Atlantic Capital Bancshares (ACBI) 10-Q 9 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	ATLANTIC CAPITAL BANCSHARES, INC.
Entity Central Index Key	1,461,755
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		26,037,219

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 39,985	$ 38,086
Interest-bearing deposits in banks	62,787	281,247
Other short-term investments	9,669	10,681
Cash and cash equivalents	112,441	330,014
Securities available-for-sale	458,730	449,117
Other investments	37,949	32,174
Loans held for sale	835	1,487
Loans held for investment	1,959,421	1,933,839
Less: allowance for loan losses	(19,885)	(19,344)
Loans held for investment, net	1,939,536	1,914,495
Premises and equipment, net	15,475	12,054
Bank owned life insurance	64,014	63,667
Goodwill and intangible assets, net	27,485	27,633
Other real estate owned	927	1,215
Other assets	61,273	59,565
Total assets	2,718,665	2,891,421
Deposits:
Noninterest-bearing demand	599,838	732,442
Interest-bearing checking	302,636	306,331
Savings	29,407	26,573
Money market	911,449	1,117,891
Time	140,594	138,612
Brokered deposits	112,376	128,816
Total deposits	2,096,300	2,450,665
Federal funds purchased and securities sold under agreements to repurchase	47,855	0
Federal Home Loan Bank borrowings	185,000	45,000
Long-term debt	49,577	49,535
Other liabilities	32,874	37,796
Total liabilities	2,411,606	2,582,996
SHAREHOLDERS’ EQUITY
Preferred Stock, no par value – 10,000,000 shares authorized; no shares issued and outstanding as of March 31, 2018 and December 31, 2017	0	0
Common stock, no par value – 100,000,000 shares authorized; 25,772,208 and 25,712,909 shares issued and outstanding as of March 31, 2018, and December 31, 2017, respectively	300,893	299,474
Retained earnings	18,693	12,810
Accumulated other comprehensive (loss) income	(12,527)	(3,859)
Total shareholders’ equity	307,059	308,425
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 2,718,665	$ 2,891,421

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock authorized (in shares)	100,000,000	100,000,000
Common stock issued (in shares)	25,772,208	25,712,909
Common stock outstanding (in shares)	25,772,208	25,712,909

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
INTEREST INCOME
Loans, including fees	$ 22,675	$ 19,994
Investment securities available-for-sale	2,592	2,018
Interest and dividends on other interest-earning assets	715	449
Total interest income	25,982	22,461
INTEREST EXPENSE
Interest on deposits	3,044	2,047
Interest on Federal Home Loan Bank advances	509	302
Interest on federal funds purchased and securities sold under agreements to repurchase	83	36
Interest on long-term debt	829	823
Total interest expense	4,465	3,208
NET INTEREST INCOME BEFORE PROVISION FOR LOAN LOSSES	21,517	19,253
Provision for loan losses	772	634
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	20,745	18,619
NONINTEREST INCOME
Service charges	1,192	1,349
Gain (loss) on sales of other assets	(46)	78
Mortgage income	304	257
Trust income	518	407
Derivatives income	114	(51)
Bank owned life insurance	369	378
SBA lending activities	1,302	1,227
Other noninterest income	230	212
Total noninterest income	3,983	3,857
NONINTEREST EXPENSE
Salaries and employee benefits	12,077	11,065
Occupancy	1,355	1,230
Equipment and software	787	805
Professional services	832	904
Postage, printing and supplies	58	85
Communications and data processing	1,043	987
Marketing and business development	190	270
FDIC premiums	147	314
Amortization of intangibles	343	470
Foreclosed property/problem asset expense	282	3
Other noninterest expense	1,278	1,611
Total noninterest expense	18,392	17,744
INCOME BEFORE PROVISION FOR INCOME TAXES	6,336	4,732
Provision for income taxes	1,298	1,502
NET INCOME	$ 5,038	$ 3,230
NET INCOME PER SHARE:
Net income per share – basic (in dollars per share)	$ 0.20	$ 0.13
Net income per share – diluted (in dollars per share)	$ 0.19	$ 0.13

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 5,038	$ 3,230
Unrealized gains (losses) on available-for-sale securities:
Unrealized holding gains (losses) arising during the period, net of tax of ($2,137) and $227, respectively	(6,414)	364
Unrealized gains on available-for-sale securities, net of tax	(6,414)	364
Cash flow hedges:
Net unrealized derivative gains (losses) on cash flow hedges, net of tax of ($470) and ($91), respectively	(1,410)	(146)
Changes from cash flow hedges	(1,410)	(146)
Other comprehensive income (loss), net of tax	(7,824)	218
Comprehensive income (loss)	$ (2,786)	$ 3,448

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Unrealized holding gains arising during the period, net of tax	$ (2,137)	$ 227
Net unrealized derivative (losses) gains on cash flow hedges, net of tax	$ (470)	$ (91)

Consolidated Statements of Shar

Consolidated Statements of Shareholders’ Equity - USD ($)	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016		25,093,135
Accumulated other comprehensive income (loss) beginning of period at Dec. 31, 2016	$ 303,658,000	$ 292,747,000	$ 16,536,000	$ (5,625,000)
Comprehensive income:
Net income	3,230,000		3,230,000
Change in unrealized gains on investment securities available-for-sale, net	364,000			364,000
Change in unrealized gains (losses) on cash flow hedges	(146,000)			(146,000)
Comprehensive income (loss)	3,448,000
Issuance of common stock for option exercises (in shares)		380,079
Issuance of common stock for option exercises	2,281,000	$ 2,281,000
Issuance of common stock for long-term incentive plan (in shares)		61,799
Issuance of common stock for long-term incentive plan	1,209,000	$ 1,209,000
Restricted stock activity	229,000	229,000
Stock-based compensation	142,000	$ 142,000
Ending balance (in shares) at Mar. 31, 2017		25,535,013
Accumulated other comprehensive income (loss) end of period at Mar. 31, 2017	$ 310,967,000	$ 296,608,000	19,766,000	(5,407,000)
Beginning balance (in shares) at Dec. 31, 2017	25,712,909	25,712,909
Accumulated other comprehensive income (loss) beginning of period at Dec. 31, 2017	$ 308,425,000	$ 299,474,000	12,810,000	(3,859,000)
Comprehensive income:
Reclassification of tax effects from AOCI	$ 0
Beginning balance (in shares) at Dec. 31, 2017	25,712,909	25,712,909
Accumulated other comprehensive income (loss) beginning of period at Dec. 31, 2017	$ 308,425,000	$ 299,474,000	12,810,000	(3,859,000)
Comprehensive income:
Net income	5,038,000		5,038,000
Reclassification of tax effects from AOCI	0		844,000	(844,000)
Change in unrealized gains on investment securities available-for-sale, net	(6,414,000)			(6,414,000)
Change in unrealized gains (losses) on cash flow hedges	(1,410,000)			(1,410,000)
Comprehensive income (loss)	$ (2,786,000)
Net forfeitures of restricted stock (in shares)	0	(2,023)
Issuance of common stock for option exercises (in shares)	25,376	22,481
Issuance of common stock for option exercises	$ 325,000	$ 325,000
Issuance of common stock for long-term incentive plan (in shares)		38,841
Issuance of common stock for long-term incentive plan	687,000	$ 687,000
Restricted stock activity	349,000	349,000
Stock-based compensation	$ 58,000	$ 58,000
Ending balance (in shares) at Mar. 31, 2018	25,772,208	25,772,208
Accumulated other comprehensive income (loss) end of period at Mar. 31, 2018	$ 307,059,000	$ 300,893,000	18,693,000	$ (12,527,000)
Comprehensive income:
Change in accounting principle - Revenue Recognition | Accounting Standards Update 2014-09	$ 1,000		$ 1,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES
Net income	$ 5,038	$ 3,230
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	772	634
Depreciation, amortization, and accretion	1,078	1,428
Amortization of restricted stock compensation	349	229
Stock option compensation	58	142
Loss on disposition of premises and equipment, net	44	0
Net write downs and losses (gains) on sales of other real estate owned	279	(78)
Net increase in cash value of bank owned life insurance	(347)	(356)
Origination of servicing assets	(371)	(267)
Proceeds from sales of SBA loans	19,337	11,698
Net gains on sale of SBA loans	(1,113)	(762)
Changes in operating assets and liabilities -
Net change in loans held for sale	652	5,978
Net (increase) decrease in other assets	(98)	3,774
Net decrease in accrued expenses and other liabilities	(4,234)	(4,202)
Net cash provided by operating activities	21,444	21,448
Activity in securities available-for-sale:
Prepayments	11,622	10,804
Maturities and calls	65	1,000
Purchases	(30,560)	(121,427)
Net change in loans held for investment	(44,037)	67,244
(Purchases) proceeds of Federal Home Loan Bank stock, net	(6,097)	(4,631)
Proceeds from sales of other real estate	9	216
(Purchases) of premises and equipment, net	(3,834)	(703)
Net cash (used in) investing activities	(72,832)	(47,497)
FINANCING ACTIVITIES
Net change in deposits	(354,365)	(34,541)
Net change in short-term borrowings	47,855	0
Proceeds from Federal Home Loan Bank advances	430,000	474,000
Repayments of Federal Home Loan Bank advances	(290,000)	(367,000)
Proceeds from exercise of stock options	325	2,281
Net cash (used in) provided by financing activities	(166,185)	74,740
NET CHANGE IN CASH AND CASH EQUIVALENTS	(217,573)	48,691
CASH AND CASH EQUIVALENTS – beginning of period	330,014	165,725
CASH AND CASH EQUIVALENTS – end of period	112,441	214,416
SUPPLEMENTAL SCHEDULE OF CASH FLOWS
Interest paid	3,715	4,028
Income taxes paid	$ 0	$ 110

Accounting Policies and Basis o

Accounting Policies and Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Accounting Policies and Basis of Presentation	ACCOUNTING POLICIES AND BASIS OF PRESENTATION Basis of Presentation The accounting and financial reporting policies of Atlantic Capital Bancshares, Inc. (“Atlantic Capital” or the “Company”) and its subsidiary, Atlantic Capital Bank, N.A. (the “Bank”), conform to accounting principles generally accepted in the United States of America (“GAAP”) and general banking industry practices. The accompanying interim consolidated financial statements have not been audited. All material intercompany balances and transactions have been eliminated. In management’s opinion, all accounting adjustments necessary to accurately reflect the financial position and results of operations on the accompanying financial statements have been made. These adjustments are normal and recurring accruals considered necessary for a fair and accurate presentation. The accompanying consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in Atlantic Capital’s filing on Form 10-K. The results for interim periods are not necessarily indicative of results for the full year or any other interim periods. Certain prior period amounts have been reclassified to conform to the current year presentation.

Accounting Standards Updates an

Accounting Standards Updates and Recently Adopted Standards	3 Months Ended
	Mar. 31, 2018
Accounting Changes and Error Corrections [Abstract]
Accounting Standards Updates and Recently Adopted Standards	ACCOUNTING STANDARDS UPDATES AND RECENTLY ADOPTED STANDARDS In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The guidance gives entities the option to reclassify into retained earnings tax effects related to items in accumulated other comprehensive income (“OCI”) that were stranded in accumulated OCI as a result of tax reform. It is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption in any period is permitted and Atlantic Capital adopted ASU 2018-02 as of January 1, 2018. The adoption of this update resulted in a reclassification of approximately $844,000 between accumulated OCI and retained earnings, and a net impact of zero to total shareholders’ equity. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities.” The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. Atlantic Capital adopted ASU 2017-12 as of January 1, 2018. The guidance requires a modified retrospective transition method resulting in the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. Adoption did not have a material impact on Atlantic Capital’s consolidated financial statements. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation (Topic 718): Scope and Modification Accounting.” The amendments in this ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in accordance with Topic 718. The amendments were effective for interim and annual reporting periods beginning after December 15, 2017. This ASU did not have a material impact on Atlantic Capital’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” to address diversity in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The amendments provide guidance on the following eight specific cash flow issues: 1) debt prepayment or debt extinguishment costs; 2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; 3) contingent consideration payments made after a business combination; 4) proceeds from the settlement of insurance claims; 5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; 6) distributions received from equity method investees; 7) beneficial interests in securitization transactions; and 8) separately identifiable cash flows and application of the predominance principle. The amendments were effective for public companies for fiscal years beginning after December 31, 2017, and interim periods within those fiscal years. This ASU did not have a material impact on the Company’s consolidated financial statements. In January 2016, the FASB issued ASU 2016-1, “Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Liabilities.” The guidance in this update requires that equity investments (except those accounted for under the equity method of accounting) be measured at fair value with changes in fair value recognized in net income. However, an entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. The guidance also simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment. In addition, the guidance requires that public business entities base their fair value disclosures for financial instruments that are not measured at fair value in the financial statements on the exit price notion. For public entities, this update was effective for fiscal years beginning after December 15, 2017. The adoption of this update did not have a material impact on Atlantic Capital’s consolidated financial statements, however Atlantic Capital changed the disclosure of financial instruments not measured at fair value to reflect the exit price notion. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. For public companies, this guidance was effective for annual and interim periods beginning after December 15, 2017. Atlantic Capital completed its review of the impact of ASU 2014-09 on components of non-interest income and did not find any significant changes to its methodology of recognizing revenue. Revenue streams impacted by the ASU included service charges, trust income, sales of financed other real estate, and check printing revenue. The Company recorded a cumulative effect adjustment to first quarter 2018 opening retained earnings in an amount less than $2,000 , and included newly applicable revenue disclosures. In March 2017, the FASB issued ASU 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” This guidance shortens the premium amortization period for certain callable debt securities by requiring amortization to the earliest call date. The standard is effective for public companies for annual and interim periods beginning after December 15, 2020. The adoption of this update is not expected to have a material impact on Atlantic Capital’s consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” which intends to simplify goodwill impairment testing by eliminating the second step of the analysis under which the implied fair value of goodwill is determined as if the reporting unit were being acquired in a business combination. The update instead requires entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit’s fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. ASU 2017-04 must be applied prospectively and is effective for the Company on January 1, 2020. Early adoption is permitted. Atlantic Capital does not expect the new guidance to have a material impact on its financial condition or results of operations. In June 2016, the FASB issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires an entity to utilize a new impairment model known as the current expected credit loss (“CECL”) model to estimate its lifetime “expected credit loss” and record an allowance that, when deducted from the amortized cost basis of the financial asset, presents the net amount expected to be collected on the financial asset. The CECL model is expected to result in more timely recognition of credit losses. ASU 2016-13 also requires new disclosures for financial assets measured at amortized cost, loans and available-for-sale debt securities. ASU 2016-13 is effective for public companies for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. Atlantic Capital is in the process of evaluating the impact of the adoption of ASU 2016-13 on the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-2, “Leases.” Under the new guidance, leases classified as operating leases under previous GAAP must be recorded on the balance sheet. A lessee should recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. The standard is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Upon adoption, Atlantic Capital expects to report higher assets and liabilities as a result of including leases on the consolidated balance sheet. The Company does not expect the new guidance to have a material impact on the consolidated statement of income or the consolidated statement of shareholders’ equity.

Acquisitions and Divestitures

Acquisitions and Divestitures	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Acquisitions and Divestitures	ACQUISITIONS AND DIVESTITURES Sale of Southeastern Trust Company (“SETCO”) On December 14, 2017, the Bank entered into an agreement with The Banc Group, LLC to sell its trust business, a division of the Bank known as Southeastern Trust Company (“SETCO”), for approximately $1.7 million . The Banc Group, LLC is controlled by a former director and Chief Operating Officer of the Company. Subject to customary closing conditions, including the receipt of all regulatory approvals, the sale of SETCO is expected to close during the second quarter of 2018.

Balance Sheet Offsetting

Balance Sheet Offsetting	3 Months Ended
	Mar. 31, 2018
Offsetting [Abstract]
Balance Sheet Offsetting	BALANCE SHEET OFFSETTING Atlantic Capital enters into reverse repurchase agreements in order to invest short-term funds. Atlantic Capital enters into repurchase agreements for short-term financing needs. The following table presents a summary of amounts outstanding under reverse repurchase agreements, repurchase agreements, and derivative financial instruments including those entered into in connection with the same counterparty under master netting agreements as of March 31, 2018 and December 31, 2017 . While these agreements are typically over-collateralized, U.S. GAAP requires disclosures in this table to limit the amount of such collateral to the amount of the related recognized asset or liability for each counterparty. (in thousands) Gross Amounts not Offset in the Balance Sheet March 31, 2018 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 9,669 $ — $ 9,669 $ (9,669 ) $ — $ — Derivatives 2,614 — 2,614 — — 2,614 Total $ 12,283 $ — $ 12,283 $ (9,669 ) $ — $ 2,614 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ 7,855 $ — $ 7,855 $ (11,532 ) $ — $ — Derivatives 5,360 — 5,360 (4,039 ) (1,321 ) — Total $ 13,215 $ — $ 13,215 $ (15,571 ) $ (1,321 ) $ — Gross Amounts not Offset in the Balance Sheet December 31, 2017 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 10,681 $ — $ 10,681 $ (10,681 ) $ — $ — Derivatives 3,018 — 3,018 — — 3,018 Total $ 13,699 $ — $ 13,699 $ (10,681 ) $ — $ 3,018 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ — $ — $ — $ — $ — $ — Derivatives 4,023 — 4,023 (2,705 ) (1,318 ) — Total $ 4,023 $ — $ 4,023 $ (2,705 ) $ (1,318 ) $ —

Securities

Securities	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	SECURITIES The following table presents the amortized cost, unrealized gains and losses, and fair value of securities available-for-sale at March 31, 2018 and December 31, 2017 . Available-For-Sale Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) March 31, 2018 Debt securities— U.S. Government agencies $ 37,364 $ 2 $ (834 ) $ 36,532 U.S. states and political divisions 92,005 18 (6,210 ) 85,813 Trust preferred securities 4,761 — (111 ) 4,650 Corporate debt securities 12,925 — (468 ) 12,457 Residential mortgage-backed securities 325,809 2,414 (8,945 ) 319,278 Total $ 472,864 $ 2,434 $ (16,568 ) $ 458,730 December 31, 2017 Debt securities— U.S. Government agencies $ 34,699 $ 11 $ (599 ) $ 34,111 U.S. states and political divisions 92,169 237 (2,405 ) 90,001 Trust preferred securities 4,754 — (104 ) 4,650 Corporate debt securities 12,948 60 (386 ) 12,622 Residential mortgage-backed securities 310,129 2,423 (4,819 ) 307,733 Total $ 454,699 $ 2,731 $ (8,313 ) $ 449,117 The following table presents the amortized cost and fair value of debt securities by contractual maturity at March 31, 2018 . Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Available-For-Sale Amortized Cost Fair Value (in thousands) Within 1 year $ — $ — Over 1 year through 5 years 23,099 22,605 5 years to 10 years 52,910 51,238 Over 10 years 71,046 65,609 147,055 139,452 Residential mortgage-backed securities 325,809 319,278 Total $ 472,864 $ 458,730 The following table summarizes available-for-sale securities in an unrealized loss position as of March 31, 2018 and December 31, 2017 . Less than 12 months 12 months or greater Totals Available-For-Sale Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) March 31, 2018 U.S. Government agencies $ 25,903 $ (499 ) $ 8,848 $ (335 ) $ 34,751 $ (834 ) U.S. states and political divisions 28,017 (1,017 ) 54,396 (5,193 ) 82,413 (6,210 ) Trust preferred securities — — 4,650 (111 ) 4,650 (111 ) Corporate debt securities 9,464 (147 ) 2,993 (321 ) 12,457 (468 ) Residential mortgage-backed securities 183,751 (3,844 ) 118,906 (5,101 ) 302,657 (8,945 ) Totals $ 247,135 $ (5,507 ) $ 189,793 $ (11,061 ) $ 436,928 $ (16,568 ) December 31, 2017 U.S. Government agencies $ 22,148 $ (348 ) $ 9,145 $ (251 ) $ 31,293 $ (599 ) U.S. states and political divisions 14,009 (183 ) 58,744 (2,222 ) 72,753 (2,405 ) Trust preferred securities — — 4,650 (104 ) 4,650 (104 ) Corporate debt securities 2,989 (27 ) 2,970 (359 ) 5,959 (386 ) Residential mortgage-backed securities 155,637 (1,344 ) 126,580 (3,475 ) 282,217 (4,819 ) Totals $ 194,783 $ (1,902 ) $ 202,089 $ (6,411 ) $ 396,872 $ (8,313 ) At March 31, 2018 , there were 318 available-for-sale securities that were in an unrealized loss position. Atlantic Capital does not intend to sell and does not believe it will be required to sell securities in an unrealized loss position prior to the recovery of their amortized cost basis. Unrealized losses at March 31, 2018 and December 31, 2017 were attributable to changes in interest rates. Management evaluates securities for other-than-temporary impairment on a quarterly basis. Consideration is given to the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, among other factors. In analyzing an issuer’s financial condition, management considers whether the securities are issued by the federal government or its agencies, whether downgrades by bond rating agencies have occurred, and industry analysts’ reports. No impairment charges were recognized during the three months ended March 31, 2018 or 2017 . Realized gains and losses are derived using the specific identification method for determining the cost of securities sold. No securities were sold during the three months ended March 31, 2018 and 2017 . Investment securities with a carrying value of $79.9 million and $93.9 million were pledged to secure public funds and other borrowings at March 31, 2018 and December 31, 2017 , respectively.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2018
Loans and Leases Receivable Disclosure [Abstract]
Loans and Allowance for Loan Losses	LOANS AND ALLOWANCE FOR LOAN LOSSES The composition of the loan portfolio as of March 31, 2018 and December 31, 2017 , is summarized below. March 31, December 31, (in thousands) Loans held for sale Other loans held for sale $ 835 $ 1,487 Total loans held for sale $ 835 $ 1,487 Loans held for investment Commercial loans: Commercial and industrial $ 636,181 $ 615,359 Commercial real estate 914,100 940,415 Construction and land 145,904 115,495 Mortgage warehouse participations 44,575 39,981 Total commercial loans 1,740,760 1,711,250 Residential: Residential mortgages 105,255 104,484 Home equity 70,712 76,244 Total residential loans 175,967 180,728 Consumer 30,966 29,393 Other 15,181 16,278 Total loans 1,962,874 1,937,649 Less net deferred fees and other unearned income (3,453 ) (3,810 ) Less allowance for loan losses (19,885 ) (19,344 ) Loans held for investment, net $ 1,939,536 $ 1,914,495 At March 31, 2018 and December 31, 2017 , loans with a carrying value of $717.3 million and $667.2 million , respectively, were pledged as collateral to secure FHLB advances and the Federal Reserve discount window. At March 31, 2018 , the carrying value and outstanding balance of Purchased Credit Impaired (“PCI”) loans accounted for under ASC 310-30 was $11.8 million and $14.0 million , respectively. At December 31, 2017 , the carrying value and outstanding balance of PCI loans accounted for under ASC 310-30 was $11.8 million and $14.1 million , respectively. The following table presents changes in the value of the accretable yield for acquired loans accounted for under ASC 310-30. For the Three Months Ended March 31, 2018 March 31, 2017 (in thousands) Balance at beginning of period $ 2,316 $ 3,467 Accretion (298 ) (444 ) Reclassification of nonaccretable discount due to change in expected cash flows 96 251 Other changes, net 295 95 Balance at end of period $ 2,409 $ 3,369 In addition to the accretable yield on PCI loans, the fair value adjustments on purchased loans outside the scope of ASC 310-30 are also accreted to interest income over the life of the loans. At March 31, 2018 , the remaining accretable fair value discount on loans acquired through a business combination and not accounted for under ASC 310-30 was $2.5 million compared to $2.8 million at December 31, 2017 . The allowance for loan losses represents management’s estimate of probable incurred losses in the loan portfolio as of the end of the period. It is comprised of specific reserves for impaired loans and a general allowance for pools of loans with similar characteristics not individually evaluated. The allowance is regularly evaluated for loan losses to maintain an adequate level to absorb probable current inherent losses in the loan portfolio. Factors contributing to the determination of the allowance include the credit worthiness of the borrower, changes in the value of pledged collateral, and general economic conditions. Most loan commitments rated substandard or worse are specifically reviewed for loss potential. For loans deemed to be impaired, a specific allocation is assigned based on the losses expected to be realized from those loans. The following table presents the balance and activity in the allowance for credit losses by portfolio segment for the three months ended March 31, 2018 and 2017 . 2018 2017 Three Months Ended March 31, Commercial Residential Consumer Total Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Beginning balance $ 18,267 $ 802 $ 275 $ 19,344 $ 18,717 $ 1,418 $ 460 $ 20,595 Provision for loan losses 637 154 (19 ) 772 297 34 303 634 Loans charged-off (126 ) (128 ) (3 ) (257 ) (913 ) (46 ) (332 ) (1,291 ) Recoveries 19 — 7 26 — — 1 1 Total ending allowance balance $ 18,797 $ 828 $ 260 $ 19,885 $ 18,101 $ 1,406 $ 432 $ 19,939 The general component of the allowance for loan losses is based on the incurred losses inherent in the portfolio. The loss factors are determined through the generation of probabilities of default (“PDs”) and losses given default (“LGDs”) for groups of similar loans with similar credit grades where Loss Rate = PD x LGD. The PDs and LGDs for the loan portfolio are calculated based on Atlantic Capital’s loss history as well as available market-based data. The loss factor for each pool of loans is adjusted based on qualitative and environmental factors to account for conditions in the current environment which management believes are likely to cause a difference between the calculated loss based on historical performance and the incurred loss in the existing portfolio. These factors include: changes in policies and procedures, changes in the economy, changes in nature or volume of the portfolio and in the terms of loans, changes in lending management, changes in past dues and credit migration, changes in the loan review system, changes in the value of collateral and concentration risk and changes in external factors, such as competition, legal and regulatory. Quarterly, management evaluates these factors to determine an adjustment unique to Atlantic Capital and its market. Charge-offs are recognized when the amount of the loss is quantifiable and timing is known. Collateral based loan charge-offs are measured based on the difference between the loan’s carrying value, including deferred fees, and the estimated net realizable value of the loan. When assessing property value for the purpose of determining a charge-off, a third-party appraisal or an independently derived internal evaluation is generally employed. A loan is considered to be impaired when, based on current information and events, it is probable that all amounts due according to the contractual terms of the loan agreement will not be collected. Loans for which the terms have been modified or granted an economic concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings (“TDRs”) and classified as impaired. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. A specific allowance is established for individually evaluated impaired loans as needed. Reserves on impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or the observable market price, or the fair value of the underlying collateral of the loan if the loan is collateral dependent. Atlantic Capital’s policy is to place loans on nonaccrual status, when, in the opinion of management, the principal and interest on a loan is not likely to be repaid in accordance with the loan terms or when the loan becomes 90 days past due and is not both well secured and in the process of collection. When a loan is classified on nonaccrual status, interest previously accrued but not collected is reversed against current interest revenue. Principal and interest payments received on a nonaccrual loan are applied to reduce outstanding principal. PCI loans are considered past due or delinquent when the contractual principal or interest due in accordance with the terms of the loan agreement remains unpaid after the due date of the scheduled payment. Loans accounted for under ASC 310-30 were not classified as nonaccrual at March 31, 2018 or December 31, 2017 , as the carrying value of the respective loan or pool of loans’ cash flows were considered estimable and collection was probable. Therefore, interest revenue, through accretion of the difference between the carrying value of the loans and the expected cash flows (accretable yield), is being recognized on all acquired loans accounted for under ASC 310-30. The balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method is presented in the following table as of March 31, 2018 and December 31, 2017 . March 31, 2018 Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Ending allowance balance attributable to loans Individually evaluated for impairment $ 276 $ — $ — $ 276 Collectively evaluated for impairment 18,516 828 260 19,604 PCI 5 — — 5 Total ending allowance balance $ 18,797 $ 828 $ 260 $ 19,885 Loans: Loans individually evaluated for impairment $ 6,731 $ 183 $ — $ 6,914 Loans collectively evaluated for impairment 1,724,816 173,172 46,135 1,944,123 PCI 9,213 2,612 12 11,837 Total ending loans balance $ 1,740,760 $ 175,967 $ 46,147 $ 1,962,874 December 31, 2017 Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Ending allowance balance attributable to loans Individually evaluated for impairment $ 306 $ — $ — $ 306 Collectively evaluated for impairment 17,918 800 275 18,993 PCI 43 2 — 45 Total ending allowance balance $ 18,267 $ 802 $ 275 $ 19,344 Loans: Loans individually evaluated for impairment $ 6,886 $ 186 $ — $ 7,072 Loans collectively evaluated for impairment 1,694,948 178,204 45,671 1,918,823 PCI 9,416 2,338 — 11,754 Total ending loans balance $ 1,711,250 $ 180,728 $ 45,671 $ 1,937,649 The following table presents information on Atlantic Capital’s impaired loans for the three months ended March 31, 2018 and 2017 : For the Three Months Ended March 31, 2018 2017 Unpaid Principal Balance Recorded Investment Related Allowance Average Balance of Recorded Investment While Impaired Interest Income Recognized During Impairment Unpaid Principal Balance Recorded Investment Related Allowance Average Balance of Recorded Investment While Impaired Interest Income Recognized During Impairment (in thousands) Impaired loans with no related allowance recorded: Commercial and industrial $ 1,035 $ 972 $ — $ 973 $ 13 $ 1,132 $ 1,069 $ — $ 1,550 $ 17 Commercial real estate 1,755 1,592 — 1,592 — 2,388 2,226 — 2,303 — Construction and land — — — — — — — — — — Residential mortgages 228 183 — 184 — 244 198 — 225 — Home equity — — — — — 549 549 — 549 — Mortgage warehouse — — — — — — — — — — Consumer — — — — — — — — — — Total $ 3,018 $ 2,747 $ — $ 2,749 $ 13 $ 4,313 $ 4,042 $ — $ 4,627 $ 17 Impaired loans with an allowance recorded: Commercial and industrial $ 3,643 $ 3,643 $ 168 $ 3,691 $ 46 $ 8,316 $ 8,316 $ 2,077 $ 8,357 $ 108 Commercial real estate 524 524 108 544 6 750 750 159 753 7 Construction and land — — — — — — — — — — Residential mortgages — — — — — 147 147 4 147 — Home equity — — — — — — — — — — Mortgage warehouse — — — — — — — — — — Consumer — — — — — — — — — — Total $ 4,167 $ 4,167 $ 276 $ 4,235 $ 52 $ 9,213 $ 9,213 $ 2,240 $ 9,257 $ 115 Total impaired loans $ 7,185 $ 6,914 $ 276 $ 6,984 $ 65 $ 13,526 $ 13,255 $ 2,240 $ 13,884 $ 132 Atlantic Capital evaluates loans in accordance with ASC 310-40, Troubled Debt Restructurings by Creditors. TDRs are loans in which Atlantic Capital has modified the terms or granted an economic concession to a borrower who is experiencing financial difficulties. These modifications may include interest rate reductions, term extensions and other concessions intended to minimize losses. As of March 31, 2018 and December 31, 2017 , the Company had a recorded investment in TDRs of $5.2 million and $5.3 million , respectively. The Company had commitments to lend additional funds of $28,000 and $26,000 on loans modified as TDRs, as of March 31, 2018 and December 31, 2017 , respectively. The Company did not modify any new loans as a TDR during the three months ended March 31, 2018 or 2017 and there were no subsequent defaults on prior TDRs. Atlantic Capital individually rates loans based on internal credit risk ratings using numerous factors, including thorough analysis of historical and expected cash flows, consumer credit risk scores (FICO scores), rating agency information, LTV ratios, collateral, collection experience, and other internal metrics. Atlantic Capital uses a dual rating system. The likelihood of default of a credit transaction is graded in the Obligor Rating. The risk of loss given default is graded in the Facility Rating. The Obligor Rating is determined through credit analysis. Facility Ratings are used to describe the value to the Company that the collateral represents. Facility Ratings are based on the collateral package or market expectations regarding the value and liquidity of the collateral. Ratings are generally reviewed at least annually or more frequently if there is a material change in creditworthiness. Exceptions to this policy may include well collateralized term loans and loans to individuals with limited exposure or complexity. Atlantic Capital uses the following definitions for risk ratings: Pass: Loans that are analyzed individually as part of the above described process and that do not meet the criteria of special mention, substandard or doubtful. Special Mention: Loans classified as special mention have a potential weakness that requires management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution’s credit position at some future date. Substandard: Loans classified as substandard are inadequately protected by the current net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful: Loans classified as doubtful have all the weaknesses inherent in those classified as substandard, with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. As of March 31, 2018 and December 31, 2017 , and based on the most recent analysis performed, the risk category of loans by class of loans is as follows. Pass Special Mention Substandard Accruing Substandard Nonaccruing Doubtful Nonaccruing Total (in thousands) March 31, 2018 Commercial and industrial $ 593,133 $ 16,089 $ 21,656 $ 14 $ — $ 630,892 Commercial real estate 879,885 11,453 17,483 — 1,592 910,413 Construction and land 145,667 — — — — 145,667 Residential mortgages 100,871 1,063 746 322 315 103,317 Home equity 68,869 642 304 223 — 70,038 Mortgage warehouse 44,575 — — — — 44,575 Consumer/Other 45,895 — 240 — — 46,135 Total loans, excluding PCI loans $ 1,878,895 $ 29,247 $ 40,429 $ 559 $ 1,907 $ 1,951,037 Commercial and industrial $ — $ — $ 5,289 $ — $ — $ 5,289 Commercial real estate 3,130 188 256 — 113 3,687 Construction and land 222 6 9 — — 237 Residential mortgages 467 699 772 — — 1,938 Home equity 34 288 352 — — 674 Mortgage warehouse — — — — — — Consumer/Other — — 12 — — 12 Total PCI loans $ 3,853 $ 1,181 $ 6,690 $ — $ 113 $ 11,837 Pass Special Mention Substandard Accruing Substandard Nonaccruing Doubtful Total (in thousands) December 31, 2017 Commercial and industrial $ 572,942 $ 15,643 $ 21,332 $ 16 $ 2 $ 609,935 Commercial real estate 919,939 6,227 8,906 — 1,592 936,664 Construction and land 115,255 — — — — 115,255 Residential mortgages 100,342 1,075 753 398 321 102,889 Home equity 74,841 64 310 285 — 75,500 Mortgage warehouse 39,981 — — — — 39,981 Consumer/Other 45,422 57 192 — — 45,671 Total loans, excluding PCI loans $ 1,868,722 $ 23,066 $ 31,493 $ 699 $ 1,915 $ 1,925,895 Commercial and industrial $ — $ 3,881 $ 1,543 $ — $ — $ 5,424 Commercial real estate 3,151 212 276 — 112 3,751 Construction and land 222 7 11 — — 240 Residential mortgages 428 493 674 — — 1,595 Home equity 34 354 356 — — 744 Mortgage warehouse — — — — — — Consumer/Other — — — — — — Total PCI loans $ 3,835 $ 4,947 $ 2,860 $ — $ 112 $ 11,754 Atlantic Capital monitors loans by past due status. The following table presents the aging of the recorded investment in past due loans as of March 31, 2018 and December 31, 2017 by class of loans. As of March 31, 2018 Accruing Current Accruing 30-89 Days Past Due Accruing 90+ Days Past Due Nonaccruing PCI Loans Total (in thousands) Loans by Classification Commercial and industrial $ 627,685 $ 3,193 $ — $ 14 $ 5,289 $ 636,181 Commercial real estate 908,300 521 — 1,592 3,687 914,100 Construction and land 145,667 — — — 237 145,904 Residential mortgages 102,129 551 — 637 1,938 105,255 Home equity 69,775 5 35 223 674 70,712 Mortgage warehouse 44,575 — — — — 44,575 Consumer 45,900 235 — — 12 46,147 Total Loans $ 1,944,031 $ 4,505 $ 35 $ 2,466 $ 11,837 $ 1,962,874 As of December 31, 2017 Accruing Current Accruing 30-89 Days Past Due Accruing 90+ Days Past Due Nonaccruing PCI Loans Total (in thousands) Loans by Classification Commercial and industrial $ 606,677 $ 3,239 $ — $ 19 $ 5,424 $ 615,359 Commercial real estate 932,916 2,156 — 1,592 3,751 940,415 Construction and land 114,988 267 — — 240 115,495 Residential mortgages 100,402 1,470 298 719 1,595 104,484 Home equity 75,081 135 — 284 744 76,244 Mortgage warehouse 39,981 — — — — 39,981 Consumer 45,599 72 — — — 45,671 Total Loans $ 1,915,644 $ 7,339 $ 298 $ 2,614 $ 11,754 $ 1,937,649

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS The carrying amount of goodwill and other intangible assets as of March 31, 2018 and December 31, 2017 is summarized below: March 31, December 31, 2018 2017 (in thousands) Core deposit intangible $ 9,544 $ 9,544 Less: accumulated amortization (4,967 ) (4,624 ) Less: impairment related to divested branches (2,286 ) (2,286 ) Core deposit intangible, net 2,291 2,634 Servicing assets, net 3,435 3,240 Total other intangibles, net 5,726 5,874 Goodwill 21,759 21,759 Total goodwill and other intangible assets, net $ 27,485 $ 27,633 There were no goodwill impairment charges recorded in the three months ended March 31, 2018 and 2017 . The following table presents activity for goodwill and other intangible assets: For the Three Months Ended March 31, Goodwill Core Deposit Intangible Total (in thousands) 2018 Balance, beginning of period $ 21,759 $ 2,634 $ 24,393 Amortization — (343 ) (343 ) Balance, end of period $ 21,759 $ 2,291 $ 24,050 2017 Balance, beginning of period $ 21,759 $ 4,624 $ 26,383 Amortization — (470 ) (470 ) Balance, end of period $ 21,759 $ 4,154 $ 25,913

Servicing Assets

Servicing Assets	3 Months Ended
	Mar. 31, 2018
Transfers and Servicing [Abstract]
Servicing Assets	SERVICING ASSETS SBA Servicing Assets SBA servicing assets are initially recorded at fair value. Subsequently, Atlantic Capital accounts for SBA servicing assets using the amortization method and they are included in other assets. As of March 31, 2018 and December 31, 2017 , the balance of SBA loans sold and serviced by Atlantic Capital totaled $151.0 million and $135.8 million , respectively. Changes in the balance of servicing assets for the three months ended March 31, 2018 and 2017 are presented in the following table . Three months ended March 31, SBA Loan Servicing Assets 2018 2017 (in thousands) Beginning carrying value, net $ 2,635 $ 2,359 Additions 371 267 Amortization (134 ) (131 ) Impairment — — Ending carrying value $ 2,872 $ 2,495 At March 31, 2018 and December 31, 2017 , the sensitivity of the fair value of the SBA loan servicing assets to immediate changes in key economic assumptions are presented in the table below . Sensitivity of the SBA Servicing Assets March 31, 2018 December 31, 2017 (dollars in thousands) Fair value of retained servicing assets $ 3,114 $ 2,865 Weighted average life 5.96 years 6.22 years Prepayment speed: 9.45 % 8.64 % Decline in fair value due to a 10% adverse change $ (111 ) $ (103 ) Decline in fair value due to a 20% adverse change $ (199 ) $ (181 ) Weighted average discount rate 12.98 % 13.01 % Decline in fair value due to a 100 bps adverse change $ (103 ) $ (103 ) Decline in fair value due to a 200 bps adverse change $ (185 ) $ (180 ) The above sensitivities are hypothetical and should be used with caution. As the amounts indicate, changes in fair value based on valuation assumptions generally cannot be extrapolated because the relationship of the change in assumption to the change in fair value may not be linear. Also, the effect of a variation in a particular assumption on the fair value of the retained interest is calculated without changing any other assumption. In reality, changes in one factor may result in changes in another, which might magnify or counteract the sensitivities. TriNet Servicing Assets Changes in the balance of TriNet servicing assets for the three months ended March 31, 2018 and 2017 are presented in the following table. Three months ended March 31, TriNet Servicing Assets 2018 2017 (in thousands) Beginning carrying value, net $ 605 $ 825 Additions — — Amortization (42 ) (47 ) Impairment — — Ending carrying value $ 563 $ 778 At March 31, 2018 and December 31, 2017 , the sensitivity of the fair value of the TriNet servicing assets to immediate changes in key economic assumptions are presented in the table below . Sensitivity of the TriNet Servicing Assets March 31, 2018 December 31, 2017 (dollars in thousands) Fair value of retained servicing assets $ 652 $ 697 Weighted average life 7.35 years 7.37 years Prepayment speed: 5.00 % 5.00 % Decline in fair value due to a 10% adverse change $ (9 ) $ (10 ) Decline in fair value due to a 20% adverse change $ (18 ) $ (20 ) Weighted average discount rate 8.00 % 8.00 % Decline in fair value due to a 100 bps adverse change $ (17 ) $ (19 ) Decline in fair value due to a 200 bps adverse change $ (33 ) $ (37 ) The above sensitivities are hypothetical and should be used with caution. As the amounts indicate, changes in fair value based on valuation assumptions generally cannot be extrapolated because the relationship of the change in assumption to the change in fair value may not be linear. Also, the effect of a variation in a particular assumption on the fair value of the retained interest is calculated without changing any other assumption. In reality, changes in one factor may result in changes in another, which might magnify or counteract the sensitivities.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Other Comprehensive Income (Loss)	OTHER COMPREHENSIVE INCOME (LOSS) Other comprehensive income (loss) for Atlantic Capital consists of changes in net unrealized gains and losses on investment securities available-for-sale and derivatives. The following tables present a summary of the changes in accumulated other comprehensive income (loss) balances for the applicable periods. For the Three Months Ended March 31, 2018 Pre-Tax Amount Income Tax (Expense) Benefit After-Tax Amount (in thousands) Accumulated other comprehensive income (loss) beginning of period $ (6,274 ) $ 2,415 $ (3,859 ) Reclassification of tax effects from AOCI — (844 ) (844 ) Unrealized net gains (losses) on investment securities available-for-sale (8,551 ) 2,137 (6,414 ) Unrealized net gains (losses) on derivatives (1,880 ) 470 (1,410 ) Accumulated other comprehensive income (loss) end of period $ (16,705 ) $ 4,178 $ (12,527 ) For the Three Months Ended March 31, 2017 Pre-Tax Amount Income Tax (Expense) Benefit After-Tax Amount (in thousands) Accumulated other comprehensive income (loss) beginning of period $ (9,144 ) $ 3,519 $ (5,625 ) Unrealized net gains (losses) on investment securities available-for-sale 591 (227 ) 364 Unrealized net gains (losses) on derivatives (237 ) 91 (146 ) Accumulated other comprehensive income (loss) end of period $ (8,790 ) $ 3,383 $ (5,407 )

Earnings Per Common Share

Earnings Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	EARNINGS PER COMMON SHARE Basic earnings per share amounts are computed by dividing net income by the weighted average number of shares of common stock outstanding. Diluted earnings per share amounts are computed by dividing net income by the weighted average number of shares of common stock outstanding and the dilutive effects of the shares awarded under the stock option plan, based on the treasury stock method using an average fair market value of the stock during the respective periods. The following table represents the earnings per share calculations for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 (in thousands, except share and per share amounts) Net income available to common shareholders $ 5,038 $ 3,230 Weighted average shares outstanding Basic (1) 25,750,824 25,320,690 Effect of dilutive securities: Stock options and warrants 194,949 351,596 Diluted 25,945,773 25,672,286 Income per common share: Basic $ 0.20 $ 0.13 Diluted $ 0.19 $ 0.13 (1) Unvested restricted shares are participating securities and included in basic share calculations. Stock options outstanding of 432 at March 31, 2018 and 747 at March 31, 2017 have not been included in diluted earnings per share because to do so would have been anti-dilutive for the periods presented. These awards were considered anti-dilutive because the exercise price of the award was higher than the market value of the shares. The Amended and Restated Articles of Incorporation of Atlantic Capital, which were approved by the Board of Directors on March 24, 2015 and by Atlantic Capital’s shareholders on May 21, 2015, authorize Atlantic Capital to issue 110,000,000 shares of capital stock, of which 10,000,000 shares are designated as preferred stock, no par value per share, and 100,000,000 shares are designated as common stock, no par value per share. At March 31, 2018 , 25,772,208 shares of common stock were issued and outstanding. At December 31, 2017 , 25,712,909 shares of common stock were issued and outstanding. The primary source of funds available to Atlantic Capital is payments of dividends from the Bank. The Bank has not paid any dividends to Atlantic Capital in 2018 or 2017. Banking laws and other regulations limit the amount of dividends a bank subsidiary may pay without prior regulatory approval. Additionally, Atlantic Capital’s ability to pay dividends to its shareholders will depend on the ability of the Bank to pay dividends to Atlantic Capital. The Bank is subject to regulatory restrictions on the payment of cash dividends, which generally may be paid only from current earnings.

Derivatives and Hedging

Derivatives and Hedging	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging	DERIVATIVES AND HEDGING Risk Management Atlantic Capital’s objectives in using interest rate derivatives are to add stability to net interest revenue and to manage its exposure to interest rate movements. To accomplish these objectives, Atlantic Capital primarily uses interest rate swaps as part of its interest rate risk management strategy. Cash Flow Hedges At March 31, 2018 , Atlantic Capital’s interest rate swaps designated as cash flow hedges involve the payment of floating-rate amounts to a counterparty in exchange for receiving fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. At March 31, 2018 and December 31, 2017 , Atlantic Capital had interest rate swaps designated as cash flow hedges with aggregate notional amounts of $100.0 million , respectively. No hedge ineffectiveness gains or losses were recognized on active cash flow hedges for the three months ended March 31, 2018 and 2017 . The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. Atlantic Capital expects that approximately $83,000 will be reclassified as a decrease to loan interest income over the next twelve months related to these cash flow hedges. Customer Swaps Atlantic Capital also enters into derivative contracts, which consist of interest rate swaps, to facilitate the needs of customers desiring to manage interest rate risk. These swaps are not designated as accounting hedges under ASC 815, Derivatives and Hedging . To economically hedge the interest rate risk associated with offering this product, Atlantic Capital simultaneously enters into derivative contracts with third parties to offset the customer contracts, such that Atlantic Capital minimizes its net risk exposure resulting from such transactions. The derivative contracts are structured such that the notional amounts reduce over time to generally match the expected amortization of the underlying loans. These derivatives are not speculative and arise from a service provided to clients. Atlantic Capital’s derivative instruments are recorded at fair value in other assets and accrued interest receivable and other liabilities and accrued interest payable in the Consolidated Balance Sheets. The changes in the fair value of the derivative instruments are recognized in other noninterest income in the Consolidated Statements of Income. At March 31, 2018 and December 31, 2017 , Atlantic Capital had interest rate swaps related to this program with an aggregate notional amount of $129.9 million and $142.3 million , respectively. Atlantic Capital acquired a loan level hedging program, which First Security utilized to accommodate clients preferring a fixed rate loan. The loan documents include an addendum with a zero premium collar. The zero premium collar is a cap and a floor at the same interest rate, resulting in a fixed rate to the borrower. To hedge this embedded option, First Security entered into a dealer facing trade exactly mirroring the terms in the loan addendum. Counterparty Credit Risk As a result of its derivative contracts, Atlantic Capital is exposed to credit risk. Specifically approved counterparties and exposure limits are defined. Quarterly, the customer derivative contracts and related counterparties are evaluated for credit risk and an adjustment is made to the contract’s fair value. This adjustment is recognized in the Consolidated Statements of Income. Most derivative contracts with clients are secured by collateral. Additionally, in accordance with the interest rate agreements with derivatives dealers, Atlantic Capital may be required to post margin to these counterparties. At March 31, 2018 and December 31, 2017 , Atlantic Capital had minimum collateral posting thresholds with certain of its derivative counterparties and posted collateral of $8.3 million and $8.8 million , respectively, against its obligations under these agreements. Cash collateral related to derivative contracts is recorded in other assets in the Consolidated Balance Sheets. Atlantic Capital has master netting agreements with the derivatives dealers with which it does business, but reflects gross assets and liabilities on the Consolidated Balance Sheets. In conjunction with the FASB’s fair value measurement guidance, management made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting arrangements on a net basis. To accommodate clients, Atlantic Capital occasionally enters into credit risk participation agreements with counterparty banks to accept a portion of the credit risk related to interest rate swaps. This allows clients to execute an interest rate swap with one bank while allowing for distribution of the credit risk among participating members. Credit risk participation agreements arise when Atlantic Capital contracts with other financial institutions, as a guarantor, to share credit risk associated with certain interest rate swaps. These agreements provide for reimbursement of losses resulting from a third party default on the underlying swap. At March 31, 2018 and December 31, 2017 , Atlantic Capital had credit risk participation agreements with a notional amount of $14.1 million and $14.8 million , respectively. The following table reflects the estimated fair value positions of derivative contracts and credit risk participation agreements as of March 31, 2018 and December 31, 2017 : Derivatives designated as hedging instruments under ASC 815 (in thousands) March 31, 2018 December 31, 2017 Interest Rate Products Balance Sheet Location Notional Amount Fair Value Notional Amount Fair Value Cash flow hedge of LIBOR based loans Other liabilities $ 100,000 $ 2,739 $ 100,000 $ 887 Derivatives not designated as hedging instruments under ASC 815 (in thousands) March 31, 2018 December 31, 2017 Interest Rate Products Balance Sheet Location Notional Amount Fair Value Notional Amount Fair Value Customer swap positions Other assets $ 64,958 $ 1,065 $ 71,160 $ 946 Zero premium collar Other assets 94,189 1,549 94,953 2,072 $ 159,147 $ 2,614 $ 166,113 $ 3,018 Dealer offsets to customer swap positions Other liabilities $ 64,958 $ 1,061 $ 71,160 $ 975 Credit risk participation Other liabilities 14,058 2 14,807 4 Dealer offset to zero premium collar Other liabilities 94,189 1,558 94,953 2,157 $ 173,205 $ 2,621 $ 180,920 $ 3,136 The following table presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the Consolidated Statements of Income for the three months ended March 31, 2018 and 2017 . Derivatives not designated as hedging instruments under ASC 815 (in thousands) Location of Gain or (Loss) Recognized in Income on Derivative Amount of Gain or (Loss) Recognized in Income on Derivative Three Months Ended March 31, 2018 2017 Interest rate products Other income / (expense) $ 108 $ (51 ) Other contracts Other income / (expense) 3 — Total $ 111 $ (51 ) Fee income Other income / (expense) $ 3 $ — The following table reflects the impact to the Consolidated Statements of Income related to derivative contracts for the three months ended March 31, 2018 and 2017 : Derivatives in Cash Flow Hedging Relationships Three Months Ended March 31, (in thousands) Amount of Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion) Gain or (Loss) Reclassified from Accumulated OCI in Income (Effective Portion) 2018 2017 Location 2018 2017 Interest rate swaps $ (1,778 ) $ (100 ) Interest income $ 102 $ 137

Other Borrowings and Long Term

Other Borrowings and Long Term Debt	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Other Borrowings and Long Term Debt	OTHER BORROWINGS AND LONG TERM DEBT Federal Home Loan Bank borrowings as of March 31, 2018 and December 31, 2017 are as follows: March 31, 2018 December 31, 2017 Balance Interest Rate Balance Interest Rate (in thousands) (in thousands) FHLB short-term borrowings: FHLB short-term borrowings: Fixed rate advance maturing April 3, 2018 40,000 1.61 % Fixed rate advance maturing January 16, 2018 45,000 1.40 % Fixed rate advance maturing April 6, 2018 40,000 1.70 % Fixed rate advance maturing April 12, 2018 30,000 1.70 % Fixed rate advance maturing April 16, 2018 45,000 1.86 % Fixed rate advance maturing April 23, 2018 30,000 1.85 % Total $ 185,000 Total $ 45,000 On September 28, 2015, Atlantic Capital issued subordinated notes (the “Notes”) totaling $50.0 million in aggregate principal amount. The Notes are due September 30, 2025 and bear a fixed rate of interest of 6.25% per year until September 29, 2020. From September 30, 2020 to the maturity date, the interest rate will be a floating rate equal to the three-month LIBOR plus 468 basis points. The Notes were priced at 100% of their par value. The Notes qualify as Tier 2 regulatory capital. Subordinated debt is summarized as follows. March 31, 2018 December 31, 2017 (in thousands Floating rate 10 year capital securities, with interest paid semi-annually at an annual fixed rate of 6.25% until September 30, 2020 $ 50,000 $ 50,000 Principal amount of subordinated debt $ 50,000 $ 50,000 Less debt issuance costs 423 465 Subordinated debt, net $ 49,577 $ 49,535 All subordinated debt outstanding at March 31, 2018 matures after more than five years.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	SHARE-BASED COMPENSATION Atlantic Capital sponsors a stock incentive plan for the benefit of directors and employees. Under the 2015 Stock Incentive Plan, there were approximately 4,525,000 shares reserved for issuance to directors and employees. The Compensation Committee has the authority to grant the following: an incentive or nonqualified option; a restricted stock award (including a restricted stock award or a restricted unit award); a performance award (including a performance share award or a performance unit award); a phantom stock award; a dividend equivalent award; or any other award granted under the plan. As of March 31, 2018 , approximately 3,660,000 additional awards were available to be granted under the plan. Stock options are granted at a price which is no less than the fair market value of a share of Atlantic Capital common stock on the grant date. Stock options generally vest over three years and expire after ten years. As of March 31, 2018 and December 31, 2017 , no warrants were outstanding for the purchase of common stock. The Company estimates the fair value of its options and warrants awards using the Black-Scholes option pricing model. The risk-free rate for periods within the contractual life of the option and warrant is based on the U.S. Treasury yield curve in effect at the time of grant. There were no options or warrants granted during the three months ended March 31, 2017. The table below summarizes the assumptions used to calculate the fair value of options granted/modified during the three months ended March 31, 2018: 2018 Risk‑free interest rate 1.66 % Expected term in years 0.25 Expected stock price volatility 24.2 % Dividend yield — % The following table represents stock option activity for the three months ended March 31, 2018 : Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding, December 31, 2017 757,711 $ 12.66 Granted 15,000 14.64 Exercised (25,376 ) 12.80 Forfeited (15,000 ) 14.64 Expired (118 ) 482.97 Outstanding, March 31, 2018 732,217 $ 12.58 5.31 $ 4,127 Exercisable, March 31, 2018 645,522 $ 12.32 5.02 $ 3,813 Atlantic Capital recognized compensation expense relating to stock options of $58,000 and $142,000 for the three months ended March 31, 2018 and 2017, respectively. Using the Black-Scholes pricing model, the amount of compensation expense was determined based on the fair value of the options at the time of grant, multiplied by the number of options granted that were expected to vest, which was then amortized over the vesting period. The following table represents restricted stock activity for the three months ended March 31, 2018 : Shares Weighted Average Grant-Date Fair Value Outstanding, December 31, 2017 239,468 $ 15.69 Granted 19,882 12.61 Vested (8,769 ) 4.93 Forfeited (21,905 ) 15.94 Outstanding, March 31, 2018 228,676 $ 15.81 Compensation expense for restricted stock is based on the fair value of restricted stock awards at the time of grant, which is equal to the value of Atlantic Capital’s common stock on the date of grant. The value of restricted stock grants that are expected to vest is amortized into expense over the vesting period. For the three months ended March 31, 2018 and 2017, compensation expense of $401,000 and $229,000 , respectively, was recognized related to restricted stock awards. As of March 31, 2018 , there was $ 2.2 million of unrecognized compensation cost related to restricted stock awards granted under the plan. That cost is expected to be recognized over a weighted-average period of 2.83 years. During the three months ended March 31, 2018, the Company modified options for 15,000 shares and 6,869 restricted stock awards to two individuals. The modifications allowed for the immediate vesting of the awards upon termination of service. The total incremental cost resulting from the modifications was $111,000 for the three months ended March 31, 2018.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Atlantic Capital follows the guidance pursuant to ASC 820-10, Fair Value Measurements and Disclosures . This guidance defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. This issuance applies to reported balances that are required or permitted to be measured at fair value under existing accounting pronouncements; accordingly, the standard does not require any new fair value measurements of reported balances. Atlantic Capital measures its investment securities and interest rate derivative assets and liabilities at fair value on a recurring basis. Fair value is used on a nonrecurring basis either when assets are evaluated for impairment or for disclosure purposes. Atlantic Capital measures its servicing assets, goodwill, intangible assets, loans held for sale, impaired loans and other real estate owned at fair value on a nonrecurring basis if necessary. The guidance emphasizes that fair value is a market-based measurement, not an entity-specific measurement and defines fair value as the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, this guidance establishes a fair value hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within Levels 1 and 2 of the hierarchy) and the reporting entity’s own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy). Atlantic Capital applied the following fair value hierarchy: Level 1 – Assets or liabilities for which the identical item is traded on an active exchange, such as publicly-traded instruments or futures contracts. Level 2 – Assets or liabilities valued based on observable market data for similar instruments. Level 3 – Assets or liabilities for which significant valuation assumptions are not readily observable in the market, instruments valued based on the best available data, some of which is internally-developed, and risk premiums that a market participant would require. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement. There were no transfers between Level 1 and Level 2 or Level 2 and Level 3 during the three months ended March 31, 2018 and 2017. Atlantic Capital records investment securities available-for-sale at fair value on a recurring basis. Investment securities classified as available-for-sale are reported at fair value utilizing Level 2 inputs. For these securities, Atlantic Capital obtains fair value measurements from an independent pricing service. In estimating the fair values for investment securities, Atlantic Capital believes that independent third-party market prices are the best evidence of an exit price. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the Treasury Department yield curve, trade execution data, market consensus prepayment speeds, credit information and the securities’ terms and conditions, among other things. Derivative instruments are primarily transacted as over-the-counter trades and priced with observable market assumptions. Ongoing measurements include observable market assumptions with appropriate valuation adjustments for liquidity and for credit risk of counterparties and Atlantic Capital’s own credit. For these instruments, Atlantic Capital obtains fair value measurements from an independent pricing service. The fair value measurements consider factors such as the likelihood of default by Atlantic Capital and its counterparties, total exposure and remaining maturities in determining the appropriate fair value adjustments to record. Generally, the expected loss of each client counterparty is estimated using Atlantic Capital’s internal risk rating system. For financial institution counterparties that are rated by national rating agencies, those ratings are used in determining the credit risk. This approach used to estimate exposures to counterparties is also used by Atlantic Capital to estimate its own credit risk on derivative liability positions. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents the assets that were measured at fair value on a recurring basis by level within the fair value hierarchy as reported in the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 . Fair Value Measurements at March 31, 2018 Using: Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Securities available-for-sale— U.S. government agencies $ — $ 36,532 $ — $ 36,532 U.S. states and political subdivisions — 85,813 — 85,813 Trust preferred securities — 4,650 — 4,650 Corporate debt securities — 12,457 — 12,457 Mortgage-backed securities — 319,278 — 319,278 Total securities available-for-sale $ — $ 458,730 $ — $ 458,730 Interest rate derivative assets $ — $ 2,614 $ — $ 2,614 Interest rate derivative liabilities $ — $ 5,360 $ — $ 5,360 Fair Value Measurements at December 31, 2017 Using: Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Securities available-for-sale— U.S. government agencies $ — $ 34,111 $ — $ 34,111 U.S. states and political subdivisions — 90,001 — 90,001 Trust preferred securities — 4,650 — 4,650 Corporate debt securities — 12,622 — 12,622 Mortgage-backed securities — 307,733 — 307,733 Total securities available-for-sale $ — $ 449,117 $ — $ 449,117 Interest rate derivative assets $ — $ 3,018 $ — $ 3,018 Interest rate derivative liabilities $ — $ 4,023 $ — $ 4,023 For the three months ended March 31, 2018 and 2017 , there was not a change in the methods and significant assumptions used to estimate fair value. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis The following table presents the assets that were measured at fair value on a nonrecurring basis by level within the fair value hierarchy as reported in the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 . March 31, 2018 Level 1 Fair Value Measurement Level 2 Fair Value Measurement Level 3 Fair Value Measurement Total (in thousands) Impaired Loans $ — $ — $ 2,142 $ 2,142 December 31, 2017 Level 1 Fair Value Measurement Level 2 Fair Value Measurement Level 3 Fair Value Measurement Total (in thousands) Impaired Loans $ — $ — $ 2,199 $ 2,199 Level 3 loans consist of impaired loans which have been partially charged-off or have specific valuation allowances. The fair value of Level 3 assets is estimated based on the underlying collateral value. For loans which the cash proceeds from the sale of the underlying collateral is the expected source of repayment, the fair value of these loans was derived from internal estimates of the underlying collateral incorporating market data, including third party appraisals or evaluations, when available. Appraised values may be discounted based on management’s assessment of the level of inactivity in the real estate market and other markets for the underlying collateral, changes in market conditions from the time of the valuation, and other information that in management’s judgment may affect the value. Impaired loans are evaluated on at least a quarterly basis and adjusted accordingly. Assets and Liabilities Not Measured at Fair Value For financial instruments that have quoted market prices, those quotes are used to determine fair value. Financial instruments that have no defined maturity, have a remaining maturity of 180 days or less, or reprice frequently to a market rate, are assumed to have a fair value that approximates the reported book value, after taking into consideration any applicable credit risk. If no market quotes are available, financial instruments are valued by discounting the expected cash flows using an estimated current market interest rate for the financial instrument. For loans held for investment, fair value is measured using the exit price notion. For off-balance sheet derivative instruments, fair value is estimated as the amount that Atlantic Capital would receive or pay to terminate the contracts at the reporting date, taking into account the current unrealized gains or losses on open contracts. The short maturity of Atlantic Capital’s assets and liabilities results in having a significant number of financial instruments whose fair value equals or closely approximates carrying value. Such financial instruments are reported in the following balance sheet captions: cash and due from banks, interest-bearing deposits in other banks, other short-term investments, and FHLB stock. The fair value of securities available-for-sale equals the balance sheet value. Due to the short-term settlement of accrued interest receivable and payable, the carrying amount closely approximates fair value. Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect the premium or discount on any particular financial instrument that could result from the sale of Atlantic Capital’s entire holdings. Because no ready market exists for a significant portion of Atlantic Capital’s financial instruments, fair value estimates are based on many judgments. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates. Off-balance sheet financial instruments (commitments to extend credit and standby letters of credit) are generally short-term and at variable rates. Therefore, both the carrying amount and the estimated fair value associated with these instruments are immaterial. The following table presents the estimated fair values of Atlantic Capital’s financial instruments at March 31, 2018 and December 31, 2017 . Fair Value Measurements at March 31, 2018 Using: Carrying Value Quoted Prices in Active markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Financial assets Cash and due from banks $ 39,985 $ 39,985 $ — $ — Interest bearing deposits in banks 62,787 62,787 — — Other short-term investments 9,669 9,669 — — Total securities available-for-sale 458,730 — 458,730 — FHLB stock 10,485 — — 10,485 Federal Reserve Bank stock 9,792 — — 9,792 Loans held for investment, net 1,939,536 — — 1,893,372 Loans held for sale 835 — 835 — Derivative assets 2,614 — 2,614 — Financial liabilities Deposits $ 2,096,300 $ — $ 2,037,010 $ — Federal funds purchased and securities sold under agreements to repurchase 47,855 47,855 — — Subordinated debt 49,577 — 48,823 — FHLB advances 185,000 — 185,276 — Derivative financial instruments 5,360 — 5,360 — Fair Value Measurements at December 31, 2017 Using: Carrying Value Quoted Prices in Active markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Financial assets Cash and due from banks $ 38,086 $ 38,086 $ — $ — Interest-bearing deposits in other banks 281,247 281,247 — — Other short-term investments 10,681 10,681 — — Total securities available-for-sale 449,117 — 449,117 — FHLB stock 4,388 — — 4,388 Federal Reserve Bank stock 9,792 — — 9,792 Loans held for investment, net 1,914,495 — — 1,955,705 Loans held for sale 1,487 — 1,487 — Derivative assets 3,018 — 3,018 — Financial liabilities Deposits $ 2,450,665 $ — $ 2,411,810 $ — Subordinated debt 49,535 — 49,888 — FHLB advances 45,000 — 45,057 — Derivative financial instruments 4,023 — 4,023 —

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Atlantic Capital is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and letters of credit, most of which are standby letters of credit. These instruments involve, to varying degrees, elements of credit risk in excess of the amounts recognized in the Consolidated Balance Sheets. The contract amounts of these instruments reflect the extent of involvement Atlantic Capital has in particular classes of financial instruments. Standby letters of credit are written conditional commitments issued by Atlantic Capital to guarantee the performance of a customer to a third party. Those guarantees are primarily issued to support public and private borrowing arrangements. Most letters of credit expire in less than one year. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. Atlantic Capital’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit and standby letters of credit is represented by the contractual amount of those instruments. Atlantic Capital uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. Atlantic Capital’s maximum exposure to credit risk for unfunded loan commitments and standby letters of credit at March 31, 2018 and December 31, 2017 was as follows: March 31, December 31, (in thousands) Financial Instruments whose contract amount represents credit risk: Commitments to extend credit $ 688,312 $ 689,753 Standby letters of credit 13,560 10,958 $ 701,872 $ 700,711 Atlantic Capital, in the normal course of business, is subject to various pending and threatened lawsuits in which claims for monetary damages are asserted. Although it is not possible to predict the outcome of these lawsuits, or the range of any possible loss, management, after consultation with legal counsel, does not anticipate that the ultimate aggregate liability, if any, arising from these lawsuits will have a material adverse effect on Atlantic Capital’s financial position or results of operations.

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION On January 1, 2018, the Company adopted ASU No. 2014-09 “Revenue from Contracts with Customers” (Topic 606) and all subsequent ASUs that modified Topic 606. As stated in Note 2, Accounting Standards Updates and Recently Adopted Standards , the implementation of the new standard did not result in any significant changes to the Company’s methodology of recognizing revenue; as such, the Company recorded a cumulative effect adjustment to first quarter 2018 opening retained earnings in an amount less than $2,000 . Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with the Company’s historic accounting under Topic 605. Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with financial guarantees and derivatives are also not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as service charges on deposit accounts and trust and asset management income. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Substantially all of the Company’s revenue is generated from contracts with customers. Noninterest revenue streams within the scope of Topic 606 are discussed below. Service Charges on Deposit Accounts Service charges represent general service fees for monthly account maintenance and activity, or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when the performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed, such as a wire transfer or ATM withdrawal. Payment for such performance obligations are generally received at the time the performance obligations are satisfied. The following table presents service charges by type of service provided for the three months ended March 31, 2018 and 2017: For the three months ended March 31, 2018 2017 (in thousands) Deposit account analysis fees and charges $ 571 $ 499 ATM fees 290 407 NSF fees 193 248 Wire fees 90 91 Foreign Exchange Fees 38 84 Other 10 20 $ 1,192 $ 1,349 Trust and Asset Management Trust and asset management income is primarily comprised of fees earned from the management and administration of trusts and other customer assets. The Company’s 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. The Company’s performance obligation for these transactional-based services is generally satisfied, and related revenue recognized, at a point in time (i.e., as incurred). Payment is received shortly after services are rendered. The following table presents trust income by type of service provided for the three months ended March 31, 2018 and 2017: For the three months ended March 31, 2018 2017 (in thousands) Personal trust and agency accounts $ 313 $ 232 Employee benefit and retirement-related trust and agency accounts 60 52 Investment management and investment advisory agency accounts 107 88 Custody and safekeeping accounts 13 18 Other 25 17 $ 518 $ 407 Other Other noninterest income consists of other recurring revenue streams such as check printing income, safety deposit box rental fees, and other miscellaneous revenue streams. Check printing income is recognized ratably over the contract period as the Company satisfies its performance obligation to sell a specific number of check packages. Safe deposit box rental fees are charged to the customer annually and recognized upon receipt of payment. The Company determined that since rentals and renewals occur fairly consistently over time, revenue is recognized on a basis consistent with the duration of the performance obligation. 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. The Company’s noninterest 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 the Company satisfies its performance obligation and revenue is recognized. The Company 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, the Company did not have any significant contract balances.

Accounting Policies and Basis25

Accounting Policies and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accounting and financial reporting policies of Atlantic Capital Bancshares, Inc. (“Atlantic Capital” or the “Company”) and its subsidiary, Atlantic Capital Bank, N.A. (the “Bank”), conform to accounting principles generally accepted in the United States of America (“GAAP”) and general banking industry practices. The accompanying interim consolidated financial statements have not been audited. All material intercompany balances and transactions have been eliminated. In management’s opinion, all accounting adjustments necessary to accurately reflect the financial position and results of operations on the accompanying financial statements have been made. These adjustments are normal and recurring accruals considered necessary for a fair and accurate presentation. The accompanying consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in Atlantic Capital’s filing on Form 10-K. The results for interim periods are not necessarily indicative of results for the full year or any other interim periods. Certain prior period amounts have been reclassified to conform to the current year presentation.
Accounting Standards Updates and Recently Adopted Standards	In February 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The guidance gives entities the option to reclassify into retained earnings tax effects related to items in accumulated other comprehensive income (“OCI”) that were stranded in accumulated OCI as a result of tax reform. It is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption in any period is permitted and Atlantic Capital adopted ASU 2018-02 as of January 1, 2018. The adoption of this update resulted in a reclassification of approximately $844,000 between accumulated OCI and retained earnings, and a net impact of zero to total shareholders’ equity. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities.” The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. Atlantic Capital adopted ASU 2017-12 as of January 1, 2018. The guidance requires a modified retrospective transition method resulting in the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. Adoption did not have a material impact on Atlantic Capital’s consolidated financial statements. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation (Topic 718): Scope and Modification Accounting.” The amendments in this ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in accordance with Topic 718. The amendments were effective for interim and annual reporting periods beginning after December 15, 2017. This ASU did not have a material impact on Atlantic Capital’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” to address diversity in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The amendments provide guidance on the following eight specific cash flow issues: 1) debt prepayment or debt extinguishment costs; 2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing; 3) contingent consideration payments made after a business combination; 4) proceeds from the settlement of insurance claims; 5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies; 6) distributions received from equity method investees; 7) beneficial interests in securitization transactions; and 8) separately identifiable cash flows and application of the predominance principle. The amendments were effective for public companies for fiscal years beginning after December 31, 2017, and interim periods within those fiscal years. This ASU did not have a material impact on the Company’s consolidated financial statements. In January 2016, the FASB issued ASU 2016-1, “Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Liabilities.” The guidance in this update requires that equity investments (except those accounted for under the equity method of accounting) be measured at fair value with changes in fair value recognized in net income. However, an entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. The guidance also simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment. In addition, the guidance requires that public business entities base their fair value disclosures for financial instruments that are not measured at fair value in the financial statements on the exit price notion. For public entities, this update was effective for fiscal years beginning after December 15, 2017. The adoption of this update did not have a material impact on Atlantic Capital’s consolidated financial statements, however Atlantic Capital changed the disclosure of financial instruments not measured at fair value to reflect the exit price notion. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. For public companies, this guidance was effective for annual and interim periods beginning after December 15, 2017. Atlantic Capital completed its review of the impact of ASU 2014-09 on components of non-interest income and did not find any significant changes to its methodology of recognizing revenue. Revenue streams impacted by the ASU included service charges, trust income, sales of financed other real estate, and check printing revenue. The Company recorded a cumulative effect adjustment to first quarter 2018 opening retained earnings in an amount less than $2,000 , and included newly applicable revenue disclosures. In March 2017, the FASB issued ASU 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” This guidance shortens the premium amortization period for certain callable debt securities by requiring amortization to the earliest call date. The standard is effective for public companies for annual and interim periods beginning after December 15, 2020. The adoption of this update is not expected to have a material impact on Atlantic Capital’s consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” which intends to simplify goodwill impairment testing by eliminating the second step of the analysis under which the implied fair value of goodwill is determined as if the reporting unit were being acquired in a business combination. The update instead requires entities to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for any amount by which the carrying amount exceeds the reporting unit’s fair value, to the extent that the loss recognized does not exceed the amount of goodwill allocated to that reporting unit. ASU 2017-04 must be applied prospectively and is effective for the Company on January 1, 2020. Early adoption is permitted. Atlantic Capital does not expect the new guidance to have a material impact on its financial condition or results of operations. In June 2016, the FASB issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires an entity to utilize a new impairment model known as the current expected credit loss (“CECL”) model to estimate its lifetime “expected credit loss” and record an allowance that, when deducted from the amortized cost basis of the financial asset, presents the net amount expected to be collected on the financial asset. The CECL model is expected to result in more timely recognition of credit losses. ASU 2016-13 also requires new disclosures for financial assets measured at amortized cost, loans and available-for-sale debt securities. ASU 2016-13 is effective for public companies for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Entities will apply the standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. Atlantic Capital is in the process of evaluating the impact of the adoption of ASU 2016-13 on the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-2, “Leases.” Under the new guidance, leases classified as operating leases under previous GAAP must be recorded on the balance sheet. A lessee should recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. The standard is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted. The new standard must be adopted using a modified retrospective transition, and provides for certain practical expedients. Upon adoption, Atlantic Capital expects to report higher assets and liabilities as a result of including leases on the consolidated balance sheet. The Company does not expect the new guidance to have a material impact on the consolidated statement of income or the consolidated statement of shareholders’ equity.

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	3 Months Ended
	Mar. 31, 2018
Offsetting [Abstract]
Offsetting Assets	The following table presents a summary of amounts outstanding under reverse repurchase agreements, repurchase agreements, and derivative financial instruments including those entered into in connection with the same counterparty under master netting agreements as of March 31, 2018 and December 31, 2017 . While these agreements are typically over-collateralized, U.S. GAAP requires disclosures in this table to limit the amount of such collateral to the amount of the related recognized asset or liability for each counterparty. (in thousands) Gross Amounts not Offset in the Balance Sheet March 31, 2018 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 9,669 $ — $ 9,669 $ (9,669 ) $ — $ — Derivatives 2,614 — 2,614 — — 2,614 Total $ 12,283 $ — $ 12,283 $ (9,669 ) $ — $ 2,614 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ 7,855 $ — $ 7,855 $ (11,532 ) $ — $ — Derivatives 5,360 — 5,360 (4,039 ) (1,321 ) — Total $ 13,215 $ — $ 13,215 $ (15,571 ) $ (1,321 ) $ — Gross Amounts not Offset in the Balance Sheet December 31, 2017 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 10,681 $ — $ 10,681 $ (10,681 ) $ — $ — Derivatives 3,018 — 3,018 — — 3,018 Total $ 13,699 $ — $ 13,699 $ (10,681 ) $ — $ 3,018 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ — $ — $ — $ — $ — $ — Derivatives 4,023 — 4,023 (2,705 ) (1,318 ) — Total $ 4,023 $ — $ 4,023 $ (2,705 ) $ (1,318 ) $ —
Offsetting Liabilities	The following table presents a summary of amounts outstanding under reverse repurchase agreements, repurchase agreements, and derivative financial instruments including those entered into in connection with the same counterparty under master netting agreements as of March 31, 2018 and December 31, 2017 . While these agreements are typically over-collateralized, U.S. GAAP requires disclosures in this table to limit the amount of such collateral to the amount of the related recognized asset or liability for each counterparty. (in thousands) Gross Amounts not Offset in the Balance Sheet March 31, 2018 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 9,669 $ — $ 9,669 $ (9,669 ) $ — $ — Derivatives 2,614 — 2,614 — — 2,614 Total $ 12,283 $ — $ 12,283 $ (9,669 ) $ — $ 2,614 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ 7,855 $ — $ 7,855 $ (11,532 ) $ — $ — Derivatives 5,360 — 5,360 (4,039 ) (1,321 ) — Total $ 13,215 $ — $ 13,215 $ (15,571 ) $ (1,321 ) $ — Gross Amounts not Offset in the Balance Sheet December 31, 2017 Gross Amounts of Recognized Assets Gross Amounts Offset on the Balance Sheet Net Asset Balance Financial Instruments Cash Collateral Received Net Amount Reverse repurchase agreements $ 10,681 $ — $ 10,681 $ (10,681 ) $ — $ — Derivatives 3,018 — 3,018 — — 3,018 Total $ 13,699 $ — $ 13,699 $ (10,681 ) $ — $ 3,018 Gross Amounts not Offset in the Balance Sheet Gross Amounts of Recognized Liabilities Gross Amounts Offset on the Balance Sheet Net Liability Balance Financial Instruments Cash Collateral Pledged Net Amount Repurchase agreements $ — $ — $ — $ — $ — $ — Derivatives 4,023 — 4,023 (2,705 ) (1,318 ) — Total $ 4,023 $ — $ 4,023 $ (2,705 ) $ (1,318 ) $ —

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following table presents the amortized cost, unrealized gains and losses, and fair value of securities available-for-sale at March 31, 2018 and December 31, 2017 . Available-For-Sale Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) March 31, 2018 Debt securities— U.S. Government agencies $ 37,364 $ 2 $ (834 ) $ 36,532 U.S. states and political divisions 92,005 18 (6,210 ) 85,813 Trust preferred securities 4,761 — (111 ) 4,650 Corporate debt securities 12,925 — (468 ) 12,457 Residential mortgage-backed securities 325,809 2,414 (8,945 ) 319,278 Total $ 472,864 $ 2,434 $ (16,568 ) $ 458,730 December 31, 2017 Debt securities— U.S. Government agencies $ 34,699 $ 11 $ (599 ) $ 34,111 U.S. states and political divisions 92,169 237 (2,405 ) 90,001 Trust preferred securities 4,754 — (104 ) 4,650 Corporate debt securities 12,948 60 (386 ) 12,622 Residential mortgage-backed securities 310,129 2,423 (4,819 ) 307,733 Total $ 454,699 $ 2,731 $ (8,313 ) $ 449,117
Investments Classified by Contractual Maturity Date	The following table presents the amortized cost and fair value of debt securities by contractual maturity at March 31, 2018 . Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Available-For-Sale Amortized Cost Fair Value (in thousands) Within 1 year $ — $ — Over 1 year through 5 years 23,099 22,605 5 years to 10 years 52,910 51,238 Over 10 years 71,046 65,609 147,055 139,452 Residential mortgage-backed securities 325,809 319,278 Total $ 472,864 $ 458,730
Continuous Unrealized Loss Position, Fair Value	The following table summarizes available-for-sale securities in an unrealized loss position as of March 31, 2018 and December 31, 2017 . Less than 12 months 12 months or greater Totals Available-For-Sale Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) March 31, 2018 U.S. Government agencies $ 25,903 $ (499 ) $ 8,848 $ (335 ) $ 34,751 $ (834 ) U.S. states and political divisions 28,017 (1,017 ) 54,396 (5,193 ) 82,413 (6,210 ) Trust preferred securities — — 4,650 (111 ) 4,650 (111 ) Corporate debt securities 9,464 (147 ) 2,993 (321 ) 12,457 (468 ) Residential mortgage-backed securities 183,751 (3,844 ) 118,906 (5,101 ) 302,657 (8,945 ) Totals $ 247,135 $ (5,507 ) $ 189,793 $ (11,061 ) $ 436,928 $ (16,568 ) December 31, 2017 U.S. Government agencies $ 22,148 $ (348 ) $ 9,145 $ (251 ) $ 31,293 $ (599 ) U.S. states and political divisions 14,009 (183 ) 58,744 (2,222 ) 72,753 (2,405 ) Trust preferred securities — — 4,650 (104 ) 4,650 (104 ) Corporate debt securities 2,989 (27 ) 2,970 (359 ) 5,959 (386 ) Residential mortgage-backed securities 155,637 (1,344 ) 126,580 (3,475 ) 282,217 (4,819 ) Totals $ 194,783 $ (1,902 ) $ 202,089 $ (6,411 ) $ 396,872 $ (8,313 )

Loans and Allowance for Loan 28

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Loans and Leases Receivable Disclosure [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The composition of the loan portfolio as of March 31, 2018 and December 31, 2017 , is summarized below. March 31, December 31, (in thousands) Loans held for sale Other loans held for sale $ 835 $ 1,487 Total loans held for sale $ 835 $ 1,487 Loans held for investment Commercial loans: Commercial and industrial $ 636,181 $ 615,359 Commercial real estate 914,100 940,415 Construction and land 145,904 115,495 Mortgage warehouse participations 44,575 39,981 Total commercial loans 1,740,760 1,711,250 Residential: Residential mortgages 105,255 104,484 Home equity 70,712 76,244 Total residential loans 175,967 180,728 Consumer 30,966 29,393 Other 15,181 16,278 Total loans 1,962,874 1,937,649 Less net deferred fees and other unearned income (3,453 ) (3,810 ) Less allowance for loan losses (19,885 ) (19,344 ) Loans held for investment, net $ 1,939,536 $ 1,914,495
Schedule of Accretable Yield	The following table presents changes in the value of the accretable yield for acquired loans accounted for under ASC 310-30. For the Three Months Ended March 31, 2018 March 31, 2017 (in thousands) Balance at beginning of period $ 2,316 $ 3,467 Accretion (298 ) (444 ) Reclassification of nonaccretable discount due to change in expected cash flows 96 251 Other changes, net 295 95 Balance at end of period $ 2,409 $ 3,369
Schedule of Credit Losses Related to Financing Receivables, Current and Noncurrent	The following table presents the balance and activity in the allowance for credit losses by portfolio segment for the three months ended March 31, 2018 and 2017 . 2018 2017 Three Months Ended March 31, Commercial Residential Consumer Total Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Beginning balance $ 18,267 $ 802 $ 275 $ 19,344 $ 18,717 $ 1,418 $ 460 $ 20,595 Provision for loan losses 637 154 (19 ) 772 297 34 303 634 Loans charged-off (126 ) (128 ) (3 ) (257 ) (913 ) (46 ) (332 ) (1,291 ) Recoveries 19 — 7 26 — — 1 1 Total ending allowance balance $ 18,797 $ 828 $ 260 $ 19,885 $ 18,101 $ 1,406 $ 432 $ 19,939
Allowance for Credit Losses on Financing Receivables	The balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method is presented in the following table as of March 31, 2018 and December 31, 2017 . March 31, 2018 Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Ending allowance balance attributable to loans Individually evaluated for impairment $ 276 $ — $ — $ 276 Collectively evaluated for impairment 18,516 828 260 19,604 PCI 5 — — 5 Total ending allowance balance $ 18,797 $ 828 $ 260 $ 19,885 Loans: Loans individually evaluated for impairment $ 6,731 $ 183 $ — $ 6,914 Loans collectively evaluated for impairment 1,724,816 173,172 46,135 1,944,123 PCI 9,213 2,612 12 11,837 Total ending loans balance $ 1,740,760 $ 175,967 $ 46,147 $ 1,962,874 December 31, 2017 Commercial Residential Consumer Total (in thousands) Allowance for loan losses: Ending allowance balance attributable to loans Individually evaluated for impairment $ 306 $ — $ — $ 306 Collectively evaluated for impairment 17,918 800 275 18,993 PCI 43 2 — 45 Total ending allowance balance $ 18,267 $ 802 $ 275 $ 19,344 Loans: Loans individually evaluated for impairment $ 6,886 $ 186 $ — $ 7,072 Loans collectively evaluated for impairment 1,694,948 178,204 45,671 1,918,823 PCI 9,416 2,338 — 11,754 Total ending loans balance $ 1,711,250 $ 180,728 $ 45,671 $ 1,937,649
Impaired Financing Receivables	The following table presents information on Atlantic Capital’s impaired loans for the three months ended March 31, 2018 and 2017 : For the Three Months Ended March 31, 2018 2017 Unpaid Principal Balance Recorded Investment Related Allowance Average Balance of Recorded Investment While Impaired Interest Income Recognized During Impairment Unpaid Principal Balance Recorded Investment Related Allowance Average Balance of Recorded Investment While Impaired Interest Income Recognized During Impairment (in thousands) Impaired loans with no related allowance recorded: Commercial and industrial $ 1,035 $ 972 $ — $ 973 $ 13 $ 1,132 $ 1,069 $ — $ 1,550 $ 17 Commercial real estate 1,755 1,592 — 1,592 — 2,388 2,226 — 2,303 — Construction and land — — — — — — — — — — Residential mortgages 228 183 — 184 — 244 198 — 225 — Home equity — — — — — 549 549 — 549 — Mortgage warehouse — — — — — — — — — — Consumer — — — — — — — — — — Total $ 3,018 $ 2,747 $ — $ 2,749 $ 13 $ 4,313 $ 4,042 $ — $ 4,627 $ 17 Impaired loans with an allowance recorded: Commercial and industrial $ 3,643 $ 3,643 $ 168 $ 3,691 $ 46 $ 8,316 $ 8,316 $ 2,077 $ 8,357 $ 108 Commercial real estate 524 524 108 544 6 750 750 159 753 7 Construction and land — — — — — — — — — — Residential mortgages — — — — — 147 147 4 147 — Home equity — — — — — — — — — — Mortgage warehouse — — — — — — — — — — Consumer — — — — — — — — — — Total $ 4,167 $ 4,167 $ 276 $ 4,235 $ 52 $ 9,213 $ 9,213 $ 2,240 $ 9,257 $ 115 Total impaired loans $ 7,185 $ 6,914 $ 276 $ 6,984 $ 65 $ 13,526 $ 13,255 $ 2,240 $ 13,884 $ 132
Troubled Debt Restructurings on Financing Receivables	As of March 31, 2018 and December 31, 2017 , and based on the most recent analysis performed, the risk category of loans by class of loans is as follows. Pass Special Mention Substandard Accruing Substandard Nonaccruing Doubtful Nonaccruing Total (in thousands) March 31, 2018 Commercial and industrial $ 593,133 $ 16,089 $ 21,656 $ 14 $ — $ 630,892 Commercial real estate 879,885 11,453 17,483 — 1,592 910,413 Construction and land 145,667 — — — — 145,667 Residential mortgages 100,871 1,063 746 322 315 103,317 Home equity 68,869 642 304 223 — 70,038 Mortgage warehouse 44,575 — — — — 44,575 Consumer/Other 45,895 — 240 — — 46,135 Total loans, excluding PCI loans $ 1,878,895 $ 29,247 $ 40,429 $ 559 $ 1,907 $ 1,951,037 Commercial and industrial $ — $ — $ 5,289 $ — $ — $ 5,289 Commercial real estate 3,130 188 256 — 113 3,687 Construction and land 222 6 9 — — 237 Residential mortgages 467 699 772 — — 1,938 Home equity 34 288 352 — — 674 Mortgage warehouse — — — — — — Consumer/Other — — 12 — — 12 Total PCI loans $ 3,853 $ 1,181 $ 6,690 $ — $ 113 $ 11,837 Pass Special Mention Substandard Accruing Substandard Nonaccruing Doubtful Total (in thousands) December 31, 2017 Commercial and industrial $ 572,942 $ 15,643 $ 21,332 $ 16 $ 2 $ 609,935 Commercial real estate 919,939 6,227 8,906 — 1,592 936,664 Construction and land 115,255 — — — — 115,255 Residential mortgages 100,342 1,075 753 398 321 102,889 Home equity 74,841 64 310 285 — 75,500 Mortgage warehouse 39,981 — — — — 39,981 Consumer/Other 45,422 57 192 — — 45,671 Total loans, excluding PCI loans $ 1,868,722 $ 23,066 $ 31,493 $ 699 $ 1,915 $ 1,925,895 Commercial and industrial $ — $ 3,881 $ 1,543 $ — $ — $ 5,424 Commercial real estate 3,151 212 276 — 112 3,751 Construction and land 222 7 11 — — 240 Residential mortgages 428 493 674 — — 1,595 Home equity 34 354 356 — — 744 Mortgage warehouse — — — — — — Consumer/Other — — — — — — Total PCI loans $ 3,835 $ 4,947 $ 2,860 $ — $ 112 $ 11,754
Past Due Financing Receivables	The following table presents the aging of the recorded investment in past due loans as of March 31, 2018 and December 31, 2017 by class of loans. As of March 31, 2018 Accruing Current Accruing 30-89 Days Past Due Accruing 90+ Days Past Due Nonaccruing PCI Loans Total (in thousands) Loans by Classification Commercial and industrial $ 627,685 $ 3,193 $ — $ 14 $ 5,289 $ 636,181 Commercial real estate 908,300 521 — 1,592 3,687 914,100 Construction and land 145,667 — — — 237 145,904 Residential mortgages 102,129 551 — 637 1,938 105,255 Home equity 69,775 5 35 223 674 70,712 Mortgage warehouse 44,575 — — — — 44,575 Consumer 45,900 235 — — 12 46,147 Total Loans $ 1,944,031 $ 4,505 $ 35 $ 2,466 $ 11,837 $ 1,962,874 As of December 31, 2017 Accruing Current Accruing 30-89 Days Past Due Accruing 90+ Days Past Due Nonaccruing PCI Loans Total (in thousands) Loans by Classification Commercial and industrial $ 606,677 $ 3,239 $ — $ 19 $ 5,424 $ 615,359 Commercial real estate 932,916 2,156 — 1,592 3,751 940,415 Construction and land 114,988 267 — — 240 115,495 Residential mortgages 100,402 1,470 298 719 1,595 104,484 Home equity 75,081 135 — 284 744 76,244 Mortgage warehouse 39,981 — — — — 39,981 Consumer 45,599 72 — — — 45,671 Total Loans $ 1,915,644 $ 7,339 $ 298 $ 2,614 $ 11,754 $ 1,937,649

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Goodwill	The following table presents activity for goodwill and other intangible assets: For the Three Months Ended March 31, Goodwill Core Deposit Intangible Total (in thousands) 2018 Balance, beginning of period $ 21,759 $ 2,634 $ 24,393 Amortization — (343 ) (343 ) Balance, end of period $ 21,759 $ 2,291 $ 24,050 2017 Balance, beginning of period $ 21,759 $ 4,624 $ 26,383 Amortization — (470 ) (470 ) Balance, end of period $ 21,759 $ 4,154 $ 25,913 The carrying amount of goodwill and other intangible assets as of March 31, 2018 and December 31, 2017 is summarized below: March 31, December 31, 2018 2017 (in thousands) Core deposit intangible $ 9,544 $ 9,544 Less: accumulated amortization (4,967 ) (4,624 ) Less: impairment related to divested branches (2,286 ) (2,286 ) Core deposit intangible, net 2,291 2,634 Servicing assets, net 3,435 3,240 Total other intangibles, net 5,726 5,874 Goodwill 21,759 21,759 Total goodwill and other intangible assets, net $ 27,485 $ 27,633

Servicing Assets (Tables)

Servicing Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Transfers and Servicing [Abstract]
Changes in the Balance of Servicing Assets	Changes in the balance of servicing assets for the three months ended March 31, 2018 and 2017 are presented in the following table . Three months ended March 31, SBA Loan Servicing Assets 2018 2017 (in thousands) Beginning carrying value, net $ 2,635 $ 2,359 Additions 371 267 Amortization (134 ) (131 ) Impairment — — Ending carrying value $ 2,872 $ 2,495 Changes in the balance of TriNet servicing assets for the three months ended March 31, 2018 and 2017 are presented in the following table. Three months ended March 31, TriNet Servicing Assets 2018 2017 (in thousands) Beginning carrying value, net $ 605 $ 825 Additions — — Amortization (42 ) (47 ) Impairment — — Ending carrying value $ 563 $ 778
Schedule of Sensitivity to Immediate Changes in Key Economic Assumptions	At March 31, 2018 and December 31, 2017 , the sensitivity of the fair value of the SBA loan servicing assets to immediate changes in key economic assumptions are presented in the table below . Sensitivity of the SBA Servicing Assets March 31, 2018 December 31, 2017 (dollars in thousands) Fair value of retained servicing assets $ 3,114 $ 2,865 Weighted average life 5.96 years 6.22 years Prepayment speed: 9.45 % 8.64 % Decline in fair value due to a 10% adverse change $ (111 ) $ (103 ) Decline in fair value due to a 20% adverse change $ (199 ) $ (181 ) Weighted average discount rate 12.98 % 13.01 % Decline in fair value due to a 100 bps adverse change $ (103 ) $ (103 ) Decline in fair value due to a 200 bps adverse change $ (185 ) $ (180 ) At March 31, 2018 and December 31, 2017 , the sensitivity of the fair value of the TriNet servicing assets to immediate changes in key economic assumptions are presented in the table below . Sensitivity of the TriNet Servicing Assets March 31, 2018 December 31, 2017 (dollars in thousands) Fair value of retained servicing assets $ 652 $ 697 Weighted average life 7.35 years 7.37 years Prepayment speed: 5.00 % 5.00 % Decline in fair value due to a 10% adverse change $ (9 ) $ (10 ) Decline in fair value due to a 20% adverse change $ (18 ) $ (20 ) Weighted average discount rate 8.00 % 8.00 % Decline in fair value due to a 100 bps adverse change $ (17 ) $ (19 ) Decline in fair value due to a 200 bps adverse change $ (33 ) $ (37 )

Other Comprehensive Income (L31

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables present a summary of the changes in accumulated other comprehensive income (loss) balances for the applicable periods. For the Three Months Ended March 31, 2018 Pre-Tax Amount Income Tax (Expense) Benefit After-Tax Amount (in thousands) Accumulated other comprehensive income (loss) beginning of period $ (6,274 ) $ 2,415 $ (3,859 ) Reclassification of tax effects from AOCI — (844 ) (844 ) Unrealized net gains (losses) on investment securities available-for-sale (8,551 ) 2,137 (6,414 ) Unrealized net gains (losses) on derivatives (1,880 ) 470 (1,410 ) Accumulated other comprehensive income (loss) end of period $ (16,705 ) $ 4,178 $ (12,527 ) For the Three Months Ended March 31, 2017 Pre-Tax Amount Income Tax (Expense) Benefit After-Tax Amount (in thousands) Accumulated other comprehensive income (loss) beginning of period $ (9,144 ) $ 3,519 $ (5,625 ) Unrealized net gains (losses) on investment securities available-for-sale 591 (227 ) 364 Unrealized net gains (losses) on derivatives (237 ) 91 (146 ) Accumulated other comprehensive income (loss) end of period $ (8,790 ) $ 3,383 $ (5,407 )

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The following table represents the earnings per share calculations for the three months ended March 31, 2018 and 2017 . Three Months Ended March 31, 2018 2017 (in thousands, except share and per share amounts) Net income available to common shareholders $ 5,038 $ 3,230 Weighted average shares outstanding Basic (1) 25,750,824 25,320,690 Effect of dilutive securities: Stock options and warrants 194,949 351,596 Diluted 25,945,773 25,672,286 Income per common share: Basic $ 0.20 $ 0.13 Diluted $ 0.19 $ 0.13 (1) Unvested restricted shares are participating securities and included in basic share calculations.

Derivatives and Hedging (Tables

Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following table reflects the estimated fair value positions of derivative contracts and credit risk participation agreements as of March 31, 2018 and December 31, 2017 : Derivatives designated as hedging instruments under ASC 815 (in thousands) March 31, 2018 December 31, 2017 Interest Rate Products Balance Sheet Location Notional Amount Fair Value Notional Amount Fair Value Cash flow hedge of LIBOR based loans Other liabilities $ 100,000 $ 2,739 $ 100,000 $ 887 Derivatives not designated as hedging instruments under ASC 815 (in thousands) March 31, 2018 December 31, 2017 Interest Rate Products Balance Sheet Location Notional Amount Fair Value Notional Amount Fair Value Customer swap positions Other assets $ 64,958 $ 1,065 $ 71,160 $ 946 Zero premium collar Other assets 94,189 1,549 94,953 2,072 $ 159,147 $ 2,614 $ 166,113 $ 3,018 Dealer offsets to customer swap positions Other liabilities $ 64,958 $ 1,061 $ 71,160 $ 975 Credit risk participation Other liabilities 14,058 2 14,807 4 Dealer offset to zero premium collar Other liabilities 94,189 1,558 94,953 2,157 $ 173,205 $ 2,621 $ 180,920 $ 3,136 The following table presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the Consolidated Statements of Income for the three months ended March 31, 2018 and 2017 . Derivatives not designated as hedging instruments under ASC 815 (in thousands) Location of Gain or (Loss) Recognized in Income on Derivative Amount of Gain or (Loss) Recognized in Income on Derivative Three Months Ended March 31, 2018 2017 Interest rate products Other income / (expense) $ 108 $ (51 ) Other contracts Other income / (expense) 3 — Total $ 111 $ (51 ) Fee income Other income / (expense) $ 3 $ — The following table reflects the impact to the Consolidated Statements of Income related to derivative contracts for the three months ended March 31, 2018 and 2017 : Derivatives in Cash Flow Hedging Relationships Three Months Ended March 31, (in thousands) Amount of Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion) Gain or (Loss) Reclassified from Accumulated OCI in Income (Effective Portion) 2018 2017 Location 2018 2017 Interest rate swaps $ (1,778 ) $ (100 ) Interest income $ 102 $ 137

Other Borrowings and Long Ter34

Other Borrowings and Long Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments and Borrowings	Subordinated debt is summarized as follows. March 31, 2018 December 31, 2017 (in thousands Floating rate 10 year capital securities, with interest paid semi-annually at an annual fixed rate of 6.25% until September 30, 2020 $ 50,000 $ 50,000 Principal amount of subordinated debt $ 50,000 $ 50,000 Less debt issuance costs 423 465 Subordinated debt, net $ 49,577 $ 49,535 Federal Home Loan Bank borrowings as of March 31, 2018 and December 31, 2017 are as follows: March 31, 2018 December 31, 2017 Balance Interest Rate Balance Interest Rate (in thousands) (in thousands) FHLB short-term borrowings: FHLB short-term borrowings: Fixed rate advance maturing April 3, 2018 40,000 1.61 % Fixed rate advance maturing January 16, 2018 45,000 1.40 % Fixed rate advance maturing April 6, 2018 40,000 1.70 % Fixed rate advance maturing April 12, 2018 30,000 1.70 % Fixed rate advance maturing April 16, 2018 45,000 1.86 % Fixed rate advance maturing April 23, 2018 30,000 1.85 % Total $ 185,000 Total $ 45,000

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Fair Value of Options Assumptions	The table below summarizes the assumptions used to calculate the fair value of options granted/modified during the three months ended March 31, 2018: 2018 Risk‑free interest rate 1.66 % Expected term in years 0.25 Expected stock price volatility 24.2 % Dividend yield — %
Schedule of Share-based Compensation, Stock Options and Warrants Activity	The following table represents stock option activity for the three months ended March 31, 2018 : Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding, December 31, 2017 757,711 $ 12.66 Granted 15,000 14.64 Exercised (25,376 ) 12.80 Forfeited (15,000 ) 14.64 Expired (118 ) 482.97 Outstanding, March 31, 2018 732,217 $ 12.58 5.31 $ 4,127 Exercisable, March 31, 2018 645,522 $ 12.32 5.02 $ 3,813
Schedule of Share-based Compensation, Restricted Stock Award Activity	The following table represents restricted stock activity for the three months ended March 31, 2018 : Shares Weighted Average Grant-Date Fair Value Outstanding, December 31, 2017 239,468 $ 15.69 Granted 19,882 12.61 Vested (8,769 ) 4.93 Forfeited (21,905 ) 15.94 Outstanding, March 31, 2018 228,676 $ 15.81

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities, Measured on Recurring Basis	The following table presents the assets that were measured at fair value on a recurring basis by level within the fair value hierarchy as reported in the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 . Fair Value Measurements at March 31, 2018 Using: Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Securities available-for-sale— U.S. government agencies $ — $ 36,532 $ — $ 36,532 U.S. states and political subdivisions — 85,813 — 85,813 Trust preferred securities — 4,650 — 4,650 Corporate debt securities — 12,457 — 12,457 Mortgage-backed securities — 319,278 — 319,278 Total securities available-for-sale $ — $ 458,730 $ — $ 458,730 Interest rate derivative assets $ — $ 2,614 $ — $ 2,614 Interest rate derivative liabilities $ — $ 5,360 $ — $ 5,360 Fair Value Measurements at December 31, 2017 Using: Quoted Prices in Active Markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (in thousands) Securities available-for-sale— U.S. government agencies $ — $ 34,111 $ — $ 34,111 U.S. states and political subdivisions — 90,001 — 90,001 Trust preferred securities — 4,650 — 4,650 Corporate debt securities — 12,622 — 12,622 Mortgage-backed securities — 307,733 — 307,733 Total securities available-for-sale $ — $ 449,117 $ — $ 449,117 Interest rate derivative assets $ — $ 3,018 $ — $ 3,018 Interest rate derivative liabilities $ — $ 4,023 $ — $ 4,023
Fair Value Measurements, Nonrecurring	The following table presents the assets that were measured at fair value on a nonrecurring basis by level within the fair value hierarchy as reported in the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017 . March 31, 2018 Level 1 Fair Value Measurement Level 2 Fair Value Measurement Level 3 Fair Value Measurement Total (in thousands) Impaired Loans $ — $ — $ 2,142 $ 2,142 December 31, 2017 Level 1 Fair Value Measurement Level 2 Fair Value Measurement Level 3 Fair Value Measurement Total (in thousands) Impaired Loans $ — $ — $ 2,199 $ 2,199
Fair Value Measurements, Recurring and Nonrecurring	The following table presents the estimated fair values of Atlantic Capital’s financial instruments at March 31, 2018 and December 31, 2017 . Fair Value Measurements at March 31, 2018 Using: Carrying Value Quoted Prices in Active markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Financial assets Cash and due from banks $ 39,985 $ 39,985 $ — $ — Interest bearing deposits in banks 62,787 62,787 — — Other short-term investments 9,669 9,669 — — Total securities available-for-sale 458,730 — 458,730 — FHLB stock 10,485 — — 10,485 Federal Reserve Bank stock 9,792 — — 9,792 Loans held for investment, net 1,939,536 — — 1,893,372 Loans held for sale 835 — 835 — Derivative assets 2,614 — 2,614 — Financial liabilities Deposits $ 2,096,300 $ — $ 2,037,010 $ — Federal funds purchased and securities sold under agreements to repurchase 47,855 47,855 — — Subordinated debt 49,577 — 48,823 — FHLB advances 185,000 — 185,276 — Derivative financial instruments 5,360 — 5,360 — Fair Value Measurements at December 31, 2017 Using: Carrying Value Quoted Prices in Active markets for Identical Securities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Financial assets Cash and due from banks $ 38,086 $ 38,086 $ — $ — Interest-bearing deposits in other banks 281,247 281,247 — — Other short-term investments 10,681 10,681 — — Total securities available-for-sale 449,117 — 449,117 — FHLB stock 4,388 — — 4,388 Federal Reserve Bank stock 9,792 — — 9,792 Loans held for investment, net 1,914,495 — — 1,955,705 Loans held for sale 1,487 — 1,487 — Derivative assets 3,018 — 3,018 — Financial liabilities Deposits $ 2,450,665 $ — $ 2,411,810 $ — Subordinated debt 49,535 — 49,888 — FHLB advances 45,000 — 45,057 — Derivative financial instruments 4,023 — 4,023 —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Exposure to Credit Risk By Commitment	Atlantic Capital’s maximum exposure to credit risk for unfunded loan commitments and standby letters of credit at March 31, 2018 and December 31, 2017 was as follows: March 31, December 31, (in thousands) Financial Instruments whose contract amount represents credit risk: Commitments to extend credit $ 688,312 $ 689,753 Standby letters of credit 13,560 10,958 $ 701,872 $ 700,711

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents trust income by type of service provided for the three months ended March 31, 2018 and 2017: For the three months ended March 31, 2018 2017 (in thousands) Personal trust and agency accounts $ 313 $ 232 Employee benefit and retirement-related trust and agency accounts 60 52 Investment management and investment advisory agency accounts 107 88 Custody and safekeeping accounts 13 18 Other 25 17 $ 518 $ 407 The following table presents service charges by type of service provided for the three months ended March 31, 2018 and 2017: For the three months ended March 31, 2018 2017 (in thousands) Deposit account analysis fees and charges $ 571 $ 499 ATM fees 290 407 NSF fees 193 248 Wire fees 90 91 Foreign Exchange Fees 38 84 Other 10 20 $ 1,192 $ 1,349

Accounting Standards Updates 39

Accounting Standards Updates and Recently Adopted Standards - Narrative (Details) - USD ($)	Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from AOCI	$ 0	$ 0
Retained earnings		18,693,000	$ 12,810,000
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from AOCI		844,000
Accounting Standards Update 2018-02 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from AOCI		$ 844,000
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 2,000

Acquisitions and Divestitures (

Acquisitions and Divestitures (Details) $ in Millions	Dec. 14, 2017USD ($)
Business Combinations [Abstract]
Proceeds from divestiture of business	$ 1.7

Balance Sheet Offsetting (Detai

Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Offsetting Securities Purchased under Agreements to Resell [Abstract]
Reverse repurchase agreements, Gross amounts of recognized assets	$ 9,669	$ 10,681
Reverse repurchase agreements, Gross amounts offset on the Balance Sheet	0	0
Reversed repurchase agreements, Net asset balance	9,669	10,681
Reverse repurchase agreements, Financial instruments	(9,669)	(10,681)
Reverse repurchase agreements, Cash collateral received	0	0
Reverse repurchase agreements, Net amount	0	0
Offsetting Derivative Assets [Abstract]
Derivatives, Gross amounts of recognized assets	2,614	3,018
Derivatives, Gross amounts offset on the Balance Sheet	0	0
Derivatives, Net asset balance	2,614	3,018
Derivatives, Financial instruments	0	0
Derivatives, Cash collateral received	0	0
Derivatives, Net amount	2,614	3,018
Offsetting Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed [Abstract]
Total, Gross amounts of recognized assets	12,283	13,699
Total, Gross amounts offset on the Balance Sheet	0	0
Total, Net asset balance	12,283	13,699
Total, Financial instruments	(9,669)	(10,681)
Total, Cash Cash collateral received	0	0
Total, Net amount	2,614	3,018
Offsetting Securities Sold under Agreements to Repurchase [Abstract]
Repurchase agreements, Gross amounts of recognized liability	7,855	0
Repurchase agreements, Gross amounts offset on the Balance Sheet	0	0
Repurchase agreements, Net liability balance	7,855	0
Repurchase agreements, Financial instruments	(11,532)	0
Repurchase agreements, Cash collateral pledged	0	0
Repurchase agreements, Net amount	0	0
Offsetting Derivative Liabilities [Abstract]
Derivative, Gross amounts of recognized liability	5,360	4,023
Derivatives, Gross amounts offset on the Balance Sheet	0	0
Derivative, Net liability balance	5,360	4,023
Derivatives, Financial instruments	(4,039)	(2,705)
Derivatives, Cash collateral pledged	(1,321)	(1,318)
Derivatives, Net amount	0	0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Total, Gross amounts of recognized liability	13,215	4,023
Total, Gross amounts offset on the Balance Sheet	0	0
Total, Net liability balance	13,215	4,023
Total, Financial instruments	(15,571)	(2,705)
Total, Cash collateral pledged	(1,321)	(1,318)
Total, Net amount	$ 0	$ 0

Securities (Securities Availabl

Securities (Securities Available-For-Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 472,864	$ 454,699
Gross Unrealized Gains	2,434	2,731
Gross Unrealized Losses	(16,568)	(8,313)
Fair Value	458,730	449,117
U.S. Government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	37,364	34,699
Gross Unrealized Gains	2	11
Gross Unrealized Losses	(834)	(599)
Fair Value	36,532	34,111
U.S. states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	92,005	92,169
Gross Unrealized Gains	18	237
Gross Unrealized Losses	(6,210)	(2,405)
Fair Value	85,813	90,001
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,761	4,754
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(111)	(104)
Fair Value	4,650	4,650
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,925	12,948
Gross Unrealized Gains	0	60
Gross Unrealized Losses	(468)	(386)
Fair Value	12,457	12,622
Residential mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	325,809	310,129
Gross Unrealized Gains	2,414	2,423
Gross Unrealized Losses	(8,945)	(4,819)
Fair Value	$ 319,278	$ 307,733

Securities (Maturities) (Detail

Securities (Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized Cost
Within 1 year	$ 0
Over 1 year through 5 years	23,099
5 years to 10 years	52,910
Over 10 years	71,046
Total with Single Maturity Date	147,055
Residential mortgage-backed securities	325,809
Total	472,864
Fair Value
Within 1 year	0
Over 1 year through 5 years	22,605
5 years to 10 years	51,238
Over 10 years	65,609
Total with Single Maturity Date	139,452
Residential mortgage-backed securities	319,278
Total	$ 458,730	$ 449,117

Securities (Unrealized Losses -

Securities (Unrealized Losses - Available-For-Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	$ 247,135	$ 194,783
12 months or greater, fair value	189,793	202,089
Total fair value	436,928	396,872
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	(5,507)	(1,902)
12 months or greater, unrealized losses	(11,061)	(6,411)
Total unrealized losses	(16,568)	(8,313)
U.S. Government agencies
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	25,903	22,148
12 months or greater, fair value	8,848	9,145
Total fair value	34,751	31,293
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	(499)	(348)
12 months or greater, unrealized losses	(335)	(251)
Total unrealized losses	(834)	(599)
U.S. states and political divisions
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	28,017	14,009
12 months or greater, fair value	54,396	58,744
Total fair value	82,413	72,753
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	(1,017)	(183)
12 months or greater, unrealized losses	(5,193)	(2,222)
Total unrealized losses	(6,210)	(2,405)
Trust preferred securities
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	0	0
12 months or greater, fair value	4,650	4,650
Total fair value	4,650	4,650
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	0	0
12 months or greater, unrealized losses	(111)	(104)
Total unrealized losses	(111)	(104)
Corporate debt securities
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	9,464	2,989
12 months or greater, fair value	2,993	2,970
Total fair value	12,457	5,959
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	(147)	(27)
12 months or greater, unrealized losses	(321)	(359)
Total unrealized losses	(468)	(386)
Residential mortgage-backed securities
Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	183,751	155,637
12 months or greater, fair value	118,906	126,580
Total fair value	302,657	282,217
Continuous Unrealized Loss Position, Unrealized Losses [Abstract]
Less than 12 months, unrealized losses	(3,844)	(1,344)
12 months or greater, unrealized losses	(5,101)	(3,475)
Total unrealized losses	$ (8,945)	$ (4,819)

Securities (Narrative) (Details

Securities (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018USD ($)security	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities in unrealized loss positions (security) | security	318
Impairment charges	$ 0	$ 0
Investment securities pledged to secure borrowings	$ 79,900,000		$ 93,900,000

Loans and Allowance for Loan 46

Loans and Allowance for Loan Losses (Summary of Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other loans held for sale	$ 835	$ 1,487
Total loans held for sale	835	1,487
Loans	1,962,874	1,937,649
Less net deferred fees and other unearned income	(3,453)	(3,810)
Less allowance for loan losses	(19,885)	(19,344)	$ (19,939)	$ (20,595)
Loans held for investment, net	1,939,536	1,914,495
Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	105,255	104,484
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	70,712	76,244
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	15,181	16,278
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,740,760	1,711,250
Less allowance for loan losses	(18,797)	(18,267)	(18,101)	(18,717)
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	636,181	615,359
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	914,100	940,415
Commercial | Construction and land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	145,904	115,495
Commercial | Mortgage warehouse participations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	44,575	39,981
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	175,967	180,728
Less allowance for loan losses	(828)	(802)	(1,406)	(1,418)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	30,966	29,393
Less allowance for loan losses	$ (260)	$ (275)	$ (432)	$ (460)

Loans and Allowance for Loan 47

Loans and Allowance for Loan Losses (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral	$ 717,300	$ 667,200
Carrying value of loans	1,962,874	1,937,649
Accretable yield	2,500	2,800
Troubled debt restructurings	5,200	5,300
PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	11,837	11,754
Loans receivable	14,000	14,100
Commercial and industrial | PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	5,289	5,424
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	1,740,760	1,711,250
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Additional loan amounts	28	26
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	636,181	615,359
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	175,967	180,728
Residential | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	70,712	76,244
Residential | Home equity | PCI Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans	$ 674	$ 744

Loans and Allowance for Loan 48

Loans and Allowance for Loan Losses (Accretable Yield Movement) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 2,316	$ 3,467
Accretion	(298)	(444)
Reclassification of nonaccretable discount due to change in expected cash flows	96	251
Other changes, net	295	95
Balance at end of period	$ 2,409	$ 3,369

Loans and Allowance for Loan 49

Loans and Allowance for Loan Losses (Allowance Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 19,344	$ 20,595
Provision for loan losses	772	634
Loans charged-off	(257)	(1,291)
Recoveries	26	1
Total ending allowance balance	19,885	19,939
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	18,267	18,717
Provision for loan losses	637	297
Loans charged-off	(126)	(913)
Recoveries	19	0
Total ending allowance balance	18,797	18,101
Residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	802	1,418
Provision for loan losses	154	34
Loans charged-off	(128)	(46)
Recoveries	0	0
Total ending allowance balance	828	1,406
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	275	460
Provision for loan losses	(19)	303
Loans charged-off	(3)	(332)
Recoveries	7	1
Total ending allowance balance	$ 260	$ 432

Loans and Allowance for Loan 50

Loans and Allowance for Loan Losses (Allowance Additional Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Individually evaluated for impairment	$ 276	$ 306
Allowance for loan losses, Collectively evaluated for impairment	19,604	18,993
Allowance for loan losses, PCI	5	45
Allowance for loan losses, Total ending allowance balance	19,885	19,344
Loans, Individually evaluated for impairment	6,914	7,072
Loans, Collectively evaluated for impairment	1,944,123	1,918,823
Loans, PCI	11,837	11,754
Loans, Total ending allowance balance	1,962,874	1,937,649
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Individually evaluated for impairment	276	306
Allowance for loan losses, Collectively evaluated for impairment	18,516	17,918
Allowance for loan losses, PCI	5	43
Allowance for loan losses, Total ending allowance balance	18,797	18,267
Loans, Individually evaluated for impairment	6,731	6,886
Loans, Collectively evaluated for impairment	1,724,816	1,694,948
Loans, PCI	9,213	9,416
Loans, Total ending allowance balance	1,740,760	1,711,250
Residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Individually evaluated for impairment	0	0
Allowance for loan losses, Collectively evaluated for impairment	828	800
Allowance for loan losses, PCI	0	2
Allowance for loan losses, Total ending allowance balance	828	802
Loans, Individually evaluated for impairment	183	186
Loans, Collectively evaluated for impairment	173,172	178,204
Loans, PCI	2,612	2,338
Loans, Total ending allowance balance	175,967	180,728
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Individually evaluated for impairment	0	0
Allowance for loan losses, Collectively evaluated for impairment	260	275
Allowance for loan losses, PCI	0	0
Allowance for loan losses, Total ending allowance balance	260	275
Loans, Individually evaluated for impairment	0	0
Loans, Collectively evaluated for impairment	46,135	45,671
Loans, PCI	12	0
Loans, Total ending allowance balance	$ 46,147	$ 45,671

Loans and Allowance for Loan 51

Loans and Allowance for Loan Losses (Impaired Loans) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	$ 3,018	$ 4,313
Impaired loans with an allowance recorded, Unpaid principal balance	4,167	9,213
Total impaired loans, Unpaid principal balance	7,185	13,526
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	2,747	4,042
Impaired loans with an allowance recorded, Recorded investment	4,167	9,213
Total impaired loans, Recorded investment	6,914	13,255
Impaired loans with an allowance recorded, Related allowance	276	2,240
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	2,749	4,627
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	4,235	9,257
Total impaired loans, Average balance of recorded investment while impaired	6,984	13,884
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	13	17
Impaired loans with an allowance recorded, Interest income recognized during impairment	52	115
Total impaired loans, Interest income recognized during impairment	65	132
Commercial | Commercial and industrial
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	1,035	1,132
Impaired loans with an allowance recorded, Unpaid principal balance	3,643	8,316
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	972	1,069
Impaired loans with an allowance recorded, Recorded investment	3,643	8,316
Impaired loans with an allowance recorded, Related allowance	168	2,077
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	973	1,550
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	3,691	8,357
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	13	17
Impaired loans with an allowance recorded, Interest income recognized during impairment	46	108
Commercial | Commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	1,755	2,388
Impaired loans with an allowance recorded, Unpaid principal balance	524	750
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	1,592	2,226
Impaired loans with an allowance recorded, Recorded investment	524	750
Impaired loans with an allowance recorded, Related allowance	108	159
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	1,592	2,303
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	544	753
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	6	7
Commercial | Construction and land
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	0	0
Impaired loans with an allowance recorded, Unpaid principal balance	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Related allowance	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	0	0
Commercial | Mortgage warehouse participations
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	0	0
Impaired loans with an allowance recorded, Unpaid principal balance	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Related allowance	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	0	0
Residential | Residential mortgages
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	228	244
Impaired loans with an allowance recorded, Unpaid principal balance	0	147
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	183	198
Impaired loans with an allowance recorded, Recorded investment	0	147
Impaired loans with an allowance recorded, Related allowance	0	4
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	184	225
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	0	147
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	0	0
Residential | Home equity
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	0	549
Impaired loans with an allowance recorded, Unpaid principal balance	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	0	549
Impaired loans with an allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Related allowance	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	0	549
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	0	0
Consumer
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired loans with no related allowance recorded, Unpaid principal balance	0	0
Impaired loans with an allowance recorded, Unpaid principal balance	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Recorded investment	0	0
Impaired loans with an allowance recorded, Related allowance	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired loans with no related allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired loans with an allowance recorded, Average balance of recorded investment while impaired	0	0
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired loans with no related allowance recorded, Interest income recognized during impairment	0	0
Impaired loans with an allowance recorded, Interest income recognized during impairment	$ 0	$ 0

Loans and Allowance for Loan 52

Loans and Allowance for Loan Losses (Risk Category of Loan by Class of Loan) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	$ 1,962,874	$ 1,937,649
Non-PCI Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,951,037	1,925,895
Non-PCI Loans | Pass
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,878,895	1,868,722
Non-PCI Loans | Special Mention
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	29,247	23,066
Non-PCI Loans | Substandard | Accruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	40,429	31,493
Non-PCI Loans | Substandard | Nonaccruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	559	699
Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,907	1,915
PCI Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	11,837	11,754
PCI Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	5,289	5,424
PCI Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	3,687	3,751
PCI Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	237	240
PCI Loans | Pass
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	3,853	3,835
PCI Loans | Pass | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Pass | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	3,130	3,151
PCI Loans | Pass | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	222	222
PCI Loans | Special Mention
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,181	4,947
PCI Loans | Special Mention | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	3,881
PCI Loans | Special Mention | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	188	212
PCI Loans | Special Mention | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	6	7
PCI Loans | Substandard | Accruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	6,690	2,860
PCI Loans | Substandard | Accruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	5,289	1,543
PCI Loans | Substandard | Accruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	256	276
PCI Loans | Substandard | Accruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	9	11
PCI Loans | Substandard | Nonaccruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Substandard | Nonaccruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Substandard | Nonaccruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Substandard | Nonaccruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	113	112
PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	113	112
PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,740,760	1,711,250
Commercial | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	636,181	615,359
Commercial | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	914,100	940,415
Commercial | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	145,904	115,495
Commercial | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	44,575	39,981
Commercial | Non-PCI Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	630,892	609,935
Commercial | Non-PCI Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	910,413	936,664
Commercial | Non-PCI Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	145,667	115,255
Commercial | Non-PCI Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	44,575	39,981
Commercial | Non-PCI Loans | Pass | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	593,133	572,942
Commercial | Non-PCI Loans | Pass | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	879,885	919,939
Commercial | Non-PCI Loans | Pass | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	145,667	115,255
Commercial | Non-PCI Loans | Pass | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	44,575	39,981
Commercial | Non-PCI Loans | Special Mention | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	16,089	15,643
Commercial | Non-PCI Loans | Special Mention | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	11,453	6,227
Commercial | Non-PCI Loans | Special Mention | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Special Mention | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Substandard | Accruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	21,656	21,332
Commercial | Non-PCI Loans | Substandard | Accruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	17,483	8,906
Commercial | Non-PCI Loans | Substandard | Accruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Substandard | Accruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Substandard | Nonaccruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	14	16
Commercial | Non-PCI Loans | Substandard | Nonaccruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Substandard | Nonaccruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Substandard | Nonaccruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	2
Commercial | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Commercial real estate
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,592	1,592
Commercial | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Construction and land
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Pass | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Special Mention | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Substandard | Accruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Substandard | Nonaccruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Commercial | PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Mortgage warehouse participations
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Residential
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	175,967	180,728
Residential | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	105,255	104,484
Residential | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	70,712	76,244
Residential | Non-PCI Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	103,317	102,889
Residential | Non-PCI Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	70,038	75,500
Residential | Non-PCI Loans | Pass | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	100,871	100,342
Residential | Non-PCI Loans | Pass | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	68,869	74,841
Residential | Non-PCI Loans | Special Mention | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,063	1,075
Residential | Non-PCI Loans | Special Mention | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	642	64
Residential | Non-PCI Loans | Substandard | Accruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	746	753
Residential | Non-PCI Loans | Substandard | Accruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	304	310
Residential | Non-PCI Loans | Substandard | Nonaccruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	322	398
Residential | Non-PCI Loans | Substandard | Nonaccruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	223	285
Residential | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	315	321
Residential | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Residential | PCI Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	1,938	1,595
Residential | PCI Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	674	744
Residential | PCI Loans | Pass | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	467	428
Residential | PCI Loans | Pass | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	34	34
Residential | PCI Loans | Special Mention | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	699	493
Residential | PCI Loans | Special Mention | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	288	354
Residential | PCI Loans | Substandard | Accruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	772	674
Residential | PCI Loans | Substandard | Accruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	352	356
Residential | PCI Loans | Substandard | Nonaccruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Residential | PCI Loans | Substandard | Nonaccruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Residential | PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Residential mortgages
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Residential | PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Home equity
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	46,147	45,671
Consumer | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	46,147	45,671
Consumer | Non-PCI Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	46,135	45,671
Consumer | Non-PCI Loans | Pass | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	45,895	45,422
Consumer | Non-PCI Loans | Special Mention | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	57
Consumer | Non-PCI Loans | Substandard | Accruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	240	192
Consumer | Non-PCI Loans | Substandard | Nonaccruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer | Non-PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer | PCI Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	12	0
Consumer | PCI Loans | Pass | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer | PCI Loans | Special Mention | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer | PCI Loans | Substandard | Accruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	12	0
Consumer | PCI Loans | Substandard | Nonaccruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	0	0
Consumer | PCI Loans | Doubtful Nonaccruing | Nonaccruing Loans | Other
Financing Receivable, Impaired [Line Items]
Financing receivable, gross	$ 0	$ 0

Loans and Allowance for Loan 53

Loans and Allowance for Loan Losses (Financing Receivables Past Due) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	$ 1,944,031	$ 1,915,644
Nonaccruing	2,466	2,614
Loans, Total ending allowance balance	1,962,874	1,937,649
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	1,740,760	1,711,250
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	627,685	606,677
Nonaccruing	14	19
Loans, Total ending allowance balance	636,181	615,359
Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	908,300	932,916
Nonaccruing	1,592	1,592
Loans, Total ending allowance balance	914,100	940,415
Commercial | Construction and land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	145,667	114,988
Nonaccruing	0	0
Loans, Total ending allowance balance	145,904	115,495
Commercial | Mortgage warehouse participations
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	44,575	39,981
Nonaccruing	0	0
Loans, Total ending allowance balance	44,575	39,981
Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	175,967	180,728
Residential | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	102,129	100,402
Nonaccruing	637	719
Loans, Total ending allowance balance	105,255	104,484
Residential | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	69,775	75,081
Nonaccruing	223	284
Loans, Total ending allowance balance	70,712	76,244
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	46,147	45,671
Consumer | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	45,900	45,599
Nonaccruing	0	0
Loans, Total ending allowance balance	46,147	45,671
Accruing 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	4,505	7,339
Accruing 30-89 Days Past Due | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	3,193	3,239
Accruing 30-89 Days Past Due | Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	521	2,156
Accruing 30-89 Days Past Due | Commercial | Construction and land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	267
Accruing 30-89 Days Past Due | Commercial | Mortgage warehouse participations
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
Accruing 30-89 Days Past Due | Residential | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	551	1,470
Accruing 30-89 Days Past Due | Residential | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	5	135
Accruing 30-89 Days Past Due | Consumer | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	235	72
Accruing 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	35	298
Accruing 90 Days Past Due | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
Accruing 90 Days Past Due | Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
Accruing 90 Days Past Due | Commercial | Construction and land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
Accruing 90 Days Past Due | Commercial | Mortgage warehouse participations
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
Accruing 90 Days Past Due | Residential | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	298
Accruing 90 Days Past Due | Residential | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	35	0
Accruing 90 Days Past Due | Consumer | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing past due	0	0
PCI Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	11,837	11,754
Loans, Total ending allowance balance	11,837	11,754
PCI Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	5,289	5,424
PCI Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	3,687	3,751
PCI Loans | Construction and land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Total ending allowance balance	237	240
PCI Loans | Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	5,289	5,424
PCI Loans | Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	3,687	3,751
PCI Loans | Commercial | Construction and land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	237	240
PCI Loans | Commercial | Mortgage warehouse participations
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	0	0
Loans, Total ending allowance balance	0	0
PCI Loans | Residential | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	1,938	1,595
Loans, Total ending allowance balance	1,938	1,595
PCI Loans | Residential | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	674	744
Loans, Total ending allowance balance	674	744
PCI Loans | Consumer | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Current	12	0
Loans, Total ending allowance balance	$ 12	$ 0

Goodwill and Intangible Asset54

Goodwill and Intangible Assets (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Total other intangibles, net	$ 5,726,000		$ 5,874,000
Goodwill	21,759,000	$ 21,759,000	21,759,000	$ 21,759,000
Total goodwill and other intangible assets, net	27,485,000		27,633,000
Goodwill impairment	0	0
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Core deposit intangible	9,544,000		9,544,000
Less: accumulated amortization	(4,967,000)		(4,624,000)
Less: impairment related to divested branches	(2,286,000)		(2,286,000)
Core deposit intangible, net	2,291,000	$ 4,154,000	2,634,000	$ 4,624,000
Servicing assets, net	9,544,000		9,544,000
Servicing Assets
Finite-Lived Intangible Assets [Line Items]
Core deposit intangible	3,435,000		3,240,000
Servicing assets, net	$ 3,435,000		$ 3,240,000

Goodwill and Intangible Asset55

Goodwill and Intangible Assets (Goodwill and Other Intangible Assets Activity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill
Balance, beginning of period	$ 21,759	$ 21,759
Balance, end of period	21,759	21,759
Core Deposit Intangible
Amortization	(343)	(470)
Intangible Assets, Net (Including Goodwill) [Abstract]
Balance, beginning of period	24,393	26,383
Amortization	(343)	(470)
Balance, end of period	24,050	25,913
Core Deposits
Core Deposit Intangible
Balance, beginning of period	2,634	4,624
Amortization	(343)	(470)
Balance, end of period	2,291	4,154
Intangible Assets, Net (Including Goodwill) [Abstract]
Amortization	$ (343)	$ (470)

Servicing Assets (Narrative) (D

Servicing Assets (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Transfers and Servicing [Abstract]
Loans sold and serviced	$ 151	$ 135.8

Servicing Assets (SBA) (Details

Servicing Assets (SBA) (Details) - SBA Loan Servicing Assets - Commercial Loan - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
SBA Loan Servicing Rights
Beginning carrying value, net	$ 2,635	$ 2,359
Additions	371	267
Amortization	(134)	(131)
Impairment	0	0
Ending carrying value	$ 2,872	$ 2,495

Servicing Assets (Sensitivity o

Servicing Assets (Sensitivity of the Fair Value to Immediate Changes in Key Economic Assumptions) (Details) - Commercial - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
SBA Loan Servicing Assets
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value of retained servicing assets	$ 3,114	$ 2,865
Weighted average life	5 years 11 months 15 days	6 years 2 months 19 days
Prepayment speed:	9.45%	8.64%
Decline in fair value due to a 10% adverse change	$ (111)	$ (103)
Decline in fair value due to a 20% adverse change	$ (199)	$ (181)
Weighted average discount rate	12.98%	13.01%
Decline in fair value due to a 100 bps adverse change	$ (103)	$ (103)
Decline in fair value due to a 200 bps adverse change	(185)	(180)
TriNet Servicing Assets
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value of retained servicing assets	$ 652	$ 697
Weighted average life	7 years 4 months 5 days	7 years 4 months 15 days
Prepayment speed:	5.00%	5.00%
Decline in fair value due to a 10% adverse change	$ (9)	$ (10)
Decline in fair value due to a 20% adverse change	$ (18)	$ (20)
Weighted average discount rate	8.00%	8.00%
Decline in fair value due to a 100 bps adverse change	$ (17)	$ (19)
Decline in fair value due to a 200 bps adverse change	$ (33)	$ (37)

Servicing Assets (TriNet) (Deta

Servicing Assets (TriNet) (Details) - TriNet Servicing Assets - Commercial Loan - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Servicing Rights
Beginning carrying value, net	$ 605	$ 825
Additions	0	0
Amortization	(42)	(47)
Impairment	0	0
Ending carrying value	$ 563	$ 778

Other Comprehensive Income (L60

Other Comprehensive Income (Loss) (Summary of Changes) (Details) - USD ($)	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017
Income Tax (Expense) Benefit
Reclassification of tax effects from AOCI	$ 0	$ 0
After-Tax Amount
Accumulated other comprehensive income (loss) beginning of period	308,425,000	308,425,000	$ 303,658,000
Other comprehensive income (loss), net of tax		(7,824,000)	218,000
Accumulated other comprehensive income (loss) end of period		307,059,000	310,967,000
Unrealized net gains (losses) on investment securities available-for-sale
Pre-Tax Amount
Unrealized net gains (losses) on investment securities available-for-sale		(8,551,000)	591,000
Income Tax (Expense) Benefit
Unrealized net gains (losses) on investment securities available-for-sale		2,137,000	(227,000)
After-Tax Amount
Unrealized net gains (losses) on investment securities available-for-sale		(6,414,000)	364,000
Unrealized net gains (losses) on derivatives
Pre-Tax Amount
Unrealized net gains (losses) on derivatives		(1,880,000)	(237,000)
Income Tax (Expense) Benefit
Unrealized net gains (losses) on derivatives		470,000	91,000
After-Tax Amount
Other comprehensive income (loss), net of tax		(1,410,000)	(146,000)
Accumulated Other Comprehensive Income (Loss)
Pre-Tax Amount
Accumulated other comprehensive income (loss) beginning of period	(6,274,000)	(6,274,000)	(9,144,000)
Reclassification of tax effects from AOCI		0
Accumulated other comprehensive income (loss) end of period		(16,705,000)	(8,790,000)
Income Tax (Expense) Benefit
Accumulated other comprehensive income (loss) beginning of period	2,415,000	2,415,000	3,519,000
Reclassification of tax effects from AOCI		(844,000)
Accumulated other comprehensive income (loss) end of period		4,178,000	3,383,000
After-Tax Amount
Accumulated other comprehensive income (loss) beginning of period	$ (3,859,000)	(3,859,000)	(5,625,000)
Reclassification of tax effects from AOCI		(844,000)
Accumulated other comprehensive income (loss) end of period		$ (12,527,000)	$ (5,407,000)

Earnings Per Common Share (Comp

Earnings Per Common Share (Computation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 5,038	$ 3,230
Weighted average shares outstanding
Basic (in shares)	25,750,824	25,320,690
Effect of dilutive securities:
Stock options and warrants (in shares)	194,949	351,596
Diluted (in shares)	25,945,773	25,672,286
Income per common share:
Basic (in dollars per share)	$ 0.20	$ 0.13
Diluted (in dollars per share)	$ 0.19	$ 0.13

Earnings Per Common Share (Narr

Earnings Per Common Share (Narrative) (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Mar. 24, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded (in shares)	432	747
Capital shares, authorized (in shares)				110,000,000
Preferred stock authorized (in shares)	10,000,000		10,000,000	10,000,000
Common stock authorized (in shares)	100,000,000		100,000,000	100,000,000
Common stock issued (in shares)	25,772,208		25,712,909
Common stock outstanding (in shares)	25,772,208		25,712,909

Derivatives and Hedging (Narrat

Derivatives and Hedging (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 14,100,000		$ 14,800,000
Expected reclassification from AOCI in the next twelve months	83,000
Collateral posted	8,300,000		8,800,000
Not designated as hedging instrument | Other assets
Derivative [Line Items]
Notional Amount	159,147,000		166,113,000
Swap | Not designated as hedging instrument
Derivative [Line Items]
Notional Amount	129,900,000		142,300,000
Swap | Not designated as hedging instrument | Other assets
Derivative [Line Items]
Notional Amount	64,958,000		71,160,000
Cash Flow Hedging
Derivative [Line Items]
Hedge ineffectiveness gain (loss) recognized	0	$ 0
Cash Flow Hedging | Designated as hedging instrument | LIBOR
Derivative [Line Items]
Notional Amount	$ 100,000,000		$ 100,000,000

Derivatives and Hedging (Deriva

Derivatives and Hedging (Derivative Contracts and Credit Risk Participation Agreements) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 14,100	$ 14,800
Designated as hedging instrument | Cash Flow Hedging | LIBOR
Derivative [Line Items]
Notional Amount	100,000	100,000
Not designated as hedging instrument | Swap
Derivative [Line Items]
Notional Amount	129,900	142,300
Other assets | Not designated as hedging instrument
Derivative [Line Items]
Notional Amount	159,147	166,113
Fair Value	2,614	3,018
Other assets | Not designated as hedging instrument | Swap
Derivative [Line Items]
Notional Amount	64,958	71,160
Fair Value	1,065	946
Other assets | Not designated as hedging instrument | Zero premium collar
Derivative [Line Items]
Notional Amount	94,189	94,953
Fair Value	1,549	2,072
Other liabilities | Designated as hedging instrument | Cash Flow Hedging | LIBOR
Derivative [Line Items]
Notional Amount	100,000	100,000
Fair Value	2,739	887
Other liabilities | Not designated as hedging instrument
Derivative [Line Items]
Notional Amount	173,205	180,920
Fair Value	2,621	3,136
Other liabilities | Not designated as hedging instrument | Swap
Derivative [Line Items]
Notional Amount	64,958	71,160
Fair Value	1,061	975
Other liabilities | Not designated as hedging instrument | Credit risk participation
Derivative [Line Items]
Notional Amount	14,058	14,807
Fair Value	2	4
Other liabilities | Not designated as hedging instrument | Dealer offset to zero premium collar
Derivative [Line Items]
Notional Amount	94,189	94,953
Fair Value	$ 1,558	$ 2,157

Derivatives and Hedging (Impact

Derivatives and Hedging (Impact to Consolidated Statements of Income Related to Derivative Contracts) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ (1,778)	$ (100)
Gain or (Loss) Reclassified from Accumulated OCI in Income (Effective Portion)	102	137
Not designated as hedging instrument
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	111	(51)
Not designated as hedging instrument | Other income / (expense) | Interest rate products
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	108	(51)
Not designated as hedging instrument | Other income / (expense) | Other contracts
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	3	0
Not designated as hedging instrument | Other income / (expense) | Fee income
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ 3	$ 0

Other Borrowings and Long Ter66

Other Borrowings and Long Term Debt (Schedule of Borrowings) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 185,000	$ 45,000
FHLB short-term borrowings
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	185,000	45,000
FHLB short-term borrowings | Fixed rate advance maturing April 3, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 40,000
Interest Rate	1.61%
FHLB short-term borrowings | Fixed rate advance maturing April 6, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 40,000
Interest Rate	1.70%
FHLB short-term borrowings | Fixed rate advance maturing April 12, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 30,000
Interest Rate	1.70%
FHLB short-term borrowings | Fixed rate advance maturing April 16, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 45,000
Interest Rate	1.86%
FHLB short-term borrowings | Fixed rate advance maturing April 23, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings	$ 30,000
Interest Rate	1.85%
FHLB short-term borrowings | Fixed rate advance maturing January 16, 2018
Debt Instrument [Line Items]
Federal Home Loan Bank borrowings		$ 45,000
Interest Rate		1.40%

Other Borrowings and Long Ter67

Other Borrowings and Long Term Debt (Narrative) (Details) - Subordinated Debt - USD ($)	Sep. 28, 2015	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Aggregate principal amount		$ 50,000,000	$ 50,000,000
Maturity, more than		5 years
6.25% Subordinated Note, Due September 2020
Debt Instrument [Line Items]
Aggregate principal amount	$ 50,000,000	$ 50,000,000	$ 50,000,000
Stated interest rate	6.25%	6.25%
Debt instrument redemption price	100.00%
Maturity, more than		10 years
Subordinated Note After September 30, 2020 Due September 2025
Debt Instrument [Line Items]
Basis spread on variable rate		4.68%

Other Borrowings and Long Ter68

Other Borrowings and Long Term Debt (Schedule of Subordinated Debt) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 28, 2015
Debt Instrument [Line Items]
Long-term debt	$ 49,577,000	$ 49,535,000
Subordinated Debt
Debt Instrument [Line Items]
Aggregate principal amount	50,000,000	50,000,000
Less debt issuance costs	423,000	465,000
Long-term debt	$ 49,577,000	49,535,000
Debt instrument term	5 years
Subordinated Debt | 6.25% Subordinated Note, Due September 2020
Debt Instrument [Line Items]
Aggregate principal amount	$ 50,000,000	$ 50,000,000	$ 50,000,000
Debt instrument term	10 years
Stated interest rate	6.25%		6.25%

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)individualshares	Mar. 31, 2017USD ($)	Dec. 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense | $	$ 58	$ 142
Number of employees affected | individual	2
Total incremental cost resulting from modifications | $	$ 111
Warrant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants outstanding (shares)	0		0
2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)	4,525,000
Number of additional shares authorized (shares)	3,660,000
Award vesting period	3 years
Term of award	10 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense | $	$ 401	$ 229
Compensation cost not yet recognized | $	$ 2,200
Compensation cost not yet recognized, period for recognition	2 years 9 months 29 days
Number of awards modified (in shares)	6,869
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards modified (in shares)	15,000

Share-Based Compensation (Fair

Share-Based Compensation (Fair Value of Options Assumptions) (Details) - Employee Stock Option	3 Months Ended
	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk‑free interest rate	1.66%
Expected term in years	3 months
Expected stock price volatility	24.20%

Share-Based Compensation (Stock

Share-Based Compensation (Stock Option and Warrant Activity) (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Shares
Outstanding, Beginning of period (in shares) | shares	757,711
Granted (in shares) | shares	15,000
Exercised (in shares) | shares	(25,376)
Forfeited (in shares) | shares	(15,000)
Expired (in shares) | shares	(118)
Outstanding, End of period (in shares) | shares	732,217
Exercisable, End of period (in shares) | shares	645,522
Weighted Average Exercise Price
Outstanding, Weighted average exercise price, Beginning of period (dollars per share) | $ / shares	$ 12.66
Granted, Weighted average exercise price (dollars per share) | $ / shares	14.64
Exercised, Weighted average exercise price (dollars per share) | $ / shares	12.80
Forfeited, Weighted average exercise price (dollars per share) | $ / shares	14.64
Expired, Weighted average exercise price (dollars per share) | $ / shares	482.97
Outstanding, Weighted average exercise price, End of period (dollars per share) | $ / shares	12.58
Exercisable, Weighted average exercise price, End of period (dollars per share) | $ / shares	$ 12.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted average remaining contractual term, End of period (in years)	5 years 3 months 22 days
Exercisable, Weighted average remaining contractual term, End of period (in years)	5 years 8 days
Outstanding, Aggregate intrinsic value, End of period | $	$ 4,127
Exercisable, Aggregate intrinsic value, End of period | $	$ 3,813

Share-Based Compensation (Restr

Share-Based Compensation (Restricted Stock Activity) (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning of period (in shares) | shares	239,468
Granted (in shares) | shares	19,882
Vested (in shares) | shares	(8,769)
Forfeited (in shares) | shares	(21,905)
End of period (in shares) | shares	228,676
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted average grant date fair value, Nonvested, Beginning of period (dollars per share) | $ / shares	$ 15.69
Weighted average grant date fair value, Granted (dollars per share) | $ / shares	12.61
Weighted average grant date fair value, Vested (dollars per share) | $ / shares	4.93
Weighted average grant date fair value, Forfeited (dollars per share) | $ / shares	15.94
Weighted average grant date fair value, Nonvested, End of period (dollars per share) | $ / shares	$ 15.81

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurements Recurring) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	$ 458,730	$ 449,117
Interest rate derivative assets	2,614	3,018
Interest rate derivative liabilities	5,360	4,023
Fair Value | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	458,730	449,117
Interest rate derivative assets	2,614	3,018
Interest rate derivative liabilities	5,360	4,023
Fair Value | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Interest rate derivative assets	0	0
Interest rate derivative liabilities	0	0
Fair Value | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	458,730	449,117
Interest rate derivative assets	2,614	3,018
Interest rate derivative liabilities	5,360	4,023
Fair Value | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Interest rate derivative assets	0	0
Interest rate derivative liabilities	0	0
Fair Value | U.S. government agencies | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	36,532	34,111
Fair Value | U.S. government agencies | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | U.S. government agencies | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	36,532	34,111
Fair Value | U.S. government agencies | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | U.S. states and political subdivisions | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	85,813	90,001
Fair Value | U.S. states and political subdivisions | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | U.S. states and political subdivisions | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	85,813	90,001
Fair Value | U.S. states and political subdivisions | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Trust preferred securities | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	4,650	4,650
Fair Value | Trust preferred securities | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Trust preferred securities | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	4,650	4,650
Fair Value | Trust preferred securities | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Corporate debt securities | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	12,457	12,622
Fair Value | Corporate debt securities | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Corporate debt securities | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	12,457	12,622
Fair Value | Corporate debt securities | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Mortgage-backed securities | Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	319,278	307,733
Fair Value | Mortgage-backed securities | Fair value, measurements, recurring | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	0	0
Fair Value | Mortgage-backed securities | Fair value, measurements, recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	319,278	$ 307,733
Fair Value | Mortgage-backed securities | Fair value, measurements, recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	$ 0

Fair Value Measurements (Fair74

Fair Value Measurements (Fair Value Measurements Nonrecurring) (Details) - Impaired Loans - Fair Value - Fair value, measurements, nonrecurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 2,142	$ 2,199
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 2,142	$ 2,199

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Value and Carrying Value Summary) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	$ 39,985	$ 38,086
Interest-bearing deposits in banks	62,787	281,247
Other short-term investments	9,669	10,681
Total securities available-for-sale	458,730	449,117
Loans held for investment, net	1,939,536	1,914,495
Derivative assets	2,614	3,018
Subordinated debt	49,577	49,535
FHLB advances	185,000	45,000
Derivative financial instruments	5,360	4,023
Fair value, measurements, recurring | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	39,985	38,086
Interest-bearing deposits in banks	62,787	281,247
Other short-term investments	9,669	10,681
Total securities available-for-sale	458,730	449,117
FHLB stock	10,485	4,388
Federal Reserve Bank stock	9,792	9,792
Loans held for investment, net	1,939,536	1,914,495
Loans held for sale	835	1,487
Derivative assets	2,614	3,018
Deposits	2,096,300	2,450,665
Federal funds purchased and securities sold under agreements to repurchase	47,855
Subordinated debt	49,577	49,535
FHLB advances	185,000	45,000
Derivative financial instruments	5,360	4,023
Fair value, measurements, recurring | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total securities available-for-sale	458,730	449,117
Derivative assets	2,614	3,018
Derivative financial instruments	5,360	4,023
Fair value, measurements, recurring | Fair Value | Quoted Prices in Active Markets for Identical Securities (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	39,985	38,086
Interest-bearing deposits in banks	62,787	281,247
Other short-term investments	9,669	10,681
Total securities available-for-sale	0	0
FHLB stock	0	0
Federal Reserve Bank stock	0	0
Loans held for investment, net	0	0
Loans held for sale	0	0
Derivative assets	0	0
Deposits	0	0
Federal funds purchased and securities sold under agreements to repurchase	47,855
Subordinated debt	0	0
FHLB advances	0	0
Derivative financial instruments	0	0
Fair value, measurements, recurring | Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits in banks	0	0
Other short-term investments	0	0
Total securities available-for-sale	458,730	449,117
FHLB stock	0	0
Federal Reserve Bank stock	0	0
Loans held for investment, net	0	0
Loans held for sale	835	1,487
Derivative assets	2,614	3,018
Deposits	2,037,010	2,411,810
Federal funds purchased and securities sold under agreements to repurchase	0
Subordinated debt	48,823	49,888
FHLB advances	185,276	45,057
Derivative financial instruments	5,360	4,023
Fair value, measurements, recurring | Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits in banks	0	0
Other short-term investments	0	0
Total securities available-for-sale	0	0
FHLB stock	10,485	4,388
Federal Reserve Bank stock	9,792	9,792
Loans held for investment, net	1,893,372	1,955,705
Loans held for sale	0	0
Derivative assets	0	0
Deposits	0	0
Federal funds purchased and securities sold under agreements to repurchase	0
Subordinated debt	0	0
FHLB advances	0	0
Derivative financial instruments	$ 0	$ 0

Commitments and Contingencies76

Commitments and Contingencies (Exposure to Credit Risk) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Maximum credit risk exposure	$ 701,872	$ 700,711
Commitments to extend credit
Loss Contingencies [Line Items]
Maximum credit risk exposure	688,312	689,753
Standby letters of credit
Loss Contingencies [Line Items]
Maximum credit risk exposure	$ 13,560	$ 10,958

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Retained earnings	$ 18,693			$ 12,810
Deposit account analysis fees and charges
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	571	$ 499
ATM fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	290	407
NSF fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	193	248
Wire fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	90	91
Foreign Exchange Fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	38	84
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	10	20
Service Charges
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	1,192	1,349
Personal trust and agency accounts
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	313	232
Employee benefit and retirement-related trust and agency accounts
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	60	52
Investment management and investment advisory agency accounts
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	107	88
Custody and safekeeping accounts
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	13	18
Other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	25	17
Trust Income
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, including assessed tax	$ 518	$ 407
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Retained earnings			$ 2