Synovus Financial (SNV) 10-Q 7 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Entity Registrant Name	SYNOVUS FINANCIAL CORP
Entity Central Index Key	18,349
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		118,640,312,000

CONSOLIDATED BALANCE SHEETS (un

CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks		$ 348,027	$ 397,848
Interest bearing funds with Federal Reserve Bank		636,947	460,928
Interest earning deposits with banks		16,851	26,311
Federal funds sold and securities purchased under resale agreements		57,192	47,846
Total cash, cash equivalents, restricted cash, and restricted cash equivalents	[1],[2]	1,059,017	932,933
Mortgage loans held for sale, at fair value		50,439	48,024
Investment securities available for sale, at fair value		3,990,978	3,987,069
Loans, net of deferred fees and costs		24,883,037	24,787,464
Allowance for loan losses		(257,764)	(249,268)
Loans, net		24,625,273	24,538,196
Cash surrender value of bank-owned life insurance		543,684	540,958
Premises and equipment, net		424,342	426,813
Goodwill		57,315	57,315
Other intangible assets		10,750	11,254
Deferred tax asset, net		179,343	165,788
Other assets		559,887	513,487
Total assets		31,501,028	31,221,837
Deposits:
Non-interest bearing deposits		7,381,070	7,686,339
Interest bearing deposits, excluding brokered deposits		16,865,859	16,500,436
Brokered deposits		2,006,578	1,961,125
Total deposits		26,253,507	26,147,900
Federal funds purchased and securities sold under repurchase agreements		185,531	161,190
Long-term debt		1,856,392	1,706,138
Other liabilities		249,103	245,043
Total liabilities		28,544,533	28,260,271
Shareholders' Equity
Series C Preferred Stock – no par value. Authorized 100,000,000 shares; 5,200,000 shares issued and outstanding at March 31, 2018 and December 31, 2017		125,980	125,980
Common stock - $1.00 par value. Authorized 342,857,143 shares; 143,017,301 issued at March 31, 2018 and 142,677,449 issued at December 31, 2017; 118,702,497 outstanding at March 31, 2018 and 118,897,295 outstanding at December 31, 2017		143,017	142,678
Additional paid-in capital		3,039,757	3,043,129
Treasury stock, at cost – 24,314,804 shares at March 31, 2018 and 23,780,154 shares at December 31, 2017		(866,407)	(839,674)
Accumulated other comprehensive loss		(107,777)	(54,754)
Retained earnings		621,925	544,207
Total shareholders’ equity		2,956,495	2,961,566
Total liabilities and shareholders' equity		$ 31,501,028	$ 31,221,837
[1]	See "Note 1 - Significant Accounting Policies" of this Report for information on Synovus' change in presentation of cash and cash equivalents.
[2]	See "Note 1 - Significant Accounting Policies" of this Report for information on Synovus' change in presentation of cash and cash equivalents.

CONSOLIDATED BALANCE SHEETS (u3

CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred Stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred Stock, shares issued (in shares)	5,200,000	5,200,000
Preferred stock, shares outstanding (in shares)	5,200,000	5,200,000
Common stock, par value (USD per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	342,857,143	342,857,143
Common stock, shares issued (in shares)	143,017,301	142,677,449
Common stock, shares outstanding (in shares)	118,702,497	118,897,295
Treasury stock, shares at cost (in shares)	24,314,804	23,780,154

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest income:
Loans, including fees	$ 285,340	$ 249,348
Investment securities available for sale	23,928	19,834
Trading account assets	54	28
Mortgage loans held for sale	379	467
Federal Reserve Bank balances	1,750	1,211
Other earning assets	1,683	1,513
Total interest income	313,134	272,401
Interest expense:
Deposits	26,375	16,958
Federal funds purchased and securities sold under repurchase agreements	107	38
Long-term debt	12,368	15,478
Total interest expense	38,850	32,474
Net interest income	274,284	239,927
Provision for loan losses	12,776	8,674
Net interest income after provision for loan losses	261,508	231,253
Non-interest income:
Service charges on deposit accounts	19,940	20,118
Fiduciary and asset management fees	13,435	12,151
Card fees	10,199	9,844
Brokerage revenue	8,695	7,226
Mortgage banking income	5,047	5,766
Income from bank-owned life insurance	4,217	3,056
Investment securities gains, net	0	7,668
Decrease in fair value of private equity investments, net	(3,056)	(1,814)
Other fee income	4,618	4,868
Other non-interest income	3,951	2,956
Total non-interest income	67,046	71,839
Non-interest expense:
Salaries and other personnel expense	113,720	107,191
Net occupancy and equipment expense	31,480	29,331
Third-party processing expense	13,945	12,603
FDIC insurance and other regulatory fees	6,793	6,770
Professional fees	5,505	5,355
Advertising expense	5,092	5,912
Foreclosed real estate expense, net	856	2,134
Restructuring charges, net	(315)	6,511
Other operating expenses	18,103	21,581
Total non-interest expense	195,179	197,388
Income before income taxes	133,375	105,704
Income tax expense	30,209	33,847
Net income	103,166	71,857
Dividends on preferred stock	2,559	2,559
Net income available to common shareholders	$ 100,607	$ 69,298
Net income per common share, basic (in dollars per share)	$ 0.85	$ 0.57
Net income per common share, diluted (in dollars per share)	$ 0.84	$ 0.56
Weighted average common shares outstanding, basic (in shares)	118,666	122,300
Weighted average common shares outstanding, diluted (in shares)	119,321	123,059

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income, Before-tax Amount	$ 133,375	$ 105,704
Net income, Tax (Expense) Benefit	(30,209)	(33,847)
Net income	103,166	71,857
Reclassification adjustment for losses realized in net income, Before-tax Amount	0	65
Reclassification adjustment for losses realized in net income, Tax (Expense) Benefit	0	(25)
Reclassification adjustment for losses realized in net income, Net of Tax Amount	0	40
Net unrealized gains on investment securities available for sale:
Reclassification adjustment for net losses (gains) realized in net income, Before-tax Amount	0	(7,668)
Net unrealized gains arising during the period, Before-tax Amount	(61,445)	9,099
Net unrealized gain, Before-tax Amount	(61,445)	1,431
Net unrealized gains on investment securities available for sale: Tax (Expense) Benefit
Reclassification adjustment for net losses (gains) realized in net income, Tax (Expense) Benefit	0	2,952
Net unrealized gains arising during the period, Tax (Expense) Benefit	15,914	(3,503)
Net unrealized gains, Tax (Expense) Benefit	15,914	(551)
Net unrealized gains on investment securities available for sale: Net of Tax Amount
Reclassification adjustment for net losses (gains) realized in net income, Net of Tax Amount	0	(4,716)
Net unrealized gains arising during the period, Net of Tax Amount	(45,531)	5,596
Net unrealized gains, Net of Tax Amount	(45,531)	880
Post-retirement unfunded health benefit: Before-tax Amount
Reclassification adjustment for gains realized in net income, Before-tax Amount	(34)	(20)
Post-retirement unfunded health benefit: Tax (Expense) Benefit
Reclassification adjustment for gains realized in net income, Tax (Expense) Benefit	13	8
Post-retirement unfunded health benefit: Net of Tax Amount
Reclassification adjustment for gains realized in net income, Net of Tax Amount	(21)	(12)
Other comprehensive income (loss), Before-tax Amount	(61,479)	1,476
Other comprehensive income (loss), Tax (Expense) Benefit	15,927	(568)
Other comprehensive income (loss), Net of Tax Amount	(45,552)	908
Comprehensive income, Net of Tax Amount	$ 57,614	$ 72,765

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands	Total	Preferred StockSeries C Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU	$ 0
Balance at Dec. 31, 2016	2,927,924	$ 125,980	$ 142,026	$ 3,028,405	$ (664,595)	$ (55,659)	$ 351,767
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	71,857						71,857
Other comprehensive income, net of income taxes	908					908
Cash dividends declared on common stock	(18,347)						(18,347)
Cash dividends paid on Series C Preferred Stock	(2,559)						(2,559)
Repurchases of common stock	(15,151)			0	(15,151)
Restricted share unit activity	(7,784)		305	(7,799)			(290)
Stock options exercised	1,919		110	1,809
Share-based compensation expense	3,360			3,360
Balance at Mar. 31, 2017	2,962,127	125,980	142,441	3,025,775	(679,746)	(54,751)	402,428
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU	(685)
Adoption of ASU | ASU 2014-09	(685)						(685)
Adoption of ASU | ASU 2018-02	0					(7,588)	7,588
Adoption of ASU | ASU 2016-01	0					117	(117)
Balance at Dec. 31, 2017	2,961,566	125,980	142,678	3,043,129	(839,674)	(54,754)	544,207
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	103,166						103,166
Other comprehensive income, net of income taxes	(45,552)					(45,552)
Cash dividends declared on common stock	(29,675)						(29,675)
Cash dividends paid on Series C Preferred Stock	(2,559)						(2,559)
Repurchases of common stock	(26,733)				(26,733)
Restricted share unit activity	(8,228)		266	(8,494)
Stock options exercised	1,240		73	1,167
Share-based compensation expense	3,955			3,955
Balance at Mar. 31, 2018	2,956,495	$ 125,980	$ 143,017	$ 3,039,757	$ (866,407)	$ (107,777)	$ 621,925
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU | ASU 2016-01	$ 3,200

CONSOLIDATED STATEMENTS OF CHA7

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Stockholders' Equity [Abstract]
Cash dividends declared on common stock, per share	$ 0.25	$ 0.15

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017
Operating Activities
Net income		$ 103,166		$ 71,857
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses		12,776		8,674
Depreciation, amortization, and accretion, net		14,823		14,479
Deferred income tax expense		2,599		36,014
Originations of mortgage loans held for sale		(128,618)		(156,043)
Proceeds from sales of mortgage loans held for sale		130,805		155,245
Gain on sales of mortgage loans held for sale, net		(3,445)		(3,560)
(Increase) decrease in other assets		(52,159)		7,375
(Decrease) increase in other liabilities		(8,466)		4,963
Investment securities gains, net		0		(7,668)
Share-based compensation expense		3,955		3,360
Net cash provided by operating activities		75,436		134,696
Investing Activities
Proceeds from maturities and principal collections of investment securities available for sale		139,929		163,386
Proceeds from sales of investment securities available for sale		0		282,629
Purchases of investment securities available for sale		(211,085)		(410,814)
Proceeds from sales of loans		10,885		0
Proceeds from sales of other real estate		2,090		2,773
Net increase in loans		(109,180)		(419,552)
Purchases of bank-owned life insurance policies, net of settlements		1,523		(73,110)
Net increase in premises and equipment		(9,212)		(5,497)
Proceeds from sales of other assets held for sale		0		1,328
Net cash used in investing activities		(175,050)		(458,857)
Financing Activities
Net (decrease) increase in demand and savings deposits		(216,836)		364,517
Net increase in certificates of deposit		322,338		92,955
Net increase (decrease) in federal funds purchased and securities sold under repurchase agreements		24,341		(13,219)
Repayments and redemption of long-term debt		(2,130,030)		(275,000)
Proceeds from issuance of long-term debt		2,280,000		275,000
Dividends paid to common shareholders		(17,835)		(18,347)
Dividends paid to preferred shareholders		(2,559)		(2,559)
Stock options exercised		1,240		1,919
Repurchase of common stock		(26,733)		(15,151)
Taxes paid related to net share settlement of equity awards		8,228		7,784
Net cash provided by financing activities		225,698		402,331
Increase in cash and cash equivalents including restricted cash		126,084		78,170
Cash, cash equivalents, restricted cash, and restricted cash equivalents at beginning of period	[2]	932,933	[1]	999,045
Cash, cash equivalents, restricted cash, and restricted cash equivalents at end of period	[2]	1,059,017	[1]	1,077,215
Supplemental Cash Flow Information
Income tax payments, net		183		210
Interest paid		33,431		31,714
Non-cash Activities
Loans foreclosed and transferred to other real estate		3,407		2,679
Loans transferred to other loans held for sale at fair value		5,233		8,442
Equity investment securities available for sale transferred to other assets at fair value		3,162		0
Securities purchased during the period but settled after period-end		0		94,560
Dividends declared on common stock during the period but paid after period-end		$ 29,675		$ 0
[1]	See "Note 1 - Significant Accounting Policies" of this Report for information on Synovus' change in presentation of cash and cash equivalents.
[2]	See "Note 1 - Significant Accounting Policies" of this Report for information on Synovus' change in presentation of cash and cash equivalents.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Note 1 - Significant Accounting Policies Business Operations The accompanying unaudited interim consolidated financial statements of Synovus Financial Corp. include the accounts of the Parent Company and its consolidated subsidiaries. Synovus Financial Corp. is a financial services company based in Columbus, Georgia. Through its wholly-owned subsidiary, Synovus Bank, a Georgia state-chartered bank that is a member of the Federal Reserve System, the company provides commercial and retail banking in addition to a full suite of specialized products and services including private banking, treasury management, wealth management, premium finance and international banking. Synovus Bank is positioned in some of the highest growth markets in the Southeast, with 250 branches and 328 ATMs in Georgia, Alabama, South Carolina, Florida, and Tennessee. Basis of Presentation The accompanying unaudited interim consolidated financial statements have been prepared in accordance with the instructions to the SEC Form 10-Q and Article 10 of Regulation S-X; therefore, they do not include all information and footnotes necessary for a fair presentation of financial position, results of operations, comprehensive income, and cash flows in conformity with GAAP. All adjustments consisting of normally recurring accruals that, in the opinion of management, are necessary for a fair presentation of the consolidated financial position and results of operations for the periods covered by this Report have been included. The accompanying unaudited interim consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes appearing in Synovus' 2017 Form 10-K . In connection with the adoption of ASU 2016-18, Statement of Cash Flows-Restricted Cash, Synovus changed its presentation of cash and cash equivalents, effective January 1, 2018, to include cash and due from banks as well as interest bearing funds with the Federal Reserve Bank, interest earning deposits with banks, and federal funds sold and securities purchased under resale agreements, which are inclusive of any restricted cash and restricted cash equivalents. Prior to 2018, cash and cash equivalents only included cash and due from banks. Prior periods have been revised to maintain comparability. Excluding the aforementioned presentation change, there have been no significant changes to the accounting policies as disclosed in Synovus' 2017 Form 10-K . In preparing the unaudited interim consolidated financial statements in accordance with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the respective consolidated balance sheets and the reported amounts of revenues and expenses for the periods presented. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses, the fair value of investment securities, and the fair value of private equity investments. Cash and Cash Equivalents Cash and cash equivalents consist of cash and due from banks, interest bearing funds with the Federal Reserve Bank, interest earning deposits with banks, federal funds sold and securities purchased under resale agreements, and is inclusive of any restricted cash and restricted cash equivalents. Restricted cash and restricted cash equivalents primarily relate to cash held on deposit with the Federal Reserve to meet reserve requirements as well as cash posted as collateral for derivatives in a liability position. At March 31, 2018 and December 31, 2017 , interest bearing funds with the Federal Reserve Bank included $14.1 million and $8.6 million , respectively, on deposit to meet Federal Reserve Bank requirements. Interest earning deposits with banks include $6.3 million and $5.9 million at March 31, 2018 and December 31, 2017 , respectively, which are pledged as collateral in connection with certain letters of credit. Federal funds sold include $32.7 million and $43.8 million at March 31, 2018 and December 31, 2017 , respectively, which are pledged to collateralize certain derivative financial instruments. Federal funds sold and securities purchased under resale agreements generally mature in one day. Income Taxes On December 22, 2017, Federal Tax Reform was enacted into law. The new legislation included a decrease in the corporate federal income tax rate from 35% to 21% effective January 1, 2018. Under ASC 740, the effects of the changes in tax rates and laws are recognized in the period in which the new legislation is enacted. Therefore, Synovus was required to remeasure its deferred tax assets and liabilities and record the adjustment to income tax expense effective December 22, 2017. In December 2017, the SEC issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which allowed companies to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. Since Federal Tax Reform was enacted late in 2017, management expects that certain deferred tax assets and liabilities will continue to be evaluated in the context of Federal Tax Reform through the date of the filing of our 2017 federal income tax return, and may change as a result of evolving management interpretations, elections, and assumptions, as well as new guidance that may be issued by the Internal Revenue Service. Accordingly, the federal income tax expense of $47.2 million recorded in 2017 relating to the effects from Federal Tax Reform is considered provisional. Management expects to complete its analysis within the measurement period in accordance with SAB 118. Recently Adopted Accounting Standards Updates ASU 2014-09, Revenue from Contracts with Customers (Topic 606) issued by the FASB in May 2014 , and all subsequent ASUs that modified 606. ASU 2014-09 implements a common revenue standard that establishes principles for reporting information about the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts to provide goods or services to customers. The core principle of the revenue model is that a company will recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The scope of the guidance explicitly excludes net interest income as well as many other revenues from financial assets. Management reviewed its revenue streams and contracts with customers and did not identify material changes to the timing or amount of revenue recognition. Synovus adopted these ASUs on the required effective date of January 1, 2018 utilizing the modified retrospective method of adoption. The adoption resulted in a cumulative effect adjustment of ($685) thousand to the opening balance of retained earnings. Beginning January 1, 2018, in connection with the adoption of this standard, Synovus began including merchant discounts and other card-related fees in card fees. For periods prior to January 1, 2018, these amounts were previously presented in other non-interest income and have been reclassified for comparability. See "Part I - Item 1. Financial Statements and Supplementary Data - Note 12 - Non-interest Income" for the required disclosures in accordance with this ASU. ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. In February 2018, the FASB issued final guidance on reclassification of tax effects stranded in other comprehensive income due to Federal Tax Reform. The guidance provides entities the option to reclassify the tax effects that are stranded in accumulated other comprehensive income (AOCI) as a result of Federal Tax Reform to retained earnings. The guidance is effective for fiscal years beginning after December 15, 2018; early adoption is permitted. Synovus elected to early adopt ASU 2018-02 as of January 1, 2018 and elected to reclassify the income tax effects of Federal Tax Reform from AOCI to retained earnings. For Synovus, tax effects stranded in AOCI due to Federal Tax Reform totaled $7.6 million at December 31, 2017 and primarily related to unrealized losses on the available-for-sale investment securities portfolio. The reclassification adjustment resulted in an increase to retained earnings as of January 1, 2018 of $7.6 million and a corresponding decrease to AOCI for the same amount. Synovus utilizes the portfolio approach when releasing income tax effects from AOCI for its investment securities. The reclassification adjustment increased regulatory capital by $7.6 million , resulting in an approximate 3 b.p.s increase to Tier 1 capital, common equity Tier 1 capital, and total risk based capital ratios, and an approximate 2 b.p.s increase to the leverage ratio. ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilitie s. In January 2016, the FASB issued ASU 2016-01 that included targeted amendments to accounting guidance for recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or consolidated) to be measured at fair value with changes in fair value recognized in net income. This ASU requires a cumulative-effect adjustment to retained earnings as of the beginning of the reporting period of adoption to reclassify the cumulative change in fair value of equity securities previously recognized in AOCI. ASU 2016-01 became effective for Synovus on January 1, 2018. The adoption of the guidance resulted in a transfer of investments in mutual funds of $3.2 million , at fair value, from investment securities available for sale to other assets and a $117 thousand cumulative-effect adjustment that decreased retained earnings, with offsetting related adjustments to deferred taxes and AOCI. ASU 2016-01 also emphasizes the existing requirement to use an exit price concept to measure fair value for disclosure purposes in determining the fair value of loans. Determination of the fair value under the exit price method requires judgment because substantially all of the loans within the loan portfolio do not have observable market prices. The adoption of this guidance did not have a significant impact on Synovus' fair value disclosures. ASU 2016-18, Statement of Cash Flows-Restricted Cash. In November 2016, the FASB issued new accounting guidance which addressed classification and presentation of changes in restricted cash on the statement of cash flows. The standard requires a reconciliation of the beginning-of-period and end-of-period total amounts shown on the statement of cash flows to include in cash and cash equivalents amounts generally described as restricted cash and restricted cash equivalents. The ASU does not define restricted cash or restricted cash equivalents; however, the nature of the restrictions should be disclosed. The guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. This ASU is to be applied using a retrospective transition method for each period presented. Synovus adopted ASU 2016-18 on January 1, 2018 and concurrently revised its presentation of cash and cash equivalents. For periods prior to January 1, 2018, the presentation of cash and cash equivalents has been revised to conform to the current presentation. Reclassifications Prior periods' consolidated financial statements are reclassified whenever necessary to conform to the current periods' presentation.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Acquisitions	Note 2 - Acquisitions Cabela's Transaction On September 25, 2017, Synovus' wholly owned subsidiary, Synovus Bank, completed the acquisition of certain assets and assumption of certain liabilities of World's Foremost Bank, or WFB. Immediately following the closing of this transaction, Synovus Bank sold WFB’s credit card assets and related liabilities to Capital One Bank (USA), National Association, a bank subsidiary of Capital One Financial Corporation. Synovus retained WFB’s $1.10 billion brokered time deposits portfolio, which had a weighted average remaining maturity of approximately 2.53 years and a weighted average rate of 1.83% as of September 25, 2017. The transaction was accounted for as an assumption of a liability (accounted for under the asset acquisition model). In accordance with ASC 820, Fair Value Measurements and Disclosures, the brokered time deposit portfolio was recorded at $1.10 billion , which was the amount of cash received for the deposits and represented the estimated fair value of the deposits at the transaction date. Additionally, Synovus received a $75.0 million transaction fee from Cabela’s Incorporated and Capital One, which was recognized into earnings on September 25, 2017 upon closing of the transaction, based on having achieved the recognition criteria outlined in SEC SAB Topic 13.A, Revenue Recognition . Acquisition of Global One On October 1, 2016, Synovus completed its acquisition of all of the outstanding stock of Global One. Prior to its acquisition, Global One was an Atlanta-based private specialty financial services company that provided financing primarily to commercial entities, with all loans fully collateralized by cash value life insurance policies and/or annuities issued by investment grade life insurance companies. Under the terms of the merger agreement, Synovus acquired Global One for an up-front payment of $30 million , consisting of the issuance of 821 thousand shares of Synovus common stock valued at $26.6 million and $3.4 million in cash, with additional payments to Global One's former shareholders over a three to five year period based on earnings from the Global One business, as further discussed below. The acquisition of Global One constituted a business combination. Accordingly, the assets acquired and liabilities assumed were recorded at their estimated fair values on October 1, 2016. The determination of fair value required management to make estimates about discount rates, future expected earnings and cash flows, market conditions, future loan growth, and other future events that are highly subjective in nature and subject to change. During the three months ended September 30, 2017, Synovus completed the determination of the final allocation of the purchase price with respect to the assets acquired and liabilities assumed. Under the terms of the merger agreement, the purchase price includes additional annual payments ("Earnout Payments") to Global One's former shareholders over a three to five year period, with amounts based on a percentage of "Global One Earnings," as defined in the merger agreement. The Earnout Payments consist of shares of Synovus common stock as well as a smaller cash consideration component. The first annual Earnout Payment of stock and cash valued at $6.4 million was made during November 2017. The balance of the earnout liability at March 31, 2018 was $11.3 million based on the estimated fair value of the remaining Earnout Payments.

Share Repurchase Program

Share Repurchase Program	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Share Repurchase Program	Note 3 - Share Repurchase Program On January 23, 2018, Synovus announced a $150 million share repurchase program to be completed during 2018. As of March 31, 2018 , Synovus had repurchased under this program a total of $26.7 million , or 535 thousand shares of its common stock, at an average price of $49.98 per share.

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Investment Securities	Note 4 - Investment Securities Available for Sale The amortized cost, gross unrealized gains and losses, and estimated fair values of investment securities available for sale at March 31, 2018 and December 31, 2017 are summarized below. March 31, 2018 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities $ 122,655 $ — $ (1,724 ) $ 120,931 U.S. Government agency securities 10,769 128 — 10,897 Mortgage-backed securities issued by U.S. Government agencies 115,888 237 (3,257 ) 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises 2,734,650 483 (71,133 ) 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 1,102,361 — (37,320 ) 1,065,041 State and municipal securities 115 — — 115 Corporate debt and other debt securities 17,000 274 (148 ) 17,126 Total investment securities available for sale $ 4,103,438 $ 1,122 $ (113,582 ) $ 3,990,978 December 31, 2017 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities $ 83,608 $ — $ (934 ) $ 82,674 U.S. Government agency securities 10,771 91 — 10,862 Mortgage-backed securities issued by U.S. Government agencies 121,283 519 (1,362 ) 120,440 Mortgage-backed securities issued by U.S. Government sponsored enterprises 2,666,818 5,059 (31,354 ) 2,640,523 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 1,135,259 144 (23,404 ) 1,111,999 State and municipal securities 180 — — 180 Corporate debt and other securities 20,320 294 (223 ) 20,391 Total investment securities available for sale $ 4,038,239 $ 6,107 $ (57,277 ) $ 3,987,069 At March 31, 2018 and December 31, 2017 , investment securities with a carrying value of $1.01 billion and $2.00 billion , respectively, were pledged to secure certain deposits and securities sold under repurchase agreements as required by law and contractual agreements. Synovus has reviewed investment securities that are in an unrealized loss position as of March 31, 2018 and December 31, 2017 for OTTI and does not consider any securities in an unrealized loss position to be other-than-temporarily impaired. If Synovus intended to sell a security in an unrealized loss position, the entire unrealized loss would be reflected in earnings. Synovus does not intend to sell investment securities in an unrealized loss position prior to the recovery of the unrealized loss, which may not be until maturity, and has the ability and intent to hold those securities for that period of time. Additionally, Synovus is not currently aware of any circumstances which will require it to sell any of the securities that are in an unrealized loss position prior to the respective securities' recovery of all such unrealized losses. Declines in the fair value of available for sale securities below their cost that are deemed to have OTTI are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of the impairment related to other factors is recognized in other comprehensive income. Currently, unrealized losses on debt securities are attributable to increases in interest rates on comparable securities from the date of purchase. Synovus regularly evaluates its investment securities portfolio to ensure that there are no conditions that would indicate that unrealized losses represent OTTI. These factors include the length of time the security has been in a loss position, the extent that the fair value is below amortized cost, and the credit standing of the issuer. As of March 31, 2018 , Synovus had 75 investment securities in a loss position for less than twelve months and 54 investment securities in a loss position for twelve months or longer. Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2018 and December 31, 2017 are presented below. March 31, 2018 Less than 12 Months 12 Months or Longer Total (in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses U.S. Treasury securities $ 72,694 $ 989 $ 29,313 $ 735 $ 102,007 $ 1,724 Mortgage-backed securities issued by U.S. Government agencies 39,763 1,045 52,763 2,212 92,526 3,257 Mortgage-backed securities issued by U.S. Government sponsored enterprises 1,656,562 38,195 882,984 32,938 2,539,546 71,133 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 629,793 17,650 435,247 19,670 1,065,040 37,320 Corporate debt and other debt securities — — 1,852 148 1,852 148 Total $ 2,398,812 $ 57,879 $ 1,402,159 $ 55,703 $ 3,800,971 $ 113,582 December 31, 2017 Less than 12 Months 12 Months or Longer Total (in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses U.S. Treasury securities $ 34,243 $ 443 $ 29,562 $ 491 $ 63,805 $ 934 Mortgage-backed securities issued by U.S. Government agencies 36,810 357 55,740 1,005 92,550 1,362 Mortgage-backed securities issued by U.S. Government sponsored enterprises 1,271,012 10,263 929,223 21,091 2,200,235 31,354 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 653,781 9,497 426,237 13,907 1,080,018 23,404 Corporate debt and other securities — — 5,097 223 5,097 223 Total $ 1,995,846 $ 20,560 $ 1,445,859 $ 36,717 $ 3,441,705 $ 57,277 The amortized cost and fair value by contractual maturity of investment securities available for sale at March 31, 2018 are shown below. The expected life of mortgage-backed securities or CMOs may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. For purposes of the maturity table, mortgage-backed securities and CMOs, which are not due at a single maturity date, have been classified based on the final contractual maturity date. Distribution of Maturities at March 31, 2018 (in thousands) Within One Year 1 to 5 Years 5 to 10 Years More Than 10 Years Total Amortized Cost U.S. Treasury securities $ 18,924 $ 103,731 $ — $ — $ 122,655 U.S. Government agency securities 2,330 6,437 2,002 — 10,769 Mortgage-backed securities issued by U.S. Government agencies — — 29,355 86,533 115,888 Mortgage-backed securities issued by U.S. Government sponsored enterprises 7 1,657 578,774 2,154,212 2,734,650 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — — 18,652 1,083,709 1,102,361 State and municipal securities 115 — — — 115 Corporate debt and other debt securities — — 15,000 2,000 17,000 Total amortized cost $ 21,376 $ 111,825 $ 643,783 $ 3,326,454 $ 4,103,438 Fair Value U.S. Treasury securities $ 18,924 $ 102,007 $ — $ — $ 120,931 U.S. Government agency securities 2,355 6,514 2,028 — 10,897 Mortgage-backed securities issued by U.S. Government agencies — — 28,993 83,875 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises 7 1,723 565,331 2,096,939 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — — 18,218 1,046,823 1,065,041 State and municipal securities 115 — — — 115 Corporate debt and other debt securities — — 15,274 1,852 17,126 Total fair value $ 21,401 $ 110,244 $ 629,844 $ 3,229,489 $ 3,990,978 Synovus did not sell any securities available for sale during the three months ended March 31, 2018 . Proceeds from sales, gross gains, and gross losses on sales of securities available for sale for the three months ended March 31, 2017 are presented below. The specific identification method is used to reclassify gains and losses out of other comprehensive income at the time of sale. On January 1, 2018, Synovus transferred $3.2 million , at fair value, from investment securities available for sale to other assets upon adoption of ASU 2016-01. Three Months Ended March 31, (in thousands) 2018 2017 Proceeds from sales of investment securities available for sale $ — $ 282,629 Gross realized gains on sales — 7,702 Gross realized losses on sales — (34 ) Investment securities gains, net $ — $ 7,668

Restructuring Charges

Restructuring Charges	3 Months Ended
	Mar. 31, 2018
Restructuring Charges [Abstract]
Restructuring Charges	Note 5 - Restructuring Charges For the three months ended March 31, 2018 and 2017 , total restructuring charges consist of the following components: Three Months Ended March 31, (in thousands) 2018 2017 Severance charges $ — $ 6,453 Other charges, net (315 ) 58 Total restructuring charges, net $ (315 ) $ 6,511 For the three months ended March 31, 2018, Synovus recorded net lease termination accrual reversals of $377 thousand related to branches closed in prior years. During the three months ended March 31, 2017 , Synovus recorded severance charges of $6.5 million including $6.2 million for termination benefits incurred in conjunction with a voluntary early retirement program offered to Synovus employees during the first quarter of 2017. The following tables present aggregate activity within the accrual for restructuring charges for the three months ended March 31, 2018 and 2017 : (in thousands) Severance Charges Lease Termination Charges Total Balance at December 31, 2017 $ 336 $ 3,276 $ 3,612 Accruals for lease terminations — (377 ) (377 ) Payments (336 ) (393 ) (729 ) Balance at March 31, 2018 $ — $ 2,506 $ 2,506 (in thousands) Severance Charges Lease Termination Charges Total Balance at December 31, 2016 $ 81 $ 3,968 $ 4,049 Accrual for voluntary and involuntary termination benefits 6,453 — 6,453 Payments (219 ) (279 ) (498 ) Balance at March 31, 2017 $ 6,315 $ 3,689 $ 10,004 All other charges were paid in the quarters in which they were incurred. No other restructuring charges resulted in payment accruals.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2018
Loans and Allowance for Loan Losses [Abstract]
Loans and Allowance for Loan Losses	Note 6 - Loans and Allowance for Loan Losses The following is a summary of current, accruing past due, and non-accrual loans by portfolio class as of March 31, 2018 and December 31, 2017 . Current, Accruing Past Due, and Non-accrual Loans March 31, 2018 (in thousands) Current Accruing 30-89 Days Past Due Accruing 90 Days or Greater Past Due Total Accruing Past Due Non-accrual Total Investment properties $ 5,613,811 $ 1,986 $ 323 $ 2,309 $ 2,930 $ 5,619,050 1-4 family properties 753,255 2,232 783 3,015 2,634 758,904 Land and development 449,700 3,450 49 3,499 4,574 457,773 Total commercial real estate 6,816,766 7,668 1,155 8,823 10,138 6,835,727 Commercial, financial and agricultural 7,093,270 15,872 783 16,655 81,606 7,191,531 Owner-occupied 4,901,542 3,841 936 4,777 4,067 4,910,386 Total commercial and industrial 11,994,812 19,713 1,719 21,432 85,673 12,101,917 Home equity lines 1,450,454 6,718 431 7,149 14,868 1,472,471 Consumer mortgages 2,651,758 3,905 — 3,905 7,708 2,663,371 Credit cards 223,232 1,599 1,882 3,481 — 226,713 Other consumer loans 1,595,745 9,131 229 9,360 1,694 1,606,799 Total consumer 5,921,189 21,353 2,542 23,895 24,270 5,969,354 Total loans $ 24,732,767 $ 48,734 $ 5,416 $ 54,150 $ 120,081 $ 24,906,998 (1 ) December 31, 2017 (in thousands) Current Accruing 30-89 Days Past Due Accruing 90 Days or Greater Past Due Total Accruing Past Due Non-accrual Total Investment properties $ 5,663,665 $ 2,506 $ 90 $ 2,596 $ 3,804 $ 5,670,065 1-4 family properties 775,023 3,545 202 3,747 2,849 781,619 Land and development 476,131 1,609 67 1,676 5,797 483,604 Total commercial real estate 6,914,819 7,660 359 8,019 12,450 6,935,288 Commercial, financial and agricultural 7,097,127 11,214 1,016 12,230 70,130 7,179,487 Owner-occupied 4,830,150 6,880 479 7,359 6,654 4,844,163 Total commercial and industrial 11,927,277 18,094 1,495 19,589 76,784 12,023,650 Home equity lines 1,490,808 5,629 335 5,964 17,455 1,514,227 Consumer mortgages 2,622,061 3,971 268 4,239 7,203 2,633,503 Credit cards 229,015 1,930 1,731 3,661 — 232,676 Other consumer loans 1,461,223 10,333 226 10,559 1,669 1,473,451 Total consumer 5,803,107 21,863 2,560 24,423 26,327 5,853,857 Total loans $ 24,645,203 $ 47,617 $ 4,414 $ 52,031 $ 115,561 $ 24,812,795 (2 ) (1) Total before net deferred fees and costs of $24.0 million . (2) Total before net deferred fees and costs of $25.3 million . The credit quality of the loan portfolio is reviewed and updated no less frequently than quarterly using the standard asset classification system utilized by the federal banking agencies. These classifications are divided into three groups – Not Criticized (Pass), Special Mention, and Classified or Adverse rating (Substandard, Doubtful, and Loss) and are defined as follows: Pass - loans which are well protected by the current net worth and paying capacity of the obligor (or guarantors, if any) or by the fair value, less cost to acquire and sell in a timely manner, of any underlying collateral. Special Mention - loans which have potential weaknesses that deserve management's close attention. These loans are not adversely classified and do not expose an institution to sufficient risk to warrant an adverse classification. Substandard - loans which are inadequately protected by the current net worth and paying capacity of the obligor or by the collateral pledged, if any. Loans with this classification are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful - loans which have all the weaknesses inherent in loans classified as Substandard with the added characteristic that the weaknesses make collection or liquidation in full highly questionable and improbable on the basis of currently known facts, conditions, and values. Loss - loans which are considered by management to be uncollectible and of such little value that their continuance on the institution's books as an asset, without establishment of a specific valuation allowance or charge-off, is not warranted. In the following tables, consumer loans are generally assigned a risk grade similar to the classifications described above; however, upon reaching 90 days and 120 days past due, they are generally downgraded to Substandard and Loss, respectively, in accordance with the FFIEC Uniform Retail Credit Classification and Account Management Policy. Additionally, in accordance with the Interagency Supervisory Guidance on Allowance for Loan and Lease Losses Estimation Practices for Loans and Lines of Credit Secured by Junior Liens on 1-4 Family Residential Properties, the risk grade classifications of consumer loans (home equity lines and consumer mortgages) secured by junior liens on 1-4 family residential properties also consider available information on the payment status of any associated senior liens with other financial institutions. Loan Portfolio Credit Exposure by Risk Grade March 31, 2018 (in thousands) Pass Special Mention Substandard (1) Doubtful (2) Loss Total Investment properties $ 5,545,689 $ 53,193 $ 20,168 $ — $ — $ 5,619,050 1-4 family properties 729,023 14,331 15,550 — — 758,904 Land and development 408,128 33,858 12,654 3,133 — 457,773 Total commercial real estate 6,682,840 101,382 48,372 3,133 — 6,835,727 Commercial, financial and agricultural 6,895,133 132,582 154,863 8,953 — 7,191,531 Owner-occupied 4,778,913 55,627 75,773 73 — 4,910,386 Total commercial and industrial 11,674,046 188,209 230,636 9,026 — 12,101,917 Home equity lines 1,452,171 — 18,421 271 1,608 (3) 1,472,471 Consumer mortgages 2,654,285 — 8,951 103 32 (3) 2,663,371 Credit cards 224,831 — 564 — 1,318 (4) 226,713 Other consumer loans 1,604,979 — 1,556 257 7 (3) 1,606,799 Total consumer 5,936,266 — 29,492 631 2,965 5,969,354 Total loans $ 24,293,152 $ 289,591 $ 308,500 $ 12,790 $ 2,965 $ 24,906,998 (5 ) December 31, 2017 (in thousands) Pass Special Mention Substandard (1) Doubtful (2) Loss Total Investment properties $ 5,586,792 $ 64,628 $ 18,645 $ — $ — $ 5,670,065 1-4 family properties 745,299 19,419 16,901 — — 781,619 Land and development 431,759 33,766 14,950 3,129 — 483,604 Total commercial real estate 6,763,850 117,813 50,496 3,129 — 6,935,288 Commercial, financial and agricultural 6,929,506 115,912 132,818 1,251 — 7,179,487 Owner-occupied 4,713,877 50,140 80,073 73 — 4,844,163 Total commercial and industrial 11,643,383 166,052 212,891 1,324 — 12,023,650 Home equity lines 1,491,105 — 21,079 285 1,758 (3) 1,514,227 Consumer mortgages 2,622,499 — 10,607 291 106 (3) 2,633,503 Credit cards 230,945 — 399 — 1,332 (4) 232,676 Other consumer loans 1,470,944 — 2,168 329 10 (3) 1,473,451 Total consumer 5,815,493 — 34,253 905 3,206 5,853,857 Total loans $ 24,222,726 $ 283,865 $ 297,640 $ 5,358 $ 3,206 $ 24,812,795 (6 ) (1) Includes $204.2 million and $190.6 million of Substandard accruing loans at March 31, 2018 and December 31, 2017 , respectively. (2) The loans within this risk grade are on non-accrual status. Commercial loans generally have an allowance for loan losses in accordance with ASC 310, and retail loans generally have an allowance for loan losses equal to 50% of the loan amount. (3) The loans within this risk grade are on non-accrual status and have an allowance for loan losses equal to the full loan amount. (4) Represent amounts that were 120 days past due. These credits are downgraded to the Loss category with an allowance for loan losses equal to the full loan amount and are generally charged off upon reaching 181 days past due in accordance with the FFIEC Uniform Retail Credit Classification and Account Management Policy. (5) Total before net deferred fees and costs of $24.0 million . (6) Total before net deferred fees and costs of $25.3 million . The following table details the changes in the allowance for loan losses by loan segment for the three months ended March 31, 2018 . Allowance for Loan Losses and Recorded Investment in Loans As Of and For The Three Months Ended March 31, 2018 (in thousands) Commercial Real Estate Commercial & Industrial Consumer Total Allowance for loan losses: Beginning balance $ 74,998 $ 126,803 $ 47,467 $ 249,268 Charge-offs (1,911 ) (8,015 ) (4,455 ) (14,381 ) Recoveries 5,723 3,112 1,266 10,101 Provision for loan losses (4,819 ) 12,845 4,750 12,776 Ending balance (1) $ 73,991 $ 134,745 $ 49,028 $ 257,764 Ending balance: individually evaluated for impairment 3,740 14,405 797 18,942 Ending balance: collectively evaluated for impairment $ 70,251 $ 120,340 $ 48,231 $ 238,822 Loans: Ending balance: total loans (1)(2) $ 6,835,727 $ 12,101,917 $ 5,969,354 $ 24,906,998 Ending balance: individually evaluated for impairment 49,221 112,823 29,608 191,652 Ending balance: collectively evaluated for impairment $ 6,786,506 $ 11,989,094 $ 5,939,746 $ 24,715,346 As Of and For The Three Months Ended March 31, 2017 (in thousands) Commercial Real Estate Commercial & Industrial Consumer Total Allowance for loan losses: Beginning balance $ 81,816 $ 125,778 $ 44,164 $ 251,758 Charge-offs (1,908 ) (6,893 ) (3,934 ) (12,735 ) Recoveries 2,889 1,824 1,104 5,817 Provision for loan losses (4,483 ) 6,387 6,770 8,674 Ending balance (1) $ 78,314 $ 127,096 $ 48,104 $ 253,514 Ending balance: individually evaluated for impairment 6,917 11,085 1,705 19,707 Ending balance: collectively evaluated for impairment $ 71,397 $ 116,011 $ 46,399 $ 233,807 Loans: Ending balance: total loans (1)(3) $ 7,467,288 $ 11,732,701 $ 5,084,199 $ 24,284,188 Ending balance: individually evaluated for impairment 79,203 120,470 35,083 234,756 Ending balance: collectively evaluated for impairment $ 7,388,085 $ 11,612,231 $ 5,049,116 $ 24,049,432 (1 ) As of and for the three months ended March 31, 2018 and 2017 , there were no purchased credit-impaired loans and no allowance for loan losses for purchased credit-impaired loans. (2) Total before net deferred fees and costs of $24.0 million . (3) Total before net deferred fees and costs of $25.7 million . The tables below summarize impaired loans (including accruing TDRs) as of March 31, 2018 and December 31, 2017 . Impaired Loans (including accruing TDRs) March 31, 2018 Three Months Ended March 31, 2018 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded Investment properties $ — $ — $ — $ — $ — 1-4 family properties — — — — — Land and development — — — 37 — Total commercial real estate — — — 37 — Commercial, financial and agricultural 9,614 12,039 — 8,682 — Owner-occupied — — — — — Total commercial and industrial 9,614 12,039 — 8,682 — Home equity lines 1,086 1,086 — 2,122 — Consumer mortgages 2,640 2,665 — 880 — Credit cards — — — — — Other consumer loans — — — — — Total consumer 3,726 3,751 — 3,002 — Total impaired loans with no related allowance recorded $ 13,340 $ 15,790 $ — $ 11,721 $ — With allowance recorded Investment properties $ 19,388 $ 19,388 $ 753 $ 22,769 $ 198 1-4 family properties 12,008 12,008 392 11,715 216 Land and development 17,825 19,565 2,595 18,133 76 Total commercial real estate 49,221 50,961 3,740 52,617 490 Commercial, financial and agricultural 65,422 65,691 12,491 67,198 273 Owner-occupied 37,787 37,841 1,914 37,715 357 Total commercial and industrial 103,209 103,532 14,405 104,913 630 Home equity lines 3,475 3,475 44 4,383 45 Consumer mortgages 17,378 17,378 447 19,106 194 Credit cards — — — — — Other consumer loans 5,029 5,031 306 5,391 71 Total consumer 25,882 25,884 797 28,880 310 Total impaired loans with allowance recorded $ 178,312 $ 180,377 $ 18,942 $ 186,410 $ 1,430 Total impaired loans Investment properties $ 19,388 $ 19,388 $ 753 $ 22,769 $ 198 1-4 family properties 12,008 12,008 392 11,715 216 Land and development 17,825 19,565 2,595 18,170 76 Total commercial real estate 49,221 50,961 3,740 52,654 490 Commercial, financial and agricultural 75,036 77,730 12,491 75,880 273 Owner-occupied 37,787 37,841 1,914 37,715 357 Total commercial and industrial 112,823 115,571 14,405 113,595 630 Home equity lines 4,561 4,561 44 6,505 45 Consumer mortgages 20,018 20,043 447 19,986 194 Credit cards — — — — — Other consumer loans 5,029 5,031 306 5,391 71 Total consumer 29,608 29,635 797 31,882 310 Total impaired loans $ 191,652 196,167 18,942 198,131 1,430 Impaired Loans (including accruing TDRs) December 31, 2017 Year Ended December 31, 2017 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded Investment properties $ — — — 123 — 1-4 family properties — — — 323 — Land and development 56 1,740 — 1,816 — Total commercial real estate 56 1,740 — 2,262 — Commercial, financial and agricultural 8,220 9,576 — 21,686 — Owner-occupied — — — 6,665 — Total commercial and industrial 8,220 9,576 — 28,351 — Home equity lines 2,746 2,943 — 1,205 — Consumer mortgages — — — 496 — Credit cards — — — — — Other consumer loans — — — — — Total consumer 2,746 2,943 — 1,701 — Total impaired loans with no related allowance recorded $ 11,022 14,259 — 32,314 — With allowance recorded Investment properties $ 23,364 23,364 1,100 28,749 1,144 1-4 family properties 15,056 15,056 504 16,257 925 Land and development 18,420 18,476 2,636 23,338 404 Total commercial real estate 56,840 56,896 4,240 68,344 2,473 Commercial, financial and agricultural 65,715 65,851 7,406 50,468 1,610 Owner-occupied 37,399 37,441 2,109 40,498 1,382 Total commercial and industrial 103,114 103,292 9,515 90,966 2,992 Home equity lines 5,096 5,096 114 7,476 334 Consumer mortgages 18,668 18,668 569 19,144 896 Credit cards — — — — — Other consumer loans 5,546 5,546 470 4,765 266 Total consumer 29,310 29,310 1,153 31,385 1,496 Total impaired loans with allowance recorded $ 189,264 189,498 14,908 190,695 6,961 Total impaired loans Investment properties $ 23,364 23,364 1,100 28,872 1,144 1-4 family properties 15,056 15,056 504 16,580 925 Land and development 18,476 20,216 2,636 25,154 404 Total commercial real estate 56,896 58,636 4,240 70,606 2,473 Commercial, financial and agricultural 73,935 75,427 7,406 72,154 1,610 Owner-occupied 37,399 37,441 2,109 47,163 1,382 Total commercial and industrial 111,334 112,868 9,515 119,317 2,992 Home equity lines 7,842 8,039 114 8,681 334 Consumer mortgages 18,668 18,668 569 19,640 896 Credit cards — — — — — Other consumer loans 5,546 5,546 470 4,765 266 Total consumer 32,056 32,253 1,153 33,086 1,496 Total impaired loans $ 200,286 $ 203,757 $ 14,908 $ 223,009 $ 6,961 The average recorded investment in impaired loans was $235.6 million for the three months ended March 31, 2017 . Excluding accruing TDRs, there was no interest income recognized for the investment in impaired loans for the three months ended March 31, 2017 . Interest income recognized for accruing TDRs was $1.7 million for the three months ended March 31, 2017 . At March 31, 2018 and December 31, 2017 , impaired loans of $62.2 million and $49.0 million , respectively, were on non-accrual status. Concessions provided in a TDR are primarily in the form of providing a below market interest rate given the borrower's credit risk, a period of time generally less than one year with a reduction of required principal and/or interest payments (e.g., interest only for a period of time), or an extension of the maturity of the loan generally for less than one year. Insignificant periods of reduction of principal and/or interest payments, or one-time deferrals of 3 months or less, are generally not considered to be financial concessions. The following tables represent, by concession type, the post-modification balance for loans modified or renewed during the three months ended March 31, 2018 and 2017 that were reported as accruing or non-accruing TDRs. TDRs by Concession Type Three Months Ended March 31, 2018 (in thousands, except contract data) Number of Contracts Principal Forgiveness Below Market Interest Rate Term Extensions and/or Other Concessions Total Investment properties 1 $ — $ — $ 1,959 $ 1,959 1-4 family properties 6 — 963 — 963 Total commercial real estate 7 — 963 1,959 2,922 Commercial, financial and agricultural 9 — — 989 989 Owner-occupied 2 — 2,705 93 2,798 Total commercial and industrial 11 — 2,705 1,082 3,787 Consumer mortgages 7 — 1,733 — 1,733 Other consumer loans 14 — 537 508 1,045 Total consumer 21 — 2,270 508 2,778 Total TDRs 39 $ — $ 5,938 $ 3,549 $ 9,487 (1 ) (1) No net charge-offs were recorded during the three months ended March 31, 2018 upon restructuring of these loans. TDRs by Concession Type Three Months Ended March 31, 2017 (in thousands, except contract data) Number of Contracts Principal Forgiveness Below Market Interest Rate Term Extensions and/or Other Concessions Total 1-4 family properties 8 — 1,611 317 1,928 Total commercial real estate 8 — 1,611 317 1,928 Commercial, financial and agricultural 18 — 3,865 5,539 9,404 Total commercial and industrial 18 — 3,865 5,539 9,404 Other consumer loans 3 — — 275 275 Total consumer 3 — — 275 275 Total TDRs 29 $ — $ 5,476 $ 6,131 $ 11,607 (2 ) (2) No net charge-offs were recorded during the three months ended March 31, 2017 upon restructuring of these loans. For the three months ended March 31, 2018 and March 31, 2017 there were no defaults on accruing TDRs restructured during the previous twelve months (defaults are defined as the earlier of the TDR being placed on non-accrual status or reaching 90 days past due with respect to principal and/or interest payments). If, at the time a loan was designated as a TDR, the loan was not already impaired, the measurement of impairment that resulted from the TDR designation closely approximates the reserve derived through specific loan measurement of impairment in accordance with ASC 310-10-35. Generally, the change in the allowance for loan losses resulting from such TDR designation is not significant. At March 31, 2018 , the allowance for loan losses allocated to accruing TDRs totaling $129.4 million was $6.1 million compared to accruing TDRs of $151.3 million with an allocated allowance for loan losses of $8.7 million at December 31, 2017 . Non-accrual, non-homogeneous loans (commercial-type impaired loans greater than $1 million ) that are designated as TDRs are individually measured for the amount of impairment, if any, both before and after the TDR designation .

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Other Comprehensive Income (Loss)	Note 7 - Other Comprehensive Income (Loss) The following tables illustrate activity within the balances in accumulated other comprehensive income (loss) by component for the three months ended March 31, 2018 and 2017 . Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) (in thousands) Net unrealized gains (losses) on cash flow hedges Net unrealized gains (losses) on investment securities available for sale Post-retirement unfunded health benefit Total Balance at December 31, 2017 $ (12,137 ) $ (43,470 ) $ 853 $ (54,754 ) Other comprehensive income before reclassifications — (45,531 ) — (45,531 ) Amounts reclassified from accumulated other comprehensive income (loss) — — (21 ) (21 ) Net current period other comprehensive income — (45,531 ) (21 ) (45,552 ) Reclassification from adoption of ASU 2018-02 — (7,763 ) 175 (7,588 ) Cumulative-effect adjustment from adoption of ASU 2016-01 — 117 — 117 Balance as of March 31, 2018 $ (12,137 ) $ (96,647 ) $ 1,007 $ (107,777 ) Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) (in thousands) Net unrealized gains (losses) on cash flow hedges Net unrealized gains (losses) on investment securities available for sale Post-retirement unfunded health benefit Total Balance at December 31, 2016 $ (12,217 ) $ (44,324 ) $ 882 $ (55,659 ) Other comprehensive income before reclassifications — 5,596 — 5,596 Amounts reclassified from accumulated other comprehensive income (loss) 40 (4,716 ) (12 ) (4,688 ) Net current period other comprehensive income 40 880 (12 ) 908 Balance as of March 31, 2017 $ (12,177 ) $ (43,444 ) $ 870 $ (54,751 ) In accordance with ASC 740-20-45-11(b), a deferred tax asset valuation allowance associated with unrealized gains and losses not recognized in income is charged directly to other comprehensive income (loss). During the years 2010 and 2011, Synovus recorded a deferred tax asset valuation allowance associated with net unrealized losses not recognized in income directly to other comprehensive income (loss) by applying the portfolio approach for allocation of the valuation allowance. Synovus has consistently applied the portfolio approach which treats derivative instruments and available for sale securities as a single portfolio. As of March 31, 2018 , the ending balance in net unrealized gains (losses) on cash flow hedges and net unrealized gains (losses) on investment securities available for sale includes unrealized losses of $12.1 million and $13.3 million , respectively, related to the residual tax effects remaining in OCI due to the previously established deferred tax asset valuation allowance. Under the portfolio approach, these unrealized losses are realized at the time the entire portfolio is sold or disposed. Reclassifications out of Accumulated Other Comprehensive Income (Loss) Details About Accumulated Other Comprehensive Income (Loss) Components Amount Reclassified from Accumulated Other Comprehensive Income (Loss) Affected Line Item in the Statement Where Net Income is Presented For the Three Months Ended March 31, 2018 2017 Net unrealized gains (losses) on cash flow hedges: Amortization of deferred losses $ — $ (65 ) Interest expense — 25 Income tax (expense) benefit $ — $ (40 ) Reclassifications, net of income taxes Net unrealized gains on investment securities available for sale: Realized gains on sale of securities $ — $ 7,668 Investment securities gains, net — (2,952 ) Income tax (expense) benefit $ — $ 4,716 Reclassifications, net of income taxes Post-retirement unfunded health benefit: Amortization of actuarial gains $ 34 $ 20 Salaries and other personnel expense (13 ) (8 ) Income tax (expense) benefit $ 21 $ 12 Reclassifications, net of income taxes

Fair Value Accounting

Fair Value Accounting	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Accounting	Note 8 - Fair Value Accounting Synovus carries various assets and liabilities at fair value based on the fair value accounting guidance under ASC 820, Fair Value Measurements , and ASC 825, Financial Instruments . Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an “exit price”) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair Value Hierarchy Synovus determines the fair value of its financial instruments based on the fair value hierarchy established under ASC 820-10, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the financial instrument's fair value measurement in its entirety. There are three levels of inputs that may be used to measure fair value. The three levels of inputs of the valuation hierarchy are defined below: Level 1 Quoted prices (unadjusted) in active markets for identical assets and liabilities for the instrument or security to be valued. Level 1 assets include U.S. Treasury securities and mutual funds. Level 2 Observable inputs other than Level 1 quoted prices, such as quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active or model-based valuation techniques for which all significant assumptions are derived principally from or corroborated by observable market data. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments and derivative contracts whose value is determined by using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. U.S. Government sponsored agency securities, mortgage-backed securities issued by GSEs and agencies, obligations of states and municipalities, collateralized mortgage obligations issued by GSEs, and mortgage loans held-for-sale are generally included in this category. Level 3 Unobservable inputs that are supported by little, if any, market activity for the asset or liability. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow models and similar techniques, and may also include the use of market prices of assets or liabilities that are not directly comparable to the subject asset or liability. These methods of valuation may result in a significant portion of the fair value being derived from unobservable assumptions that reflect Synovus' own estimates for assumptions that market participants would use in pricing the asset or liability. This category primarily includes collateral-dependent impaired loans, other loans held for sale, other real estate, certain corporate securities, private equity investments, GGL/SBA loan servicing assets, and the earnout liability. See "Part II - Item 8. Financial Statements and Supplementary Data - Note 15 - Fair Value Accounting" to the consolidated financial statements of Synovus' 2017 Form 10-K for a description of valuation methodologies for assets and liabilities measured at fair value on a recurring and non-recurring basis. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents all financial instruments measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 , according to the valuation hierarchy included in ASC 820-10. For debt securities, class was determined based on the nature and risks of the investments. Synovus did not have any transfers between levels during the three months ended March 31, 2018 and year ended December 31, 2017 . March 31, 2018 (in thousands) Level 1 Level 2 Level 3 Total Assets and Liabilities at Fair Value Assets Trading securities: U.S. Government agency securities $ — $ 25,971 $ — $ 25,971 Collateralized mortgage obligations issued by U.S. Government sponsored enterprises — 240 — 240 State and municipal securities — 40 — 40 Total trading securities $ — $ 26,251 $ — $ 26,251 Mortgage loans held for sale — 50,439 — 50,439 Investment securities available for sale: U.S. Treasury securities 120,931 — — 120,931 U.S. Government agency securities — 10,897 — 10,897 Mortgage-backed securities issued by U.S. Government agencies — 112,868 — 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises — 2,664,000 — 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — 1,065,041 — 1,065,041 State and municipal securities — 115 — 115 Corporate debt and other debt securities (1) — 15,274 1,852 17,126 Total investment securities available for sale $ 120,931 $ 3,868,195 $ 1,852 $ 3,990,978 Private equity investments — — 12,715 12,715 Mutual funds 3,131 — — 3,131 Mutual funds held in rabbi trusts 13,385 — — 13,385 GGL/SBA loans servicing asset — — 3,971 3,971 Derivative assets: Interest rate contracts — 7,672 — 7,672 Mortgage derivatives (2) — 1,735 — 1,735 Total derivative assets $ — $ 9,407 $ — $ 9,407 Liabilities Trading account liabilities — 23,856 — 23,856 Earnout liability (3) — — 11,348 11,348 Derivative liabilities: Interest rate contracts — 16,122 — 16,122 Visa derivative — — 3,974 3,974 Total derivative liabilities $ — $ 16,122 $ 3,974 $ 20,096 December 31, 2017 (in thousands) Level 1 Level 2 Level 3 Total Assets and Liabilities at Fair Value Assets Trading securities: Mortgage-backed securities issued by U.S. Government agencies $ — $ 3,002 $ — $ 3,002 Collateralized mortgage obligations issued by U.S. Government sponsored enterprises — 296 — 296 Other investments 522 — — 522 Total trading securities $ 522 $ 3,298 $ — $ 3,820 Mortgage loans held for sale — 48,024 — 48,024 Investment securities available for sale: U.S. Treasury securities 82,674 — — 82,674 U.S. Government agency securities — 10,862 — 10,862 Mortgage-backed securities issued by U.S. Government agencies — 120,440 — 120,440 Mortgage-backed securities issued by U.S. Government sponsored enterprises — 2,640,523 — 2,640,523 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — 1,111,999 — 1,111,999 State and municipal securities — 180 — 180 Corporate debt and other securities (1) 3,162 15,294 1,935 20,391 Total investment securities available for sale $ 85,836 $ 3,899,298 $ 1,935 $ 3,987,069 Private equity investments — — 15,771 15,771 Mutual funds held in rabbi trusts 14,140 — — 14,140 GGL/SBA loan servicing asset — — 4,101 4,101 Derivative assets: Interest rate contracts — 10,786 — 10,786 Mortgage derivatives (2) — 936 — 936 Total derivative assets $ — $ 11,722 $ — $ 11,722 Liabilities Trading account liabilities — 1,000 — 1,000 Earnout liability (3) — — 11,348 11,348 Derivative liabilities: Interest rate contracts — 12,638 — 12,638 Mortgage derivatives (2) — 129 — 129 Visa derivative — — 4,330 4,330 Total derivative liabilities $ — $ 12,767 $ 4,330 $ 17,097 (1) Based on an analysis of the nature and risks of these investments, Synovus has determined that presenting these investments as a single asset class is appropriate. (2) Mortgage derivatives consist of customer interest rate lock commitments that relate to the potential origination of mortgage loans, which would be classified as held for sale and forward loan sales commitments with third-party investors. (3) Earnout liability consists of contingent consideration obligation related to the Global One acquisition. Fair Value Option The following table summarizes the difference between the fair value and the unpaid principal balance of mortgage loans held for sale measured at fair value and the changes in fair value of these loans. Mortgage loans held for sale are initially measured at fair value with subsequent changes in fair value recognized in earnings. Changes in fair value are recorded as a component of mortgage banking income in the consolidated statements of income. An immaterial portion of these changes in fair value was attributable to changes in instrument-specific credit risk. Changes in Fair Value Included in Net Income For the Three Months Ended March 31, (in thousands) 2018 2017 Mortgage loans held for sale $ 115 $ 1,203 Mortgage Loans Held for Sale (in thousands) As of March 31, 2018 As of December 31, 2017 Fair value $ 50,439 $ 48,024 Unpaid principal balance 49,139 46,839 Fair value less aggregate unpaid principal balance $ 1,300 $ 1,185 Changes in Level 3 Fair Value Measurements and Quantitative Information about Level 3 Fair Value Measurements As noted above, Synovus uses significant unobservable inputs in determining the fair value of assets and liabilities classified as Level 3 in the fair value hierarchy. The table below includes a roll-forward of the amounts on the consolidated balance sheet for the three months ended March 31, 2018 and 2017 (including the change in fair value) for financial instruments of a material nature that are classified by Synovus within Level 3 of the fair value hierarchy and are measured at fair value on a recurring basis. Transfers between fair value levels are recognized at the end of the reporting period in which the associated changes in inputs occur. During the three months ended March 31, 2018 and 2017 , Synovus did not have any transfers between levels in the fair value hierarchy. Three Months Ended March 31, 2018 (in thousands) Investment Securities Available for Sale Private Equity Investments Visa Derivative Earnout Liability (1) GGL / SBA Loans Servicing Asset Beginning balance, January 1, 2018 $ 1,935 $ 15,771 $ (4,330 ) $ (11,348 ) $ 4,101 Total (losses) gains realized/unrealized: Included in earnings — (3,056 ) — — (422 ) Unrealized (losses) gains included in other comprehensive income (83 ) — — — — Additions — — — — 292 Settlements — — 356 — — Ending balance, March 31, 2018 $ 1,852 $ 12,715 $ (3,974 ) $ (11,348 ) $ 3,971 Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held at March 31, 2018 $ — $ (3,056 ) $ — $ — $ (422 ) Three Months Ended March 31, 2017 (in thousands) Investment Securities Available for Sale Private Equity Investments Visa Derivative Earnout Liability (1) GGL / SBA Loans Servicing Asset (2) Beginning balance, January 1, 2017 $ 1,796 $ 25,493 $ (5,768 ) $ (14,000 ) $ — Total gains (losses) realized/unrealized: Included in earnings — (1,814 ) — — — Unrealized gains included in other comprehensive income 55 — — — — Settlements — — 356 — — Transfer from amortization method to fair value — — — — 4,178 Measurement period adjustments related to Global One acquisition $ — — — 2,579 — Ending balance, March 31, 2017 $ 1,851 $ 23,679 $ (5,412 ) $ (11,421 ) $ 4,178 Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets still held at March 31, 2017 $ — $ (1,814 ) $ — $ — $ — (1) Earnout liability consists of contingent consideration obligation related to the Global One acquisition. (2) Effective January 1, 2017, Synovus elected the fair value option for determining the value of the GGL/SBA loans servicing asset. Prior to 2017, Synovus accounted for the GGL/SBA loans servicing asset using the amortization method. The table below provides an overview of the valuation techniques and significant unobservable inputs used in those techniques to measure financial instruments that are classified within Level 3 of the valuation hierarchy and are measured at fair value on a recurring basis. March 31, 2018 December 31, 2017 Valuation Technique Significant Unobservable Input Level 3 Fair Value Range/Weighted Average Level 3 Fair Value Range/Weighted Average Assets and liabilities measured at fair value on a recurring basis Investment Securities Available for Sale - Other Investments: Trust preferred securities Discounted cash flow analysis Credit spread embedded in discount rate $1,852 439 bps $1,935 398 bps Private equity investments Individual analysis of each investee company Multiple factors, including but not limited to, current operations, financial condition, cash flows, evaluation of business management and financial plans, and recently executed financing transactions related to the investee companies 12,715 N/A 15,771 N/A GGL/SBA loans servicing asset Discounted cash flow analysis Discount rate Prepayment speeds 3,971 13.57% 7.98% 4,101 13.16% 7.50% Earnout liability Option pricing methods and Monte Carlo simulation Financial projections of Global One 11,348 N/A 11,348 N/A Visa derivative liability Discounted cash flow analysis Estimated timing of resolution of covered litigation, future cumulative deposits to the litigation escrow for settlement of the covered litigation, and estimated future monthly fees payable to the derivative counterparty 3,974 1-4 years 4,330 1-4 years Assets Measured at Fair Value on a Non-recurring Basis Certain assets are recorded at fair value on a non-recurring basis. These assets are not measured at fair value on an ongoing basis. Non-recurring fair value adjustments typically are a result of the application of lower of cost or fair value accounting or a write-down occurring during the period. For example, if the fair value of an asset in these categories falls below its cost basis, it is considered to be at fair value at the end of the period of the adjustment. The following table presents assets measured at fair value on a non-recurring basis as of the dates indicated for which there was a fair value adjustment during the period. March 31, 2018 December 31, 2017 (in thousands) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Impaired loans * $ — $ — $ 4,531 $ 4,531 $ — $ — $ 3,603 $ 3,603 Other loans held for sale — — 3,295 3,295 — — 10,197 10,197 Other real estate — — 1,447 1,447 — — 3,363 3,363 Other assets held for sale — — 1,395 1,395 — — 5,334 5,334 * Collateral-dependent impaired loans that were written down to fair value during the period. Other real estate (ORE) properties are included in other assets on the consolidated balance sheet. The carrying value of ORE at March 31, 2018 and December 31, 2017 was $4.5 million and $3.8 million , respectively. The following table presents fair value adjustments recognized in earnings for the three months ended March 31, 2018 and 2017 for assets measured at fair value on a non-recurring basis still held at period-end. Three Months Ended March 31, (in thousands) 2018 2017 Impaired loans * $ 720 $ 2,230 Other loans held for sale 1,512 3,519 Other real estate 731 399 Other assets held for sale 107 238 * Collateral-dependent impaired loans that were written down to fair value during the period. The table below provides an overview of the valuation techniques and significant unobservable inputs used in those techniques to measure financial instruments that are classified within Level 3 of the valuation hierarchy and are measured at fair value on a non-recurring basis. The range of sensitivities that management utilized in its fair value calculations is deemed acceptable in the industry with respect to the identified financial instruments. March 31, 2018 December 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) (1) Range (Weighted Average) (1) Assets measured at fair value on a non-recurring basis Collateral dependent impaired loans Third-party appraised value of collateral less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 23% (9%) 0% - 10% (7%) 0%-50% (15%) 0%-10% (7%) Other loans held for sale Third-party appraised value of collateral less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 85% (30%) 0% - 10% (2%) 5% - 99% (54%) 0% - 10% (2%) Other real estate Third-party appraised value of real estate less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 39% (21%) 0% - 10% (7%) 0%-85% (35%) 0%-10% (7%) Other assets held for sale Third-party appraised value less estimated selling costs or BOV Discount to appraised value (2) Estimated selling costs N/A 0%-10% (7%) 21%-52% (25%) 0%-10% (7%) (1) The range represents management's estimate of the high and low of the value that would be assigned to a particular input. For assets measured at fair value on a non-recurring basis, the weighted average is the measure of central tendencies; it is not the value that management is using for the asset or liability. (2) Synovus also makes adjustments to the values of the assets listed above for reasons including age of the appraisal, information known by management about the property, such as occupancy rates, changes to the physical condition of the property, and other factors. Fair Value of Financial Instruments The following table presents the carrying and fair values of financial instruments at March 31, 2018 and December 31, 2017 . The fair values represent management’s estimates based on various methodologies and assumptions. For financial instruments that are not recorded at fair value on the balance sheet, such as loans held for investment, interest bearing deposits (including brokered deposits), and long-term debt, the fair value amounts should not be taken as an estimate of the amount that would be realized if all such financial instruments were to be settled immediately. The carrying and estimated fair values of financial instruments, as well as the level within the fair value hierarchy, as of March 31, 2018 and December 31, 2017 are as follows: March 31, 2018 (in thousands) Carrying Value Fair Value Level 1 Level 2 Level 3 Financial assets Total cash, cash equivalents, restricted cash, and restricted cash equivalents $ 1,059,017 $ 1,059,017 $ 1,059,017 $ — $ — Trading account assets 26,251 26,251 — 26,251 — Mortgage loans held for sale 50,439 50,439 — 50,439 — Other loans held for sale 6,591 6,591 — — 6,591 Investment securities available for sale 3,990,978 3,990,978 120,931 3,868,195 1,852 Private equity investments 12,715 12,715 — — 12,715 Mutual funds 3,131 3,131 3,131 — — Mutual funds held in rabbi trusts 13,385 13,385 13,385 — — Loans, net 24,625,273 24,538,259 — — 24,538,259 GGL/SBA loans servicing asset 3,971 3,971 — — 3,971 Derivative assets 9,407 9,407 — 9,407 — Financial liabilities Trading account liabilities 23,856 — — 23,856 — Non-interest bearing deposits 7,381,070 7,381,070 — 7,381,070 — Non-time interest bearing deposits 14,030,247 14,030,247 — 14,030,247 — Time deposits 4,842,190 4,834,135 — 4,834,135 — Total deposits $ 26,253,507 $ 26,245,452 $ — $ 26,245,452 $ — Federal funds purchased, other short-term borrowings and other short-term liabilities 185,531 185,531 185,531 — — Long-term debt 1,856,392 1,861,008 — 1,861,008 — Earnout liabilities 11,348 11,348 — — 11,348 Derivative liabilities 20,096 20,096 — 16,122 3,974 December 31, 2017 (in thousands) Carrying Value Fair Value Level 1 Level 2 Level 3 Financial assets Total cash, cash equivalents, restricted cash, and restricted cash equivalents $ 932,933 $ 932,933 $ 932,933 $ — $ — Trading account assets 3,820 3,820 522 3,298 — Mortgage loans held for sale 48,024 48,024 — 48,024 — Other loans for sale 11,356 11,356 — — 11,356 Investment securities available for sale 3,987,069 3,987,069 85,836 3,899,298 1,935 Private equity investments 15,771 15,771 — — 15,771 Mutual funds held in rabbi trusts 14,140 14,140 14,140 — — Loans, net 24,538,196 24,507,141 — — 24,507,141 GGL/SBA loans servicing asset 4,101 4,101 — — 4,101 Derivative assets 11,722 11,722 — 11,722 — Financial liabilities Trading account liabilities 1,000 1,000 — 1,000 — Non-interest bearing deposits 7,686,339 7,686,339 — 7,686,339 — Non-time interest bearing deposits 13,941,814 13,941,814 — 13,941,814 — Time deposits 4,519,747 4,523,661 — 4,523,661 — Total deposits $ 26,147,900 $ 26,151,814 $ — $ 26,151,814 $ — Federal funds purchased, other short-term borrowings and other short-term liabilities 161,190 161,190 161,190 — — Long-term debt 1,706,138 1,721,814 — 1,721,814 — Earnout liabilities 11,348 11,348 — — 11,348 Derivative liabilities 17,097 17,097 — 12,767 4,330

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2018
Summary of Derivative Instruments [Abstract]
Derivative Instruments	Note 9 - Derivative Instruments As part of its overall interest rate risk management activities, Synovus utilizes derivative instruments to manage its exposure to various types of interest rate risk. These derivative instruments generally consist of interest rate swaps, interest rate lock commitments made to prospective mortgage loan customers, and commitments to sell fixed-rate mortgage loans. Interest rate lock commitments represent derivative instruments since it is intended that such loans will be sold. Synovus may also utilize interest rate swaps to manage interest rate risks primarily arising from its core banking activities. These interest rate swap transactions generally involve the exchange of fixed and floating interest rate payment obligations without the exchange of underlying principal amounts. Swaps may be designated as either cash flow hedges or fair value hedges, as discussed below. As of March 31, 2018 and December 31, 2017 , Synovus had no outstanding interest rate swap contracts utilized to manage interest rate risk related to core banking activities. Synovus is party to master netting arrangements with its dealer counterparties; however, Synovus does not offset assets and liabilities under these arrangements for financial statement presentation purposes. Counterparty Credit Risk and Collateral Entering into derivative contracts potentially exposes Synovus to the risk of counterparties’ failure to fulfill their legal obligations, including, but not limited to, potential amounts due or payable under each derivative contract. Notional principal amounts are often used to express the volume of these transactions, but the amounts potentially subject to credit risk are much smaller. Synovus assesses the credit risk of its dealer counterparties by regularly monitoring publicly available credit rating information, evaluating other market indicators, and periodically reviewing detailed financials. Dealer collateral requirements are determined via risk-based policies and procedures and in accordance with existing agreements. Synovus seeks to minimize dealer credit risk by dealing with highly rated counterparties and by obtaining collateral for exposures above certain predetermined limits. Management closely monitors credit conditions within the customer swap portfolio, which management deems to be of higher risk than dealer counterparties. Collateral is secured at origination and credit related fair value adjustments are recorded against the asset value of the derivative as deemed necessary based upon an analysis, which includes consideration of the current asset value of the swap, customer credit rating, collateral value, and customer standing with regards to its swap contractual obligations and other related matters. Such asset values fluctuate based upon changes in interest rates regardless of changes in notional amounts and changes in customer specific risk. Customer Related Derivative Positions Synovus enters into interest rate swap agreements to facilitate the risk management strategies of a small number of commercial banking customers. Synovus mitigates this risk by entering into equal and offsetting interest rate swap agreements with highly rated counterparties. The interest rate swap agreements are free-standing derivatives and are recorded at fair value on Synovus' consolidated balance sheet. Fair value changes are recorded as a component of non-interest income. As of March 31, 2018 , the notional amount of customer related interest rate derivative financial instruments, including both the customer position and the offsetting position, was $1.55 billion , an increase of $82.0 million compared to December 31, 2017 . Visa Derivative In conjunction with the sale of Class B shares of common stock issued by Visa to Synovus as a Visa USA member, Synovus entered into a derivative contract with the purchaser, which provides for settlements between the parties based upon a change in the ratio for conversion of Visa Class B shares to Visa Class A shares. The conversion ratio changes when Visa deposits funds to a litigation escrow established by Visa to pay settlements for certain litigation, for which Visa is indemnified by Visa USA members. The litigation escrow is funded by proceeds from Visa’s conversion of Class B shares. The fair value of the derivative contract was $4.0 million and $4.3 million at March 31, 2018 and December 31, 2017 , respectively. The fair value of the derivative contract is determined based on management's estimate of the timing and amount of the Covered Litigation settlement, and the resulting payments due to the counterparty under the terms of the contract. Management believes that the estimate of Synovus' exposure to the Visa indemnification and fees associated with the Visa derivative is adequate based on current information, including Visa's recent announcements and disclosures. However, future developments in the litigation could require potentially significant changes to Synovus' estimate. See "Part II - Item 8. Financial Statements and Supplementary Data - Note 18 - Visa Shares and Related Agreements" of Synovus' 2017 Form 10-K for further information. Mortgage Derivatives Synovus originates first lien residential mortgage loans for sale into the secondary market. Mortgage loans are sold by Synovus for conversion to securities and the servicing of these loans is generally sold to a third-party servicing aggregator, or Synovus sells the mortgage loans as whole loans to investors either individually or in bulk on a servicing released basis. Synovus enters into interest rate lock commitments for residential mortgage loans which commits it to lend funds to a potential borrower at a specific interest rate and within a specified period of time. Interest rate lock commitments that relate to the origination of mortgage loans that, if originated, will be held for sale, are considered derivative financial instruments under applicable accounting guidance. Outstanding interest rate lock commitments expose Synovus to the risk that the price of the mortgage loans underlying the commitments may decline due to increases in mortgage interest rates from inception of the rate lock to the funding of the loan. At March 31, 2018 and December 31, 2017 , Synovus had commitments to fund at a locked interest rate, primarily fixed-rate mortgage loans to customers in the amount of $ 93.1 million and $49.3 million , respectively. Fair value adjustments related to these commitments resulted in a gain of $192 thousand and $674 thousand for the three months ended March 31, 2018 and 2017 , respectively, which was recorded as a component of mortgage banking income in the consolidated statements of income. At March 31, 2018 and December 31, 2017 , outstanding commitments to sell primarily fixed-rate mortgage loans amounted to $113.0 million and $72.5 million , respectively. Such commitments are entered into to reduce the exposure to market risk arising from potential changes in interest rates, which could affect the fair value of mortgage loans held for sale and outstanding rate lock commitments, which guarantee a certain interest rate if the loan is ultimately funded or granted by Synovus as a mortgage loan held for sale. The commitments to sell mortgage loans are at fixed prices and are scheduled to settle at specified dates that generally do not exceed 90 days. Fair value adjustments related to these outstanding commitments to sell mortgage loans resulted in a gain of $735 thousand and a loss of $2.5 million for the three months ended March 31, 2018 and 2017 , respectively, which were recorded as a component of mortgage banking income in the Consolidated Statements of Income. Collateral Requirements Pursuant to the Dodd-Frank Act, certain derivative transactions have collateral requirements, both at the inception of the trade and as the value of each derivative position changes. As of March 31, 2018 , collateral totaling $32.7 million of federal funds sold was pledged to the derivative counterparties to comply with collateral requirements. Effective January 3, 2017, the CME amended its rulebook to legally characterize variation margin cash payments for cleared OTC derivatives as settlement rather than as collateral. As a result, in 2017, Synovus began reducing the corresponding derivative asset and liability balances for CME-cleared OTC derivatives to reflect the settlement of those positions via the exchange of variation margin. At March 31, 2018 and December 31, 2017, Synovus had a variation margin of $8.1 million and $1.5 million , respectively, reducing the derivative asset. The impact of derivative instruments on the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 is presented below. Fair Value of Derivative Assets Fair Value of Derivative Liabilities (in thousands) Location on Consolidated Balance Sheets March 31, 2018 December 31, 2017 Location on Consolidated Balance Sheets March 31, 2018 December 31, 2017 Derivatives not designated as hedging instruments: Interest rate contracts Other assets $ 7,672 $ 10,786 Other liabilities $ 16,122 $ 12,638 Mortgage derivatives Other assets 1,735 936 Other liabilities — 129 Visa derivative — — Other liabilities 3,974 4,330 Total derivatives not designated as hedging instruments $ 9,407 $ 11,722 $ 20,096 $ 17,097 The pre-tax effect of fair value hedges on the Consolidated Statements of Income for the three months ended March 31, 2018 and 2017 is presented below. Gain (Loss) Recognized in Income (in thousands) Three Months Ended March 31, Derivatives not designated as hedging instruments Location of Gain (Loss) Recognized in Income 2018 2017 Interest rate contracts (1) Other non-interest income $ 7 $ (1 ) Mortgage derivatives (2) Mortgage banking income 927 (1,784 ) Total $ 934 $ (1,785 ) (1) Gain (loss) represents net fair value adjustments (including credit related adjustments) for customer swaps and offsetting positions. (2) Gain (loss) represents net fair value adjustments recorded for interest rate lock commitments and commitments to sell mortgage loans to third-party investors.

Net Income Per Common Share

Net Income Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Net Income Per Common Share	Note 10 - Net Income Per Common Share The following table displays a reconciliation of the information used in calculating basic and diluted earnings per common share for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, (in thousands, except per share data) 2018 2017 Basic Net Income Per Common Share: Net income available to common shareholders $ 100,607 $ 69,298 Weighted average common shares outstanding 118,666 122,300 Net income per common share, basic $ 0.85 $ 0.57 Diluted Net Income Per Common Share: Net income available to common shareholders $ 100,607 $ 69,298 Weighted average common shares outstanding 118,666 122,300 Potentially dilutive shares from outstanding equity-based awards and Earnout Payments 655 759 Weighted average diluted common shares 119,321 123,059 Net income per common share, diluted $ 0.84 $ 0.56 Basic net income per common share is computed by dividing net income by the average common shares outstanding for the period. Diluted net income per common share reflects the dilution that could occur if securities or other contracts to issue common stock were exercised or converted. The dilutive effect of outstanding stock options and restricted share units is reflected in diluted net income per common share, unless the impact is anti-dilutive, by application of the treasury stock method. As of March 31, 2018 and 2017 there were 2.2 million potentially dilutive shares related to the Warrant to purchase shares of common stock that were outstanding during 2018 and 2017 but were not included in the computation of diluted net income per common share because the effect would have been anti-dilutive.

Share-based Compensation

Share-based Compensation	3 Months Ended
	Mar. 31, 2018
Share-based Compensation [Abstract]
Share-based Compensation	Note 11 - Share-based Compensation General Description of Share-based Plans Synovus has a long-term incentive plan under which the Compensation Committee of the Board of Directors has the authority to grant share-based awards to Synovus employees. The 2013 Omnibus Plan authorizes 8.6 million common share equivalents available for grant, where grants of options count as one share equivalent and grants of full value awards (e.g., restricted share units, market restricted share units, and performance share units) count as two share equivalents. Any restricted share units that are forfeited and options that expire unexercised will again become available for issuance under the Plan. At March 31, 2018 , Synovus had a total of 4.9 million shares of its authorized but unissued common stock reserved for future grants under the 2013 Omnibus Plan. The Plan permits grants of share-based compensation including stock options, restricted share units, market restricted share units, and performance share units. The grants generally include vesting periods ranging from three to five years and contractual terms of ten years. Vesting for grants made in 2018 accelerates upon retirement for plan participants who have reached age 65 and who also have no less than 10 years of service at the date of their election to retire. Market restricted share units and performance share units are granted at a defined target level and are compared annually to required market and performance metrics to determine actual units vested and compensation expense. Synovus has historically issued new shares to satisfy share option exercises and share unit conversions. Dividend equivalents are paid on outstanding restricted share units, market restricted share units, and performance share units in the form of additional restricted share units that vest over the same vesting period or the vesting period left on the original restricted share unit grant. Share-based Compensation Expense Total share-based compensation expense was $4.0 million for the three months ended March 31, 2018 and $3.4 million for the three months ended March 31, 2017 . Accelerated share-based compensation expense associated with the provision in 2018 of a retirement vesting provision was approximately $170 thousand for the three months ended March 31, 2018 for retirement eligible employees. Stock Options No stock option grants were made during the three months ended March 31, 2018 . At March 31, 2018 , there were 693 thousand outstanding stock options to purchase shares of common stock with a weighted average exercise price of $16.94 per share. Restricted Share Units, Performance Share Units, and Market Restricted Share Units During the three months ended March 31, 2018 , Synovus awarded 213 thousand restricted share units that have a service-based vesting period of three years and awarded 87 thousand performance share units that vest upon service and performance conditions. Synovus also granted 58 thousand market restricted share units during the three months ended March 31, 2018 . The weighted average grant-date fair value of the awarded restricted share units, performance share units and market restricted share units was $47.43 per share. Market restricted share units and performance share units are granted at target and are compared annually to required market and performance metrics. The performance share units vest upon meeting certain service and performance conditions. Return on average assets (ROAA) and return on average tangible common equity (ROATCE) performance is evaluated each year over a three-year performance period, with share distribution determined at the end of the three years. The number of performance share units that will ultimately vest ranges from 0% to 150% of target based on Synovus' three-year weighted average ROAA (as defined) and ROATCE (as defined). The market restricted share units have a three -year service-based vesting component as well as a total shareholder return multiplier. The number of market restricted share units that will ultimately vest ranges from 75% to 125% of target based on Synovus' total shareholder return. At March 31, 2018 , including dividend equivalents granted, there were 921 thousand restricted share units, performance share units and market restricted share units outstanding with a weighted average grant-date fair value of $39.94 per share.

Non-interest Income

Non-interest Income	3 Months Ended
	Mar. 31, 2018
Noninterest Income [Abstract]
Non-interest Income	Note 12 - Non-interest Income The following table reflects revenue disaggregated by revenue type and line of business for the three months ended March 31, 2018 and 2017. Non-interest Income by Line of Business For Three Months Ended March 31, 2018 (in thousands) Total Community Banking Corporate Banking Retail Banking Financial Management Services Other Service charges on deposit accounts $ 19,940 $ 5,680 $ 533 $ 13,422 $ — $ 305 Fiduciary and asset management fees 13,435 — — — 13,435 — Card fees 10,199 205 — 9,994 — — Brokerage revenue 8,695 — — — 8,695 — Insurance revenue 1,213 — — — 1,213 — Other fees 832 — — 559 — 273 $ 54,314 $ 5,885 $ 533 $ 23,975 $ 23,343 $ 578 Other revenues (1) 12,732 2,452 1,733 1,529 5,843 1,175 Total non-interest income $ 67,046 $ 8,337 $ 2,266 $ 25,504 $ 29,186 $ 1,753 Non-interest Income by Line of Business For Three Months Ended March 31, 2017 (in thousands) Total Community Banking Corporate Banking Retail Banking Financial Management Services Other Service charges on deposit accounts $ 20,118 $ 5,771 $ 459 $ 13,437 $ — $ 451 Fiduciary and asset management fees 12,151 — — — 12,151 — Card fees 9,844 219 — 9,625 — — Brokerage revenue 7,226 — — — 7,226 — Insurance revenue 1,304 — — — 1,304 — Other fees 842 — — 574 — 268 $ 51,485 $ 5,990 $ 459 $ 23,636 $ 20,681 $ 719 Other revenues (1) 20,354 1,648 1,619 1,566 6,597 8,924 Total non-interest income $ 71,839 $ 7,638 $ 2,078 $ 25,202 $ 27,278 $ 9,643 ( 1) Other revenues primarily relate to revenues not derived from contracts with customers. Following is a discussion of key revenues within the scope of the new revenue guidance: Service Charges on Deposit Accounts : Revenue from service charges on deposit accounts is earned through cash management, wire transfer, and other deposit-related services, as well as overdraft, non-sufficient funds, account management and other deposit-related fees. Revenue is recognized for these services either over time, corresponding with deposit accounts' monthly cycle, or at a point in time for transaction related services and fees. Payment for service charges on deposit accounts is primarily received immediately or in the following month through a direct charge to customers' accounts. Fiduciary and Asset Management Fees : Fiduciary and asset management fees are primarily comprised of fees earned from the management and administration of trusts and other customer assets. Synovus' performance obligation is generally satisfied over time and the resulting fees are recognized monthly, based upon the month-end market value of the assets under management and the applicable fee rate. Payment is generally received a few days after month-end through a direct charge to customers' accounts. Synovus does not earn performance-based incentives. Card Fees: Card fees consist primarily of interchange fees from consumer credit and debit cards processed by card association networks, as well as merchant discounts, and other card related services. Interchange rates are generally set by the credit card associations and based on purchase volumes and other factors. Interchange fees and merchant discounts are recognized concurrently with the delivery of service on a daily basis as transactions occur. Payment is typically received immediately or in the following month. Card fees are reported net of certain associated expense items including loyalty program expenses and network expenses. Brokerage Revenue: Brokerage revenue consists primarily of commissions. Additionally, brokerage revenue includes advisory fees earned from the management of customer assets. Advisory fees for brokerage services are recognized and collected monthly and are based upon the month-end market value of the assets under management at a rate predetermined in the contract. Transactional revenues are based on the size and number of transactions executed at the client's direction and are generally recognized on the trade date with payment received on the settlement date. Insurance Revenue: Insurance revenue primarily consists of commissions received on annuity and life product sales. Synovus acts as an intermediary between the customer and the insurance carrier. Synovus' performance obligation is generally satisfied upon the issuance of the insurance policy; thus, revenue is recognized upon issuance of the policy. Shortly after the policy is issued, the carrier remits the commission payment to Synovus. Synovus earns an insignificant amount of trailer fees on sales of insurance products. Other Fees: Other fees primarily consist of revenues generated from safe deposit box rental fees and lockbox services. Fees are recognized over time, on a monthly basis, as Synovus' performance obligation for services is satisfied. Payment is received upfront for safe deposit box rentals and in the following month for lockbox services. Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity's obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. Synovus' non-interest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is often received immediately or shortly after Synovus satisfies its performance obligation and revenue is recognized. Synovus does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of March 31, 2018 and December 31, 2017, Synovus did not have any significant contract balances.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 13 - Commitments and Contingencies In the normal course of business, Synovus enters into commitments to extend credit such as loan commitments and letters of credit to meet the financing needs of its customers. Synovus uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. The contractual amount of these financial instruments represents Synovus' maximum credit risk should the counterparty draw upon the commitment, and should the counterparty subsequently fail to perform according to the terms of the contract. Since many of the commitments are expected to expire without being drawn upon, total commitment amounts do not necessarily represent future cash requirements. Additionally, certain commitments (primarily consumer) may generally be canceled by providing notice to the borrower. The allowance for credit losses associated with unfunded commitments and letters of credit is a component of the unfunded commitments reserve recorded within other liabilities on the consolidated balance sheet. Additionally, unearned fees relating to letters of credit are recorded within other liabilities on the consolidated balance sheet. These amounts are not material to Synovus' consolidated balance sheet. Unfunded letters of credit and lending commitments at March 31, 2018 and December 31, 2017 are presented below. (in thousands) March 31, 2018 December 31, 2017 Letters of credit* $ 175,164 $ 153,372 Commitments to fund commercial and industrial loans 5,143,323 5,090,827 Commitments to fund commercial real estate, construction, and land development loans 1,541,810 1,567,583 Commitments under home equity lines of credit 1,156,283 1,137,714 Unused credit card lines 780,704 779,254 Other loan commitments 369,636 351,358 Total unfunded lending commitments and letters of credit $ 9,166,920 $ 9,080,108 * Represent the contractual amount net of risk participations of approximately $60 million and $77 million at March 31, 2018 and December 31, 2017, respectively. Legal Proceedings Synovus and its subsidiaries are subject to various legal proceedings and claims that arise in the ordinary course of its business. Additionally, in the ordinary course of business, Synovus and its subsidiaries are subject to regulatory examinations, information gathering requests, inquiries and investigations. Synovus, like many other financial institutions, has been the target of numerous legal actions and other proceedings asserting claims for damages and related relief for losses. These actions include claims and counterclaims asserted by individual borrowers related to their loans and allegations of violations of state and federal laws and regulations relating to banking practices, including putative class action matters. In addition to actual damages, if Synovus does not prevail in asserted legal actions, credit-related litigation could result in additional write-downs or charge-offs of loans, which could adversely affect Synovus' results of operations during the period in which the write-down or charge-off were to occur. Synovus carefully examines and considers each legal matter, and, in those situations where Synovus determines that a particular legal matter presents loss contingencies that are both probable and reasonably estimable, Synovus establishes an appropriate accrual. An event is considered to be probable if the future event is likely to occur. While the final outcome of any legal proceeding is inherently uncertain, based on the information currently available, advice of counsel and available insurance coverage, management believes that the amounts accrued with respect to legal matters as of March 31, 2018 are adequate. The actual costs of resolving legal claims may be higher or lower than the amounts accrued. In addition, where Synovus determines that there is a reasonable possibility of a loss in respect of legal matters, Synovus considers whether it is able to estimate the total reasonably possible loss or range of loss. An event is “reasonably possible” if “the chance of the future event or events occurring is more than remote but less than likely.” An event is “remote” if “the chance of the future event or events occurring is more than slight but less than reasonably possible." In many situations, Synovus may be unable to estimate reasonably possible losses due to the preliminary nature of the legal matters, as well as a variety of other factors and uncertainties. For those legal matters where Synovus is able to estimate a range of reasonably possible losses, management currently estimates the aggregate range from our outstanding litigation is from zero to $5 million in excess of the amounts accrued, if any, related to those matters. This estimated aggregate range is based upon information currently available to Synovus, and the actual losses could prove to be lower or higher. As there are further developments in these legal matters, Synovus will reassess these matters, and the estimated range of reasonably possible losses may change as a result of this assessment. Based on Synovus' current knowledge and advice of counsel, management presently does not believe that the liabilities arising from these legal matters will have a material adverse effect on Synovus' consolidated financial condition, results of operations or cash flows. However, it is possible that the ultimate resolution of these legal matters could have a material adverse effect on Synovus' results of operations for any particular period. Synovus intends to vigorously pursue all available defenses to these legal matters, but will also consider other alternatives, including settlement, in situations where there is an opportunity to resolve such legal matters on terms that Synovus considers to be favorable, including in light of the continued expense and distraction of defending such legal matters. Synovus maintains insurance coverage, which may be available to cover legal fees, or potential losses that might be incurred in connection with such legal matters. The above-noted estimated range of reasonably possible losses does not take into consideration insurance coverage which may or may not be available for the respective legal matters.

Significant Accounting Polici22

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited interim consolidated financial statements have been prepared in accordance with the instructions to the SEC Form 10-Q and Article 10 of Regulation S-X; therefore, they do not include all information and footnotes necessary for a fair presentation of financial position, results of operations, comprehensive income, and cash flows in conformity with GAAP. All adjustments consisting of normally recurring accruals that, in the opinion of management, are necessary for a fair presentation of the consolidated financial position and results of operations for the periods covered by this Report have been included. The accompanying unaudited interim consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes appearing in Synovus' 2017 Form 10-K . In connection with the adoption of ASU 2016-18, Statement of Cash Flows-Restricted Cash, Synovus changed its presentation of cash and cash equivalents, effective January 1, 2018, to include cash and due from banks as well as interest bearing funds with the Federal Reserve Bank, interest earning deposits with banks, and federal funds sold and securities purchased under resale agreements, which are inclusive of any restricted cash and restricted cash equivalents. Prior to 2018, cash and cash equivalents only included cash and due from banks. Prior periods have been revised to maintain comparability. Excluding the aforementioned presentation change, there have been no significant changes to the accounting policies as disclosed in Synovus' 2017 Form 10-K . In preparing the unaudited interim consolidated financial statements in accordance with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the respective consolidated balance sheets and the reported amounts of revenues and expenses for the periods presented. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses, the fair value of investment securities, and the fair value of private equity investments.
Cash and Cash Equivalents	Cash and cash equivalents consist of cash and due from banks, interest bearing funds with the Federal Reserve Bank, interest earning deposits with banks, federal funds sold and securities purchased under resale agreements, and is inclusive of any restricted cash and restricted cash equivalents. Restricted cash and restricted cash equivalents primarily relate to cash held on deposit with the Federal Reserve to meet reserve requirements as well as cash posted as collateral for derivatives in a liability position. At March 31, 2018 and December 31, 2017 , interest bearing funds with the Federal Reserve Bank included $14.1 million and $8.6 million , respectively, on deposit to meet Federal Reserve Bank requirements. Interest earning deposits with banks include $6.3 million and $5.9 million at March 31, 2018 and December 31, 2017 , respectively, which are pledged as collateral in connection with certain letters of credit. Federal funds sold include $32.7 million and $43.8 million at March 31, 2018 and December 31, 2017 , respectively, which are pledged to collateralize certain derivative financial instruments. Federal funds sold and securities purchased under resale agreements generally mature in one day.
Income Taxes	On December 22, 2017, Federal Tax Reform was enacted into law. The new legislation included a decrease in the corporate federal income tax rate from 35% to 21% effective January 1, 2018. Under ASC 740, the effects of the changes in tax rates and laws are recognized in the period in which the new legislation is enacted. Therefore, Synovus was required to remeasure its deferred tax assets and liabilities and record the adjustment to income tax expense effective December 22, 2017. In December 2017, the SEC issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118), which allowed companies to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. Since Federal Tax Reform was enacted late in 2017, management expects that certain deferred tax assets and liabilities will continue to be evaluated in the context of Federal Tax Reform through the date of the filing of our 2017 federal income tax return, and may change as a result of evolving management interpretations, elections, and assumptions, as well as new guidance that may be issued by the Internal Revenue Service. Accordingly, the federal income tax expense of $47.2 million recorded in 2017 relating to the effects from Federal Tax Reform is considered provisional. Management expects to complete its analysis within the measurement period in accordance with SAB 118.
Recently Adopted Accounting Standards Updates	ASU 2014-09, Revenue from Contracts with Customers (Topic 606) issued by the FASB in May 2014 , and all subsequent ASUs that modified 606. ASU 2014-09 implements a common revenue standard that establishes principles for reporting information about the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts to provide goods or services to customers. The core principle of the revenue model is that a company will recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The scope of the guidance explicitly excludes net interest income as well as many other revenues from financial assets. Management reviewed its revenue streams and contracts with customers and did not identify material changes to the timing or amount of revenue recognition. Synovus adopted these ASUs on the required effective date of January 1, 2018 utilizing the modified retrospective method of adoption. The adoption resulted in a cumulative effect adjustment of ($685) thousand to the opening balance of retained earnings. Beginning January 1, 2018, in connection with the adoption of this standard, Synovus began including merchant discounts and other card-related fees in card fees. For periods prior to January 1, 2018, these amounts were previously presented in other non-interest income and have been reclassified for comparability. See "Part I - Item 1. Financial Statements and Supplementary Data - Note 12 - Non-interest Income" for the required disclosures in accordance with this ASU. ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. In February 2018, the FASB issued final guidance on reclassification of tax effects stranded in other comprehensive income due to Federal Tax Reform. The guidance provides entities the option to reclassify the tax effects that are stranded in accumulated other comprehensive income (AOCI) as a result of Federal Tax Reform to retained earnings. The guidance is effective for fiscal years beginning after December 15, 2018; early adoption is permitted. Synovus elected to early adopt ASU 2018-02 as of January 1, 2018 and elected to reclassify the income tax effects of Federal Tax Reform from AOCI to retained earnings. For Synovus, tax effects stranded in AOCI due to Federal Tax Reform totaled $7.6 million at December 31, 2017 and primarily related to unrealized losses on the available-for-sale investment securities portfolio. The reclassification adjustment resulted in an increase to retained earnings as of January 1, 2018 of $7.6 million and a corresponding decrease to AOCI for the same amount. Synovus utilizes the portfolio approach when releasing income tax effects from AOCI for its investment securities. The reclassification adjustment increased regulatory capital by $7.6 million , resulting in an approximate 3 b.p.s increase to Tier 1 capital, common equity Tier 1 capital, and total risk based capital ratios, and an approximate 2 b.p.s increase to the leverage ratio. ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilitie s. In January 2016, the FASB issued ASU 2016-01 that included targeted amendments to accounting guidance for recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or consolidated) to be measured at fair value with changes in fair value recognized in net income. This ASU requires a cumulative-effect adjustment to retained earnings as of the beginning of the reporting period of adoption to reclassify the cumulative change in fair value of equity securities previously recognized in AOCI. ASU 2016-01 became effective for Synovus on January 1, 2018. The adoption of the guidance resulted in a transfer of investments in mutual funds of $3.2 million , at fair value, from investment securities available for sale to other assets and a $117 thousand cumulative-effect adjustment that decreased retained earnings, with offsetting related adjustments to deferred taxes and AOCI. ASU 2016-01 also emphasizes the existing requirement to use an exit price concept to measure fair value for disclosure purposes in determining the fair value of loans. Determination of the fair value under the exit price method requires judgment because substantially all of the loans within the loan portfolio do not have observable market prices. The adoption of this guidance did not have a significant impact on Synovus' fair value disclosures. ASU 2016-18, Statement of Cash Flows-Restricted Cash. In November 2016, the FASB issued new accounting guidance which addressed classification and presentation of changes in restricted cash on the statement of cash flows. The standard requires a reconciliation of the beginning-of-period and end-of-period total amounts shown on the statement of cash flows to include in cash and cash equivalents amounts generally described as restricted cash and restricted cash equivalents. The ASU does not define restricted cash or restricted cash equivalents; however, the nature of the restrictions should be disclosed. The guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. This ASU is to be applied using a retrospective transition method for each period presented. Synovus adopted ASU 2016-18 on January 1, 2018 and concurrently revised its presentation of cash and cash equivalents. For periods prior to January 1, 2018, the presentation of cash and cash equivalents has been revised to conform to the current presentation.
Reclassifications	Prior periods' consolidated financial statements are reclassified whenever necessary to conform to the current periods' presentation.

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments [Abstract]
Summary of Available-for-Sale Investment Securities	The amortized cost, gross unrealized gains and losses, and estimated fair values of investment securities available for sale at March 31, 2018 and December 31, 2017 are summarized below. March 31, 2018 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities $ 122,655 $ — $ (1,724 ) $ 120,931 U.S. Government agency securities 10,769 128 — 10,897 Mortgage-backed securities issued by U.S. Government agencies 115,888 237 (3,257 ) 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises 2,734,650 483 (71,133 ) 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 1,102,361 — (37,320 ) 1,065,041 State and municipal securities 115 — — 115 Corporate debt and other debt securities 17,000 274 (148 ) 17,126 Total investment securities available for sale $ 4,103,438 $ 1,122 $ (113,582 ) $ 3,990,978 December 31, 2017 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Treasury securities $ 83,608 $ — $ (934 ) $ 82,674 U.S. Government agency securities 10,771 91 — 10,862 Mortgage-backed securities issued by U.S. Government agencies 121,283 519 (1,362 ) 120,440 Mortgage-backed securities issued by U.S. Government sponsored enterprises 2,666,818 5,059 (31,354 ) 2,640,523 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 1,135,259 144 (23,404 ) 1,111,999 State and municipal securities 180 — — 180 Corporate debt and other securities 20,320 294 (223 ) 20,391 Total investment securities available for sale $ 4,038,239 $ 6,107 $ (57,277 ) $ 3,987,069
Schedule of Unrealized Loss on Investments	Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2018 and December 31, 2017 are presented below. March 31, 2018 Less than 12 Months 12 Months or Longer Total (in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses U.S. Treasury securities $ 72,694 $ 989 $ 29,313 $ 735 $ 102,007 $ 1,724 Mortgage-backed securities issued by U.S. Government agencies 39,763 1,045 52,763 2,212 92,526 3,257 Mortgage-backed securities issued by U.S. Government sponsored enterprises 1,656,562 38,195 882,984 32,938 2,539,546 71,133 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 629,793 17,650 435,247 19,670 1,065,040 37,320 Corporate debt and other debt securities — — 1,852 148 1,852 148 Total $ 2,398,812 $ 57,879 $ 1,402,159 $ 55,703 $ 3,800,971 $ 113,582 December 31, 2017 Less than 12 Months 12 Months or Longer Total (in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses U.S. Treasury securities $ 34,243 $ 443 $ 29,562 $ 491 $ 63,805 $ 934 Mortgage-backed securities issued by U.S. Government agencies 36,810 357 55,740 1,005 92,550 1,362 Mortgage-backed securities issued by U.S. Government sponsored enterprises 1,271,012 10,263 929,223 21,091 2,200,235 31,354 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises 653,781 9,497 426,237 13,907 1,080,018 23,404 Corporate debt and other securities — — 5,097 223 5,097 223 Total $ 1,995,846 $ 20,560 $ 1,445,859 $ 36,717 $ 3,441,705 $ 57,277
Amortized Cost and Estimated Fair Value by Contractual Maturity of Investment Securities Available-for-Sale	For purposes of the maturity table, mortgage-backed securities and CMOs, which are not due at a single maturity date, have been classified based on the final contractual maturity date. Distribution of Maturities at March 31, 2018 (in thousands) Within One Year 1 to 5 Years 5 to 10 Years More Than 10 Years Total Amortized Cost U.S. Treasury securities $ 18,924 $ 103,731 $ — $ — $ 122,655 U.S. Government agency securities 2,330 6,437 2,002 — 10,769 Mortgage-backed securities issued by U.S. Government agencies — — 29,355 86,533 115,888 Mortgage-backed securities issued by U.S. Government sponsored enterprises 7 1,657 578,774 2,154,212 2,734,650 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — — 18,652 1,083,709 1,102,361 State and municipal securities 115 — — — 115 Corporate debt and other debt securities — — 15,000 2,000 17,000 Total amortized cost $ 21,376 $ 111,825 $ 643,783 $ 3,326,454 $ 4,103,438 Fair Value U.S. Treasury securities $ 18,924 $ 102,007 $ — $ — $ 120,931 U.S. Government agency securities 2,355 6,514 2,028 — 10,897 Mortgage-backed securities issued by U.S. Government agencies — — 28,993 83,875 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises 7 1,723 565,331 2,096,939 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — — 18,218 1,046,823 1,065,041 State and municipal securities 115 — — — 115 Corporate debt and other debt securities — — 15,274 1,852 17,126 Total fair value $ 21,401 $ 110,244 $ 629,844 $ 3,229,489 $ 3,990,978
Schedule of Activity for Available-for-Sale Securities	Proceeds from sales, gross gains, and gross losses on sales of securities available for sale for the three months ended March 31, 2017 are presented below. The specific identification method is used to reclassify gains and losses out of other comprehensive income at the time of sale. On January 1, 2018, Synovus transferred $3.2 million , at fair value, from investment securities available for sale to other assets upon adoption of ASU 2016-01. Three Months Ended March 31, (in thousands) 2018 2017 Proceeds from sales of investment securities available for sale $ — $ 282,629 Gross realized gains on sales — 7,702 Gross realized losses on sales — (34 ) Investment securities gains, net $ — $ 7,668

Restructuring Charges (Tables)

Restructuring Charges (Tables)	3 Months Ended
	Mar. 31, 2018
Restructuring Charges [Abstract]
Schedule of Restructuring and Related Costs	The following tables present aggregate activity within the accrual for restructuring charges for the three months ended March 31, 2018 and 2017 : (in thousands) Severance Charges Lease Termination Charges Total Balance at December 31, 2017 $ 336 $ 3,276 $ 3,612 Accruals for lease terminations — (377 ) (377 ) Payments (336 ) (393 ) (729 ) Balance at March 31, 2018 $ — $ 2,506 $ 2,506 (in thousands) Severance Charges Lease Termination Charges Total Balance at December 31, 2016 $ 81 $ 3,968 $ 4,049 Accrual for voluntary and involuntary termination benefits 6,453 — 6,453 Payments (219 ) (279 ) (498 ) Balance at March 31, 2017 $ 6,315 $ 3,689 $ 10,004 For the three months ended March 31, 2018 and 2017 , total restructuring charges consist of the following components: Three Months Ended March 31, (in thousands) 2018 2017 Severance charges $ — $ 6,453 Other charges, net (315 ) 58 Total restructuring charges, net $ (315 ) $ 6,511

Loans and Allowance for Loan 25

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Loans and Allowance for Loan Losses [Abstract]
Schedule of Current, Accruing Past Due, and Nonaccrual Loans	The following is a summary of current, accruing past due, and non-accrual loans by portfolio class as of March 31, 2018 and December 31, 2017 . Current, Accruing Past Due, and Non-accrual Loans March 31, 2018 (in thousands) Current Accruing 30-89 Days Past Due Accruing 90 Days or Greater Past Due Total Accruing Past Due Non-accrual Total Investment properties $ 5,613,811 $ 1,986 $ 323 $ 2,309 $ 2,930 $ 5,619,050 1-4 family properties 753,255 2,232 783 3,015 2,634 758,904 Land and development 449,700 3,450 49 3,499 4,574 457,773 Total commercial real estate 6,816,766 7,668 1,155 8,823 10,138 6,835,727 Commercial, financial and agricultural 7,093,270 15,872 783 16,655 81,606 7,191,531 Owner-occupied 4,901,542 3,841 936 4,777 4,067 4,910,386 Total commercial and industrial 11,994,812 19,713 1,719 21,432 85,673 12,101,917 Home equity lines 1,450,454 6,718 431 7,149 14,868 1,472,471 Consumer mortgages 2,651,758 3,905 — 3,905 7,708 2,663,371 Credit cards 223,232 1,599 1,882 3,481 — 226,713 Other consumer loans 1,595,745 9,131 229 9,360 1,694 1,606,799 Total consumer 5,921,189 21,353 2,542 23,895 24,270 5,969,354 Total loans $ 24,732,767 $ 48,734 $ 5,416 $ 54,150 $ 120,081 $ 24,906,998 (1 ) December 31, 2017 (in thousands) Current Accruing 30-89 Days Past Due Accruing 90 Days or Greater Past Due Total Accruing Past Due Non-accrual Total Investment properties $ 5,663,665 $ 2,506 $ 90 $ 2,596 $ 3,804 $ 5,670,065 1-4 family properties 775,023 3,545 202 3,747 2,849 781,619 Land and development 476,131 1,609 67 1,676 5,797 483,604 Total commercial real estate 6,914,819 7,660 359 8,019 12,450 6,935,288 Commercial, financial and agricultural 7,097,127 11,214 1,016 12,230 70,130 7,179,487 Owner-occupied 4,830,150 6,880 479 7,359 6,654 4,844,163 Total commercial and industrial 11,927,277 18,094 1,495 19,589 76,784 12,023,650 Home equity lines 1,490,808 5,629 335 5,964 17,455 1,514,227 Consumer mortgages 2,622,061 3,971 268 4,239 7,203 2,633,503 Credit cards 229,015 1,930 1,731 3,661 — 232,676 Other consumer loans 1,461,223 10,333 226 10,559 1,669 1,473,451 Total consumer 5,803,107 21,863 2,560 24,423 26,327 5,853,857 Total loans $ 24,645,203 $ 47,617 $ 4,414 $ 52,031 $ 115,561 $ 24,812,795 (2 ) (1) Total before net deferred fees and costs of $24.0 million . (2) Total before net deferred fees and costs of $25.3 million .
Loan Portfolio Credit Exposure	In the following tables, consumer loans are generally assigned a risk grade similar to the classifications described above; however, upon reaching 90 days and 120 days past due, they are generally downgraded to Substandard and Loss, respectively, in accordance with the FFIEC Uniform Retail Credit Classification and Account Management Policy. Additionally, in accordance with the Interagency Supervisory Guidance on Allowance for Loan and Lease Losses Estimation Practices for Loans and Lines of Credit Secured by Junior Liens on 1-4 Family Residential Properties, the risk grade classifications of consumer loans (home equity lines and consumer mortgages) secured by junior liens on 1-4 family residential properties also consider available information on the payment status of any associated senior liens with other financial institutions. Loan Portfolio Credit Exposure by Risk Grade March 31, 2018 (in thousands) Pass Special Mention Substandard (1) Doubtful (2) Loss Total Investment properties $ 5,545,689 $ 53,193 $ 20,168 $ — $ — $ 5,619,050 1-4 family properties 729,023 14,331 15,550 — — 758,904 Land and development 408,128 33,858 12,654 3,133 — 457,773 Total commercial real estate 6,682,840 101,382 48,372 3,133 — 6,835,727 Commercial, financial and agricultural 6,895,133 132,582 154,863 8,953 — 7,191,531 Owner-occupied 4,778,913 55,627 75,773 73 — 4,910,386 Total commercial and industrial 11,674,046 188,209 230,636 9,026 — 12,101,917 Home equity lines 1,452,171 — 18,421 271 1,608 (3) 1,472,471 Consumer mortgages 2,654,285 — 8,951 103 32 (3) 2,663,371 Credit cards 224,831 — 564 — 1,318 (4) 226,713 Other consumer loans 1,604,979 — 1,556 257 7 (3) 1,606,799 Total consumer 5,936,266 — 29,492 631 2,965 5,969,354 Total loans $ 24,293,152 $ 289,591 $ 308,500 $ 12,790 $ 2,965 $ 24,906,998 (5 ) December 31, 2017 (in thousands) Pass Special Mention Substandard (1) Doubtful (2) Loss Total Investment properties $ 5,586,792 $ 64,628 $ 18,645 $ — $ — $ 5,670,065 1-4 family properties 745,299 19,419 16,901 — — 781,619 Land and development 431,759 33,766 14,950 3,129 — 483,604 Total commercial real estate 6,763,850 117,813 50,496 3,129 — 6,935,288 Commercial, financial and agricultural 6,929,506 115,912 132,818 1,251 — 7,179,487 Owner-occupied 4,713,877 50,140 80,073 73 — 4,844,163 Total commercial and industrial 11,643,383 166,052 212,891 1,324 — 12,023,650 Home equity lines 1,491,105 — 21,079 285 1,758 (3) 1,514,227 Consumer mortgages 2,622,499 — 10,607 291 106 (3) 2,633,503 Credit cards 230,945 — 399 — 1,332 (4) 232,676 Other consumer loans 1,470,944 — 2,168 329 10 (3) 1,473,451 Total consumer 5,815,493 — 34,253 905 3,206 5,853,857 Total loans $ 24,222,726 $ 283,865 $ 297,640 $ 5,358 $ 3,206 $ 24,812,795 (6 ) (1) Includes $204.2 million and $190.6 million of Substandard accruing loans at March 31, 2018 and December 31, 2017 , respectively. (2) The loans within this risk grade are on non-accrual status. Commercial loans generally have an allowance for loan losses in accordance with ASC 310, and retail loans generally have an allowance for loan losses equal to 50% of the loan amount. (3) The loans within this risk grade are on non-accrual status and have an allowance for loan losses equal to the full loan amount. (4) Represent amounts that were 120 days past due. These credits are downgraded to the Loss category with an allowance for loan losses equal to the full loan amount and are generally charged off upon reaching 181 days past due in accordance with the FFIEC Uniform Retail Credit Classification and Account Management Policy. (5) Total before net deferred fees and costs of $24.0 million . (6) Total before net deferred fees and costs of $25.3 million .
Schedule of Allowances for Loan Losses and Recorded Investment in Loans	The following table details the changes in the allowance for loan losses by loan segment for the three months ended March 31, 2018 . Allowance for Loan Losses and Recorded Investment in Loans As Of and For The Three Months Ended March 31, 2018 (in thousands) Commercial Real Estate Commercial & Industrial Consumer Total Allowance for loan losses: Beginning balance $ 74,998 $ 126,803 $ 47,467 $ 249,268 Charge-offs (1,911 ) (8,015 ) (4,455 ) (14,381 ) Recoveries 5,723 3,112 1,266 10,101 Provision for loan losses (4,819 ) 12,845 4,750 12,776 Ending balance (1) $ 73,991 $ 134,745 $ 49,028 $ 257,764 Ending balance: individually evaluated for impairment 3,740 14,405 797 18,942 Ending balance: collectively evaluated for impairment $ 70,251 $ 120,340 $ 48,231 $ 238,822 Loans: Ending balance: total loans (1)(2) $ 6,835,727 $ 12,101,917 $ 5,969,354 $ 24,906,998 Ending balance: individually evaluated for impairment 49,221 112,823 29,608 191,652 Ending balance: collectively evaluated for impairment $ 6,786,506 $ 11,989,094 $ 5,939,746 $ 24,715,346 As Of and For The Three Months Ended March 31, 2017 (in thousands) Commercial Real Estate Commercial & Industrial Consumer Total Allowance for loan losses: Beginning balance $ 81,816 $ 125,778 $ 44,164 $ 251,758 Charge-offs (1,908 ) (6,893 ) (3,934 ) (12,735 ) Recoveries 2,889 1,824 1,104 5,817 Provision for loan losses (4,483 ) 6,387 6,770 8,674 Ending balance (1) $ 78,314 $ 127,096 $ 48,104 $ 253,514 Ending balance: individually evaluated for impairment 6,917 11,085 1,705 19,707 Ending balance: collectively evaluated for impairment $ 71,397 $ 116,011 $ 46,399 $ 233,807 Loans: Ending balance: total loans (1)(3) $ 7,467,288 $ 11,732,701 $ 5,084,199 $ 24,284,188 Ending balance: individually evaluated for impairment 79,203 120,470 35,083 234,756 Ending balance: collectively evaluated for impairment $ 7,388,085 $ 11,612,231 $ 5,049,116 $ 24,049,432 (1 ) As of and for the three months ended March 31, 2018 and 2017 , there were no purchased credit-impaired loans and no allowance for loan losses for purchased credit-impaired loans. (2) Total before net deferred fees and costs of $24.0 million . (3) Total before net deferred fees and costs of $25.7 million .
Schedule of Impaired Loans	The tables below summarize impaired loans (including accruing TDRs) as of March 31, 2018 and December 31, 2017 . Impaired Loans (including accruing TDRs) March 31, 2018 Three Months Ended March 31, 2018 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded Investment properties $ — $ — $ — $ — $ — 1-4 family properties — — — — — Land and development — — — 37 — Total commercial real estate — — — 37 — Commercial, financial and agricultural 9,614 12,039 — 8,682 — Owner-occupied — — — — — Total commercial and industrial 9,614 12,039 — 8,682 — Home equity lines 1,086 1,086 — 2,122 — Consumer mortgages 2,640 2,665 — 880 — Credit cards — — — — — Other consumer loans — — — — — Total consumer 3,726 3,751 — 3,002 — Total impaired loans with no related allowance recorded $ 13,340 $ 15,790 $ — $ 11,721 $ — With allowance recorded Investment properties $ 19,388 $ 19,388 $ 753 $ 22,769 $ 198 1-4 family properties 12,008 12,008 392 11,715 216 Land and development 17,825 19,565 2,595 18,133 76 Total commercial real estate 49,221 50,961 3,740 52,617 490 Commercial, financial and agricultural 65,422 65,691 12,491 67,198 273 Owner-occupied 37,787 37,841 1,914 37,715 357 Total commercial and industrial 103,209 103,532 14,405 104,913 630 Home equity lines 3,475 3,475 44 4,383 45 Consumer mortgages 17,378 17,378 447 19,106 194 Credit cards — — — — — Other consumer loans 5,029 5,031 306 5,391 71 Total consumer 25,882 25,884 797 28,880 310 Total impaired loans with allowance recorded $ 178,312 $ 180,377 $ 18,942 $ 186,410 $ 1,430 Total impaired loans Investment properties $ 19,388 $ 19,388 $ 753 $ 22,769 $ 198 1-4 family properties 12,008 12,008 392 11,715 216 Land and development 17,825 19,565 2,595 18,170 76 Total commercial real estate 49,221 50,961 3,740 52,654 490 Commercial, financial and agricultural 75,036 77,730 12,491 75,880 273 Owner-occupied 37,787 37,841 1,914 37,715 357 Total commercial and industrial 112,823 115,571 14,405 113,595 630 Home equity lines 4,561 4,561 44 6,505 45 Consumer mortgages 20,018 20,043 447 19,986 194 Credit cards — — — — — Other consumer loans 5,029 5,031 306 5,391 71 Total consumer 29,608 29,635 797 31,882 310 Total impaired loans $ 191,652 196,167 18,942 198,131 1,430 Impaired Loans (including accruing TDRs) December 31, 2017 Year Ended December 31, 2017 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded Investment properties $ — — — 123 — 1-4 family properties — — — 323 — Land and development 56 1,740 — 1,816 — Total commercial real estate 56 1,740 — 2,262 — Commercial, financial and agricultural 8,220 9,576 — 21,686 — Owner-occupied — — — 6,665 — Total commercial and industrial 8,220 9,576 — 28,351 — Home equity lines 2,746 2,943 — 1,205 — Consumer mortgages — — — 496 — Credit cards — — — — — Other consumer loans — — — — — Total consumer 2,746 2,943 — 1,701 — Total impaired loans with no related allowance recorded $ 11,022 14,259 — 32,314 — With allowance recorded Investment properties $ 23,364 23,364 1,100 28,749 1,144 1-4 family properties 15,056 15,056 504 16,257 925 Land and development 18,420 18,476 2,636 23,338 404 Total commercial real estate 56,840 56,896 4,240 68,344 2,473 Commercial, financial and agricultural 65,715 65,851 7,406 50,468 1,610 Owner-occupied 37,399 37,441 2,109 40,498 1,382 Total commercial and industrial 103,114 103,292 9,515 90,966 2,992 Home equity lines 5,096 5,096 114 7,476 334 Consumer mortgages 18,668 18,668 569 19,144 896 Credit cards — — — — — Other consumer loans 5,546 5,546 470 4,765 266 Total consumer 29,310 29,310 1,153 31,385 1,496 Total impaired loans with allowance recorded $ 189,264 189,498 14,908 190,695 6,961 Total impaired loans Investment properties $ 23,364 23,364 1,100 28,872 1,144 1-4 family properties 15,056 15,056 504 16,580 925 Land and development 18,476 20,216 2,636 25,154 404 Total commercial real estate 56,896 58,636 4,240 70,606 2,473 Commercial, financial and agricultural 73,935 75,427 7,406 72,154 1,610 Owner-occupied 37,399 37,441 2,109 47,163 1,382 Total commercial and industrial 111,334 112,868 9,515 119,317 2,992 Home equity lines 7,842 8,039 114 8,681 334 Consumer mortgages 18,668 18,668 569 19,640 896 Credit cards — — — — — Other consumer loans 5,546 5,546 470 4,765 266 Total consumer 32,056 32,253 1,153 33,086 1,496 Total impaired loans $ 200,286 $ 203,757 $ 14,908 $ 223,009 $ 6,961
Troubled Debt Restructurings	The following tables represent, by concession type, the post-modification balance for loans modified or renewed during the three months ended March 31, 2018 and 2017 that were reported as accruing or non-accruing TDRs. TDRs by Concession Type Three Months Ended March 31, 2018 (in thousands, except contract data) Number of Contracts Principal Forgiveness Below Market Interest Rate Term Extensions and/or Other Concessions Total Investment properties 1 $ — $ — $ 1,959 $ 1,959 1-4 family properties 6 — 963 — 963 Total commercial real estate 7 — 963 1,959 2,922 Commercial, financial and agricultural 9 — — 989 989 Owner-occupied 2 — 2,705 93 2,798 Total commercial and industrial 11 — 2,705 1,082 3,787 Consumer mortgages 7 — 1,733 — 1,733 Other consumer loans 14 — 537 508 1,045 Total consumer 21 — 2,270 508 2,778 Total TDRs 39 $ — $ 5,938 $ 3,549 $ 9,487 (1 ) (1) No net charge-offs were recorded during the three months ended March 31, 2018 upon restructuring of these loans. TDRs by Concession Type Three Months Ended March 31, 2017 (in thousands, except contract data) Number of Contracts Principal Forgiveness Below Market Interest Rate Term Extensions and/or Other Concessions Total 1-4 family properties 8 — 1,611 317 1,928 Total commercial real estate 8 — 1,611 317 1,928 Commercial, financial and agricultural 18 — 3,865 5,539 9,404 Total commercial and industrial 18 — 3,865 5,539 9,404 Other consumer loans 3 — — 275 275 Total consumer 3 — — 275 275 Total TDRs 29 $ — $ 5,476 $ 6,131 $ 11,607 (2 ) (2) No net charge-offs were recorded during the three months ended March 31, 2017 upon restructuring of these loans.

Other Comprehensive Income (L26

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes)	The following tables illustrate activity within the balances in accumulated other comprehensive income (loss) by component for the three months ended March 31, 2018 and 2017 . Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) (in thousands) Net unrealized gains (losses) on cash flow hedges Net unrealized gains (losses) on investment securities available for sale Post-retirement unfunded health benefit Total Balance at December 31, 2017 $ (12,137 ) $ (43,470 ) $ 853 $ (54,754 ) Other comprehensive income before reclassifications — (45,531 ) — (45,531 ) Amounts reclassified from accumulated other comprehensive income (loss) — — (21 ) (21 ) Net current period other comprehensive income — (45,531 ) (21 ) (45,552 ) Reclassification from adoption of ASU 2018-02 — (7,763 ) 175 (7,588 ) Cumulative-effect adjustment from adoption of ASU 2016-01 — 117 — 117 Balance as of March 31, 2018 $ (12,137 ) $ (96,647 ) $ 1,007 $ (107,777 ) Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes) (in thousands) Net unrealized gains (losses) on cash flow hedges Net unrealized gains (losses) on investment securities available for sale Post-retirement unfunded health benefit Total Balance at December 31, 2016 $ (12,217 ) $ (44,324 ) $ 882 $ (55,659 ) Other comprehensive income before reclassifications — 5,596 — 5,596 Amounts reclassified from accumulated other comprehensive income (loss) 40 (4,716 ) (12 ) (4,688 ) Net current period other comprehensive income 40 880 (12 ) 908 Balance as of March 31, 2017 $ (12,177 ) $ (43,444 ) $ 870 $ (54,751 )
Schedule of Reclassifications out of Accumulated Other Comprehensive Income (Loss)	Reclassifications out of Accumulated Other Comprehensive Income (Loss) Details About Accumulated Other Comprehensive Income (Loss) Components Amount Reclassified from Accumulated Other Comprehensive Income (Loss) Affected Line Item in the Statement Where Net Income is Presented For the Three Months Ended March 31, 2018 2017 Net unrealized gains (losses) on cash flow hedges: Amortization of deferred losses $ — $ (65 ) Interest expense — 25 Income tax (expense) benefit $ — $ (40 ) Reclassifications, net of income taxes Net unrealized gains on investment securities available for sale: Realized gains on sale of securities $ — $ 7,668 Investment securities gains, net — (2,952 ) Income tax (expense) benefit $ — $ 4,716 Reclassifications, net of income taxes Post-retirement unfunded health benefit: Amortization of actuarial gains $ 34 $ 20 Salaries and other personnel expense (13 ) (8 ) Income tax (expense) benefit $ 21 $ 12 Reclassifications, net of income taxes

Fair Value Accounting (Tables)

Fair Value Accounting (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Financial Instruments Measured at Fair Value on Recurring Basis	The following table presents all financial instruments measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017 , according to the valuation hierarchy included in ASC 820-10. For debt securities, class was determined based on the nature and risks of the investments. Synovus did not have any transfers between levels during the three months ended March 31, 2018 and year ended December 31, 2017 . March 31, 2018 (in thousands) Level 1 Level 2 Level 3 Total Assets and Liabilities at Fair Value Assets Trading securities: U.S. Government agency securities $ — $ 25,971 $ — $ 25,971 Collateralized mortgage obligations issued by U.S. Government sponsored enterprises — 240 — 240 State and municipal securities — 40 — 40 Total trading securities $ — $ 26,251 $ — $ 26,251 Mortgage loans held for sale — 50,439 — 50,439 Investment securities available for sale: U.S. Treasury securities 120,931 — — 120,931 U.S. Government agency securities — 10,897 — 10,897 Mortgage-backed securities issued by U.S. Government agencies — 112,868 — 112,868 Mortgage-backed securities issued by U.S. Government sponsored enterprises — 2,664,000 — 2,664,000 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — 1,065,041 — 1,065,041 State and municipal securities — 115 — 115 Corporate debt and other debt securities (1) — 15,274 1,852 17,126 Total investment securities available for sale $ 120,931 $ 3,868,195 $ 1,852 $ 3,990,978 Private equity investments — — 12,715 12,715 Mutual funds 3,131 — — 3,131 Mutual funds held in rabbi trusts 13,385 — — 13,385 GGL/SBA loans servicing asset — — 3,971 3,971 Derivative assets: Interest rate contracts — 7,672 — 7,672 Mortgage derivatives (2) — 1,735 — 1,735 Total derivative assets $ — $ 9,407 $ — $ 9,407 Liabilities Trading account liabilities — 23,856 — 23,856 Earnout liability (3) — — 11,348 11,348 Derivative liabilities: Interest rate contracts — 16,122 — 16,122 Visa derivative — — 3,974 3,974 Total derivative liabilities $ — $ 16,122 $ 3,974 $ 20,096 December 31, 2017 (in thousands) Level 1 Level 2 Level 3 Total Assets and Liabilities at Fair Value Assets Trading securities: Mortgage-backed securities issued by U.S. Government agencies $ — $ 3,002 $ — $ 3,002 Collateralized mortgage obligations issued by U.S. Government sponsored enterprises — 296 — 296 Other investments 522 — — 522 Total trading securities $ 522 $ 3,298 $ — $ 3,820 Mortgage loans held for sale — 48,024 — 48,024 Investment securities available for sale: U.S. Treasury securities 82,674 — — 82,674 U.S. Government agency securities — 10,862 — 10,862 Mortgage-backed securities issued by U.S. Government agencies — 120,440 — 120,440 Mortgage-backed securities issued by U.S. Government sponsored enterprises — 2,640,523 — 2,640,523 Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises — 1,111,999 — 1,111,999 State and municipal securities — 180 — 180 Corporate debt and other securities (1) 3,162 15,294 1,935 20,391 Total investment securities available for sale $ 85,836 $ 3,899,298 $ 1,935 $ 3,987,069 Private equity investments — — 15,771 15,771 Mutual funds held in rabbi trusts 14,140 — — 14,140 GGL/SBA loan servicing asset — — 4,101 4,101 Derivative assets: Interest rate contracts — 10,786 — 10,786 Mortgage derivatives (2) — 936 — 936 Total derivative assets $ — $ 11,722 $ — $ 11,722 Liabilities Trading account liabilities — 1,000 — 1,000 Earnout liability (3) — — 11,348 11,348 Derivative liabilities: Interest rate contracts — 12,638 — 12,638 Mortgage derivatives (2) — 129 — 129 Visa derivative — — 4,330 4,330 Total derivative liabilities $ — $ 12,767 $ 4,330 $ 17,097 (1) Based on an analysis of the nature and risks of these investments, Synovus has determined that presenting these investments as a single asset class is appropriate. (2) Mortgage derivatives consist of customer interest rate lock commitments that relate to the potential origination of mortgage loans, which would be classified as held for sale and forward loan sales commitments with third-party investors. (3) Earnout liability consists of contingent consideration obligation related to the Global One acquisition.
Changes in Fair Value Included in Consolidated Statements of Income	The following table summarizes the difference between the fair value and the unpaid principal balance of mortgage loans held for sale measured at fair value and the changes in fair value of these loans. Mortgage loans held for sale are initially measured at fair value with subsequent changes in fair value recognized in earnings. Changes in fair value are recorded as a component of mortgage banking income in the consolidated statements of income. An immaterial portion of these changes in fair value was attributable to changes in instrument-specific credit risk. Changes in Fair Value Included in Net Income For the Three Months Ended March 31, (in thousands) 2018 2017 Mortgage loans held for sale $ 115 $ 1,203 Mortgage Loans Held for Sale (in thousands) As of March 31, 2018 As of December 31, 2017 Fair value $ 50,439 $ 48,024 Unpaid principal balance 49,139 46,839 Fair value less aggregate unpaid principal balance $ 1,300 $ 1,185
Changes in Level 3 Fair Value Measurements	The table below includes a roll-forward of the amounts on the consolidated balance sheet for the three months ended March 31, 2018 and 2017 (including the change in fair value) for financial instruments of a material nature that are classified by Synovus within Level 3 of the fair value hierarchy and are measured at fair value on a recurring basis. Transfers between fair value levels are recognized at the end of the reporting period in which the associated changes in inputs occur. During the three months ended March 31, 2018 and 2017 , Synovus did not have any transfers between levels in the fair value hierarchy. Three Months Ended March 31, 2018 (in thousands) Investment Securities Available for Sale Private Equity Investments Visa Derivative Earnout Liability (1) GGL / SBA Loans Servicing Asset Beginning balance, January 1, 2018 $ 1,935 $ 15,771 $ (4,330 ) $ (11,348 ) $ 4,101 Total (losses) gains realized/unrealized: Included in earnings — (3,056 ) — — (422 ) Unrealized (losses) gains included in other comprehensive income (83 ) — — — — Additions — — — — 292 Settlements — — 356 — — Ending balance, March 31, 2018 $ 1,852 $ 12,715 $ (3,974 ) $ (11,348 ) $ 3,971 Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held at March 31, 2018 $ — $ (3,056 ) $ — $ — $ (422 ) Three Months Ended March 31, 2017 (in thousands) Investment Securities Available for Sale Private Equity Investments Visa Derivative Earnout Liability (1) GGL / SBA Loans Servicing Asset (2) Beginning balance, January 1, 2017 $ 1,796 $ 25,493 $ (5,768 ) $ (14,000 ) $ — Total gains (losses) realized/unrealized: Included in earnings — (1,814 ) — — — Unrealized gains included in other comprehensive income 55 — — — — Settlements — — 356 — — Transfer from amortization method to fair value — — — — 4,178 Measurement period adjustments related to Global One acquisition $ — — — 2,579 — Ending balance, March 31, 2017 $ 1,851 $ 23,679 $ (5,412 ) $ (11,421 ) $ 4,178 Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets still held at March 31, 2017 $ — $ (1,814 ) $ — $ — $ — (1) Earnout liability consists of contingent consideration obligation related to the Global One acquisition. (2) Effective January 1, 2017, Synovus elected the fair value option for determining the value of the GGL/SBA loans servicing asset. Prior to 2017, Synovus accounted for the GGL/SBA loans servicing asset using the amortization method.
Fair Value Inputs, Assets, Quantitative Information	The table below provides an overview of the valuation techniques and significant unobservable inputs used in those techniques to measure financial instruments that are classified within Level 3 of the valuation hierarchy and are measured at fair value on a recurring basis. March 31, 2018 December 31, 2017 Valuation Technique Significant Unobservable Input Level 3 Fair Value Range/Weighted Average Level 3 Fair Value Range/Weighted Average Assets and liabilities measured at fair value on a recurring basis Investment Securities Available for Sale - Other Investments: Trust preferred securities Discounted cash flow analysis Credit spread embedded in discount rate $1,852 439 bps $1,935 398 bps Private equity investments Individual analysis of each investee company Multiple factors, including but not limited to, current operations, financial condition, cash flows, evaluation of business management and financial plans, and recently executed financing transactions related to the investee companies 12,715 N/A 15,771 N/A GGL/SBA loans servicing asset Discounted cash flow analysis Discount rate Prepayment speeds 3,971 13.57% 7.98% 4,101 13.16% 7.50% Earnout liability Option pricing methods and Monte Carlo simulation Financial projections of Global One 11,348 N/A 11,348 N/A Visa derivative liability Discounted cash flow analysis Estimated timing of resolution of covered litigation, future cumulative deposits to the litigation escrow for settlement of the covered litigation, and estimated future monthly fees payable to the derivative counterparty 3,974 1-4 years 4,330 1-4 years The table below provides an overview of the valuation techniques and significant unobservable inputs used in those techniques to measure financial instruments that are classified within Level 3 of the valuation hierarchy and are measured at fair value on a non-recurring basis. The range of sensitivities that management utilized in its fair value calculations is deemed acceptable in the industry with respect to the identified financial instruments. March 31, 2018 December 31, 2017 Valuation Technique Significant Unobservable Input Range (Weighted Average) (1) Range (Weighted Average) (1) Assets measured at fair value on a non-recurring basis Collateral dependent impaired loans Third-party appraised value of collateral less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 23% (9%) 0% - 10% (7%) 0%-50% (15%) 0%-10% (7%) Other loans held for sale Third-party appraised value of collateral less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 85% (30%) 0% - 10% (2%) 5% - 99% (54%) 0% - 10% (2%) Other real estate Third-party appraised value of real estate less estimated selling costs Discount to appraised value (2) Estimated selling costs 0% - 39% (21%) 0% - 10% (7%) 0%-85% (35%) 0%-10% (7%) Other assets held for sale Third-party appraised value less estimated selling costs or BOV Discount to appraised value (2) Estimated selling costs N/A 0%-10% (7%) 21%-52% (25%) 0%-10% (7%) (1) The range represents management's estimate of the high and low of the value that would be assigned to a particular input. For assets measured at fair value on a non-recurring basis, the weighted average is the measure of central tendencies; it is not the value that management is using for the asset or liability. (2) Synovus also makes adjustments to the values of the assets listed above for reasons including age of the appraisal, information known by management about the property, such as occupancy rates, changes to the physical condition of the property, and other factors.
Assets and Liabilities Measured at Fair Value on Non-Recurring Basis	The following table presents assets measured at fair value on a non-recurring basis as of the dates indicated for which there was a fair value adjustment during the period. March 31, 2018 December 31, 2017 (in thousands) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Impaired loans * $ — $ — $ 4,531 $ 4,531 $ — $ — $ 3,603 $ 3,603 Other loans held for sale — — 3,295 3,295 — — 10,197 10,197 Other real estate — — 1,447 1,447 — — 3,363 3,363 Other assets held for sale — — 1,395 1,395 — — 5,334 5,334 * Collateral-dependent impaired loans that were written down to fair value during the period.
Assets Measured at Fair Value on a Nonrecurring Basis	The following table presents fair value adjustments recognized in earnings for the three months ended March 31, 2018 and 2017 for assets measured at fair value on a non-recurring basis still held at period-end. Three Months Ended March 31, (in thousands) 2018 2017 Impaired loans * $ 720 $ 2,230 Other loans held for sale 1,512 3,519 Other real estate 731 399 Other assets held for sale 107 238 * Collateral-dependent impaired loans that were written down to fair value during the period.
Carrying and Estimated Fair Values of Financial Instruments Carried on Balance Sheet	The carrying and estimated fair values of financial instruments, as well as the level within the fair value hierarchy, as of March 31, 2018 and December 31, 2017 are as follows: March 31, 2018 (in thousands) Carrying Value Fair Value Level 1 Level 2 Level 3 Financial assets Total cash, cash equivalents, restricted cash, and restricted cash equivalents $ 1,059,017 $ 1,059,017 $ 1,059,017 $ — $ — Trading account assets 26,251 26,251 — 26,251 — Mortgage loans held for sale 50,439 50,439 — 50,439 — Other loans held for sale 6,591 6,591 — — 6,591 Investment securities available for sale 3,990,978 3,990,978 120,931 3,868,195 1,852 Private equity investments 12,715 12,715 — — 12,715 Mutual funds 3,131 3,131 3,131 — — Mutual funds held in rabbi trusts 13,385 13,385 13,385 — — Loans, net 24,625,273 24,538,259 — — 24,538,259 GGL/SBA loans servicing asset 3,971 3,971 — — 3,971 Derivative assets 9,407 9,407 — 9,407 — Financial liabilities Trading account liabilities 23,856 — — 23,856 — Non-interest bearing deposits 7,381,070 7,381,070 — 7,381,070 — Non-time interest bearing deposits 14,030,247 14,030,247 — 14,030,247 — Time deposits 4,842,190 4,834,135 — 4,834,135 — Total deposits $ 26,253,507 $ 26,245,452 $ — $ 26,245,452 $ — Federal funds purchased, other short-term borrowings and other short-term liabilities 185,531 185,531 185,531 — — Long-term debt 1,856,392 1,861,008 — 1,861,008 — Earnout liabilities 11,348 11,348 — — 11,348 Derivative liabilities 20,096 20,096 — 16,122 3,974 December 31, 2017 (in thousands) Carrying Value Fair Value Level 1 Level 2 Level 3 Financial assets Total cash, cash equivalents, restricted cash, and restricted cash equivalents $ 932,933 $ 932,933 $ 932,933 $ — $ — Trading account assets 3,820 3,820 522 3,298 — Mortgage loans held for sale 48,024 48,024 — 48,024 — Other loans for sale 11,356 11,356 — — 11,356 Investment securities available for sale 3,987,069 3,987,069 85,836 3,899,298 1,935 Private equity investments 15,771 15,771 — — 15,771 Mutual funds held in rabbi trusts 14,140 14,140 14,140 — — Loans, net 24,538,196 24,507,141 — — 24,507,141 GGL/SBA loans servicing asset 4,101 4,101 — — 4,101 Derivative assets 11,722 11,722 — 11,722 — Financial liabilities Trading account liabilities 1,000 1,000 — 1,000 — Non-interest bearing deposits 7,686,339 7,686,339 — 7,686,339 — Non-time interest bearing deposits 13,941,814 13,941,814 — 13,941,814 — Time deposits 4,519,747 4,523,661 — 4,523,661 — Total deposits $ 26,147,900 $ 26,151,814 $ — $ 26,151,814 $ — Federal funds purchased, other short-term borrowings and other short-term liabilities 161,190 161,190 161,190 — — Long-term debt 1,706,138 1,721,814 — 1,721,814 — Earnout liabilities 11,348 11,348 — — 11,348 Derivative liabilities 17,097 17,097 — 12,767 4,330

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Summary of Derivative Instruments [Abstract]
Impact of Derivatives on Balance Sheet	The impact of derivative instruments on the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 is presented below. Fair Value of Derivative Assets Fair Value of Derivative Liabilities (in thousands) Location on Consolidated Balance Sheets March 31, 2018 December 31, 2017 Location on Consolidated Balance Sheets March 31, 2018 December 31, 2017 Derivatives not designated as hedging instruments: Interest rate contracts Other assets $ 7,672 $ 10,786 Other liabilities $ 16,122 $ 12,638 Mortgage derivatives Other assets 1,735 936 Other liabilities — 129 Visa derivative — — Other liabilities 3,974 4,330 Total derivatives not designated as hedging instruments $ 9,407 $ 11,722 $ 20,096 $ 17,097
Effect of Fair Value Hedges on Consolidated Statements of Income	The pre-tax effect of fair value hedges on the Consolidated Statements of Income for the three months ended March 31, 2018 and 2017 is presented below. Gain (Loss) Recognized in Income (in thousands) Three Months Ended March 31, Derivatives not designated as hedging instruments Location of Gain (Loss) Recognized in Income 2018 2017 Interest rate contracts (1) Other non-interest income $ 7 $ (1 ) Mortgage derivatives (2) Mortgage banking income 927 (1,784 ) Total $ 934 $ (1,785 ) (1) Gain (loss) represents net fair value adjustments (including credit related adjustments) for customer swaps and offsetting positions. (2) Gain (loss) represents net fair value adjustments recorded for interest rate lock commitments and commitments to sell mortgage loans to third-party investors.

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Basic And Diluted Earnings per Share	The following table displays a reconciliation of the information used in calculating basic and diluted earnings per common share for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, (in thousands, except per share data) 2018 2017 Basic Net Income Per Common Share: Net income available to common shareholders $ 100,607 $ 69,298 Weighted average common shares outstanding 118,666 122,300 Net income per common share, basic $ 0.85 $ 0.57 Diluted Net Income Per Common Share: Net income available to common shareholders $ 100,607 $ 69,298 Weighted average common shares outstanding 118,666 122,300 Potentially dilutive shares from outstanding equity-based awards and Earnout Payments 655 759 Weighted average diluted common shares 119,321 123,059 Net income per common share, diluted $ 0.84 $ 0.56

Non-interest Income (Tables)

Non-interest Income (Tables)	3 Months Ended
	Mar. 31, 2018
Noninterest Income [Abstract]
Schedule of Non-interest Income	The following table reflects revenue disaggregated by revenue type and line of business for the three months ended March 31, 2018 and 2017. Non-interest Income by Line of Business For Three Months Ended March 31, 2018 (in thousands) Total Community Banking Corporate Banking Retail Banking Financial Management Services Other Service charges on deposit accounts $ 19,940 $ 5,680 $ 533 $ 13,422 $ — $ 305 Fiduciary and asset management fees 13,435 — — — 13,435 — Card fees 10,199 205 — 9,994 — — Brokerage revenue 8,695 — — — 8,695 — Insurance revenue 1,213 — — — 1,213 — Other fees 832 — — 559 — 273 $ 54,314 $ 5,885 $ 533 $ 23,975 $ 23,343 $ 578 Other revenues (1) 12,732 2,452 1,733 1,529 5,843 1,175 Total non-interest income $ 67,046 $ 8,337 $ 2,266 $ 25,504 $ 29,186 $ 1,753 Non-interest Income by Line of Business For Three Months Ended March 31, 2017 (in thousands) Total Community Banking Corporate Banking Retail Banking Financial Management Services Other Service charges on deposit accounts $ 20,118 $ 5,771 $ 459 $ 13,437 $ — $ 451 Fiduciary and asset management fees 12,151 — — — 12,151 — Card fees 9,844 219 — 9,625 — — Brokerage revenue 7,226 — — — 7,226 — Insurance revenue 1,304 — — — 1,304 — Other fees 842 — — 574 — 268 $ 51,485 $ 5,990 $ 459 $ 23,636 $ 20,681 $ 719 Other revenues (1) 20,354 1,648 1,619 1,566 6,597 8,924 Total non-interest income $ 71,839 $ 7,638 $ 2,078 $ 25,202 $ 27,278 $ 9,643 ( 1) Other revenues primarily relate to revenues not derived from contracts with customers.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Loan Commitments and Letters of Credit	Unfunded letters of credit and lending commitments at March 31, 2018 and December 31, 2017 are presented below. (in thousands) March 31, 2018 December 31, 2017 Letters of credit* $ 175,164 $ 153,372 Commitments to fund commercial and industrial loans 5,143,323 5,090,827 Commitments to fund commercial real estate, construction, and land development loans 1,541,810 1,567,583 Commitments under home equity lines of credit 1,156,283 1,137,714 Unused credit card lines 780,704 779,254 Other loan commitments 369,636 351,358 Total unfunded lending commitments and letters of credit $ 9,166,920 $ 9,080,108 * Represent the contractual amount net of risk participations of approximately $60 million and $77 million at March 31, 2018 and December 31, 2017, respectively.

Significant Accounting Polici32

Significant Accounting Policies (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)ATMbranch	Dec. 31, 2017USD ($)	Jan. 01, 2018USD ($)	Dec. 31, 2016USD ($)
Accounting Policies [Abstract]
Number of branches | branch	250
Number of ATMs | ATM	328
Collateral requirements	$ 32,700	$ 43,800
Provisional income tax expense		47,200
Reclassification from AOCI to retained earnings, tax effect	7,600
Reclassification from AOCI to retained earnings, effect of regulatory capital	$ 7,600
Reclassification from AOCI to retained earnings, effect of regulatory capital, increase to Tier 1 capital	0.03%
Reclassification from AOCI to retained earnings, effect of regulatory capital, increase to common equity capital	0.03%
Reclassification from AOCI to retained earnings, effect of regulatory capital, increase to total risk based capital	0.03%
Reclassification from AOCI to retained earnings, effect of regulatory capital, increase to leverage ratio	0.02%
Basis Of Presentation [Line Items]
Retained earnings	$ 621,925	544,207
Adjustment from adoption of ASU		(685)		$ 0
ASU 2014-09
Basis Of Presentation [Line Items]
Adjustment from adoption of ASU		(685)
ASU 2016-01
Basis Of Presentation [Line Items]
Adjustment from adoption of ASU	3,200	0
ASU 2016-01 | Accumulated Other Comprehensive Income (Loss)
Basis Of Presentation [Line Items]
Adjustment from adoption of ASU		117
Difference between Revenue Guidance in Effect before and after Topic 606 | ASU 2014-09
Basis Of Presentation [Line Items]
Retained earnings			$ (685)
Cash and Cash Equivalents
Basis Of Presentation [Line Items]
Cash and cash equivalents	14,100	8,600
Interest earning deposits with banks	$ 6,300	$ 5,900

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Thousands	Sep. 25, 2017	Oct. 01, 2016	Nov. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Brokered deposits				$ 2,006,578	$ 1,961,125
Common stock, shares issued (in shares)				143,017,301	142,677,449
Common stock				$ 143,017	$ 142,678
Minimum
Business Acquisition [Line Items]
Period of additional annual payments				3 years
Maximum
Business Acquisition [Line Items]
Period of additional annual payments				5 years
World's Foremost Bank (WFB)
Business Acquisition [Line Items]
Brokered deposits	$ 1,100,000
Deposits portfolio, weighted average maturity, period	2 years 6 months 11 days
Weighted average rate of deposit, brokered	1.83%
Proceeds from fees	$ 75,000
Global One
Business Acquisition [Line Items]
Consideration transferred		$ 30,000
Common stock, shares issued (in shares)		821,000
Common stock		$ 26,600
Cash paid		$ 3,400
Earnout payment of stock and cash			$ 6,400
Earnout liability				$ 11,300
Global One | Minimum
Business Acquisition [Line Items]
Potential additional payments based on earnings, period		3 years
Global One | Maximum
Business Acquisition [Line Items]
Potential additional payments based on earnings, period		5 years

Share Repurchase Program (Detai

Share Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Thousands	2 Months Ended	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2018	Mar. 31, 2017	Jan. 23, 2018
Equity [Abstract]
Authorized amount				$ 150,000,000
Value repurchased	$ 26,700,000	$ 26,733,000	$ 15,151,000
Shares repurchased (in shares)	535
Shares repurchased, average cost per share (in dollars per share)	$ 49.98

Investment Securities (Summary

Investment Securities (Summary Of Available For Sale Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 4,103,438	$ 4,038,239
Gross Unrealized Gains	1,122	6,107
Gross Unrealized Losses	(113,582)	(57,277)
Fair Value	3,990,978	3,987,069
U.S. Treasury securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	122,655	83,608
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,724)	(934)
Fair Value	120,931	82,674
U.S. Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,769	10,771
Gross Unrealized Gains	128	91
Gross Unrealized Losses	0	0
Fair Value	10,897	10,862
Mortgage-backed securities issued by U.S. Government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	115,888	121,283
Gross Unrealized Gains	237	519
Gross Unrealized Losses	(3,257)	(1,362)
Fair Value	112,868	120,440
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,734,650	2,666,818
Gross Unrealized Gains	483	5,059
Gross Unrealized Losses	(71,133)	(31,354)
Fair Value	2,664,000	2,640,523
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,102,361	1,135,259
Gross Unrealized Gains	0	144
Gross Unrealized Losses	(37,320)	(23,404)
Fair Value	1,065,041	1,111,999
State and municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	115	180
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	115	180
Corporate debt and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,000	20,320
Gross Unrealized Gains	274	294
Gross Unrealized Losses	(148)	(223)
Fair Value	$ 17,126	$ 20,391

Investment Securities (Narrativ

Investment Securities (Narrative) (Details) $ in Thousands	Mar. 31, 2018USD ($)position	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Investments [Abstract]
Pledged to secure deposits	$ 1,010,000	$ 2,000,000
Investment securities in a loss position for less than twelve months | position	75
Investment securities in a loss position for twelve months or longer | position	54
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment from adoption of ASU		(685)	$ 0
ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment from adoption of ASU	$ 3,200	$ 0

Investment Securities (Schedule

Investment Securities (Schedule Of Unrealized Loss On Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 2,398,812	$ 1,995,846
Less than 12 Months, Unrealized Losses	57,879	20,560
12 Months or Longer, Fair Value	1,402,159	1,445,859
12 Months or Longer, Unrealized Losses	55,703	36,717
Total Fair Value, Fair Value	3,800,971	3,441,705
Total Fair Value, Unrealized Losses	113,582	57,277
U.S. Treasury securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	72,694	34,243
Less than 12 Months, Unrealized Losses	989	443
12 Months or Longer, Fair Value	29,313	29,562
12 Months or Longer, Unrealized Losses	735	491
Total Fair Value, Fair Value	102,007	63,805
Total Fair Value, Unrealized Losses	1,724	934
Mortgage-backed securities issued by U.S. Government agencies
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	39,763	36,810
Less than 12 Months, Unrealized Losses	1,045	357
12 Months or Longer, Fair Value	52,763	55,740
12 Months or Longer, Unrealized Losses	2,212	1,005
Total Fair Value, Fair Value	92,526	92,550
Total Fair Value, Unrealized Losses	3,257	1,362
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	1,656,562	1,271,012
Less than 12 Months, Unrealized Losses	38,195	10,263
12 Months or Longer, Fair Value	882,984	929,223
12 Months or Longer, Unrealized Losses	32,938	21,091
Total Fair Value, Fair Value	2,539,546	2,200,235
Total Fair Value, Unrealized Losses	71,133	31,354
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	629,793	653,781
Less than 12 Months, Unrealized Losses	17,650	9,497
12 Months or Longer, Fair Value	435,247	426,237
12 Months or Longer, Unrealized Losses	19,670	13,907
Total Fair Value, Fair Value	1,065,040	1,080,018
Total Fair Value, Unrealized Losses	37,320	23,404
Corporate debt and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	1,852	5,097
12 Months or Longer, Unrealized Losses	148	223
Total Fair Value, Fair Value	1,852	5,097
Total Fair Value, Unrealized Losses	$ 148	$ 223

Investment Securities (Amortize

Investment Securities (Amortized Cost And Estimated Fair Value By Contractual Maturity Of Investment Securities Available For Sale) (Details) $ in Thousands	Mar. 31, 2018USD ($)
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	$ 21,376
1 to 5 Years, Amortized Cost	111,825
5 to 10 Years, Amortized Cost	643,783
More Than 10 years, Amortized Cost	3,326,454
Total, Amortized Cost	4,103,438
Within One Year, Fair Value	21,401
1 to 5 Years, Fair Value	110,244
5 to 10 Years, Fair Value	629,844
More Than 10 years, Fair Value	3,229,489
Total, Fair Value	3,990,978
U.S. Treasury securities
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	18,924
1 to 5 Years, Amortized Cost	103,731
5 to 10 Years, Amortized Cost	0
More Than 10 years, Amortized Cost	0
Total, Amortized Cost	122,655
Within One Year, Fair Value	18,924
1 to 5 Years, Fair Value	102,007
5 to 10 Years, Fair Value	0
More Than 10 years, Fair Value	0
Total, Fair Value	120,931
U.S. Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	2,330
1 to 5 Years, Amortized Cost	6,437
5 to 10 Years, Amortized Cost	2,002
More Than 10 years, Amortized Cost	0
Total, Amortized Cost	10,769
Within One Year, Fair Value	2,355
1 to 5 Years, Fair Value	6,514
5 to 10 Years, Fair Value	2,028
More Than 10 years, Fair Value	0
Total, Fair Value	10,897
Mortgage-backed securities issued by U.S. Government agencies
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	0
1 to 5 Years, Amortized Cost	0
5 to 10 Years, Amortized Cost	29,355
More Than 10 years, Amortized Cost	86,533
Total, Amortized Cost	115,888
Within One Year, Fair Value	0
1 to 5 Years, Fair Value	0
5 to 10 Years, Fair Value	28,993
More Than 10 years, Fair Value	83,875
Total, Fair Value	112,868
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	7
1 to 5 Years, Amortized Cost	1,657
5 to 10 Years, Amortized Cost	578,774
More Than 10 years, Amortized Cost	2,154,212
Total, Amortized Cost	2,734,650
Within One Year, Fair Value	7
1 to 5 Years, Fair Value	1,723
5 to 10 Years, Fair Value	565,331
More Than 10 years, Fair Value	2,096,939
Total, Fair Value	2,664,000
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	0
1 to 5 Years, Amortized Cost	0
5 to 10 Years, Amortized Cost	18,652
More Than 10 years, Amortized Cost	1,083,709
Total, Amortized Cost	1,102,361
Within One Year, Fair Value	0
1 to 5 Years, Fair Value	0
5 to 10 Years, Fair Value	18,218
More Than 10 years, Fair Value	1,046,823
Total, Fair Value	1,065,041
State and municipal securities
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	115
1 to 5 Years, Amortized Cost	0
5 to 10 Years, Amortized Cost	0
More Than 10 years, Amortized Cost	0
Total, Amortized Cost	115
Within One Year, Fair Value	115
1 to 5 Years, Fair Value	0
5 to 10 Years, Fair Value	0
More Than 10 years, Fair Value	0
Total, Fair Value	115
Corporate debt and other debt securities
Schedule of Available-for-sale Securities [Line Items]
Within One year, Amortized Cost	0
1 to 5 Years, Amortized Cost	0
5 to 10 Years, Amortized Cost	15,000
More Than 10 years, Amortized Cost	2,000
Total, Amortized Cost	17,000
Within One Year, Fair Value	0
1 to 5 Years, Fair Value	0
5 to 10 Years, Fair Value	15,274
More Than 10 years, Fair Value	1,852
Total, Fair Value	$ 17,126

Investment Securities (Summar39

Investment Securities (Summary Of Sales Transactions In The Investment Securities Available For Sale Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Investments [Abstract]
Proceeds from sales of investment securities available for sale	$ 0	$ 282,629
Gross realized gains on sales	0	7,702
Gross realized losses on sales	0	(34)
Investment securities gains, net	$ 0	$ 7,668

Restructuring Charges (Schedule

Restructuring Charges (Schedule Of Restructuring And Related Costs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Charges [Abstract]
Severance charges	$ 0	$ 6,453
Other charges, net	(315)	58
Total restructuring charges, net	$ (315)	$ 6,511

Restructuring Charges (Narrativ

Restructuring Charges (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Accruals for lease terminations	$ (377)	$ 6,453
Restructuring charges	(315)	6,511
Special termination benefits		6,200
Severance Charges
Restructuring Cost and Reserve [Line Items]
Accruals for lease terminations	$ 0	6,453
Restructuring charges		$ 6,500

Restructuring Charges (Restruct

Restructuring Charges (Restructuring Reserve) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning balance	$ 3,612	$ 4,049
Accruals for lease terminations	(377)	6,453
Payments	(729)	(498)
Ending balance	2,506	10,004
Severance Charges
Restructuring Reserve [Roll Forward]
Beginning balance	336	81
Accruals for lease terminations	0	6,453
Payments	(336)	(219)
Ending balance	0	6,315
Lease Termination Charges
Restructuring Reserve [Roll Forward]
Beginning balance	3,276	3,968
Accruals for lease terminations	(377)	0
Payments	(393)	(279)
Ending balance	$ 2,506	$ 3,689

Loans and Allowance for Loan 43

Loans and Allowance for Loan Losses (Schedule Of Current, Accruing Past Due And Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	$ 24,732,767	$ 24,645,203
Accruing 30-89 Days Past Due	48,734	47,617
Accruing 90 Days or Greater Past Due	5,416	4,414
Total Accruing Past Due	54,150	52,031
Non-accrual	120,081	115,561
Total loans	24,906,998	24,812,795	$ 24,284,188
Deferred fees and costs, net	24,000	25,300	$ 25,700
Total commercial real estate
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	6,816,766	6,914,819
Accruing 30-89 Days Past Due	7,668	7,660
Accruing 90 Days or Greater Past Due	1,155	359
Total Accruing Past Due	8,823	8,019
Non-accrual	10,138	12,450
Total loans	6,835,727	6,935,288
Total commercial real estate | Investment properties
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	5,613,811	5,663,665
Accruing 30-89 Days Past Due	1,986	2,506
Accruing 90 Days or Greater Past Due	323	90
Total Accruing Past Due	2,309	2,596
Non-accrual	2,930	3,804
Total loans	5,619,050	5,670,065
Total commercial real estate | 1-4 family properties
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	753,255	775,023
Accruing 30-89 Days Past Due	2,232	3,545
Accruing 90 Days or Greater Past Due	783	202
Total Accruing Past Due	3,015	3,747
Non-accrual	2,634	2,849
Total loans	758,904	781,619
Total commercial real estate | Land and development
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	449,700	476,131
Accruing 30-89 Days Past Due	3,450	1,609
Accruing 90 Days or Greater Past Due	49	67
Total Accruing Past Due	3,499	1,676
Non-accrual	4,574	5,797
Total loans	457,773	483,604
Total commercial and industrial
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	11,994,812	11,927,277
Accruing 30-89 Days Past Due	19,713	18,094
Accruing 90 Days or Greater Past Due	1,719	1,495
Total Accruing Past Due	21,432	19,589
Non-accrual	85,673	76,784
Total loans	12,101,917	12,023,650
Total commercial and industrial | Commercial, financial and agricultural
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	7,093,270	7,097,127
Accruing 30-89 Days Past Due	15,872	11,214
Accruing 90 Days or Greater Past Due	783	1,016
Total Accruing Past Due	16,655	12,230
Non-accrual	81,606	70,130
Total loans	7,191,531	7,179,487
Total commercial and industrial | Owner-occupied
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	4,901,542	4,830,150
Accruing 30-89 Days Past Due	3,841	6,880
Accruing 90 Days or Greater Past Due	936	479
Total Accruing Past Due	4,777	7,359
Non-accrual	4,067	6,654
Total loans	4,910,386	4,844,163
Total consumer
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	5,921,189	5,803,107
Accruing 30-89 Days Past Due	21,353	21,863
Accruing 90 Days or Greater Past Due	2,542	2,560
Total Accruing Past Due	23,895	24,423
Non-accrual	24,270	26,327
Total loans	5,969,354	5,853,857
Total consumer | Home equity lines
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	1,450,454	1,490,808
Accruing 30-89 Days Past Due	6,718	5,629
Accruing 90 Days or Greater Past Due	431	335
Total Accruing Past Due	7,149	5,964
Non-accrual	14,868	17,455
Total loans	1,472,471	1,514,227
Total consumer | Consumer mortgages
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	2,651,758	2,622,061
Accruing 30-89 Days Past Due	3,905	3,971
Accruing 90 Days or Greater Past Due	0	268
Total Accruing Past Due	3,905	4,239
Non-accrual	7,708	7,203
Total loans	2,663,371	2,633,503
Total consumer | Credit cards
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	223,232	229,015
Accruing 30-89 Days Past Due	1,599	1,930
Accruing 90 Days or Greater Past Due	1,882	1,731
Total Accruing Past Due	3,481	3,661
Non-accrual	0	0
Total loans	226,713	232,676
Total consumer | Other consumer loans
Valuation and Qualifying Accounts Disclosure [Line Items]
Current	1,595,745	1,461,223
Accruing 30-89 Days Past Due	9,131	10,333
Accruing 90 Days or Greater Past Due	229	226
Total Accruing Past Due	9,360	10,559
Non-accrual	1,694	1,669
Total loans	$ 1,606,799	$ 1,473,451

Loans and Allowance for Loan 44

Loans and Allowance for Loan Losses (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment in impaired loans	$ 198,131,000	$ 235,600,000	$ 223,009,000
Interest income recognized	1,430,000	0	6,961,000
Interest income recognized for accruing TDRs		1,700,000
Non-accrual status	62,200,000		49,000,000
Provision for loan losses	12,776,000	$ 8,674,000
Accruing TDRs With Modifications And Renewals Completed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing troubled debt restructuring	129,400,000
Provision for loan losses	$ 6,100,000		8,700,000
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retail loan substandard period (in days)	90 days
Loss And Charged Off
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retail loans downgraded to loss (in days)	120 days
Accruing TDRs With Modifications And Renewals Completed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accruing troubled debt restructuring			$ 151,300,000
Accruing TDRs With Modifications And Renewals Completed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial-type impaired loans	$ 1,000,000

Loans and Allowance for Loan 45

Loans and Allowance for Loan Losses (Loan Portfolio Credit Exposure) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 24,906,998	$ 24,812,795	$ 24,284,188
Accrual substandard loans	204,200	190,600
Deferred fees and costs, net	$ 24,000	25,300	$ 25,700
Maximum
Financing Receivable, Recorded Investment [Line Items]
Allowance for loan losses, percent of loan amount	50.00%
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 24,293,152	24,222,726
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	289,591	283,865
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	308,500	297,640
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,790	5,358
Loss
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,965	3,206
Total commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,835,727	6,935,288
Total commercial real estate | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,619,050	5,670,065
Total commercial real estate | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	758,904	781,619
Total commercial real estate | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	457,773	483,604
Total commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,682,840	6,763,850
Total commercial real estate | Pass | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,545,689	5,586,792
Total commercial real estate | Pass | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	729,023	745,299
Total commercial real estate | Pass | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	408,128	431,759
Total commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	101,382	117,813
Total commercial real estate | Special Mention | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	53,193	64,628
Total commercial real estate | Special Mention | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,331	19,419
Total commercial real estate | Special Mention | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	33,858	33,766
Total commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	48,372	50,496
Total commercial real estate | Substandard | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	20,168	18,645
Total commercial real estate | Substandard | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,550	16,901
Total commercial real estate | Substandard | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,654	14,950
Total commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,133	3,129
Total commercial real estate | Doubtful | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial real estate | Doubtful | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial real estate | Doubtful | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,133	3,129
Total commercial real estate | Loss
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial real estate | Loss | Investment properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial real estate | Loss | 1-4 family properties
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial real estate | Loss | Land and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,101,917	12,023,650
Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,191,531	7,179,487
Total commercial and industrial | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,910,386	4,844,163
Total commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	11,674,046	11,643,383
Total commercial and industrial | Pass | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,895,133	6,929,506
Total commercial and industrial | Pass | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,778,913	4,713,877
Total commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	188,209	166,052
Total commercial and industrial | Special Mention | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	132,582	115,912
Total commercial and industrial | Special Mention | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	55,627	50,140
Total commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	230,636	212,891
Total commercial and industrial | Substandard | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	154,863	132,818
Total commercial and industrial | Substandard | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	75,773	80,073
Total commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,026	1,324
Total commercial and industrial | Doubtful | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,953	1,251
Total commercial and industrial | Doubtful | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	73	73
Total commercial and industrial | Loss
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial and industrial | Loss | Commercial, financial and agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total commercial and industrial | Loss | Owner-occupied
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,969,354	5,853,857
Total consumer | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,472,471	1,514,227
Total consumer | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,663,371	2,633,503
Total consumer | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	226,713	232,676
Total consumer | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,606,799	1,473,451
Total consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,936,266	5,815,493
Total consumer | Pass | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,452,171	1,491,105
Total consumer | Pass | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,654,285	2,622,499
Total consumer | Pass | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	224,831	230,945
Total consumer | Pass | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,604,979	1,470,944
Total consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Special Mention | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Special Mention | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Special Mention | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Special Mention | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	29,492	34,253
Total consumer | Substandard | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	18,421	21,079
Total consumer | Substandard | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,951	10,607
Total consumer | Substandard | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	564	399
Total consumer | Substandard | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,556	2,168
Total consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	631	905
Total consumer | Doubtful | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	271	285
Total consumer | Doubtful | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	103	291
Total consumer | Doubtful | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total consumer | Doubtful | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	257	329
Total consumer | Loss
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,965	3,206
Total consumer | Loss | Home equity lines
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,608	1,758
Total consumer | Loss | Consumer mortgages
Financing Receivable, Recorded Investment [Line Items]
Total loans	32	106
Total consumer | Loss | Credit cards
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,318	1,332
Total consumer | Loss | Other consumer loans
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 7	$ 10

Loans and Allowance for Loan 46

Loans and Allowance for Loan Losses (Schedule Of Allowances For Loan Losses And Recorded Investment In Loans) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allowance for loan losses:
Beginning balance, allowance	$ 249,268,000	$ 251,758,000	$ 251,758,000
Charge-offs	(14,381,000)	(12,735,000)
Recoveries	10,101,000	5,817,000
Provision for loan losses	12,776,000	8,674,000
Ending balance, allowance	257,764,000	253,514,000	249,268,000
Ending balance: individually evaluated for impairment, allowance	18,942,000	19,707,000
Ending balance: collectively evaluated for impairment, allowance	238,822,000	233,807,000
Total loans	24,906,998,000	24,284,188,000	24,812,795,000
Ending balance: individually evaluated for impairment, loans	191,652,000	234,756,000
Ending balance: collectively evaluated for impairment, loans	24,715,346,000	24,049,432,000
Purchased credit-impaired loans	0	0
Allowance for purchased credit-impaired loans	0	0
Deferred fees and costs, net	24,000,000	25,700,000	25,300,000
Commercial Real Estate
Allowance for loan losses:
Beginning balance, allowance	74,998,000	81,816,000	81,816,000
Charge-offs	(1,911,000)	(1,908,000)
Recoveries	5,723,000	2,889,000
Provision for loan losses	(4,819,000)	(4,483,000)
Ending balance, allowance	73,991,000	78,314,000	74,998,000
Ending balance: individually evaluated for impairment, allowance	3,740,000	6,917,000
Ending balance: collectively evaluated for impairment, allowance	70,251,000	71,397,000
Total loans	6,835,727,000	7,467,288,000
Ending balance: individually evaluated for impairment, loans	49,221,000	79,203,000
Ending balance: collectively evaluated for impairment, loans	6,786,506,000	7,388,085,000
Commercial & Industrial
Allowance for loan losses:
Beginning balance, allowance	126,803,000	125,778,000	125,778,000
Charge-offs	(8,015,000)	(6,893,000)
Recoveries	3,112,000	1,824,000
Provision for loan losses	12,845,000	6,387,000
Ending balance, allowance	134,745,000	127,096,000	126,803,000
Ending balance: individually evaluated for impairment, allowance	14,405,000	11,085,000
Ending balance: collectively evaluated for impairment, allowance	120,340,000	116,011,000
Total loans	12,101,917,000	11,732,701,000
Ending balance: individually evaluated for impairment, loans	112,823,000	120,470,000
Ending balance: collectively evaluated for impairment, loans	11,989,094,000	11,612,231,000
Retail
Allowance for loan losses:
Beginning balance, allowance	47,467,000	44,164,000	44,164,000
Charge-offs	(4,455,000)	(3,934,000)
Recoveries	1,266,000	1,104,000
Provision for loan losses	4,750,000	6,770,000
Ending balance, allowance	49,028,000	48,104,000	$ 47,467,000
Ending balance: individually evaluated for impairment, allowance	797,000	1,705,000
Ending balance: collectively evaluated for impairment, allowance	48,231,000	46,399,000
Total loans	5,969,354,000	5,084,199,000
Ending balance: individually evaluated for impairment, loans	29,608,000	35,083,000
Ending balance: collectively evaluated for impairment, loans	$ 5,939,746,000	$ 5,049,116,000

Loans and Allowance for Loan 47

Loans and Allowance for Loan Losses (Schedule Of Impaired Loans) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	$ 13,340,000		$ 11,022,000
Recorded Investment, With allowance recorded	178,312,000		189,264,000
Recorded Investment	191,652,000		200,286,000
Unpaid Principal Balance, With no related allowance recorded	15,790,000		14,259,000
Unpaid Principal Balance, With allowance recorded	180,377,000		189,498,000
Unpaid Principal Balance	196,167,000		203,757,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	18,942,000		14,908,000
Related Allowance	18,942,000		14,908,000
Average Recorded Investment, With no related allowance recorded	11,721,000		32,314,000
Average Recorded Investment, With allowance recorded	186,410,000		190,695,000
Average Recorded Investment	198,131,000	$ 235,600,000	223,009,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	1,430,000		6,961,000
Interest Income Recognized	1,430,000	$ 0	6,961,000
Total commercial real estate
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		56,000
Recorded Investment, With allowance recorded	49,221,000		56,840,000
Recorded Investment	49,221,000		56,896,000
Unpaid Principal Balance, With no related allowance recorded	0		1,740,000
Unpaid Principal Balance, With allowance recorded	50,961,000		56,896,000
Unpaid Principal Balance	50,961,000		58,636,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	3,740,000		4,240,000
Related Allowance	3,740,000		4,240,000
Average Recorded Investment, With no related allowance recorded	37,000		2,262,000
Average Recorded Investment, With allowance recorded	52,617,000		68,344,000
Average Recorded Investment	52,654,000		70,606,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	490,000		2,473,000
Interest Income Recognized	490,000		2,473,000
Total commercial real estate | Investment properties
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	19,388,000		23,364,000
Recorded Investment	19,388,000		23,364,000
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	19,388,000		23,364,000
Unpaid Principal Balance	19,388,000		23,364,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	753,000		1,100,000
Related Allowance	753,000		1,100,000
Average Recorded Investment, With no related allowance recorded	0		123,000
Average Recorded Investment, With allowance recorded	22,769,000		28,749,000
Average Recorded Investment	22,769,000		28,872,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	198,000		1,144,000
Interest Income Recognized	198,000		1,144,000
Total commercial real estate | 1-4 family properties
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	12,008,000		15,056,000
Recorded Investment	12,008,000		15,056,000
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	12,008,000		15,056,000
Unpaid Principal Balance	12,008,000		15,056,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	392,000		504,000
Related Allowance	392,000		504,000
Average Recorded Investment, With no related allowance recorded	0		323,000
Average Recorded Investment, With allowance recorded	11,715,000		16,257,000
Average Recorded Investment	11,715,000		16,580,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	216,000		925,000
Interest Income Recognized	216,000		925,000
Total commercial real estate | Land and development
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		56,000
Recorded Investment, With allowance recorded	17,825,000		18,420,000
Recorded Investment	17,825,000		18,476,000
Unpaid Principal Balance, With no related allowance recorded	0		1,740,000
Unpaid Principal Balance, With allowance recorded	19,565,000		18,476,000
Unpaid Principal Balance	19,565,000		20,216,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	2,595,000		2,636,000
Related Allowance	2,595,000		2,636,000
Average Recorded Investment, With no related allowance recorded	37,000		1,816,000
Average Recorded Investment, With allowance recorded	18,133,000		23,338,000
Average Recorded Investment	18,170,000		25,154,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	76,000		404,000
Interest Income Recognized	76,000		404,000
Total commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	9,614,000		8,220,000
Recorded Investment, With allowance recorded	103,209,000		103,114,000
Recorded Investment	112,823,000		111,334,000
Unpaid Principal Balance, With no related allowance recorded	12,039,000		9,576,000
Unpaid Principal Balance, With allowance recorded	103,532,000		103,292,000
Unpaid Principal Balance	115,571,000		112,868,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	14,405,000		9,515,000
Related Allowance	14,405,000		9,515,000
Average Recorded Investment, With no related allowance recorded	8,682,000		28,351,000
Average Recorded Investment, With allowance recorded	104,913,000		90,966,000
Average Recorded Investment	113,595,000		119,317,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	630,000		2,992,000
Interest Income Recognized	630,000		2,992,000
Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	9,614,000		8,220,000
Recorded Investment, With allowance recorded	65,422,000		65,715,000
Recorded Investment	75,036,000		73,935,000
Unpaid Principal Balance, With no related allowance recorded	12,039,000		9,576,000
Unpaid Principal Balance, With allowance recorded	65,691,000		65,851,000
Unpaid Principal Balance	77,730,000		75,427,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	12,491,000		7,406,000
Related Allowance	12,491,000		7,406,000
Average Recorded Investment, With no related allowance recorded	8,682,000		21,686,000
Average Recorded Investment, With allowance recorded	67,198,000		50,468,000
Average Recorded Investment	75,880,000		72,154,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	273,000		1,610,000
Interest Income Recognized	273,000		1,610,000
Total commercial and industrial | Owner-occupied
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	37,787,000		37,399,000
Recorded Investment	37,787,000		37,399,000
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	37,841,000		37,441,000
Unpaid Principal Balance	37,841,000		37,441,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	1,914,000		2,109,000
Related Allowance	1,914,000		2,109,000
Average Recorded Investment, With no related allowance recorded	0		6,665,000
Average Recorded Investment, With allowance recorded	37,715,000		40,498,000
Average Recorded Investment	37,715,000		47,163,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	357,000		1,382,000
Interest Income Recognized	357,000		1,382,000
Total consumer
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	3,726,000		2,746,000
Recorded Investment, With allowance recorded	25,882,000		29,310,000
Recorded Investment	29,608,000		32,056,000
Unpaid Principal Balance, With no related allowance recorded	3,751,000		2,943,000
Unpaid Principal Balance, With allowance recorded	25,884,000		29,310,000
Unpaid Principal Balance	29,635,000		32,253,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	797,000		1,153,000
Related Allowance	797,000		1,153,000
Average Recorded Investment, With no related allowance recorded	3,002,000		1,701,000
Average Recorded Investment, With allowance recorded	28,880,000		31,385,000
Average Recorded Investment	31,882,000		33,086,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	310,000		1,496,000
Interest Income Recognized	310,000		1,496,000
Total consumer | Home equity lines
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,086,000		2,746,000
Recorded Investment, With allowance recorded	3,475,000		5,096,000
Recorded Investment	4,561,000		7,842,000
Unpaid Principal Balance, With no related allowance recorded	1,086,000		2,943,000
Unpaid Principal Balance, With allowance recorded	3,475,000		5,096,000
Unpaid Principal Balance	4,561,000		8,039,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	44,000		114,000
Related Allowance	44,000		114,000
Average Recorded Investment, With no related allowance recorded	2,122,000		1,205,000
Average Recorded Investment, With allowance recorded	4,383,000		7,476,000
Average Recorded Investment	6,505,000		8,681,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	45,000		334,000
Interest Income Recognized	45,000		334,000
Total consumer | Consumer mortgages
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	2,640,000		0
Recorded Investment, With allowance recorded	17,378,000		18,668,000
Recorded Investment	20,018,000		18,668,000
Unpaid Principal Balance, With no related allowance recorded	2,665,000		0
Unpaid Principal Balance, With allowance recorded	17,378,000		18,668,000
Unpaid Principal Balance	20,043,000		18,668,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	447,000		569,000
Related Allowance	447,000		569,000
Average Recorded Investment, With no related allowance recorded	880,000		496,000
Average Recorded Investment, With allowance recorded	19,106,000		19,144,000
Average Recorded Investment	19,986,000		19,640,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	194,000		896,000
Interest Income Recognized	194,000		896,000
Total consumer | Credit cards
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	0		0
Recorded Investment	0		0
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	0		0
Unpaid Principal Balance	0		0
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	0		0
Related Allowance	0		0
Average Recorded Investment, With no related allowance recorded	0		0
Average Recorded Investment, With allowance recorded	0		0
Average Recorded Investment	0		0
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	0		0
Interest Income Recognized	0		0
Total consumer | Other consumer loans
Financing Receivable, Impaired [Line Items]
Recorded Investment, With no related allowance recorded	0		0
Recorded Investment, With allowance recorded	5,029,000		5,546,000
Recorded Investment	5,029,000		5,546,000
Unpaid Principal Balance, With no related allowance recorded	0		0
Unpaid Principal Balance, With allowance recorded	5,031,000		5,546,000
Unpaid Principal Balance	5,031,000		5,546,000
Related Allowance, With no related allowance recorded	0		0
Related Allowance, With allowance recorded	306,000		470,000
Related Allowance	306,000		470,000
Average Recorded Investment, With no related allowance recorded	0		0
Average Recorded Investment, With allowance recorded	5,391,000		4,765,000
Average Recorded Investment	5,391,000		4,765,000
Interest Income Recognized, With no related allowance recorded	0		0
Interest Income Recognized, With allowance recorded	71,000		266,000
Interest Income Recognized	$ 71,000		$ 266,000

Loans and Allowance for Loan 48

Loans and Allowance for Loan Losses (Troubled Debt Restructurings) (Details)	3 Months Ended
	Mar. 31, 2018USD ($)Contract	Mar. 31, 2017USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	39	29
Recorded Investment	$ 9,487,000	$ 11,607,000
Net charge-offs	$ 0	$ 0
Total commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	7	8
Recorded Investment	$ 2,922,000	$ 1,928,000
Total commercial real estate | Investment properties
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	1
Recorded Investment	$ 1,959,000
Total commercial real estate | 1-4 family properties
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	6	8
Recorded Investment	$ 963,000	$ 1,928,000
Total commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	11	18
Recorded Investment	$ 3,787,000	$ 9,404,000
Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	9	18
Recorded Investment	$ 989,000	$ 9,404,000
Total commercial and industrial | Owner-occupied
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	2
Recorded Investment	$ 2,798,000
Total consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	21	3
Recorded Investment	$ 2,778,000	$ 275,000
Total consumer | Consumer mortgages
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	7
Recorded Investment	$ 1,733,000
Total consumer | Other consumer loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	14	3
Recorded Investment	$ 1,045,000	$ 275,000
Principal Forgiveness
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total commercial real estate
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total commercial real estate | Investment properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	0
Principal Forgiveness | Total commercial real estate | 1-4 family properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total commercial and industrial
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total commercial and industrial | Owner-occupied
Financing Receivable, Modifications [Line Items]
Recorded Investment	0
Principal Forgiveness | Total consumer
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Principal Forgiveness | Total consumer | Consumer mortgages
Financing Receivable, Modifications [Line Items]
Recorded Investment	0
Principal Forgiveness | Total consumer | Other consumer loans
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	0
Below Market Interest Rate
Financing Receivable, Modifications [Line Items]
Recorded Investment	5,938,000	5,476,000
Below Market Interest Rate | Total commercial real estate
Financing Receivable, Modifications [Line Items]
Recorded Investment	963,000	1,611,000
Below Market Interest Rate | Total commercial real estate | Investment properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	0
Below Market Interest Rate | Total commercial real estate | 1-4 family properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	963,000	1,611,000
Below Market Interest Rate | Total commercial and industrial
Financing Receivable, Modifications [Line Items]
Recorded Investment	2,705,000	3,865,000
Below Market Interest Rate | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	3,865,000
Below Market Interest Rate | Total commercial and industrial | Owner-occupied
Financing Receivable, Modifications [Line Items]
Recorded Investment	2,705,000
Below Market Interest Rate | Total consumer
Financing Receivable, Modifications [Line Items]
Recorded Investment	2,270,000	0
Below Market Interest Rate | Total consumer | Consumer mortgages
Financing Receivable, Modifications [Line Items]
Recorded Investment	1,733,000
Below Market Interest Rate | Total consumer | Other consumer loans
Financing Receivable, Modifications [Line Items]
Recorded Investment	537,000	0
Term Extensions and/or Other Concessions
Financing Receivable, Modifications [Line Items]
Recorded Investment	3,549,000	6,131,000
Term Extensions and/or Other Concessions | Total commercial real estate
Financing Receivable, Modifications [Line Items]
Recorded Investment	1,959,000	317,000
Term Extensions and/or Other Concessions | Total commercial real estate | Investment properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	1,959,000
Term Extensions and/or Other Concessions | Total commercial real estate | 1-4 family properties
Financing Receivable, Modifications [Line Items]
Recorded Investment	0	317,000
Term Extensions and/or Other Concessions | Total commercial and industrial
Financing Receivable, Modifications [Line Items]
Recorded Investment	1,082,000	5,539,000
Term Extensions and/or Other Concessions | Total commercial and industrial | Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Recorded Investment	989,000	5,539,000
Term Extensions and/or Other Concessions | Total commercial and industrial | Owner-occupied
Financing Receivable, Modifications [Line Items]
Recorded Investment	93,000
Term Extensions and/or Other Concessions | Total consumer
Financing Receivable, Modifications [Line Items]
Recorded Investment	508,000	275,000
Term Extensions and/or Other Concessions | Total consumer | Consumer mortgages
Financing Receivable, Modifications [Line Items]
Recorded Investment	0
Term Extensions and/or Other Concessions | Total consumer | Other consumer loans
Financing Receivable, Modifications [Line Items]
Recorded Investment	$ 508,000	$ 275,000

Other Comprehensive Income (L49

Other Comprehensive Income (Loss) (Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Balance	$ 2,961,566	$ 2,927,924
Other comprehensive income (loss), Net of Tax Amount	(45,552)	908
Balance	2,956,495	2,962,127
Total
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Balance	(54,754)	(55,659)
Other comprehensive income before reclassifications	(45,531)	5,596
Amounts reclassified from accumulated other comprehensive income (loss)	(21)	(4,688)
Reclassification from adoption of ASU 2018-02	(7,588)
Cumulative-effect adjustment from adoption of ASU 2016-01	117
Other comprehensive income (loss), Net of Tax Amount	(45,552)	908
Balance	(107,777)	(54,751)
Net unrealized gains (losses) on cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Balance	(12,137)	(12,217)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	40
Reclassification from adoption of ASU 2018-02	0
Cumulative-effect adjustment from adoption of ASU 2016-01	0
Other comprehensive income (loss), Net of Tax Amount	0	40
Balance	(12,137)	(12,177)
Net unrealized gains (losses) on investment securities available for sale
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Balance	(43,470)	(44,324)
Other comprehensive income before reclassifications	(45,531)	5,596
Amounts reclassified from accumulated other comprehensive income (loss)	0	(4,716)
Reclassification from adoption of ASU 2018-02	(7,763)
Cumulative-effect adjustment from adoption of ASU 2016-01	117
Other comprehensive income (loss), Net of Tax Amount	(45,531)	880
Balance	(96,647)	(43,444)
Post-retirement unfunded health benefit
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Balance	853	882
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	(21)	(12)
Reclassification from adoption of ASU 2018-02	(175)
Cumulative-effect adjustment from adoption of ASU 2016-01	0
Other comprehensive income (loss), Net of Tax Amount	(21)	(12)
Balance	$ 1,007	$ 870

Other Comprehensive Income (L50

Other Comprehensive Income (Loss) (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Accumulated other comprehensive income (loss)	$ (107,777)	$ (54,754)
Net unrealized gains (losses) on cash flow hedges | Valuation Allowance of Deferred Tax Assets
Class of Stock [Line Items]
Accumulated other comprehensive income (loss)	(12,100)
Net unrealized gains (losses) on investment securities available for sale | Valuation Allowance of Deferred Tax Assets
Class of Stock [Line Items]
Accumulated other comprehensive income (loss)	$ (13,300)

Other Comprehensive Income (L51

Other Comprehensive Income (Loss) (Reclassifications out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (38,850)	$ (32,474)
Income tax (expense) benefit	(30,209)	(33,847)
Investment securities gains, net	0	7,668
Salaries and other personnel expense	(113,720)	(107,191)
Net income available to common shareholders	100,607	69,298
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Net unrealized gains (losses) on cash flow hedges:
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	0	(65)
Income tax (expense) benefit	0	25
Net income available to common shareholders	0	(40)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Net unrealized gains (losses) on investment securities available for sale
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	0	(2,952)
Investment securities gains, net	0	7,668
Net income available to common shareholders	0	4,716
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) | Post-retirement unfunded health benefit
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	(13)	(8)
Salaries and other personnel expense	34	20
Net income available to common shareholders	$ 21	$ 12

Fair Value Accounting (Financia

Fair Value Accounting (Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	$ 26,251
Investment securities available for sale	3,990,978	$ 3,987,069
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	1,065,041	1,111,999
State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	115	180
Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	17,126	20,391
U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	120,931	82,674
Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	112,868	120,440
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	2,664,000	2,640,523
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	522
Investment securities available for sale	120,931	85,836
Private equity investments	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	26,251	3,298
Investment securities available for sale	3,868,195	3,899,298
Private equity investments	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	9,407	11,722
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	1,852	1,935
Private equity investments	12,715	15,771
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	0	0
Fair Value, Measurements, Recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		3,820
Mortgage loans held for sale	50,439	48,024
Investment securities available for sale	3,990,978	3,987,069
Private equity investments	12,715	15,771
Mutual funds held in Rabbi Trusts	13,385	14,140
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	9,407	11,722
Trading account liabilities	23,856
Earnout liability	11,348	11,348
Derivative liabilities	20,096	17,097
Fair Value, Measurements, Recurring Basis | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities		1,000
Fair Value, Measurements, Recurring Basis | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		129
Fair Value, Measurements, Recurring Basis | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		522
Fair Value, Measurements, Recurring Basis | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	25,971
Investment securities available for sale	10,897	10,862
Fair Value, Measurements, Recurring Basis | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	240	296
Investment securities available for sale	1,065,041	1,111,999
Fair Value, Measurements, Recurring Basis | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	40
Investment securities available for sale	115	180
Fair Value, Measurements, Recurring Basis | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	17,126	20,391
Fair Value, Measurements, Recurring Basis | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	120,931	82,674
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		3,002
Investment securities available for sale	112,868	120,440
Fair Value, Measurements, Recurring Basis | Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	2,664,000	2,640,523
Fair Value, Measurements, Recurring Basis | Mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	3,131
Fair Value, Measurements, Recurring Basis | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7,672	10,786
Derivative liabilities	16,122	12,638
Fair Value, Measurements, Recurring Basis | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1,735	936
Fair Value, Measurements, Recurring Basis | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	3,974	4,330
Fair Value, Measurements, Recurring Basis | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	522
Mortgage loans held for sale	0	0
Investment securities available for sale	120,931	85,836
Private equity investments	0	0
Mutual funds held in Rabbi Trusts	13,385	14,140
GGL/SBA loans servicing asset	0	0
Derivative assets	0	0
Trading account liabilities	0
Earnout liability	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities		0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		0
Fair Value, Measurements, Recurring Basis | Level 1 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		522
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale		0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	3,162
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	120,931	82,674
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	3,131
Fair Value, Measurements, Recurring Basis | Level 1 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Fair Value, Measurements, Recurring Basis | Level 1 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	26,251	3,298
Mortgage loans held for sale	50,439	48,024
Investment securities available for sale	3,868,195	3,899,298
Private equity investments	0	0
Mutual funds held in Rabbi Trusts	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	9,407	11,722
Trading account liabilities	23,856
Earnout liability	0	0
Derivative liabilities	16,122	12,767
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities		1,000
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		129
Fair Value, Measurements, Recurring Basis | Level 2 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	25,971
Investment securities available for sale		10,862
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	240	296
Investment securities available for sale	1,065,041	1,111,999
Fair Value, Measurements, Recurring Basis | Level 2 | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	40
Investment securities available for sale	115	180
Fair Value, Measurements, Recurring Basis | Level 2 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	15,274	15,294
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		3,002
Investment securities available for sale	112,868	120,440
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	2,664,000	2,640,523
Fair Value, Measurements, Recurring Basis | Level 2 | Mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0
Fair Value, Measurements, Recurring Basis | Level 2 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7,672	10,786
Derivative liabilities	16,122	12,638
Fair Value, Measurements, Recurring Basis | Level 2 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1,735	936
Fair Value, Measurements, Recurring Basis | Level 2 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Mortgage loans held for sale	0	0
Investment securities available for sale	1,852	1,935
Private equity investments	12,715	15,771
Mutual funds held in Rabbi Trusts	0	0
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	0	0
Trading account liabilities	0
Earnout liability	11,348	11,348
Derivative liabilities	3,974	4,330
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading account liabilities		0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		0
Fair Value, Measurements, Recurring Basis | Level 3 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Government agency securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | State and municipal securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities	0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Other investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	1,852	1,935
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government agencies
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Trading securities		0
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage-backed securities issued by U.S. Government sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mutual funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities available for sale	0
Fair Value, Measurements, Recurring Basis | Level 3 | Interest rate contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Mortgage derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Fair Value, Measurements, Recurring Basis | Level 3 | Visa derivative
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	$ 3,974	$ 4,330

Fair Value Accounting (Changes

Fair Value Accounting (Changes In Fair Value Included In Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Mortgage loans held for sale	$ 115	$ 1,203
Fair value	50,439		$ 48,024
Unpaid principal balance	49,139		46,839
Fair value less aggregate unpaid principal balance	$ 1,300		$ 1,185

Fair Value Accounting (Change54

Fair Value Accounting (Changes In Level 3 Fair Value Measurements) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Visa Derivative
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1, 2017	$ (4,330)	$ (5,768)
Included in earnings	0	0
Unrealized (losses) gains included in other comprehensive income	0	0
Additions	0
Settlements	(356)	356
Transfer from amortization method to fair value		0
Measurement period adjustments related to Global One acquisition		0
Ending balance, September 30,	(3,974)	(5,412)
Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held	0	0
Other liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1, 2017	(11,348)	(14,000)
Included in earnings	0	0
Unrealized (losses) gains included in other comprehensive income	0	0
Additions	0
Settlements	0	0
Transfer from amortization method to fair value		0
Measurement period adjustments related to Global One acquisition		2,579
Ending balance, September 30,	(11,348)	(11,421)
Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held	0	0
GGL / SBA Loans Servicing Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1, 2017	4,101	0
Included in earnings	(422)	0
Unrealized (losses) gains included in other comprehensive income	0	0
Additions	292
Settlements	0	0
Transfer from amortization method to fair value		4,178
Measurement period adjustments related to Global One acquisition		0
Ending balance, September 30,	3,971	4,178
Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held	(422)	0
Investment Securities Available for Sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1, 2017	1,935	1,796
Included in earnings	0	0
Unrealized (losses) gains included in other comprehensive income	(83)	55
Additions	0
Settlements	0	0
Transfer from amortization method to fair value		0
Measurement period adjustments related to Global One acquisition		0
Ending balance, September 30,	1,852	1,851
Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held	0	0
Private Equity Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance, January 1, 2017	15,771	25,493
Included in earnings	(3,056)	(1,814)
Unrealized (losses) gains included in other comprehensive income	0	0
Additions	0
Settlements	0	0
Transfer from amortization method to fair value		0
Measurement period adjustments related to Global One acquisition		0
Ending balance, September 30,	12,715	23,679
Total net (losses) for the period included in earnings attributable to the change in unrealized losses relating to assets/liabilities still held	$ (3,056)	$ (1,814)

Fair Value Accounting (Assets A

Fair Value Accounting (Assets And Liabilities Measured At Fair Value On A Non-Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 191,652	$ 200,286
Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate	4,500	3,800
Fair Value, Measurements, Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,531	3,603
Other loans held for sale	3,295	10,197
Other real estate	1,447	3,363
Other assets held for sale	1,395	5,334
Fair Value, Measurements, Nonrecurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other loans held for sale	0	0
Other real estate	0	0
Other assets held for sale	0	0
Fair Value, Measurements, Nonrecurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other loans held for sale	0	0
Other real estate	0	0
Other assets held for sale	0	0
Fair Value, Measurements, Nonrecurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,531	3,603
Other loans held for sale	3,295	10,197
Other real estate	1,447	3,363
Other assets held for sale	$ 1,395	$ 5,334

Fair Value Accounting (Assets M

Fair Value Accounting (Assets Measured at Fair Value on Nonrecurring Basis) (Details) - Fair Value, Measurements, Nonrecurring Basis - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value adjustment	$ 720	$ 2,230
Other loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value adjustment	1,512	3,519
Other real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value adjustment	731	399
Other assets held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value adjustment	$ 107	$ 238

Fair Value Accounting (Fair Val

Fair Value Accounting (Fair Value Inputs, Assets, Quantitative Information) (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Measurements, Recurring Basis | Visa Derivative | Discounted cash flow analysis | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated future monthly fees payable to the derivative counterparty, period	1 year	1 year
Fair Value, Measurements, Recurring Basis | Visa Derivative | Discounted cash flow analysis | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Estimated future monthly fees payable to the derivative counterparty, period	4 years	4 years
Fair Value, Measurements, Recurring Basis | Earnout Liabilities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	$ 11,348	$ 11,348
Fair Value, Measurements, Recurring Basis | Visa derivative
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Liabilities, Fair Value Disclosure, Nonrecurring	3,974	4,330
Fair Value, Measurements, Recurring Basis | Trust preferred securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 1,852	$ 1,935
Fair Value, Measurements, Recurring Basis | Trust preferred securities | Discounted cash flow analysis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spread embedded in discount rate	4.39%	3.98%
Fair Value, Measurements, Recurring Basis | Private equity investments | Individual Analysis of Each Investee Company [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 12,715	$ 15,771
Fair Value, Measurements, Recurring Basis | GGL / SBA Loans Servicing Asset
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 3,971	$ 4,101
Fair Value, Measurements, Recurring Basis | GGL / SBA Loans Servicing Asset | Discounted cash flow analysis
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	13.57%	13.16%
Prepayment speeds	7.98%	7.50%
Fair Value, Measurements, Nonrecurring Basis | Collateral dependent impaired loans | Third-party appraised value of collateral less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	0.00%	0.00%
Estimated selling costs	0.00%	0.00%
Fair Value, Measurements, Nonrecurring Basis | Collateral dependent impaired loans | Third-party appraised value of collateral less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	23.00%	50.00%
Estimated selling costs	10.00%	10.00%
Fair Value, Measurements, Nonrecurring Basis | Collateral dependent impaired loans | Third-party appraised value of collateral less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	9.00%	15.00%
Estimated selling costs	7.00%	7.00%
Fair Value, Measurements, Nonrecurring Basis | Other loans held for sale | Third-party appraised value of collateral less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	0.00%	5.00%
Estimated selling costs	0.00%	0.00%
Fair Value, Measurements, Nonrecurring Basis | Other loans held for sale | Third-party appraised value of collateral less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	85.00%	99.00%
Estimated selling costs	10.00%	10.00%
Fair Value, Measurements, Nonrecurring Basis | Other loans held for sale | Third-party appraised value of collateral less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	30.00%	54.00%
Estimated selling costs	2.00%	2.00%
Fair Value, Measurements, Nonrecurring Basis | Other real estate | Third-party appraised value of collateral less estimated selling costs | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	0.00%	0.00%
Estimated selling costs	0.00%	0.00%
Fair Value, Measurements, Nonrecurring Basis | Other real estate | Third-party appraised value of collateral less estimated selling costs | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	39.00%	85.00%
Estimated selling costs	10.00%	10.00%
Fair Value, Measurements, Nonrecurring Basis | Other real estate | Third-party appraised value of collateral less estimated selling costs | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value	21.00%	35.00%
Estimated selling costs	7.00%	7.00%
Fair Value, Measurements, Nonrecurring Basis | Other assets held for sale | Third-party appraised value less estimated selling costs or BOV | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		21.00%
Estimated selling costs	0.00%	0.00%
Fair Value, Measurements, Nonrecurring Basis | Other assets held for sale | Third-party appraised value less estimated selling costs or BOV | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		52.00%
Estimated selling costs	10.00%	10.00%
Fair Value, Measurements, Nonrecurring Basis | Other assets held for sale | Third-party appraised value less estimated selling costs or BOV | Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount to appraised value		25.00%
Estimated selling costs	7.00%	7.00%

Fair Value Accounting (Carrying

Fair Value Accounting (Carrying And Estimated Fair Values Of Financial Instruments Carried On Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial assets
Trading account assets	$ 26,251
Mortgage loans held for sale	50,439	$ 48,024
Investment securities available for sale	3,990,978	3,987,069
Loans, net	24,625,273	24,538,196
Financial liabilities
Non-interest bearing deposits	7,381,070	7,686,339
Total deposits	26,253,507	26,147,900
Federal funds purchased, other short-term borrowings and other short-term liabilities	185,531	161,190
Long-term debt	1,856,392	1,706,138
Level 1
Financial assets
Cash and cash equivalents	1,059,017	932,933
Trading account assets	0	522
Mortgage loans held for sale	0	0
Other loans held for sale	0	0
Investment securities available for sale	120,931	85,836
Private equity investments	0	0
Mutual funds	3,131
Mutual funds held in rabbi trusts	13,385	14,140
Loans, net	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	0	0
Financial liabilities
Trading account liabilities	0	0
Non-interest bearing deposits	0	0
Non-time interest bearing deposits	0	0
Time deposits	0	0
Total deposits	0	0
Federal funds purchased, other short-term borrowings and other short-term liabilities	185,531	161,190
Long-term debt	0	0
Earnout liabilities	0	0
Derivative liability positions	0	0
Level 2
Financial assets
Cash and cash equivalents	0	0
Trading account assets	26,251	3,298
Mortgage loans held for sale	50,439	48,024
Other loans held for sale	0	0
Investment securities available for sale	3,868,195	3,899,298
Private equity investments	0	0
Mutual funds	0
Mutual funds held in rabbi trusts	0	0
Loans, net	0	0
GGL/SBA loans servicing asset	0	0
Derivative assets	9,407	11,722
Financial liabilities
Trading account liabilities	23,856	1,000
Non-interest bearing deposits	7,381,070	7,686,339
Non-time interest bearing deposits	14,030,247	13,941,814
Time deposits	4,834,135	4,523,661
Total deposits	26,245,452	26,151,814
Federal funds purchased, other short-term borrowings and other short-term liabilities	0	0
Long-term debt	1,861,008	1,721,814
Earnout liabilities	0	0
Derivative liability positions	16,122	12,767
Level 3
Financial assets
Cash and cash equivalents	0	0
Trading account assets	0	0
Mortgage loans held for sale	0	0
Other loans held for sale	6,591	11,356
Investment securities available for sale	1,852	1,935
Private equity investments	12,715	15,771
Mutual funds	0
Mutual funds held in rabbi trusts	0	0
Loans, net	24,538,259	24,507,141
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	0	0
Financial liabilities
Trading account liabilities	0	0
Non-interest bearing deposits	0	0
Non-time interest bearing deposits	0	0
Time deposits	0	0
Total deposits	0	0
Federal funds purchased, other short-term borrowings and other short-term liabilities	0	0
Long-term debt	0	0
Earnout liabilities	11,348	11,348
Derivative liability positions	3,974	4,330
Carrying Value
Financial assets
Cash and cash equivalents	1,059,017	932,933
Trading account assets	26,251	3,820
Mortgage loans held for sale	50,439	48,024
Other loans held for sale	6,591	11,356
Investment securities available for sale	3,990,978	3,987,069
Private equity investments	12,715	15,771
Mutual funds	3,131
Mutual funds held in rabbi trusts	13,385	14,140
Loans, net	24,625,273	24,538,196
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	9,407	11,722
Financial liabilities
Trading account liabilities	23,856	1,000
Non-interest bearing deposits	7,381,070	7,686,339
Non-time interest bearing deposits	14,030,247	13,941,814
Time deposits	4,842,190	4,519,747
Total deposits	26,253,507	26,147,900
Federal funds purchased, other short-term borrowings and other short-term liabilities	185,531	161,190
Long-term debt	1,856,392	1,706,138
Earnout liabilities	11,348	11,348
Derivative liability positions	20,096	17,097
Fair Value
Financial assets
Cash and cash equivalents	1,059,017	932,933
Trading account assets	26,251	3,820
Mortgage loans held for sale	50,439	48,024
Other loans held for sale	6,591	11,356
Investment securities available for sale	3,990,978	3,987,069
Private equity investments	12,715	15,771
Mutual funds	3,131
Mutual funds held in rabbi trusts	13,385	14,140
Loans, net	24,538,259	24,507,141
GGL/SBA loans servicing asset	3,971	4,101
Derivative assets	9,407	11,722
Financial liabilities
Trading account liabilities	0	1,000
Non-interest bearing deposits	7,381,070	7,686,339
Non-time interest bearing deposits	14,030,247	13,941,814
Time deposits	4,834,135	4,523,661
Total deposits	26,245,452	26,151,814
Federal funds purchased, other short-term borrowings and other short-term liabilities	185,531	161,190
Long-term debt	1,861,008	1,721,814
Earnout liabilities	11,348	11,348
Derivative liability positions	$ 20,096	$ 17,097

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative, fair value	$ 4,000,000		$ 4,300,000
Loss on sale of outstanding commitments	735,000	$ (2,500,000)
Collateral requirements	32,700,000		43,800,000
Variation margin, amount reducing derivative asset	8,100,000		1,500,000
Fixed Rate Residential Mortgage
Derivative [Line Items]
Commitments to fund fixed-rate mortgage loans	93,100,000		49,300,000
Unrealized gain (loss) on fair value of fixed-rate mortgage loans to customers	(192,000)	$ 674,000
Sale of outstanding commitments	113,000,000		72,500,000
Interest Rate Swap
Derivative [Line Items]
Notional amount of interest rate swap contracts	1,550,000,000
Increase in derivative, notional amount	$ 82,000,000
Cash Flow Hedges
Derivative [Line Items]
Derivative instruments			0
Fair Value Hedges
Derivative [Line Items]
Derivative instruments			$ 0

Derivative Instruments (Impact

Derivative Instruments (Impact Of Derivatives On Balance Sheet) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other assets
Derivative [Line Items]
Fair value of derivative assets	$ 9,407	$ 11,722
Other assets | Interest rate contracts
Derivative [Line Items]
Fair value of derivative assets	7,672	10,786
Other assets | Mortgage derivatives
Derivative [Line Items]
Fair value of derivative assets	1,735	936
Other assets | Visa derivative
Derivative [Line Items]
Fair value of derivative assets	0	0
Other liabilities
Derivative [Line Items]
Fair value of derivative liabilities	20,096	17,097
Other liabilities | Interest rate contracts
Derivative [Line Items]
Fair value of derivative liabilities	16,122	12,638
Other liabilities | Mortgage derivatives
Derivative [Line Items]
Fair value of derivative liabilities	0	129
Other liabilities | Visa derivative
Derivative [Line Items]
Fair value of derivative liabilities	$ 3,974	$ 4,330

Derivative Instruments (Effect

Derivative Instruments (Effect Of Fair Value Hedges On Consolidated Statements Of Income) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative [Line Items]
Gain (Loss) Recognized in Income	$ 934	$ (1,785)
Interest rate contracts | Other non-interest income
Derivative [Line Items]
Gain (Loss) Recognized in Income	7	(1)
Mortgage derivatives | Mortgage banking income
Derivative [Line Items]
Gain (Loss) Recognized in Income	$ 927	$ (1,784)

Net Income Per Common Share (Sc

Net Income Per Common Share (Schedule Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Basic Earnings (Loss) Per Share
Net income available to common shareholders	$ 100,607	$ 69,298
Weighted average common shares outstanding (in shares)	118,666	122,300
Net income per common share, basic (in dollars per share)	$ 0.85	$ 0.57
Diluted Earnings (Loss) Per Share
Net income available to common shareholders	$ 100,607	$ 69,298
Weighted average common shares outstanding (in shares)	118,666	122,300
Potentially dilutive shares from outstanding equity-based awards and Earnout Payments (in shares)	655	759
Weighted average number of diluted common shares (in shares)	119,321	123,059
Net income per common share, diluted (in dollars per share)	$ 0.84	$ 0.56

Net Income Per Common Share (Na

Net Income Per Common Share (Narrative) (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Potentially dilutive shares	2.2	2.2

Share-based Compensation (Detai

Share-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 4,000	$ 3,400
Accelerated compensation cost	$ 170
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other equity compensation, shares granted (in shares)	0
Options outstanding (in options)	693,000
Weighted-average exercise price, options (in dollars per share)	$ 16.94
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Other equity compensation, shares granted (in shares)	213,000
Weighted-average exercise price, shares granted during period (in dollars per share)	$ 47.43
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other equity compensation, shares granted (in shares)	87,000
Weighted-average exercise price, shares granted during period (in dollars per share)	$ 41.95
Market Restricted Stock Units (MRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Other equity compensation, shares granted (in shares)	58,000
Weighted-average exercise price, shares granted during period (in dollars per share)	$ 41.95
Non-Vested Synovus Shares And Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other equity compensation, non-vested shares outstanding (in shares)	921,000
Weighted-average exercise price, non-vested shares outstanding (in dollars per share)	$ 39.94
Minimum | Market Restricted Stock Units (MRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range based on shareholder return	75.00%
Minimum | Performance Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range based on return on average assets (ROAA)	0.00%
Maximum | Market Restricted Stock Units (MRSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range based on shareholder return	125.00%
Maximum | Performance Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range based on return on average assets (ROAA)	150.00%
2013 Omnibus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of authorized but unissued common stock reserved for future grants (in shares)	8,600,000
Equivalents authorized (in shares)	4,900,000
Contractual term (years)	10 years
Minimum age of plan participants	65 years
Plan participants, minimum period of service	10 years
2013 Omnibus Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share equivalents ratio (in shares)	1
2013 Omnibus Plan | Value Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share equivalents ratio (in shares)	2
2013 Omnibus Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
2013 Omnibus Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	5 years

Non-interest Income (Details)

Non-interest Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	$ 19,940	$ 20,118
Fiduciary and asset management fees	13,435	12,151
Card fees	10,199	9,844
Brokerage revenue	8,695	7,226
Insurance revenue	1,213	1,304
Other fees	832	842
Fees and commissions	54,314	51,485
Other revenues	12,732	20,354
Total non-interest income	67,046	71,839
Community Banking
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	5,680	5,771
Fiduciary and asset management fees	0	0
Card fees	205	219
Brokerage revenue	0	0
Insurance revenue	0	0
Other fees	0	0
Fees and commissions	5,885	5,990
Other revenues	2,452	1,648
Total non-interest income	8,337	7,638
Corporate Banking
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	533	459
Fiduciary and asset management fees	0	0
Card fees	0	0
Brokerage revenue	0	0
Insurance revenue	0	0
Other fees	0	0
Fees and commissions	533	459
Other revenues	1,733	1,619
Total non-interest income	2,266	2,078
Retail Banking
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	13,422	13,437
Fiduciary and asset management fees	0	0
Card fees	9,994	9,625
Brokerage revenue	0	0
Insurance revenue	0	0
Other fees	559	574
Fees and commissions	23,975	23,636
Other revenues	1,529	1,566
Total non-interest income	25,504	25,202
Financial Management Services
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	0	0
Fiduciary and asset management fees	13,435	12,151
Card fees	0	0
Brokerage revenue	8,695	7,226
Insurance revenue	1,213	1,304
Other fees	0	0
Fees and commissions	23,343	20,681
Other revenues	5,843	6,597
Total non-interest income	29,186	27,278
Other
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	305	451
Fiduciary and asset management fees	0	0
Card fees	0	0
Brokerage revenue	0	0
Insurance revenue	0	0
Other fees	273	268
Fees and commissions	578	719
Other revenues	1,175	8,924
Total non-interest income	$ 1,753	$ 9,643

Commitments and Contingencies66

Commitments and Contingencies (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Contractual amount net of risk participations	$ 60,000,000	$ 77,000,000
Minimum
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	0
Maximum
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	5,000,000
Guarantee obligations
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	9,166,920,000	9,080,108,000
Letters of credit
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	175,164,000	153,372,000
Commitments to fund commercial and industrial loans
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	5,143,323,000	5,090,827,000
Commitments to fund commercial real estate, construction, and land development loans
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	1,541,810,000	1,567,583,000
Commitments under home equity lines of credit
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	1,156,283,000	1,137,714,000
Unused credit card lines
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	780,704,000	779,254,000
Other loan commitments
Loss Contingencies [Line Items]
Total unfunded lending commitments and letters of credit	$ 369,636,000	$ 351,358,000