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

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Share-based Compensation Arrangement by Share-based Payment Award, Minimum Age Of Plan Participants

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Share-based Compensation Arrangement by Share-based Payment Award, Other than Options, Vested and Expected to Vest, Range Based on Return on Average Assets (ROAA)

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Share-based Compensation Arrangement by Share-based Payment Award, Other than Options, Vested and Expected to Vest, Range Based on Shareholder Return

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Share-based Compensation Arrangement by Share-based Payment Award, Share Equivalents Ratio

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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Additional share-based compensation cost recognized as a result of an occurrence of an event that accelerates its recognition.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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-Publisher FASB
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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Number of options outstanding, including both vested and non-vested options.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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