
Allowance for Loans and Leases Evaluated for Impairment [Abstract]
Total allowance for loan and lease losses	$ 9,144	$ 10,026	8,980	$ 9,144	$ 12,296	$ 10,026
Loan and Leases Acquired with Deteriorated Credit Quality [Abstract]
Loans and leases acquired with deteriorated credit quality			$ 557,356

Allowance for Loan and Lease _4

Allowance for Loan and Lease Losses (Allocation of Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 153,517		$ 156,130
Unpaid principal balance	810,683	$ 1,108,379
Loans and Leases Receivable, Net Amount	25,235,010		25,299,564
Non-PCI impaired loans less than $500,000 collectively evaluated	44,800		47,100
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	71,021		74,560
Commercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,243		2,298
Commercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	57,855		61,065
Commercial | Other commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	541		860
Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,045		10,046
Commercial | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	337		291
Noncommercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	82,496		81,570
Noncommercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,330		2,337
Noncommercial | Consumer and Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,953		3,021
Noncommercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	47,693		47,524
Noncommercial | Revolving mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	29,520		28,688
PCI Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Recorded Investment	17,921		18,220
Acquired loans which have adverse change in expected cash flows	160,400		186,600
Provision for Loan, Lease, and Other Losses	(164)	2,354
Financing Receivable, Allowance for Credit Losses, Write-downs	0	(84)
Recoveries	0	0
Non-PCI Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	167,080		163,902
ALLL for loans and leases individually evaluated for impairment	11,965		9,827
Impaired Financing Receivable, with Related Allowance, Recorded Investment	122,376		115,073
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	27,625		31,357
Financing Receivable, Individually Evaluated for Impairment	150,001		146,430
Average balance	147,891	155,025
Interest income recognized	1,339	1,372
Provision for Loan, Lease, and Other Losses	11,914	5,251
Financing Receivable, Allowance for Credit Losses, Write-downs	(10,154)	(9,613)
Recoveries	3,467	3,315
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	207,830		204,741
Financing Receivable, Collectively Evaluated for Impairment	24,756,428		24,770,270
Loans and Leases Receivable, Net Amount	24,906,429		24,916,700
Non-PCI Loans | Commercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	2,538		2,606
ALLL for loans and leases individually evaluated for impairment	533		490
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,932		1,897
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	191		278
Financing Receivable, Individually Evaluated for Impairment	2,123		2,175
Average balance	2,147	1,155
Interest income recognized	28	11
Provision for Loan, Lease, and Other Losses	2,119	2,225
Financing Receivable, Allowance for Credit Losses, Write-downs	(44)	0
Recoveries	131	23
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	36,943		34,780
Financing Receivable, Collectively Evaluated for Impairment	802,340		755,679
Loans and Leases Receivable, Net Amount	804,463		757,854
Non-PCI Loans | Commercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	61,845		61,317
ALLL for loans and leases individually evaluated for impairment	2,949		2,671
Impaired Financing Receivable, with Related Allowance, Recorded Investment	37,575		34,177
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	18,582		21,270
Financing Receivable, Individually Evaluated for Impairment	56,157		55,447
Average balance	56,629	72,267
Interest income recognized	564	711
Provision for Loan, Lease, and Other Losses	2,371	(1,365)
Financing Receivable, Allowance for Credit Losses, Write-downs	(761)	(46)
Recoveries	220	239
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	42,332		40,780
Financing Receivable, Collectively Evaluated for Impairment	10,691,558		10,661,787
Loans and Leases Receivable, Net Amount	10,747,715		10,717,234
Non-PCI Loans | Commercial | Other commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	629		946
ALLL for loans and leases individually evaluated for impairment	16		42
Impaired Financing Receivable, with Related Allowance, Recorded Investment	222		243
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	319		617
Financing Receivable, Individually Evaluated for Impairment	541		860
Average balance	685	1,713
Interest income recognized	8	11
Provision for Loan, Lease, and Other Losses	(83)	(1,293)
Financing Receivable, Allowance for Credit Losses, Write-downs	0	0
Recoveries	1	145
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,383		2,439
Financing Receivable, Collectively Evaluated for Impairment	426,878		426,125
Loans and Leases Receivable, Net Amount	427,419		426,985
Non-PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	14,002		14,695
ALLL for loans and leases individually evaluated for impairment	1,420		1,137
Impaired Financing Receivable, with Related Allowance, Recorded Investment	7,613		7,153
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2,374		2,715
Financing Receivable, Individually Evaluated for Impairment	9,987		9,868
Average balance	10,000	9,762
Interest income recognized	100	87
Provision for Loan, Lease, and Other Losses	2,725	562
Financing Receivable, Allowance for Credit Losses, Write-downs	(1,858)	(2,329)
Recoveries	538	1,260
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	55,605		54,483
Financing Receivable, Collectively Evaluated for Impairment	3,869,588		3,928,862
Loans and Leases Receivable, Net Amount	3,879,575		3,938,730
Non-PCI Loans | Commercial | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	353		301
ALLL for loans and leases individually evaluated for impairment	151		105
Impaired Financing Receivable, with Related Allowance, Recorded Investment	262		216
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	75		75
Financing Receivable, Individually Evaluated for Impairment	337		291
Average balance	315	0
Interest income recognized	2	0
Provision for Loan, Lease, and Other Losses	(498)	114
Financing Receivable, Allowance for Credit Losses, Write-downs	0	(3)
Recoveries	444	42
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,016		2,116
Financing Receivable, Collectively Evaluated for Impairment	280,511		296,133
Loans and Leases Receivable, Net Amount	280,848		296,424
Non-PCI Loans | Noncommercial | Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	4,045		4,035
ALLL for loans and leases individually evaluated for impairment	99		81
Impaired Financing Receivable, with Related Allowance, Recorded Investment	2,330		2,337
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,412		1,412
Financing Receivable, Individually Evaluated for Impairment	3,742		3,749
Average balance	3,747	4,104
Interest income recognized	36	48
Provision for Loan, Lease, and Other Losses	123	107
Financing Receivable, Allowance for Credit Losses, Write-downs	0	(182)
Recoveries	0	26
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	2,374		2,269
Financing Receivable, Collectively Evaluated for Impairment	255,217		253,281
Loans and Leases Receivable, Net Amount	258,959		257,030
Non-PCI Loans | Noncommercial | Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	48,216		45,226
ALLL for loans and leases individually evaluated for impairment	3,149		1,901
Impaired Financing Receivable, with Related Allowance, Recorded Investment	43,553		40,359
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,391		1,809
Financing Receivable, Individually Evaluated for Impairment	44,944		42,168
Average balance	42,626	38,724
Interest income recognized	325	275
Provision for Loan, Lease, and Other Losses	1,508	1,512
Financing Receivable, Allowance for Credit Losses, Write-downs	(166)	(806)
Recoveries	173	77
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	13,838		13,571
Financing Receivable, Collectively Evaluated for Impairment	4,258,193		4,223,519
Loans and Leases Receivable, Net Amount	4,303,137		4,265,687
Non-PCI Loans | Noncommercial | Revolving mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	32,074		31,371
ALLL for loans and leases individually evaluated for impairment	2,742		2,515
Impaired Financing Receivable, with Related Allowance, Recorded Investment	26,017		25,751
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,199		3,101
Financing Receivable, Individually Evaluated for Impairment	29,216		28,852
Average balance	28,742	24,792
Interest income recognized	247	201
Provision for Loan, Lease, and Other Losses	209	466
Financing Receivable, Allowance for Credit Losses, Write-downs	(963)	(992)
Recoveries	387	194
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	18,753		19,347
Financing Receivable, Collectively Evaluated for Impairment	2,440,682		2,514,123
Loans and Leases Receivable, Net Amount	2,469,898		2,542,975
Non-PCI Loans | Noncommercial | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Unpaid principal balance	3,378		3,405
ALLL for loans and leases individually evaluated for impairment	906		885
Impaired Financing Receivable, with Related Allowance, Recorded Investment	2,872		2,940
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	82		80
Financing Receivable, Individually Evaluated for Impairment	2,954		3,020
Average balance	3,000	2,508
Interest income recognized	29	28
Provision for Loan, Lease, and Other Losses	3,440	2,923
Financing Receivable, Allowance for Credit Losses, Write-downs	(6,362)	(5,255)
Recoveries	1,573	$ 1,309
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	33,586		34,956
Financing Receivable, Collectively Evaluated for Impairment	1,731,461		1,710,761
Loans and Leases Receivable, Net Amount	$ 1,734,415		$ 1,713,781

Allowance for Loan and Lease _5

Allowance for Loan and Lease Losses (Troubled Debt Restructuring) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)loans	Mar. 31, 2018USD ($)loans	Dec. 31, 2018USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	91	121
Financing Receivable, Modifications, Recorded Investment	$ 153,517		$ 156,130
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 5,241	$ 11,049
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	61	74
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 3,808	$ 5,291
PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	17,921		18,220
Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	71,021		74,560
Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,243		2,298
Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	57,855		61,065
Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	541		860
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,045		10,046
Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	337		291
Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	82,496		81,570
Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,330		2,337
Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	47,693		47,524
Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	29,520		28,688
Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,953		3,021
Accruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	123,711		127,093
Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	62,024		64,171
Accruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,914		1,946
Accruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	51,202		53,270
Accruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	536		851
Accruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8,253		7,986
Accruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	119		118
Accruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	61,687		62,922
Accruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,150		2,227
Accruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	37,111		37,903
Accruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,320		20,492
Accruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,106		2,300
Nonaccruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	29,806		29,037
Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8,997		10,389
Nonaccruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	329		352
Nonaccruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6,653		7,795
Nonaccruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	5		9
Nonaccruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,792		2,060
Nonaccruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	218		173
Nonaccruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,809		18,648
Nonaccruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	180		110
Nonaccruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,582		9,621
Nonaccruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,200		8,196
Nonaccruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 847		$ 721
Interest only period provided
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	0	1
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 644
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0
Loan term extension
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	3	6
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 420	$ 932
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	3	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 541	$ 305
Below market interest rate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	46	66
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 2,953	$ 5,660
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	33	30
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 2,123	$ 1,814
Discharged from bankruptcy
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	42	48
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,868	$ 3,813
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	25	43
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 1,144	$ 3,172

Allowance for Loan and Lease _6

Allowance for Loan and Lease Losses (Note Restructurings During Period) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)loans	Mar. 31, 2018USD ($)loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	91	121
Financing Receivable, Modifications, Post-Modification Recorded Investment | $	$ 5,241	$ 11,049
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	61	74
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 3,808	$ 5,291
Loan term extension
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	3	6
Financing Receivable, Modifications, Post-Modification Recorded Investment | $	$ 420	$ 932
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	3	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 541	$ 305
Interest only period provided
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	0	1
Financing Receivable, Modifications, Post-Modification Recorded Investment | $	$ 0	$ 644
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 0	$ 0
Below market interest rate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	46	66
Financing Receivable, Modifications, Post-Modification Recorded Investment | $	$ 2,953	$ 5,660
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	33	30
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 2,123	$ 1,814
Discharged from bankruptcy
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	42	48
Financing Receivable, Modifications, Post-Modification Recorded Investment | $	$ 1,868	$ 3,813
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	25	43
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 1,144	$ 3,172

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Real Estate Properties [Line Items]
Advances from Federal Home Loan Banks			$ 175,200
Mortgage Loans in Process of Foreclosure, Amount	$ 23,900		$ 22,000
Total
Beginning balance	48,030	$ 51,097
Additions	3,133	6,582
Sales	(6,934)	(7,997)
Write-downs	(923)	(1,593)
Ending balance	43,306	$ 48,089
Mortgage
Total
Beginning balance	17,200
Ending balance	15,400
Federal Home Loan Bank of Chicago
Real Estate Properties [Line Items]
Advances from Federal Home Loan Banks	$ 14,500

FDIC Shared-Loss Receivable (Na

FDIC Shared-Loss Receivable (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
FDIC Shared-Loss Receivable [Abstract]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	$ 53,900
FDIC shared-loss payable	$ 107,256	$ 105,618

FDIC Shared-Loss Receivable FDI

FDIC Shared-Loss Receivable FDIC Shared-Loss Payable (Changes in Payable to FDIC) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
FDIC Shared-Payable [Abstract]
FDIC shared-loss payable	$ 105,618
Accretion expense	1,638
FDIC shared-loss payable	$ 107,256

Mortgage Servicing Rights (MSR

Mortgage Servicing Rights (MSR Carrying Value) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Servicing Asset at Amortized Cost [Line Items]
Mortgage servicing rights	$ 20,647,000	$ 21,659,000	$ 21,396,000	$ 21,945,000
Servicing rights originated	859,000	1,200,000
Amortization of Mortgage Servicing Rights (MSRs)	(1,447,000)	(1,486,000)
Valuation allowance (provision) reversal	$ (161,000)	$ 0

Mortgage Servicing Rights (Valu

Mortgage Servicing Rights (Valuation allowance) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Valuation Allowance for Impairment of Recognized Servicing Assets [Line Items]
Valuation allowance provision (reversal)	$ 161,000	$ 0

Mortgage Servicing Rights (Econ

Mortgage Servicing Rights (Economic Assumptions) (Details) - $ / loans	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Servicing Asset Key Economic Assumptions [Line Items]
Weighted average constant prepayment rate	11.28%	9.26%
Weighted average cost to service a loan	88.07	87.52
Fixed Rate Residential Mortgage
Servicing Asset Key Economic Assumptions [Line Items]
Discount rate	9.41%	9.6851%
All Loans and Leases, Excluding Conventional Fixed Loans
Servicing Asset Key Economic Assumptions [Line Items]
Discount rate	10.41%	10.6851%

Mortgage Servicing Rights (Narr

Mortgage Servicing Rights (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Mortgage Servicing Rights [Abstract]
Residential Mortgage Loans Serviced	$ 2,970,000,000		$ 2,950,000,000
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	1,900,000	$ 1,900,000
Other servicing rights	2,400,000		$ 2,700,000
Amortization of Mortgage Servicing Rights (MSRs)	1,447,000	1,486,000
Valuation allowance provision (reversal)	$ (161,000)	$ 0

Repurchase Agreements (Details)

Repurchase Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase, Fair Value of Collateral	$ 571,600	$ 598,600
Securities sold under customer repurchase agreements	508,508	543,936
Overnight and continuous | U. S. Treasury
Assets Sold under Agreements to Repurchase [Line Items]
Securities sold under customer repurchase agreements	$ 508,508	$ 543,936

Estimated Fair Values (Estimate

Estimated Fair Values (Estimated Fair Values For Certain Financial Assets And Financial Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 268,599	$ 327,440
Overnight investments	1,386,525	797,406
Investment securities held to maturity	2,214,829	2,184,653
Investment in marketable equity securities	109,884	92,599
Loans held for sale	53,232	45,505
Loans and Leases Receivable, Net Amount	25,235,010	25,299,564
Income earned not collected	113,812	109,903
Mortgage servicing rights	20,647	21,396	$ 21,659	$ 21,945
Deposits	31,198,093	30,672,460
Securities sold under customer repurchase agreements	508,508	543,936
Federal Home Loan Bank borrowings	189,594	193,556
FDIC shared-loss payable	107,256	105,618
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	268,599	327,440
Overnight investments	1,386,525	797,406
Debt Securities, Available-for-sale	4,589,800	4,557,110
Investment securities held to maturity	2,214,829	2,184,653
Investment in marketable equity securities	109,884	92,599
Loans held for sale	53,232	45,505
Loans and Leases Receivable, Net Amount	25,235,010	25,299,564
Income earned not collected	113,812	109,903
Stock issued by Federal Home Loan Bank	25,174	25,304
Mortgage servicing rights	24,080	24,615
Deposits	31,198,093	30,672,460
Securities sold under customer repurchase agreements	508,508	543,936
Federal Home Loan Bank borrowings	189,594	193,556
Short-term borrowings	136,544	140,741
Long-term obligations	14,970	13,921
FDIC shared-loss payable	107,256	105,618
Accrued interest payable	7,169	3,712
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	268,599	327,440
Overnight investments	1,386,525	797,406
Debt Securities, Available-for-sale	4,589,800	4,557,110
Investment securities held to maturity	2,254,924	2,201,502
Investment in marketable equity securities	109,884	92,599
Loans held for sale	53,232	45,505
Loans and Leases Receivable, Net Amount	25,187,938	24,845,060
Income earned not collected	113,812	109,903
Stock issued by Federal Home Loan Bank	25,174	25,304
Mortgage servicing rights	25,769	27,435
Deposits	31,174,142	30,623,214
Securities sold under customer repurchase agreements	508,508	543,936
Federal Home Loan Bank borrowings	192,779	195,374
Short-term borrowings	140,676	151,670
Long-term obligations	14,833	13,985
FDIC shared-loss payable	109,947	105,846
Accrued interest payable	$ 7,169	$ 3,712

Estimated Fair Values (Assets A

Estimated Fair Values (Assets And Liabilities Carried At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	$ 4,589,800	$ 4,557,110
Investment in marketable equity securities	109,884	92,599
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,589,800	4,557,110
Investment in marketable equity securities	109,884
Loans held for sale	53,232	45,505
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Investment in marketable equity securities	18,250
Loans held for sale	0	0
Fair Value, Measurements, Recurring | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,443,513	4,413,884
Investment in marketable equity securities	91,634
Loans held for sale	53,232	45,505
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	146,287	143,226
Investment in marketable equity securities	0
Loans held for sale	0	0
Fair Value, Measurements, Recurring | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,197,042	1,247,710
Fair Value, Measurements, Recurring | U.S. Treasury | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | U.S. Treasury | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,197,042	1,247,710
Fair Value, Measurements, Recurring | U.S. Treasury | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	350,527	256,835
Fair Value, Measurements, Recurring | Agency Securities | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Agency Securities | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	350,527	256,835
Fair Value, Measurements, Recurring | Agency Securities | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	2,895,944	2,909,339
Fair Value, Measurements, Recurring | Mortgage Backed Securities | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Mortgage Backed Securities | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	2,895,944	2,909,339
Fair Value, Measurements, Recurring | Mortgage Backed Securities | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale		92,599
Fair Value, Measurements, Recurring | Equity Securities | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale		17,887
Fair Value, Measurements, Recurring | Equity Securities | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale		74,712
Fair Value, Measurements, Recurring | Equity Securities | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale		0
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	142,162	139,101
Fair Value, Measurements, Recurring | Corporate Bonds | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Corporate Bonds | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Corporate Bonds | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	142,162	139,101
Fair Value, Measurements, Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,125	4,125
Fair Value, Measurements, Recurring | Other | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Other | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring | Other | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	$ 4,125	$ 4,125

Estimated Fair Values (Assets_2

Estimated Fair Values (Assets and Liabilities Carried at Fair Value on a Recurring Basis Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investment securities available for sale	$ 4,589,800	$ 4,557,110
Corporate Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	139,101
Amounts included in net income	39
Unrealized net (losses) gains included in other comprehensive income	22
Purchases	3,000
Sales	0
Ending balance	142,162
Other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4,125
Amounts included in net income	6
Unrealized net (losses) gains included in other comprehensive income	(6)
Purchases	0
Sales	0
Ending balance	$ 4,125

Estimated Fair Values (Assets_3

Estimated Fair Values (Assets And Liabilities Carried At Fair Value On A Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate remeasured during current year	$ 43,306	$ 48,030	$ 48,089	$ 51,097
Mortgage servicing rights	20,647	21,396	$ 21,659	$ 21,945
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	110,411	105,994
Other real estate remeasured during current year	32,620	35,344
Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate remeasured during current year	0	0
Fair Value, Measurements, Nonrecurring | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate remeasured during current year	0	0
Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	110,411	105,994
Other real estate remeasured during current year	$ 32,620	$ 35,344

Estimated Fair Values (Fair Val

Estimated Fair Values (Fair Value Option) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Gains (Losses) from fair value changes on originated loans held for sale	$ 249	$ (455)
Loans Held For Sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value of originated loans held for sale	53,232		$ 45,505
Aggregate unpaid principle balance of originated loans held for sale	51,550		44,073
Difference between fair value and aggregate unpaid principle balance of originated loans held for sale	$ 1,682		$ 1,432

Estimated Fair Values (Narrativ

Estimated Fair Values (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$ 0
Gains (Losses) from fair value changes on originated loans held for sale	249	$ (455)
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability measured at fair value on nonrecurring basis	$ 0		$ 0
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		59,700
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		$ 5,600
Discount Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.06
OREO, measurement input	0.06
Discount Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.11
OREO, measurement input	0.11
Effective Interest Rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.02
Effective Interest Rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, measurement input	0.18

Employee Benefit Plans (Compone

Employee Benefit Plans (Components Of Pension Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
BancShares Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 2,568	$ 3,429
Interest cost	7,531	7,057
Expected return on assets	(12,867)	(11,957)
Amortization of prior service cost	14	20
Amortization of net actuarial loss	2,114	3,246
Total pension expense	(640)	1,795
Bancorporation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	545	662
Interest cost	1,760	1,587
Expected return on assets	(2,768)	(3,106)
Amortization of net actuarial loss	627	71
Total pension expense	$ 164	$ (786)

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
BancShares Plan
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions in current year	$ 0
Defined Benefit Plan, Plan Assets, Contributions by Employer	0
Bancorporation Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0

Commitments and Contingencies_2

Commitments and Contingencies (Details) $ in Thousands	Mar. 31, 2019USD ($)Advances	Dec. 31, 2018USD ($)
Guarantor Obligations [Line Items]
FDIC shared-loss payable	$ 107,256	$ 105,618
Number Of Federal Home Loan Bank Advances | Advances
Standby Letters of Credit
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 152,862	147,333
Commitments to Extend Credit
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	10,187,550	10,054,712
Qualified Affordable Housing Project Investments, Commitment	91,719	96,467
Qualified Affordable Housing Project Investments	$ 72,002	$ 67,952

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), before Tax		$ (268,650)		$ (305,438)
Deferred tax expense (benefit)		(61,790)		(70,251)
Accumulated other comprehensive income (loss), net of tax		(206,860)	$ (230,323)	(235,187)	$ (122,294)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(6,712)	(2,569)
Amortization of actuarial losses and prior service cost		(2,741)	(3,317)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax		2,755	3,337
Unrealized Losses on Investment Securities Available for Sale
Accumulated Other Comprehensive Income (Loss), before Tax		(21,936)		(50,007)
Deferred tax expense (benefit)		(5,046)		(11,502)
Accumulated other comprehensive income (loss), net of tax	[1]	(16,890)	(121,243)	(38,505)	(30,945)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	0	0
Unrealized Losses On Securities Available For Sale Transferred To Held To Maturity
Accumulated Other Comprehensive Income (Loss), before Tax		(86,439)		(92,401)
Deferred tax expense (benefit)		(19,881)		(21,252)
Accumulated other comprehensive income (loss), net of tax	[1]	(66,558)	0	(71,149)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	(4,591)	0
Funded Status of Defined Benefit Plan
Accumulated Other Comprehensive Income (Loss), before Tax		(160,275)		(163,030)
Deferred tax expense (benefit)		(36,863)		(37,497)
Accumulated other comprehensive income (loss), net of tax	[1]	(123,412)	(109,080)	$ (125,533)	$ (91,349)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	$ (2,121)	$ (2,569)
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) (Components of AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ (50,051)
Beginning balance		$ (235,187)	$ (122,294)
Net unrealized gains arising during period		21,615	(60,547)
Amounts reclassified from accumulated other comprehensive loss		6,712	2,569
Net current period other comprehensive income		28,327	(57,978)
Ending balance		(206,860)	(230,323)
Unrealized Losses on Investment Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				(29,751)
Beginning balance	[1]	(38,505)	(30,945)
Net unrealized gains arising during period	[1]	21,615	(60,547)
Amounts reclassified from accumulated other comprehensive loss	[1]	0	0
Net current period other comprehensive income	[1]	21,615	(60,547)
Ending balance	[1]	(16,890)	(121,243)
Unrealized Losses On Securities Available For Sale Transferred To Held To Maturity
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				0
Beginning balance	[1]	(71,149)	0
Net unrealized gains arising during period	[1]	0	0
Amounts reclassified from accumulated other comprehensive loss	[1]	4,591	0
Net current period other comprehensive income	[1]	4,591	0
Ending balance	[1]	(66,558)	0
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ (20,300)
Beginning balance	[1]	(125,533)	(91,349)
Net unrealized gains arising during period	[1]	0	0
Amounts reclassified from accumulated other comprehensive loss	[1]	2,121	2,569
Net current period other comprehensive income	[1]	2,121	2,569
Ending balance	[1]	$ (123,412)	$ (109,080)
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

Accumulated Other Comprehensi_5

Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of actuarial losses and prior service cost		$ (2,741)	$ (3,317)
Total before taxes		(2,755)	(3,337)
Amounts reclassified from accumulated other comprehensive income, net of tax		6,712	2,569
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax		(14)	(20)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax		634	768
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax		(2,121)	(2,569)
Other Comprehensive Income (Loss) Reclassification Adjustment Of Unrealized Losses From AOCI For Securities Available For Sale Transferred To Held To Maturity Before Tax		(5,962)
Other Comprehensive Income (Loss) Reclassification Adjustment Of Unrealized Losses From AOCI For Securities Available For Sale Transferred To Held To Maturity Tax		1,371
Other Comprehensive Income (Loss) Reclassification Adjustment Of Unrealized Losses From AOCI For Securities Available For Sale Transferred To Held To Maturity Net Of Tax		(4,591)
Unrealized Losses on Investment Securities Available for Sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	0	0
Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	$ 2,121	$ 2,569
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

Leases (Narrative) (Details)

Leases (Narrative) (Details)	Mar. 31, 2019
Minimum
Lessee, Lease, Description [Line Items]
Renewal terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal terms	25 years

Leases (Operating and Finance L

Leases (Operating and Finance Lease Assets and Liabilities) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Asset, operating	$ 70,815
Asset, finance	8,763
Total leased assets	79,578
Present value of lease liabilities	72,315
Present value of lease liabilities	7,828
Total lease liabilities	80,143
Operating lease, fair value adjustment	1,100
Accumulated deprecation on finance leases	$ 447

Leases (Net Lease Cost) (Detail

Leases (Net Lease Cost) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 3,204
Amortization of leased assets	447
Interest on lease liabilities	65
Variable lease cost	528
Sublease income	(130)
Net lease cost	$ 4,114

Leases (Lease Liability Maturit

Leases (Lease Liability Maturities) (Details) $ in Thousands	Mar. 31, 2019USD ($)
Operating Leases
2019	$ 10,310
2020	12,475
2021	10,947
2022	9,575
2023	7,772
Thereafter	35,343
Total lease payments	86,422
Less: Interest	14,107
Present value of lease liabilities	72,315
Finance Leases
2019	1,301
2020	1,748
2021	1,764
2022	1,481
2023	599
Thereafter	1,683
Total lease payments	8,576
Less: Interest	748
Present value of lease liabilities	7,828
Total
2019	11,611
2020	14,223
2021	12,711
2022	11,056
2023	8,371
Thereafter	37,026
Total lease payments	94,998
Less: Interest	14,855
Present value of lease liabilities	$ 80,143

Leases (Remaining Weighted Aver

Leases (Remaining Weighted Average Lease Terms and Discounts Rates) (Details)	Mar. 31, 2019
Leases [Abstract]
Weighted average remaining lease term, operating	9 years 8 months 12 days
Weighted average remaining lease term, finance	5 years 4 months 24 days
Weighted average discount rate, operating	3.36%
Weighted average discount rate, finance	3.22%

Leases (Supplemental Cash Flow

Leases (Supplemental Cash Flow Information) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 3,550
Operating cash flows from finance leases	65
Financing cash flows from finance leases	366
Right-of-use assets obtained in exchange for new operating lease liabilities	3,591
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 0