WEX (WEX) 10-K 1 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 26, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	WEX Inc.
Trading Symbol	WEX
Entity Central Index Key	1,309,108
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		43,031,993
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 4,405,939,486

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 508,072	$ 190,930
Accounts receivable (net of allowances of $30,207 in 2017 and $21,454 in 2016)	2,527,840	2,054,701
Securitized accounts receivable, restricted	150,235	97,417
Income taxes receivable	0	10,765
Available-for-sale securities	23,358	23,525
Property, equipment and capitalized software (net of accumulated depreciation of $264,928 in 2017 and $228,336 in 2016)	163,908	167,278
Deferred income taxes, net	7,752	6,934
Goodwill	1,876,132	1,838,441
Other intangible assets (net of accumulated amortization of $392,827 in 2017 and $254,142 in 2016)	1,154,047	1,265,468
Other assets	327,831	341,638
Total assets	6,739,175	5,997,097
Liabilities and Stockholders’ Equity
Accounts payable	811,362	617,118
Accrued expenses	323,222	331,579
Income taxes payable	1,076	0
Deposits	1,293,854	1,118,823
Securitized debt	126,901	84,323
Revolving line-of-credit facility and term loans, net	1,707,064	1,599,291
Deferred income taxes, net	119,283	152,906
Notes outstanding, net	396,269	395,534
Other debt	194,737	125,755
Amounts due under tax receivable agreement	20,273	47,302
Other liabilities	24,576	18,719
Total liabilities	5,018,617	4,491,350
Commitments and contingencies
Stockholders’ Equity
Common stock $0.01 par value; 175,000 shares authorized; 47,352 shares issued in 2017 and 47,173 in 2016; 43,022 shares outstanding in 2017 and 42,841 in 2016	473	472
Additional paid-in capital	569,319	547,627
Retained earnings	1,404,683	1,244,271
Accumulated other comprehensive loss	(90,795)	(122,839)
Treasury stock at cost; 4,428 shares in 2017 and 2016	(172,342)	(172,342)
Total WEX Inc. stockholders' equity	1,711,338	1,497,189
Non-controlling interest	9,220	8,558
Total stockholders’ equity	1,720,558	1,505,747
Total liabilities and stockholders’ equity	$ 6,739,175	$ 5,997,097

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, reserve for credit losses	$ 30,207	$ 21,454
Accumulated depreciation	264,928	228,336
Accumulated amortization	$ 392,827	$ 254,142
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares issued (in shares)	47,352,000	47,173,000
Common stock, shares outstanding (in shares)	43,022,000	42,841,000
Treasury stock, shares (in shares)	4,428,000	4,428,000

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Payment processing revenue	$ 569,166	$ 520,619	$ 495,869
Account servicing revenue	276,570	211,012	156,693
Finance fee revenue	187,582	138,940	88,993
Other revenue	217,230	147,889	113,082
Total revenues	1,250,548	1,018,460	854,637
Expenses
Salary and other personnel	363,444	286,298	234,564
Restructuring	7,139	7,486	9,010
Service fees	149,137	173,052	138,844
Provision for credit losses	61,148	33,348	22,825
Technology leasing and support	52,179	47,602	41,315
Occupancy and equipment	27,729	25,820	20,618
Depreciation and amortization	203,724	141,651	83,077
Operating interest expense	24,482	12,386	5,628
Cost of hardware and equipment	4,314	3,122	3,236
Impairment charges and asset write-offs	44,171	0	0
Gain on divestitures	(20,958)	0	(1,215)
Other	94,769	92,567	67,942
Total operating expenses	1,011,278	823,332	625,844
Operating income	239,270	195,128	228,793
Financing interest expense	(107,067)	(113,418)	(46,189)
Net foreign currency gain (loss)	29,919	(7,665)	(5,689)
Net unrealized gains on interest rate swap agreements	1,314	12,908	0
Net realized and unrealized gains on fuel price derivatives	0	711	5,848
Non-cash adjustments related to tax receivable agreement	15,259	(563)	2,145
Income before income taxes	178,695	87,101	184,908
Income taxes	19,525	29,625	75,296
Net income	159,170	57,476	109,612
Less: Net loss from non-controlling interests	(1,096)	(3,161)	(1,705)
Net earnings attributable to WEX Inc.	160,266	60,637	111,317
Accretion of non-controlling interest	0	0	(9,413)
Net earnings attributable to shareholders	$ 160,266	$ 60,637	$ 101,904
Net earnings attributable to WEX Inc. per share:
Basic (in dollars per share)	$ 3.73	$ 1.49	$ 2.63
Diluted (in dollars per share)	$ 3.72	$ 1.48	$ 2.62
Weighted average common shares outstanding:
Basic (in shares)	42,977	40,809	38,771
Diluted (in shares)	43,105	40,914	38,843

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 159,170	$ 57,476	$ 109,612
Changes in available-for-sale securities, net of tax benefit of $3 in 2017, $144 in 2016 and $49 in 2015	(5)	(251)	(83)
Foreign currency translation	33,692	(19,855)	(49,952)
Comprehensive income	192,857	37,370	59,577
Less: Comprehensive income (loss) attributable to non-controlling interest	547	(3,879)	(7,979)
Comprehensive income attributable to WEX Inc.	$ 192,310	$ 41,249	$ 67,556

CONSOLIDATED STATEMENTS OF COM6

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Changes in available-for-sale securities, tax benefit	$ 3	$ 144	$ 49

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands		Total	Common Stock Issued	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Treasury Stock	Retained Earnings	Non-Controlling Interest
Beginning Balances (in shares) at Dec. 31, 2014			43,021
Beginning balance at Dec. 31, 2014		$ 1,077,721	$ 430	$ 179,077	$ (50,581)	$ (150,331)	$ 1,081,730	$ 17,396
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued upon exercise of stock options (in shares)			3
Stock issued upon exercise of stock options		33		33
Tax benefit from stock options and restricted stock units		650		650
Stock issued upon vesting of restricted and deferred stock units (in shares)			55
Stock issued upon vesting of restricted and deferred stock units		0	$ 1	(1)
Stock-based compensation, net of share repurchases for tax withholdings		9,140		9,140
Purchase of shares of treasury stock (in shares)			0
Purchase of shares of treasury stock		(22,011)				(22,011)
Changes in available-for-sale securities, net of tax benefit of $49 in 2015, $144 in 2016, and $3 in 2017		(83)			(83)
Adjustment of redeemable non-controlling interest		(32,448)		(13,927)	(9,108)		(9,413)
Foreign currency translation		(45,742)			(43,679)			(2,063)
Net income (loss)		108,421					111,317	(2,896)
Ending Balance (in shares) at Dec. 31, 2015			43,079
Ending balance at Dec. 31, 2015		1,095,681	$ 431	174,972	(103,451)	(172,342)	1,183,634	12,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued upon exercise of stock options (in shares)			21
Stock issued upon exercise of stock options		300	$ 0	300
Tax deficiency from stock options and restricted stock units		(100)		(100)
Stock issued upon vesting of restricted and deferred stock units (in shares)			61
Stock issued upon vesting of restricted and deferred stock units		0	$ 1	(1)
Stock-based compensation, net of share repurchases for tax withholdings		17,543		17,543
Changes in available-for-sale securities, net of tax benefit of $49 in 2015, $144 in 2016, and $3 in 2017		(251)			(251)
Foreign currency translation		(19,855)			(19,137)			(718)
Stock issued for July 1, 2016 purchase of EFS (in shares)			4,012
Stock issued for July 1, 2016 purchase of EFS		354,953	$ 40	354,913
Net income (loss)		57,476					60,637	(3,161)
Ending Balance (in shares) at Dec. 31, 2016			47,173
Ending balance at Dec. 31, 2016		1,505,747	$ 472	547,627	(122,839)	(172,342)	1,244,271	8,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment	[1]	261					261
Stock issued upon exercise of stock options (in shares)			12
Stock issued upon exercise of stock options		733		733
Stock issued upon vesting of restricted and deferred stock units (in shares)			166
Stock issued upon vesting of restricted and deferred stock units		0	$ 1	(1)
Stock-based compensation, net of share repurchases for tax withholdings (in shares)			1
Stock-based compensation, net of share repurchases for tax withholdings		20,960		20,960
Changes in available-for-sale securities, net of tax benefit of $49 in 2015, $144 in 2016, and $3 in 2017		(5)			(5)
Foreign currency translation		33,692			32,049			1,643
Other		0					(115)	115
Net income (loss)		159,170					160,266	(1,096)
Ending Balance (in shares) at Dec. 31, 2017			47,352
Ending balance at Dec. 31, 2017		$ 1,720,558	$ 473	$ 569,319	$ (90,795)	$ (172,342)	$ 1,404,683	$ 9,220
[1]	Includes the impact of modified retrospective transition as part of the Company's ASU 2016-09 adoption to recognize previously disallowed excess tax benefits that increased a net operating loss.

CONSOLIDATED STATEMENTS OF STO8

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Changes in available-for-sale securities, tax effect	$ 3	$ 144	$ 49

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net income	$ 159,170,000	$ 57,476,000	$ 109,612,000
Adjustments to reconcile net income to net cash provided by operating activities:
Net unrealized loss (gain)	8,109,000	(26,478,000)	16,201,000
Stock-based compensation	30,487,000	19,742,000	12,420,000
Depreciation and amortization	203,724,000	141,651,000	83,077,000
Ticking fees expensed	0	30,045,000	0
Debt restructuring and debt issuance cost amortization	7,957,000	12,673,000	3,097,000
Gain on divestiture	(20,958,000)	0	(1,215,000)
Deferred income taxes	(888,000)	19,499,000	37,359,000
Provision for credit losses	61,148,000	33,348,000	22,825,000
Impairment charges and asset write-offs	44,171,000	0	0
Non-cash adjustments related to tax receivable agreement	(15,259,000)	0	0
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(542,017,000)	(436,071,000)	199,717,000
Other assets	503,000	(63,730,000)	(17,653,000)
Accounts payable	194,542,000	75,807,000	(33,201,000)
Accrued expenses	(2,378,000)	1,669,000	16,594,000
Income taxes	11,507,000	(14,614,000)	10,687,000
Other liabilities	4,900,000	8,086,000	(2,322,000)
Amounts due under tax receivable agreement	(11,769,000)	(10,234,000)	(12,098,000)
Net cash provided by (used for) operating activities	132,949,000	(151,131,000)	445,100,000
Cash flows from investing activities
Purchases of property, equipment and capitalized software	(79,276,000)	(61,799,000)	(63,491,000)
Purchases of available-for-sale securities	(474,000)	(5,853,000)	(349,000)
Maturities of available-for-sale securities	631,000	495,000	594,000
Acquisitions and investment, net of cash	(114,282,000)	(1,089,282,000)	(80,677,000)
Acquisition of an intangible asset	0	(4,000,000)	0
Proceeds from divestitures	29,900,000	0	17,265,000
Net cash used for investing activities	(163,501,000)	(1,160,439,000)	(126,658,000)
Cash flows from financing activities
Excess tax benefits from equity instrument share-based payment arrangements	0	597,000	650,000
Repurchase of share-based awards to satisfy tax withholdings	(9,527,000)	(2,200,000)	(2,392,000)
Proceeds from stock option exercises	733,000	300,000	33,000
Net change in deposits	173,052,000	248,926,000	(107,345,000)
Net activity on other debt	68,525,000	62,474,000	(435,000)
Borrowings on revolving line-of-credit facility	4,367,168,000	3,505,732,000	2,203,027,000
Repayments on revolving line-of-credit facility	(4,239,241,000)	(3,707,248,000)	(2,402,118,000)
Borrowings on term loans	0	1,643,000,000	0
Repayments on term loans	(34,750,000)	(476,126,000)	(27,500,000)
Loan origination fees	(985,000)	(40,868,000)	0
Net change in securitized debt	34,410,000	3,665,000	84,571,000
Ticking fees paid	0	(22,171,000)	0
Purchase of redeemable non-controlling interest	0	0	(46,018,000)
Purchase of shares of treasury stock	0	0	(22,011,000)
Net cash provided by (used for) financing activities	359,385,000	1,216,081,000	(319,538,000)
Effect of exchange rates on cash and cash equivalents	(11,691,000)	6,430,000	(3,678,000)
Net change in cash and cash equivalents	317,142,000	(89,059,000)	(4,774,000)
Cash and cash equivalents, beginning of year	190,930,000	279,989,000	284,763,000
Cash and cash equivalents, end of year	508,072,000	190,930,000	279,989,000
Supplemental cash flow information
Interest paid	128,888,000	116,272,000	49,032,000
Income taxes paid	6,679,000	23,946,000	27,186,000
Supplemental disclosure of non-cash investing and financing activities
Capital expenditures incurred but not paid	4,596,000	10,900,000	5,446,000
Issuance of common stock in a business combination	$ 0	$ 354,953,000	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies Business Description WEX Inc. (“Company”, "we" or "our”) is a provider of corporate card payment solutions. The Company provides products and services that meet the needs of businesses in various geographic regions including North and South America, Asia Pacific and Europe. The Company’s Fleet Solutions, Travel and Corporate Solutions, and Health and Employee Benefit Solutions segments provide their customers with security and control for complex payments across a wide spectrum of business sectors. The Company markets its products and services directly, as well as through strategic relationships which include major oil companies, fuel retailers, vehicle maintenance providers, online travel agencies and health partners. Basis of Presentation The accompanying consolidated financial statements of the Company for the years ended December 31, 2017 , 2016 and 2015 , include the accounts of the Company and its wholly and majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company rounds amounts in the consolidated financial statements to thousands and calculates all percentages and per-share data from underlying whole-dollar amounts. Thus, certain amounts may not foot, crossfoot, or recalculate based on reported numbers due to rounding. Use of Estimates and Assumptions The Company prepares its consolidated financial statements in conformity with GAAP and with the Rules and Regulations of the SEC, specifically Regulation S-X and the instructions to Form 10-K. These principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the period. Actual results could differ from those estimates and those differences may be material. Cash and Cash Equivalents Highly liquid investments with remaining maturities at the time of purchase of three months or less (that are readily convertible to cash) are considered to be cash equivalents and are stated at cost, which approximates fair value. Cash equivalents include federal funds sold, which are unsecured short-term investments entered into with financial institutions. Restricted Cash Restricted cash represents funds collected from individuals or employers on behalf of our customers that are to be remitted to third parties or funds required to be maintained on hand under certain vendor agreements. This restricted cash, which is not available to fund the Company’s operations, totaled $18,866 and $22,412 as of December 31, 2017 and 2016 , respectively, and is classified in other assets on the Company’s consolidated balance sheets. We maintain an offsetting liability against restricted cash collected and remitted on behalf of our customers. Accounts Receivable, Net of Allowances Accounts receivable is stated at net realizable value. The balance includes a reserve for credit losses which reflects management’s estimate of uncollectable balances resulting from credit and fraud losses. Management has consistently considered its portfolio of charge card receivables as a large group of smaller balance accounts that it has collectively evaluated for impairment. The reserve for credit losses is established based on the determination of the amount of expected credit losses inherent in the accounts receivable as of the reporting date. Management reviews delinquency reports, historical collection rates, changes in customer payment patterns, economic trends, geography and other information in order to make judgments as to probable credit losses. Management also uses historical charge off experience to determine the amount of losses inherent in accounts receivable at the reporting date. Assumptions regarding probable credit losses are reviewed periodically and may be impacted by actual performance of accounts receivable and changes in any of the factors discussed above. The balance also includes a reserve for waived finance fees, which is used to maintain customer goodwill and recorded against the late fee revenue recognized. Available-for-sale Securities The Company records certain investments as available-for-sale securities. Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of tax, reported on the consolidated balance sheets in accumulated other comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary are included in non-operating expenses. The cost basis of securities is based on the specific identification method. Interest and dividends earned on securities classified as available-for-sale are included in other revenue. Available-for-sale securities held by the Company were purchased and are held by WEX Bank in order to meet the requirements of the Community Reinvestment Act. Derivatives From time to time, the Company utilizes derivative instruments as part of its overall strategy to manage its exposure to fluctuations in fuel prices and to reduce the impact of interest and foreign currency exchange rate volatility. The Company's derivative instruments are recorded at fair value on the consolidated balance sheets . The Company’s derivative instruments have not been designated as hedges; therefore, both realized and unrealized gains and losses are recognized in earnings. For the purposes of cash flow presentation, realized and unrealized gains or losses are included within cash flows from operating activities. Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Replacements, renewals and improvements are capitalized and costs for repair and maintenance are expensed as incurred. Depreciation is primarily computed using the straight-line method over the estimated useful lives shown below. Below are the estimated useful lives for assets placed in service during 2017 and beyond: Estimated Useful Lives Furniture, fixtures and equipment 3 to 5 years Internal-use computer software 1.5 to 7 years Computer software 3 years Leasehold improvements (a) up to 5 years (a) Leasehold improvements are primarily depreciated using the straight-line method over the lesser of the useful life of the asset or the remaining lease term. Capitalized Software The Company develops software that is used to provide processing and information management services to customers. A significant portion of the Company’s capital expenditures is devoted to the development of such internal-use computer software. Costs incurred during the preliminary project stage are expensed as incurred. Software development costs are capitalized during the application development stage. Capitalization begins when the preliminary project stage is complete, as well as when management authorizes and commits to the funding of the project. Capitalization of costs ceases when the software is ready for its intended use. Costs related to maintenance of internal-use software are expensed as incurred. Software development costs are amortized using the straight-line method over the estimated useful life of the software. Below are the amounts of internal-use software capitalized and amortized: Year ended December 31, 2017 2016 2015 Amounts capitalized for internal-use computer software (including work-in-process) $ 50,682 $ 55,379 $ 52,218 Amounts expensed for amortization of internal-use computer software $ 32,582 $ 27,581 $ 20,316 Goodwill and Other Intangible Assets The Company classifies intangible assets in the following three categories: (1) intangible assets with definite lives subject to amortization, (2) intangible assets with indefinite lives not subject to amortization and (3) goodwill. The Company tests intangible assets with definite lives for impairment if conditions exist that indicate the carrying value may not be recoverable. Such conditions may include a reduction in operating cash flow or a dramatic change in the manner in which the asset is intended to be used. The Company records an impairment charge when the carrying value of the definite-lived intangible asset is not recoverable from the undiscounted cash flows generated from the use of the asset. Intangible assets with indefinite lives and goodwill are not amortized. The Company tests these intangible assets and goodwill for impairment at least annually or more frequently if facts or circumstances indicate that such intangible assets or goodwill might be impaired. All goodwill and intangible assets are assigned to reporting units, which are one level below the Company’s operating segments. The Company performs impairment tests at the reporting unit level. Such impairment tests include comparing the fair value of the respective reporting unit with its carrying value, including goodwill. The Company uses both discounted cash flow analyses and comparable company pricing multiples to determine the fair value of our reporting units. Such analyses are corroborated using market analytics. Certain assumptions are used in determining the fair value, including assumptions about future cash flows and terminal values. When appropriate, the Company considers the assumptions that it believes hypothetical marketplace participants would use in estimating future cash flows. In addition, an appropriate discount rate is used, based on the Company’s cost of capital or reporting unit-specific economic factors. When the fair value is less than the carrying value of the intangible assets or the reporting unit, the Company records an impairment charge to reduce the carrying value of the assets to the reporting unit's implied fair value. The Company's annual goodwill and intangible asset impairment tests performed as of October 1, 2017 , 2016 and 2015 did not identify any impairment. Intangible assets that are deemed to have definite lives are amortized over their useful lives, which is the period of time that the asset is expected to contribute directly or indirectly to future cash flows. The Company determines the useful lives of its identifiable intangible assets after considering the specific facts and circumstances related to each intangible asset. The factors that management considers when determining useful lives include the contractual term of agreements, the history of the asset, the Company’s long-term strategy for the use of the asset, any laws or other local regulations which could impact the useful life of the asset and other economic factors, including competition and specific market conditions. An evaluation of the remaining useful lives of the definite-lived intangible assets is performed periodically to determine if any change is warranted. Impairment and Disposals of Assets Long-lived assets are tested for impairment whenever facts or circumstances, such as a reduction in operating cash flow or a dramatic change in the manner the asset is intended to be used, indicate the carrying amount of the asset may not be recoverable. The Company compares the estimated undiscounted future cash flows associated with these assets or operations to their carrying value to determine if a write-down to fair value is required. During 2017, the Company impaired certain software currently under development for payment processing and prepaid services related to technology outsourcing as these items were determined to have no future benefit. See Note 22 , Impairment and Restructuring Activities , for further discussion. The Company did not recognize any significant impairment expense on the Company’s assets during the years ended December 31, 2016 and 2015 . Disposals in the ordinary course of business are recorded in occupancy and equipment in the consolidated statements of income. Fair Value of Financial Instruments The Company holds mortgage-backed securities, fixed-income securities, derivatives (see Note 11 , Derivative Instruments ) and certain other financial instruments that are carried at fair value. The Company determines fair value based upon quoted prices when available or through the use of alternative approaches, such as model pricing, when market quotes are not readily accessible or available. Various factors are considered in determining the fair value of the Company’s obligations, including: closing exchange or over-the-counter market price quotations; time value and volatility factors underlying options and derivatives; price activity for equivalent instruments; and the Company’s own-credit standing. These valuation techniques may be based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs create the following fair value hierarchy: • Level 1 – Quoted prices for identical instruments in active markets. • Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable. • Level 3 – Instruments whose significant value drivers are unobservable. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The carrying values of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses, and other liabilities approximate their respective fair values due to the short-term nature of such instruments. The carrying values of certificates of deposit, interest-bearing money market deposits and borrowed federal funds approximate their respective fair values as the interest rates on these financial instruments are variable market-based rates. All other financial instruments are reflected at fair value on the consolidated balance sheets. Revenue Recognition The majority of the Company’s revenues are comprised of transaction-based fees, which are generally calculated based on measures such as (i) percentage of dollar value of volume processed; (ii) number of transactions processed; or (iii) some combination thereof. The Company has entered into agreements with major oil companies, fuel retailers, vehicle maintenance providers, online travel agencies and health partners which provide products and/or services to the Company’s customers. These agreements specify that a transaction is deemed to be captured when the Company has validated that the transaction has no errors and has accepted and posted the data to the Company’s records. The Company recognizes revenues when persuasive evidence of an arrangement exists, the products and services have been provided to the client, the sales price is fixed or determinable and collectability is reasonably assured. The Company generally records revenue net of costs based on the following criteria: (i) the Company is not the primary obligor in the arrangement; (ii) the Company has no inventory risk; (iii) the Company does not have reasonable latitude with respect to establishing the price for the product; (iv) the Company does not make any changes to the product or have any involvement in the product specifications; and, (v) the amount the Company earns for its services is fixed, within a limited range. The Company enters into contracts with certain large customers or strategic relationships that provide for fee rebates tied to performance milestones. Rebates are recorded as a reduction in revenue in the same period that revenue is earned or performance occurs. Rebates and incentives are calculated based on estimated performance and the terms of the related business agreements. A description of the major components of revenue are as follows: Payment Processing Revenue . Revenue consists of transaction fees as well as interchange income: • Fleet transaction fees are assessed to major oil companies, fuel retailers and vehicle maintenance providers. We extend short-term credit to the fleet customer and pay the purchase price for the fleet customer’s transaction, less the payment processing fees we retain, to the merchant. We collect the total purchase price from the fleet customer. The fee charged is generally based upon a percentage of the total transaction amount; however, it may also be based on a fixed amount charged per transaction or on a combination of both measures. The Company records revenue at the time the transaction is captured. • In Europe, our fleet payment processing revenue is specifically derived from the difference between the negotiated price of the fuel from the supplier and the agreed upon price paid by the fleets. • Interchange income is earned from the Company’s suite of card products in the Fleet Solutions and Health and Employee Benefit Solutions segments, as well as on our virtual card technology. Interchange income is a fee paid by a merchant bank to the card-issuing bank through the interchange network. Interchange fees are set by the credit card providers. The Company recognizes interchange income as earned. With regard to fleet and travel payment processing revenue, the Company is generally responsible for the collection of the total transaction amount from the customer and the payment to the merchant of their sales amount, net of the payment processing revenue earned by the Company, and as such, recognizes revenue net of the cost of the underlying products and services. As a consequence, the Company’s accounts receivable and accounts payable related to its payment processing revenues are reflective of the total transaction amount processed by the Company, not the Company’s revenue. Account Servicing Revenue . In our Fleet Solutions segment, account servicing revenue is primarily comprised of monthly fees based on vehicles serviced. These fees are primarily in return for providing monthly vehicle data reports. In our Health and Employee Benefit Solutions segment, we also recognize account servicing fees for the per-participant per-month fee charged per consumer on our healthcare financial technology platform. Account servicing revenue is recognized monthly, as the Company fulfills its contractual service obligations. Finance Fees . The Company earns revenue by assessing monthly finance fees on accounts with overdue balances. These fees are recognized as revenue at the time the fees are assessed. The finance fee is calculated using a stated late fee rate based on the entire balance outstanding from the customer or a minimum, whichever is higher. On occasion, these fees are waived to maintain customer goodwill. The Company’s established reserve for such waived amounts is estimated and offset against the late fee revenue recognized. These waived fees amounted to approximately $16,900 , $10,900 and $6,000 in 2017 , 2016 and 2015 , respectively. The Company engages in factoring, the purchase of accounts receivable from a third party at a discount. Revenue earned in this transaction is recorded in finance fees. We also recognize fees for interest associated with the Company’s fuel desk product and revenue earned on the Company’s foreign salary advance product. Other . The Company earns transaction fees, which are principally based on the number of transactions processed; however, the fees may be a percentage of the total transaction amount. These fees are recognized at the time the transaction is captured. The Company assesses fees for providing ancillary services, such as information products and services, professional services and marketing services. Other revenues also include international settlement fees, fees for overnight shipping, certain customized electronic reporting and customer contact services provided on behalf of certain of the Company’s customers. Service related revenues are recognized in the period that the work is performed. Interest and dividends earned on investments in available-for-sale securities are included in other revenues. Such income is recognized in the period that it is earned. The Company sells telematics devices as part of its WEX Telematics program. The Company recognizes revenue from these sales when the customer has accepted delivery of the product and collectability of the sales amount is reasonably assured. From time to time the Company enters into agreements with suppliers, partners and customers and offers incentives to establish access to new channels, enter new market segments and expand the use and acceptance of WEX products and services. As part of these agreements the Company may agree to pay an up-front bonus or fee. The Company capitalizes these payments within other assets in the consolidated balance sheets and amortizes each monthly, generally on a straight-line basis against the related revenue earned throughout the life of the agreement. Stock-Based Compensation The Company recognizes the fair value of all stock-based payments to employees in its financial statements. The Company estimates the fair value of service-based stock option awards and market performance-based stock option awards on the grant date using a Black-Scholes-Merton valuation model and a Monte Carlo simulation model, respectively. The fair value of Restricted Stock Units (“RSUs”), including Performance Based Restricted Stock Units (“PBRSUs”), is determined and fixed on the grant date based on the Company's stock price. Stock-based compensation expense is net of estimated forfeitures and is recorded over each award's requisite service period. The Company uses the straight-line methodology for recognizing the expense associated with service-based stock options and RSU grants and a graded-vesting methodology for the expense recognition of market performance-based stock options and PBRSUs. Stock-based compensation is recorded in salary and other personnel expense in the consolidated statements of income. Advertising Costs Advertising and marketing costs are expensed in the period incurred. During the years ended December 31, 2017, 2016 and 2015, advertising expense was $17,141 , $14,864 and $12,891 , respectively. Income Taxes Income taxes are accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the associated temporary differences became deductible. A valuation allowance is established for those jurisdictions in which deferred tax assets realization is deemed less than more likely than not. Current accounting guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This accounting guidance also provides guidance on derecognition, classification, interest and penalties, accounting in the interim periods, disclosure, and transition. Penalties and interest related to uncertain tax positions are recognized as a component of income tax expense. To the extent penalties and interest are not assessed with respect to uncertain tax positions, amounts accrued are reduced and reflected as a reduction of the overall income tax provision. Earnings per Share Basic earnings per share is computed by dividing net earnings attributable to shareholders by the weighted average number of shares of common stock and vested deferred stock units (“DSUs”) outstanding during the year. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and assumed issuance of unvested RSUs and DSUs and unvested PBRSUs for which the performance condition has been met as of the date of determination using the treasury stock method unless the effect is anti-dilutive. The treasury stock method assumes that proceeds, including cash received from the exercise of employee stock options and the total unrecognized compensation expense for unvested share-based compensation awards, would be used to purchase the Company's common stock at the average market price during the period. Prior to the January 2017 adoption of ASU 2016-09, the treasury stock method also included excess tax benefits in its proceeds calculation. The following table summarizes net earnings attributable to shareholders and reconciles basic and diluted shares outstanding used in the earnings per share computations: Year ended December 31, 2017 2016 2015 Net earnings attributable to shareholders $ 160,266 $ 60,637 $ 101,904 Weighted average common shares outstanding – Basic 42,977 40,809 38,771 Dilutive impact of share based compensation awards 128 105 72 Weighted average common shares outstanding – Diluted 43,105 40,914 38,843 Foreign Currency Movement The financial statements of the Company’s foreign subsidiaries, where the local currency is the functional currency, are Realized and unrealized gains and losses on foreign currency transactions as well as the re-measurement of the Company's cash, receivable and payable balances that are denominated in foreign currencies, are recorded directly in net foreign currency gain (loss) in the consolidated statements of income. However, gains or losses resulting from intercompany transactions where repayment is not anticipated for the foreseeable future are not recognized in the consolidated statements of income. In these situations, the gains or losses are deferred and included as a component of accumulated other comprehensive loss. In addition, gains and losses associated with the Company's foreign currency exchange derivatives are recorded in net foreign currency gain (loss) in the consolidated statements of income. Accumulated Other Comprehensive Loss Accumulated other comprehensive loss includes unrealized gains and losses on available-for-sale securities and foreign currency translation adjustments pertaining to the net investment in foreign operations. Amounts are recognized net of tax to the extent applicable. Realized gains or losses on securities transactions are classified as non-operating in the consolidated statements of income.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	2. Recent Accounting Pronouncements The following table provides a brief description of recent accounting pronouncements that could have a material effect on our financial statements: Standard Description Date/Method of Adoption Effect on financial statements or other significant matters Adopted During the Year Ended December 31, 2017 Accounting Standards Update (“ASU”) 2016-09 Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting This standard simplifies several aspects of accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, statutory tax withholding requirements, and classification in the statement of cash flows. January 1, 2017 Prior to the adoption of this guidance, the Company used the "with and without" method to determine when excess tax benefits were realized. As a result of certain US net operating loss carryforwards, excess tax benefits to date have not reduced taxes paid and therefore were not previously recognized in our financial statements. This standard required prospective recognition of all the tax effects related to share-based payments in the income statement. The impact of adoption was recorded as a cumulative effect adjustment to retained earnings of $261. For the year ended December 31, 2017, the Company recognized approximately $1,600 of excess tax benefits within our income tax provision. The Company has elected to prospectively classify these excess tax benefits as cash flows from operating activities effective January 1, 2017. The Company will continue to estimate the number of awards expected to vest, rather than electing to account for forfeitures as they occur. Adoption of this standard has not impacted the Company's minimum statutory tax withholding practices. ASU 2017-09 Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting This standard clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as a modification. Under the new guidance, an entity will not apply modification accounting to a share-based payment award if there is no change to the award’s fair value, vesting conditions and classification as an equity or liability instrument. The Company elected to early adopt this standard effective July 1, 2017. The adoption has not impacted the Company's consolidated financial statements and related disclosures. Not Yet Adopted as of December 31, 2017 ASU 2016-18 Statement of Cash Flows (Topic 230): Restricted Cash This standard clarifies the classification and presentation of restricted cash in the statement of cash flows. The statement of cash flows must explain the change during the period in the total of cash and cash equivalents and amounts described as restricted cash or cash equivalents. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years, and requires retrospective application to all periods presented. Early adoption is permitted. Upon adoption, restricted cash will be included in cash and restricted cash equivalents when reconciling the beginning of year and end of year amounts presented on the consolidated statements of cash flows. Restricted cash totaled $18,866 and $22,412 as of December 31, 2017 and 2016, respectively, and is recorded in other assets on the consolidated balance sheets. ASU 2016-13 Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses will be based on historical experience, current conditions, and reasonable and supportable forecasts that impact the collectability of the reported amount. The standard is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2016-02 Leases (Topic 842) This standard increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Certain qualitative and quantitative disclosures are required. The standard is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period. When transitioning, the standard requires leases to be recognized and measured at the beginning of the earliest period presented using a modified retrospective approach. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. ASU 2016-01 Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities This standard requires equity investments, except those accounted for under the equity method of accounting, or those that result in consolidation of the investee, to be measured at fair value with changes in fair value recognized in net income. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is evaluating the impact the pronouncement will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2014-09 Revenue from Contracts with Customers (Topic 606) This standard supersedes most existing revenue recognition guidance under GAAP. The new revenue recognition standard requires entities to recognize revenue for 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. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted this standard on January 1, 2018. The guidance permits two methods of adoption: full retrospective approach, which requires an entity to restate each prior period that is reported in the financial statements and modified retrospective approach, which requires a cumulative adjustment to retained earnings as of the effective date, without restatement of prior period amounts. The Company adopted the standard using the modified retrospective method. Topic 606 does not apply to rights or obligations associated with financial instruments (e.g. interest income), including the Company’s finance fee and interest income from banking relationships and cardholders. In addition, fees associated with cardholder arrangements are outside the scope of Topic 606. As a result of detailed analysis, management has determined that approximately 30 percent of consolidated revenues for the year ended December 31, 2017 are outside the scope of Topic 606. The Company’s revenue from discount and interchange, transaction processing and certain fees is within the scope of Topic 606. FASB and its Transition Resource Group have issued clarifications on various aspects of ASU 2014-09. The Company has determined there will be two significant changes in the classification on our consolidated statement of income which will impact reported total revenues and operating expenses but have no impact on income from operations. • Certain amounts paid to partners in our Fleet Solutions and Travel and Corporate Solutions segments have been determined to fall under the cost to obtain a contract guidance. As a result, these amounts, which were previously presented net of revenues, will be reflected as a selling expense going forward. Based on 2017 results, this change would have increased both reported revenues and expenses by approximately $52,000. • Network fees paid to Visa and MasterCard by all three of our segments, which have previously been presented within service fees expense, will be presented net of revenue going forward. Based on 2017 results, this change would have reduced both reported revenues and expenses by approximately $24,000. The majority of network fee expenses are incurred by our Travel and Corporate Solutions segment. • Under the new guidance certain costs to obtain a contract, such as sales commissions are to be capitalized and amortized over the life of the contract, with a practical expedient available for contracts under one year in duration. We have evaluated our worldwide sales commission structure and determined that the vast majority of commission expense will continue to be expensed. In 2017, we incurred approximately $1,000 of sales commissions which meet the criteria for capitalization under the new guidance. Except for the items mentioned above, we have determined that the timing and measurement of revenue associated with the Company’s transaction processing services, including discount and interchange and other transaction processing fees, will not be significantly impacted by the new standard. As such, we estimate that applying the modified retrospective method to outstanding contracts as of our January 1, 2018 implementation date will have an immaterial cumulative effect on the opening balance of 2018 retained earnings. The Company has implemented changes to its accounting policies, business processes and internal controls to support the recognition, measurement and disclosure requirements under the new standard.

Business Acquisitions and Other

Business Acquisitions and Other Intangible Assets Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Business Acquisitions and Other Intangible Assets Acquisitions	3. Business Acquisitions and Other Intangible Asset Acquisitions The Company incurred and expensed costs directly related to completed acquisitions of $956 , $19,168 and $342 in 2017 , 2016 and 2015 , respectively, which are included primarily within service fees in the consolidated statements of income. AOC Effective O ctober 18, 2017 , the Company acquired certain assets and assumed certain liabilities of AOC Solutions and one of its affiliate companies, 3Delta Systems, Inc. (collectively “AOC”), an industry leader in commercial payments technology. The acquisition of AOC, a longstanding technology provider for our virtual card product, will broaden the Company's capabilities, increase our pool of employees with payments platform expertise and allow the Company to evolve with the needs of its customers and partners through the use of AOC’s payments processing technology platforms. The Company purchased AOC for $129,828 , which was funded with cash on hand and through borrowings under the 2016 Credit Agreement. The Company records adjustments to the assets acquired and liabilities assumed throughout the measurement period, which may be up to one year from the acquisition date. The Company has obtained information to assist in determining the fair values of certain assets acquired and liabilities assumed since the acquisition, resulting primarily in the recording of other intangible assets and goodwill. Goodwill is calculated as the consideration in excess of net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized, including synergies derived from the acquisition. The goodwill and intangible assets recorded from this business combination were assigned to our Travel and Corporate Solutions segment. The Company has not finalized the purchase accounting and is currently evaluating the tax basis and the allocation of book basis to the assets acquired and liabilities assumed in this business combination. Specifically, the Company is still reviewing the valuation as well as performing procedures to verify the completeness and accuracy of the data used in the independent valuation for intangible assets identified in the table below. Additionally, we are assessing the value of acquired in-process research and development software. The preliminary estimates could change significantly upon completion of this evaluation. The goodwill recognized in this business combination will be deductible for income tax purposes. The following is a summary of the preliminary allocation of the purchase price to the assets and liabilities acquired: As Reported December 31, 2017 Total consideration $ 129,828 Less: Cash 15,546 Accounts receivable 4,171 Property and equipment 2,530 Customer relationships (a) 15,000 Developed technologies (b) 24,100 Trademarks and trade names (c) 1,460 Other liabilities (685 ) Recorded goodwill $ 67,706 (a) Weighted average life – 8.9 years . (b) Weighted average life – 3.4 years . (c) Weighted average life – 4.0 years . (a) (b) (c) The weighted average life of these amortized intangible assets is 5.4 years . Since the acquisition date, the operations of AOC contributed net revenues of approximately $6,685 and net loss before taxes of approximately $620 during 2017. No pro forma information has been included in these financial statements as the operations of AOC for the period that they were not part of the Company are not material to the Company's revenues, net income and earnings per share. EFS On July 1, 2016, the Company acquired all of the outstanding membership interests of EFS, a provider of customized payment solutions for fleet and corporate customers with a focus on the large and mid-sized over-the-road fleets. The acquisition enabled the Company to expand its customer footprint and to utilize EFS' technology to better serve the needs of all fleet customers. In consideration for the acquisition of EFS, the Company issued 4,012 shares of its common stock valued at approximately $355,000 based on the July 1, 2016 closing price of the Company's common stock on the NYSE. This represented approximately 9.4 percent of the Company's outstanding common stock after giving effect to the issuance of the new shares in connection with this acquisition. The cash consideration for the transaction totaled approximately $1,182,000 , and was funded with amounts received under the 2016 Credit Agreement described further in Note 13 , Financing Debt . The value of the total cash and stock consideration paid for the acquisition of EFS was approximately $1,444,000 , net of approximately $93,000 in cash acquired. The Company obtained information to determine the fair values of certain assets acquired and liabilities assumed throughout the one year measurement period and recorded adjustments to the assets acquired and liabilities assumed, resulting in the recording of other intangible assets and goodwill as described below. Goodwill is calculated as the consideration in excess of net assets recognized and represents the future economic benefits arising from other assets acquired that could not be individually identified and separately recognized, including synergies derived from the acquisition. The Company finalized the EFS purchase accounting in the second quarter of 2017. The tax structure of EFS consists of limited liability companies and corporations. The Company’s tax election will allow a step-up in tax basis related to its 49.5 percent direct ownership in the parent limited liability company. The remaining 50.5 percent ownership in the parent limited liability company is held by another limited liability company, taxed as a corporation, that is part of the EFS structure and will therefore receive carry over tax basis. The difference between book and tax basis resulting from receiving carry over tax basis has been reflected in the financial statements as an investment in partnership deferred tax liability. The Company has determined that approximately $557,000 of the goodwill recognized in this business combination will be deductible for income tax purposes. The following represents the components and final allocation of the purchase price: As Reported December 31, 2016 Measurement Period Adjustments As Reported, Final Total consideration, net of cash acquired $ 1,444,235 $ — $ 1,444,235 Less: Accounts receivable 162,684 — 162,684 Property and equipment 2,387 1 2,388 Customer relationships (a)(b) 842,700 (1,300 ) 841,400 Developed technologies (a)(c) 32,120 — 32,120 Trademarks and trade names (a)(d) 13,700 — 13,700 Deferred income tax assets 34,992 6,352 41,344 Other assets — 739 739 Accounts payable (153,777 ) 248 (153,529 ) Accrued expenses (128,267 ) 9,361 (118,906 ) Deferred income tax liabilities (91,194 ) 28,071 (63,123 ) Recorded goodwill (a) $ 728,890 $ (43,472 ) $ 685,418 (a) $1,235,331 in goodwill and other intangible assets recorded from this business combination were allocated to our Fleet Solutions segment, the remaining $337,307 was allocated to our Travel and Corporate Solutions segment. (b) Weighted average life – 8.1 years . (c) Weighted average life – 2.0 years . (d) Weighted average life – 7.7 years . (b) (c) (d) The weighted average life of these amortized intangible assets is 7.9 years . The pro forma financial information presented below includes the effects of the EFS acquisition as if it had been consummated on January 1, 2015. These pro forma results have been calculated after applying the Company's accounting policies and adjusting results to reflect the intangible amortization and interest expense associated with the 2016 Credit Agreement used to fund the acquisition and related income tax results assuming they were applied and incurred since January 1, 2015. In addition, non-recurring costs that were incurred in 2016 and are directly attributable to the acquisition have been reflected in pro forma results for the year ended December 31, 2015. Such adjustments include $19,168 of transaction costs and $7,074 of expenses incurred as part of the July 2016 debt modification and extinguishment, net of the related income tax results. The pro forma results of operations do not include any cost savings or other synergies that may result from the acquisition or any estimated integration costs that have been or will be incurred by the Company. Accordingly, the following pro forma information is not necessarily indicative of either the future results of operations or results that would have been achieved if the acquisition had taken place at the beginning of 2015. Subsequent to the July 1, 2016 acquisition date, the operations of EFS contributed revenues of approximately $83,300 and net income before taxes of approximately $5,800 to the Company's 2016 consolidated statement of income. The following represents unaudited pro forma operational results as if the acquisition had occurred as of January 1, 2015: Year Ended December 31, 2016 2015 Total revenues $ 1,089,880 $ 994,619 Net earnings attributable to shareholders $ 42,821 $ 36,763 Pro forma net income attributable to shareholders per common share: Basic $ 1.00 $ 0.86 Diluted $ 1.00 $ 0.86 Benaissance On November 18, 2015, the Company purchased the stock of Benaissance for $80,677 . The transaction was financed through the Company’s cash on hand and existing credit facility. Benaissance provides financial management for health benefits administration by offering SaaS solutions for individual single point and consolidated group premium billing. The Company acquired Benaissance to enhance the Company's positioning in the growing healthcare market. The Company obtained information to determine the fair values of certain assets acquired and liabilities assumed throughout the one year measurement period and recorded adjustments to the assets acquired and liabilities assumed, resulting in the recording of other intangible assets and goodwill as described below. Goodwill is expected to be deductible for tax purposes. Since the acquisition date, the operations of Benaissance contributed net revenues of approximately $2,085 and net income of approximately $399 during 2015. The results of operations for Benaissance are presented in the Company's Health and Employee Benefit Solutions segment. The following is a summary of the final allocation of the purchase price to the assets and liabilities acquired: Consideration paid (net of cash acquired) $ 80,677 Less: Accounts receivable 1,594 Other tangible assets and liabilities, net 314 Acquired software and developed technology (a) 10,300 Customer relationships (b) 27,700 Trade name (c) 1,500 Recorded goodwill $ 39,269 (a) Weighted average life – 5.0 years . (b) Weighted average life – 7.6 years . (c) Weighted average life – 8.1 years (a) (b) (c) The weighted average life of these amortized intangible assets is 6.9 years . No pro forma information has been included in these financial statements as the operations of Benaissance for the period that they were not part of the Company are not material to the Company's revenues, net income and earnings per share. Acquisition of remaining 49% of UNIK On August 31, 2015, the Company acquired the remaining 49 percent ownership in UNIK for $46,018 .

Divestitures

Divestitures	12 Months Ended
	Dec. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	4. Divestitures Telapoint During the year ended December 31, 2017, the Company sold $8,942 in net assets of its Telapoint business for proceeds of $29,900 , subject to a working capital adjustment. The sale resulted in a pre-tax book gain of $20,958 . Costs incurred related to this divestiture were immaterial. Prior to the sale, the Telapoint business was assigned to our North American Fleet reporting unit, which is included within our Fleet Solutions reportable segment. The divestiture was not material to the Company's annual revenue, net income or earnings per share. The Company does not view this divestiture as a strategic shift in its operations. rapid! PayCard On January 7, 2015, the Company sold the assets of its rapid! PayCard operations for $ 20,000 , which resulted in a pre-tax book gain of approximately $ 1,215 . The Company's primary focus in the U.S. continues to be in the fleet, travel, and healthcare industries. As such, the Company divested the operations of rapid! PayCard, which were not material to the Company's annual revenue, net income or earnings per share. The Company does not view this divestiture as a strategic shift in its operations.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Accounts Receivable	5. Accounts Receivable In general, the Company’s trade receivables provide for payment terms of 30 days or less. Receivables not paid within the terms of the customer agreement are generally subject to late fees based upon the outstanding customer receivable balance. The Company extends revolving credit to certain small fleet customers. These accounts are also subject to late fees and balances that are not paid in full are subject to interest charges based on the revolving balance. The Company had approximately $12,200 and $3,400 in receivables with revolving credit balances as of December 31, 2017 and 2016 , respectively. Concentration of Credit Risk The receivables portfolio consists of a large group of homogeneous smaller balances from customers across a wide range of industries, which are collectively evaluated for impairment. No one customer represented 10 percent or more of the outstanding receivables balance as of December 31, 2017 . One customer represented 11 percent of the outstanding receivables balance as of December 31, 2016 . The following table presents the outstanding balance of accounts receivable that are less than 60 days past due, in each case as a percentage of total trade accounts receivable: December 31, Delinquency Status 2017 2016 29 days or less past due 95 % 93 % 59 days or less past due 97 % 98 % Reserves for Accounts Receivable Receivables are generally written off when they are 150 days past due or upon declaration of bankruptcy by the customer. The reserve for credit losses is calculated by an analytic model that also takes into account other factors, such as the actual charge-offs for the preceding reporting periods, expected charge-offs and recoveries for the subsequent reporting periods, a review of past due accounts receivable balances, changes in customer payment patterns, known fraudulent activity in the portfolio, as well as leading economic and market indicators. The following table presents changes in the accounts receivable allowances: Year ended December 31, 2017 2016 2015 Balance, beginning of year $ 21,454 $ 14,672 $ 14,627 Provision for credit losses 1 61,148 33,348 22,825 Charges to other accounts 2 16,869 10,166 6,155 Charge-offs (77,229 ) (43,309 ) (33,885 ) Recoveries of amounts previously charged-off 7,526 6,201 5,202 Currency translation 439 376 (252 ) Balance, end of year $ 30,207 $ 21,454 $ 14,672 1 During 2017, the majority of the increase relates to higher incidences of magnetic stripe card skimming fraud. 2 The Company earns revenue by assessing monthly finance fees on accounts with overdue balances. These fees are recognized as revenue at the time the fees are assessed. The finance fee is calculated using the greater of a minimum charge or a stated late fee rate multiplied by the outstanding balance that is subject to a late fee charge. On occasion, these fees are waived to maintain customer goodwill. Charges to other accounts represents the offset against the late fee revenue recognized when the Company establishes a reserve for such waived amounts.

Investments

Investments	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investments	6. Investments Available-for-sale Securities The Company’s available-for-sale securities as of December 31, 2017 and 2016 , are presented below: Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (a) 2017 Mortgage-backed securities $ 325 $ 4 $ 24 $ 305 Asset-backed securities 350 — 5 345 Municipal bonds 539 1 6 534 Equity securities (b) 22,888 — 714 22,174 Total available-for-sale securities $ 24,102 $ 5 $ 749 $ 23,358 2016 Mortgage-backed securities $ 498 $ 15 $ 23 $ 490 Asset-backed securities 650 — 2 648 Municipal bonds 697 1 16 682 Equity securities (b) 22,414 — 709 21,705 Total available-for-sale securities $ 24,259 $ 16 $ 750 $ 23,525 (a) The Company’s techniques used to measure the fair value of its investments are discussed in Note 17 , Fair Value . (b) Excludes $6,798 and $5,673 in equity securities designated as trading as of December 31, 2017 and 2016 , respectively, included in other assets on the consolidated balance sheets. See Note 16 , Employee Benefit Plans for additional information. The Company reviews its investments to identify and evaluate indications of possible impairment. Factors considered in determining whether a loss is temporary include the length of time and extent to which the fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. Substantially all of the Company’s fixed income securities are rated investment grade or better. The amount of available-for-sale securities that have been in a continuous unrealized loss position for more than twelve months is insignificant. The Company’s management has determined that these gross unrealized losses at December 31, 2017 and 2016 are temporary in nature. The Company had maturities of available-for-sale securities of $631 , $495 and $594 for the years ended December 31 2017 , 2016 and 2015 , respectively. The maturity dates of the Company’s available-for-sale securities are as follows: December 31, 2017 2016 Cost Fair Value Cost Fair Value Due after 1 year through year 5 $ — $ — $ 165 $ 165 Due after 5 years through year 10 390 385 529 529 Due after 10 years 499 494 653 636 Mortgage-backed securities with original maturities of 30 years 325 305 498 490 Equity securities with no maturity dates 22,888 22,174 22,414 21,705 Total $ 24,102 $ 23,358 $ 24,259 $ 23,525

Property, Equipment and Capital

Property, Equipment and Capitalized Software, Net	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Equipment and Capitalized Software, Net	7. Property, Equipment and Capitalized Software, Net Property, equipment and capitalized software, net consist of the following: December 31, 2017 2016 Furniture, fixtures and equipment $ 75,015 $ 69,513 Computer software 308,362 254,163 Software under development 21,452 49,922 Leasehold improvements 23,248 21,257 Capital leases 759 759 Total 428,836 395,614 Less: accumulated depreciation and amortization (264,928 ) (228,336 ) Total property, equipment and capitalized software, net $ 163,908 $ 167,278 Depreciation expense was $49,913 , $43,821 and $35,285 in 2017 , 2016 and 2015 , respectively. During the year ended December 31, 2017, the Company impaired approximately $28,000 of software under development. See Note 22 , Impairment and Restructuring Activities for further information. The Company did not incur significant impairment charges during 2016 and 2015 .

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	8. Goodwill and Other Intangible Assets Goodwill The changes in goodwill during the period January 1 to December 31, 2017 were as follows: Fleet Solutions Segment Travel and Corporate Solutions Segment Health and Employee Benefit Solutions Segment Total Gross goodwill, January 1, 2017 $ 1,293,138 $ 202,771 $ 353,722 $ 1,849,631 Acquisition adjustments for EFS (37,296 ) (6,176 ) — (43,472 ) Acquisition of AOC — 67,706 — 67,706 Divestiture of Telapoint (4,469 ) — — (4,469 ) Impact of foreign currency translation 18,345 740 (214 ) 18,871 Gross goodwill, December 31, 2017 1,269,718 265,041 353,508 1,888,267 Accumulated impairment, January 1, 2017 (855 ) (10,335 ) — (11,190 ) Impact of foreign currency translation (72 ) (873 ) — (945 ) Accumulated impairment, December 31, 2017 $ (927 ) $ (11,208 ) $ — $ (12,135 ) Net goodwill, January 1, 2017 $ 1,292,283 $ 192,436 $ 353,722 $ 1,838,441 Net goodwill, December 31, 2017 $ 1,268,791 $ 253,833 $ 353,508 $ 1,876,132 The changes in goodwill during the period January 1 to December 31, 2016 were as follows: Fleet Solutions Segment Travel and Corporate Solutions Segment Health and Employee Benefit Solutions Total Gross goodwill, January 1, 2016 $ 735,770 $ 38,134 $ 350,321 $ 1,124,225 Acquisition of EFS 561,119 167,771 — 728,890 Acquisition adjustments — — 502 502 Impact of foreign currency translation (3,751 ) (3,134 ) 2,899 (3,986 ) Gross goodwill, December 31, 2016 1,293,138 202,771 353,722 1,849,631 Accumulated impairment, January 1, 2016 (867 ) (10,480 ) — (11,347 ) Impact of foreign currency translation 12 145 — 157 Accumulated impairment, December 31, 2016 $ (855 ) $ (10,335 ) $ — $ (11,190 ) Net goodwill, January 1, 2016 $ 734,903 $ 27,654 $ 350,321 $ 1,112,878 Net goodwill, December 31, 2016 $ 1,292,283 $ 192,436 $ 353,722 $ 1,838,441 Other Intangible Assets Other intangible assets consist of the following: December 31, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Definite-lived intangible assets Acquired software and developed technology $ 203,861 $ (96,197 ) $ 107,664 $ 187,499 $ (69,483 ) $ 118,016 Customer relationships 1,257,232 (269,216 ) 988,016 1,247,624 (167,301 ) 1,080,323 Licensing agreements 34,546 (15,029 ) 19,517 30,760 (9,126 ) 21,634 Non-compete agreement — — — 4,000 — 4,000 Patent 2,581 (2,076 ) 505 2,380 (1,724 ) 656 Trade name 44,079 (10,309 ) 33,770 41,029 (6,508 ) 34,521 $ 1,542,299 $ (392,827 ) $ 1,149,472 $ 1,513,292 $ (254,142 ) $ 1,259,150 Indefinite-lived intangible assets Trademarks, trade names and brand names 4,575 6,318 Total $ 1,154,047 $ 1,265,468 During the years ended December 31, 2017, 2016 and 2015, amortization expense was $153,811 , $97,829 and $47,792 , respectively. The following table presents the estimated amortization expense related to the definite-lived intangible assets listed above for each of the next five fiscal years: 2018 $ 141,583 2019 127,393 2020 116,164 2021 100,367 2022 $ 89,267

Accounts Payable

Accounts Payable	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Accounts Payable	9. Accounts Payable Accounts payable consists of: December 31, 2017 2016 Merchant payables $ 720,553 $ 520,058 Other payables 90,809 97,060 Accounts payable $ 811,362 $ 617,118

Deposits, Borrowed Federal Fund

Deposits, Borrowed Federal Funds and Other Debt	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Deposits, Borrowed Federal Funds and Other Debt	10. Deposits, Borrowed Federal Funds and Other Debt Deposits and Borrowed Federal Funds WEX Bank has issued certificates of deposit with maturities ranging from 3 months to 3 years and with interest rates ranging from 1.00 percent to 2.15 percent as of December 31, 2017 . WEX Bank may issue certificates of deposits without limitation, subject to FDIC rules governing minimum financial ratios, which include risk-based asset and capital requirements. As of December 31, 2017 , all certificates of deposit were in denominations of $250 or less, corresponding to FDIC deposit insurance limits. The Company requires deposits from certain customers as collateral for credit that has been extended. These deposits are generally non-interest bearing. Interest-bearing money market deposits are issued in denominations of $250 or less, and pay interest at variable rates based on LIBOR or the Federal Funds rate. Money market deposits may be withdrawn by the holder at any time, although notification may be required and the monthly number of transactions is limited. The following table presents information about deposits: December 31, 2017 2016 Certificates of deposit with maturities within 1 year $ 630,879 $ 517,524 Certificates of deposit with maturities greater than 1 year and less than 5 years 306,865 208,048 Interest-bearing money market deposits 285,899 325,464 Customer deposits 70,211 67,787 Total deposits $ 1,293,854 $ 1,118,823 Weighted average cost of funds on certificates of deposit outstanding 1.51 % 0.96 % Weighted average cost of interest-bearing money market deposits 1.49 % 0.76 % The Company also had federal funds lines of credit totaling $400,000 and $250,000 at December 31, 2017 and 2016 , respectively. There were no borrowings against these lines of credit at December 31, 2017 and 2016 . Other Debt WEX Latin America Debt WEX Latin America had debt of approximately $9,747 and $30,755 as of December 31, 2017 and 2016 , respectively. This is comprised of credit facilities and loan arrangements with various maturity dates. Participation Debt WEX Bank maintains agreements with third-party banks to fund customer balances that exceed WEX Bank's lending limit to an individual customer. During the year ended December 31, 2017 , the Company increased the funding capacity of these arrangements by $90,000 to $185,000 . Associated borrowings carry a variable interest rate of 1 month to 3 month LIBOR plus a margin of 225 basis points . The balance of the debt was approximately $185,000 and $95,000 at December 31, 2017 and December 31, 2016 respectively, and was secured by an interest in the underlying customer receivables. The balance will fluctuate on a daily basis based on customer funding needs. The commitment will mature in amounts of approximately $85,000 and $50,000 on May 30, 2018 and December 31, 2021 , respectively, with the remaining $50,000 maturing on demand. The following table presents the average interest rates and balances for deposits, borrowed federal funds and other debt: Year ended December 31, 2017 2016 2015 Average interest rate: Deposits 1.22 % 0.94 % 0.65 % Borrowed federal funds 1.24 % 0.69 % 0.39 % Interest-bearing money market deposits 1.12 % 0.50 % 0.25 % WEX Latin America debt 21.21 % 19.70 % 15.21 % Participation agreement 3.46 % 2.94 % 2.57 %

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	11. Derivative Instruments The Company is exposed to certain market risks relating to its ongoing business operations. From time to time, the Company enters into derivative instrument arrangements to manage various risks including interest rate risk, foreign exchange risk, and commodity price risk. None of these derivative instruments qualify for hedge accounting treatment. Interest Rate Swap Agreements At December 31, 2017 , we had variable-rate borrowings of $1.7 billion under our 2016 Credit Agreement. During 2016 and 2017, we entered into five interest rate swap contracts. Collectively, these derivative contracts are intended to fix the future interest payments associated with $1.3 billion of our variable rate borrowings at between 0.896% to 2.212% . The notional amounts, fixed and variable interest rates and maturities of the interest rate swap agreements are as follows: Tranche A Tranche B Tranche C Tranche D Tranche E Notional amount at inception $300,000 $200,000 $400,000 $150,000 $250,000 Amortization N/A N/A 5% annually N/A N/A Maturity date 12/30/2022 12/30/2022 12/31/2020 12/31/2020 12/31/2018 Fixed interest rate 2.204% 2.212% 1.108% 1.125% 0.896% See Note 17 , Fair Value for more information regarding the valuation of the Company's interest rate swaps. Foreign Currency Exchange Program The Company utilizes a limited foreign currency exchange hedging program, entering into short-term foreign currency swaps to convert the foreign currency exposures of certain foreign currency denominated intercompany loans and investments to the base currency. The Company will continue to monitor its foreign currency exposure for discrete items and may, from time to time, hedge certain foreign currency transactions. The following table summarizes the contracts related to the Company's foreign currency swaps, which settle in U.S. dollars at various dates within 5 days after year-end: Aggregate Notional Amount December 31, 2017 2016 Australian dollar A$ 5,000 A$ 15,000 The amount of gains and losses associated with these foreign currency swaps were not material for the years ended December 31, 2017, 2016 and 2015. Fuel Derivatives Program The Company previously utilized fuel price derivative instruments, which were designed to reduce the volatility of the Company’s cash flows associated with its fuel price-related earnings exposure in North America. After the first quarter of 2016, the Company was no longer hedged for changes in fuel prices. Management will continue to monitor the fuel price market and evaluate its alternatives as it relates to this hedging program. The following table summarizes the changes in fair value of the fuel price derivatives which have been recorded on the consolidated statements of income: Year ended December 31, 2016 2015 Realized gains $ 5,718 $ 41,810 Change in unrealized fuel price derivatives (5,007 ) (35,962 ) Net realized and unrealized gains on fuel price derivatives $ 711 $ 5,848 Consolidated Derivative Instruments The following table presents information on the location and amounts of derivative fair values on the consolidated balance sheets, which are recorded at fair value: Asset Derivatives Liability Derivatives December 31, 2017 December 31, 2016 December 31, 2017 December 31, 2016 Derivatives Not Designated as Hedging Instruments Balance Fair Balance Fair Balance Fair Balance Fair Interest rate swaps Other assets $ 15,919 Other assets $ 12,908 Other liabilities $ 1,697 Other liabilities $ — Foreign currency contracts Accounts receivable $ — Accounts receivable $ 29 Accounts payable $ — Accounts payable $ — The following table presents information on the location and amounts of derivative gains and losses: Derivatives Not Designated as Hedging Instruments Location of Gain Recognized in Amount of Gain (Loss) Recognized in December 31, 2017 2016 2015 Foreign currency contracts Net foreign currency gain $ — $ 59 $ 27,236 Interest rate swap agreements - unrealized portion Net unrealized gains on interest rate swap agreements $ 1,314 $ 12,908 $ — Interest rate swap agreements - realized portion Financing interest income $ 214 $ — $ — Commodity contracts Net realized and unrealized gains on fuel price derivatives $ — $ 711 $ 5,848

Off-Balance Sheet Arrangements

Off-Balance Sheet Arrangements Off-Balance Sheet Arrangements	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Off-Balance Sheet Arrangements	12. Off-Balance Sheet Arrangements WEX Europe Services Accounts Receivable Factoring During the first quarter of 2017, WEX Europe Services entered into a factoring arrangement with an unrelated third-party financial institution (the “Purchasing Bank”) to sell certain of its accounts receivable in order to accelerate the collection of the Company's cash and reduce internal costs, thereby improving liquidity. Under this arrangement, the Purchasing Bank establishes a credit limit for each customer account. The factored receivables are without recourse to the extent that the customer balances are maintained at or below the established credit limit. For customer receivable balances in excess of the Purchasing Bank's credit limit, the Company maintains the risk of default. The Company obtained a true sale opinion from an independent attorney, which states that the factoring agreement creates a sale of receivables under local law for amounts transferred both below and above the established credit limits. Additionally, there are no indications of the Company's continuing involvement in the factored receivables. As a result, the Purchasing Bank is deemed the purchaser of these receivables and is entitled to enforce payment of these amounts from the debtor. This factoring arrangement is accounted for as a sale and accordingly the Company records the receivables sold as a reduction of accounts receivable and proceeds as cash provided by operating activities. The Company sold approximately $574,400 of receivables under this arrangement during year ended December 31, 2017. Proceeds received are recorded net of applicable expenses, interest and commissions. This resulted in a loss on factoring of approximately $3,700 for the year ended December 31, 2017, which was recorded in Other expenses in the consolidated statement of income. As of December 31, 2017, the Company had associated factoring receivables of approximately $61,800 , of which approximately $3,700 were in excess of the established credit limit. Charge-backs on balances in excess of the credit limit during the year ended December 31, 2017 were insignificant. WEX Latin America Accounts Receivable Factoring During the first quarter of 2017, WEX Latin America entered into a factoring agreement to sell certain unsecured receivables associated with our salary payment card product, without recourse, to an unrelated third-party financial institution. Under the terms of the agreement, the Company retains no rights or interest and has no obligations with respect to the receivables. As such, the factoring under this arrangement is accounted for as a sale. The Company sold $16,300 of receivables during the year ended December 31, 2017. This resulted in a loss on factoring of $800 for the year ended December 31, 2017, which was recorded in Other expenses in the consolidated statement of income. The receivables sold under this agreement were recorded as a reduction of accounts receivable and proceeds as cash provided by operating activities. There were no sales under this factoring arrangement during the second half of 2017; a securitization agreement replaced this factoring arrangement as Brazil's primary funding mechanism. See Note 13, Financing Debt , for more information on this securitization arrangement.

Financing Debt

Financing Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Financing Debt	13. Financing Debt The following table summarizes the Company's outstanding borrowings under the agreements outlined below: Year ended December 31, 2017 2016 Revolving line-of-credit facility $ 136,535 $ — Term loans 1,602,875 1,637,625 Revolving line-of-credit facility and term loans (a) $ 1,739,410 $ 1,637,625 Unamortized debt issuance costs (32,346 ) (38,334 ) Revolving line-of-credit facility and term loans, net $ 1,707,064 $ 1,599,291 Notes outstanding (a) $ 400,000 $ 400,000 Unamortized debt issuance costs (3,731 ) (4,466 ) Notes outstanding, net $ 396,269 $ 395,534 (a) See Note 17, Fair Value for more information regarding the Company's 2016 Credit Agreement and notes outstanding. 2016 Credit Agreement On July 1, 2016, the Company entered into the 2016 Credit Agreement, which replaced the 2014 Credit Agreement. The 2016 Credit Agreement provided for term loan facilities and a secured revolving credit facility, with a sublimit for letters of credit and swingline loans. Effective October 30, 2017, the Company entered into a Second Amendment to the 2016 Credit Agreement, which added $100,000 of capacity to its revolving line of credit to provide additional liquidity and flexibility. As amended, the 2016 Credit Agreement provides for a tranche A term loan facility in an amount equal to $455,000 , a tranche B term loan facility in an amount equal to $1,200,000 and a $570,000 secured revolving credit facility. Under this agreement, $1,025,000 matures on July 1, 2021 and $1,200,000 matures on July 1, 2023. Prior to maturity, amounts under the credit facility will be reduced by mandatory payments. Additional loans may be made available under the 2016 Credit Agreement upon request of the Company subject to specified terms and conditions, including receipt of lender commitments. Proceeds from the 2016 Credit Agreement may be used for working capital purposes, acquisitions, payment of dividends and other restricted payments, refinancing of indebtedness and other general corporate purposes. As of December 31, 2017, the Company had $570,000 borrowing capacity, subject to the covenants as described below. As of December 31, 2017 and 2016 , the Company has posted approximately $27,500 and $13,300 , respectively, in letters of credit as collateral for lease agreements and virtual card and fuel payment processing activity at its foreign subsidiaries. The Company had approximately $406,000 available under the revolving credit facility as of December 31, 2017. As of both December 31, 2017 and 2016 , amounts outstanding under the 2016 Credit Agreement bore a weighted average effective interest rate of 4.2% . Effective July 3, 2017, the Company repriced the secured term loans under the 2016 Credit Agreement (the “2016 First Amendment”), which reduced the applicable interest rate margin at current borrowing levels for both LIBOR borrowings and base rate borrowings for the Company's tranche A term loans and tranche B term loans. The consolidated leverage ratio as defined in the 2016 Credit Agreement (i.e. consolidated funded indebtedness less up to $350,000 in permitted securitization transactions of the Company and its subsidiaries to consolidated EBITDA) was also modified for purposes of calculating the interest rate margin for tranche A term loans and revolving loans and determining compliance with the financial covenant by allowing the Company to exclude up to $75 million of certain corporate cash balances for purposes of determining consolidated funded indebtedness. After giving effect to the terms of the 2016 First Amendment, amounts outstanding under the 2016 Credit Agreement were repriced to bear interest at a rate equal to, at the Company’s option, (a) the Eurocurrency Rate, as defined in the 2016 Credit Agreement, plus a margin of between 1.75% to 3.25% ( 2.75% at December 31, 2017 ) with respect to the revolving credit facility, between 1.75% to 2.75% ( 2.25% at December 31, 2017) with respect to the tranche A term loan facility, which represents a reduction of 50 basis points and 2.75% with respect to the tranche B term loan facility, which represents a reduction of 75 basis points (with the Eurocurrency Rate subject to a 0.00% floor), in each case, based on the consolidated leverage ratio or (b) the highest of (i) the Federal Funds Rate plus 0.50% , (ii) the prime rate announced by Bank of America, and (iii) the Eurocurrency Rate plus 1.00% , in each case plus a margin of 0.75% to 2.25% ( 1.75% at December 31, 2017 ) with respect to the revolving credit facility, 0.75% to 1.75% ( 1.25% at December 31, 2017) with respect to the tranche A term loan facility and 2.25% with respect to the tranche B term loan facility, with the margin determined in the case of the revolving credit facility and the tranche A term loan facility based on the consolidated leverage ratio. The Company maintains interest rate swap agreements to manage the interest rate risk associated with its outstanding variable-interest rate borrowings under the 2016 Credit Agreement. See Note 11 , Derivative Instruments , for further discussion. In addition, the Company has agreed to pay a quarterly commitment fee at a rate per annum ranging from 0.30% to 0.50% ( 0.45% at December 31, 2017 ) based on the consolidated leverage ratio of the daily unused portion of the 2016 Credit Agreement. The tranche B term loan facility was issued with an original issue discount of 1.00% . As the debt repricings under the 2016 First Amendment were not considered substantially different, the Company applied modification accounting and no gain or loss was recognized as a result of the debt modification. Amounts paid as part of this repricing were not material. The 2016 Credit Agreement requires the Company to prepay outstanding term loans, subject to certain exceptions: • solely with respect to the tranche B term loan facility, currently with 50% (subject to reduction to 25% and 0% based upon the Company’s consolidated leverage ratio) of the Company’s annual Excess Cash Flow (as defined in the 2016 Credit Agreement); • with 100% of the net cash proceeds of certain asset sales where the proceeds exceed certain thresholds, and certain casualty and condemnation events, subject to reinvestment rights and certain other exceptions; and • with 100% of the net cash proceeds of any incurrence or issuance of certain debt, other than debt permitted under the 2016 Credit Agreement. The Company may voluntarily prepay outstanding loans from time to time, subject to certain conditions, without premium or penalty other than customary “breakage” costs with respect to Eurocurrency Rate loans, provided, however, that if on or prior to the date that is six (6) months following the 2016 First Amendment effective date, the Company prepays any loans under the tranche B term loan facility in connection with a repricing transaction, the Company must pay a prepayment premium of 1.00% of the aggregate principal amount of the tranche B term loans so prepaid. The Company is required to make scheduled quarterly payments each equal to 1.25% in the case of the tranche A term loan facility, and 0.25% in the case of the tranche B term loan facility, of the original principal amount of the respective term loans made on the closing date, with the balance due at maturity. The 2016 Credit Agreement contains customary representations and warranties, as well as affirmative and negative covenants. The 2016 Credit Agreement also requires, solely for the benefit of the lenders under the tranche A term loan facility and the revolving credit facility, that the Company maintain at the end of each fiscal quarter the following financial ratios: • a consolidated EBITDA to consolidated interest charge coverage ratio of no less than 3.25 to 1.00 ; and • a consolidated funded indebtedness (excluding (i) up to an agreed amount of consolidated funded indebtedness under permitted securitization transactions and (ii) the non-recourse portion of any permitted factoring transaction) to consolidated EBITDA ratio of, initially, no more than 5.40 to 1.00 , which ratio shall step down to 5.25 to 1.00 at December 31, 2016 , 5.00 to 1.00 at December 31, 2017 , 4.25 to 1.00 at December 31, 2018 and 4.00 to 1.00 at December 31, 2019 . The obligations under the 2016 Credit Agreement are secured by a security interest in, subject to certain exceptions, substantially all of the assets of the Company pursuant to the terms of a U.S. Security Agreement, dated as of July 1, 2016 , in favor of Bank of America, as collateral agent for the lenders. Debt Covenants The 2016 Credit Agreement and the Indenture contain covenants that limit the Company and its subsidiaries’ ability and the ability of its restricted subsidiaries and, in certain limited circumstances, WEX Bank and the Company’s other regulated subsidiaries, to (i) incur additional debt, (ii) pay dividends or make other distributions on, redeem or repurchase capital stock, or make investments or other restricted payments, (iii) enter into transactions with affiliates, (iv) dispose of assets or issue stock of restricted subsidiaries or regulated subsidiaries, (v) create liens on assets, or (vi) effect a consolidation or merger or sell all, or substantially all, of the Company’s assets. These covenants are subject to important exceptions and qualifications. At any time that the Notes are rated investment grade, which is not currently the case, and subject to certain conditions, certain covenants will be suspended with respect to the Notes. WEX Bank and the Company’s other regulated subsidiaries will not be subject to some of the restrictive covenants in the Indenture that place limitations on the Company and its restricted subsidiaries’ actions, and where WEX Bank and the Company’s regulated subsidiaries are subject to covenants, there are significant exceptions and limitations on the application of those covenants to WEX Bank and the Company’s regulated subsidiaries. 2014 Credit Agreement On July 1, 2016, concurrently with the financing transactions discussed above, the Company repaid in full all outstanding amounts under the 2014 Credit Agreement and terminated all commitments by the lenders to extend further credit thereunder and all guarantees and security interests granted by the Company to the lenders thereunder. The Company did not incur any early termination penalties in connection with the termination of the 2014 Credit Agreement. As of June 30, 2016 , the Company had borrowings, net of loan origination fees, of $282,639 and $445,000 against its revolving credit facility and amortizing term loan arrangement, respectively. As of June 30, 2016 , amounts outstanding under the amortizing term loan bore interest at a rate of LIBOR plus 200 basis points. The revolving credit facility bore interest at a rate equal to, at the Company's option, (a) LIBOR plus 200 basis points, (b) the prime rate plus 100 basis points for domestic borrowings; and the Eurocurrency rate plus 200 basis points for international borrowings. Notes Outstanding On January 30, 2013, the Company completed a $400,000 offering in an aggregate principal amount of 4.750 percent senior notes due 2023 (the “Notes”) at an issue price of 100.0 percent of the principal amount, plus accrued interest, from January 30, 2013, in a private placement to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”), and in offshore transactions pursuant to Regulation S under the Securities Act. The Notes were issued pursuant to the Indenture among the Company, the guarantors listed therein, and The Bank of New York Mellon Trust Company, N.A., as trustee. The Notes will mature on February 1, 2023, and interest will accrue at the rate of 4.750 percent per annum. Interest is only payable semiannually in arrears on February 1 and August 1 of each year, commencing on August 1, 2013. The Notes are guaranteed on a senior secured basis by each of the Company’s restricted subsidiaries and each of the Company’s regulated subsidiaries that guarantees the Company’s 2013 Credit Agreement, which, as of the issue date, consist of four of the Company’s restricted subsidiaries. WEX Bank, which represents a substantial amount of the Company’s operations, is not a guarantor and is not subject to many of the restrictive covenants in the indenture governing the Notes. The Notes and guarantees described above are general senior secured obligations ranking equally with the Company’s existing and future senior debt, senior in right of payment to all of the Company’s subordinated debt, and effectively equal in lien priority to the Company’s 2016 Credit Agreement. In addition, the Notes and the guarantees are structurally subordinated to all liabilities of the Company’s subsidiaries that are not guarantors, including WEX Bank. At any time on or after February 1, 2018, the Company may redeem the Notes, in whole or in part, at the following redemption prices (expressed as a percentage of principal amount of the Notes) if redeemed during the twelve month period beginning on February 1 of the following years: (i) 102.375 percent in 2018, (ii) 101.583 percent in 2019, (iii) 100.792 percent in 2020, and (iv) 100.0 percent in 2021 and thereafter; plus, in each case, accrued and unpaid interest, if any, to, but excluding, the date of redemption. At any time prior to February 1, 2018, the Company could have redeemed the Notes, in whole or in part, at a redemption price equal to 100.0 percent of the principal amount of such Notes redeemed plus a “make-whole” premium (as described in the Indenture), together with any accrued and unpaid interest, if any, to, but excluding, the date of redemption. Upon the occurrence of a change of control of the Company (as described in the Indenture), the Company must offer to repurchase the Notes at 101 percent of the principal amount of the Notes, plus accrued and unpaid interest, if any, to, but excluding, the date of repurchase. Debt Commitments The table below summarizes the Company's annual principal payments on its term loans under the 2016 Credit Agreement for each of the next five years: 2018 $ 34,750 2019 34,750 2020 34,750 2021 364,625 2022 $ 12,000 WEX Latin America Securitization Facility During the second quarter of 2017, WEX Latin America entered into a securitized debt agreement to sell certain unsecured receivables associated with our salary payment card product to an investment fund managed by an unrelated third-party financial institution. Under the terms of the agreement, the investment fund's purchase price incorporates a discount relative to the face value of the transferred receivables. Additionally, the investment fund compensates WEX Latin America for continuing to service these receivables through their duration, which on average is less than six months. This securitization arrangement does not meet the derecognition conditions and accordingly WEX Latin America continues to report the transferred receivables in our consolidated balance sheet with no change in the basis of accounting. Additionally, we recognize the cash proceeds received from the investment fund and record offsetting securitized debt in our consolidated balance sheet. During 2017, WEX Latin America securitized approximately $49,100 of receivables to the investment fund for cash proceeds of approximately $43,800 . This $5,300 discount is recognized as operating interest in the Company's consolidated statements of income using the effective interest method over the weighted average term of the salary advances. The Company received approximately $3,000 of servicing fee income upon the sale of these receivables, which is recognized as other revenue in our consolidated statements of income on a straight-line basis over the anticipated loan servicing period. As of December 31, 2017, approximately $19,000 of securitized debt is recognized on our consolidated balance sheet related to this securitization arrangement. Australian Securitization Facility During the second quarter of 2017, the Company extended an existing securitized debt agreement with the Bank of Tokyo-Mitsubishi UFJ, Ltd. through April 2018. Under the terms of the agreement, each month, on a revolving basis, the Company sells certain of its Australian receivables to the Company's Australian Securitization Subsidiary. The Australian Securitization Subsidiary, in turn, uses the receivables as collateral to issue asset-backed commercial paper (“securitized debt”) for approximately 85 percent of the securitized receivables. The amount collected on the securitized receivables is restricted to pay the securitized debt and is not available for general corporate purposes. The Company pays a variable interest rate on the outstanding balance of the securitized debt, based on the Australian Bank Bill Rate plus an applicable margin. The interest rate was 2.53 percent and 2.65 percent as of December 31, 2017 and 2016 , respectively. The Company had securitized debt under this facility of approximately $90,000 and $78,600 as of December 31, 2017 and 2016 , respectively. European Securitization Facility On April 7, 2016, the Company entered into a five year securitized debt agreement with the Bank of Tokyo-Mitsubishi UFJ, Ltd. Under the terms of the agreement, the Company sells certain of its receivables from selected European countries to its European Securitization Subsidiary. The European Securitization Subsidiary, in turn, uses the receivables as collateral to issue securitized debt. The amount collected on the securitized receivables is restricted to pay the securitized debt and is not available for general corporate purposes. The amounts of receivables to be securitized under this agreement are determined by management on a monthly basis. The interest rate was 1.11 percent and 0.95 percent as of December 31, 2017 and 2016 , respectively. The Company had securitized debt under this facility of approximately $17,900 and $5,700 as of December 31, 2017 and 2016 , respectively. Debt Issuance Cost In the third quarter of 2016, the Company capitalized approximately $49,810 of debt issuance costs, including an original issue discount of $12,000 associated with the 2016 Credit Agreement. These debt issuance costs are being amortized into interest expense over the 2016 Credit Agreement's term using the effective interest method for the tranche A and B term loans and the revolver. Additionally, the Company expensed approximately $5,056 during the third quarter of 2016 related to noncapitalizable third-party costs incurred in connection with the modification of the certain 2014 Credit Agreement syndicate loans. The Company recognized a loss of $2,018 associated with the early extinguishment of the 2014 Credit Agreement during the year ended December 31, 2016, including a partial write-off of previously capitalized debt issuance costs and newly paid lender fees associated with the extinguishment of syndicate borrowings. In January 2016, the Company began to incur ticking fees for the debt financing commitment associated with the 2016 Credit Agreement in anticipation of the then pending acquisition of EFS. Pursuant to the terms set forth in the bank commitment letter, the ticking fees were calculated based on the financing commitment in the aggregate amount of $2,125,000 , and remained in place until the closing of the EFS acquisition on July 1, 2016 (see Note 3 , Business Acquisitions and Other Intangible Asset Acquisitions ). Total ticking fees expensed to financing interest were $30,045 for the year ended December 31, 2016. In conjunction with the continued negotiation of the Company's new credit agreement, the amount of ticking fees to be paid at the time of closing was reduced by $7,874 to $22,171 . The excess ticking fees were reflected as a reduction of the $49,810 debt issuance costs related to the 2016 Credit Agreement noted above and will be amortized over the 2016 Credit Agreement's term using the effective interest method for the tranche A and B term loans and the revolver. Other As of December 31, 2017 , WEX Bank pledged approximately $343,800 of fleet receivables held by WEX Bank to the Federal Reserve Bank as collateral for potential borrowings, through the Federal Reserve Bank Discount Window. Amounts that can be borrowed are based on the amount of collateral pledged to the Federal Reserve Bank and were $277,326 as of December 31, 2017 . WEX Bank had no borrowings on this line of credit through the Federal Reserve Bank Discount Window as of December 31, 2017 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes Income (losses) before income taxes consisted of the following: Year ended December 31, 2017 2016 2015 United States $ 149,344 $ 32,622 $ 203,692 Foreign 29,351 54,479 (18,784 ) Total $ 178,695 $ 87,101 $ 184,908 Income taxes from continuing operations consisted of the following for the years ended December 31: United States State Foreign Total 2017 Current $ 2,253 $ 3,687 $ 14,473 $ 20,413 Deferred $ (11,234 ) $ 13,280 $ (2,934 ) (888 ) Income taxes $ 19,525 2016 Current $ (1,232 ) $ 3,033 $ 8,325 $ 10,126 Deferred $ 21,565 $ (5,106 ) $ 3,040 19,499 Income taxes $ 29,625 2015 Current $ 22,570 $ 4,288 $ 9,173 $ 36,031 Deferred $ 37,553 $ 5,631 $ (3,919 ) 39,265 Income taxes $ 75,296 2017 Tax Act On December 22, 2017, the 2017 Tax Act was signed into law making significant changes to the Internal Revenue Code. Changes include, but are not limited to, a federal corporate tax rate decrease from 35% to 21% for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a territorial system and a one-time transition tax on the mandatory deemed repatriation of foreign earnings. The Company has estimated the provision for income taxes in accordance with the 2017 Tax Act and guidance available as of the date of this filing and as a result has recorded a provisional amount of one-time income tax benefit of $60,636 in the fourth quarter of 2017, the period in which the legislation was enacted. The one-time income tax benefit includes: • a tax benefit of $62,488 related to the remeasurement of certain deferred tax assets and liabilities based on the tax rates at which they are expected to reverse in the future; • as discussed in Note 15, Tax Receivable Agreement, for the year ended December 31, 2017, the amount due under our tax receivable agreement decreased primarily as a result of the decline in the federal corporate income tax rate, resulting in the Company recognizing non-taxable income of $15,259 . The favorable tax effect of this permanent difference was $5,726 ; • an income tax expense of $9,098 related to the one-time transition tax on the mandatory deemed repatriation of foreign earnings; and • the reversal of net deferred tax liabilities of $1,520 related to the cumulative undistributed earnings. The 2017 Tax Act also changes the taxation of foreign earnings, and companies generally will not be subject to United States federal income taxes upon the receipt of dividends from foreign subsidiaries and will not be permitted foreign tax credits related to such dividends. However, the 2017 Tax Act creates a new requirement to tax certain foreign earnings relating to GILTI. Based on the recent FASB guidance, the Company can elect an accounting policy choice of either treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current period expense when incurred or factoring such amounts into the Company’s measurement of its deferred taxes. Because of the complexity of the new GILTI tax rules, and anticipated guidance from the U.S. Treasury, we will continue to evaluate this provision of the 2017 Tax Act. Therefore, we have not recorded any deferred taxes related to GILTI and have not elected an accounting policy for GILTI at this time. Undistributed earnings of certain foreign subsidiaries of the Company amounted to $58,675 and $25,824 at December 31, 2017 and 2016, respectively. These earnings are considered to be indefinitely reinvested. Beginning in 2018, except for GILTI, the Company will no longer record United States federal income tax on its share of the income of its foreign subsidiaries, nor will it record a benefit for foreign tax credits related to that income. Accordingly, the Company reversed net deferred tax liabilities related to its cumulative undistributed foreign earnings and deferred tax assets for related foreign tax credits, resulting in a corresponding net tax benefit in 2017. Upon distribution of these earnings in the form of dividends or otherwise, the Company would be subject to withholding taxes payable, where applicable, to foreign countries, but would have no further federal income tax liability. On December 22, 2017, Staff Accounting Bulletin No. 118 was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the 2017 Tax Act. Accordingly, any subsequent adjustments to the amount of one-time benefit of $60,636 will be recorded to current income tax provision during the measurement period which is not expected to extend beyond one year from the enactment date. The effects of other provisions of the 2017 Tax Act are not expected to have a material impact on our consolidated financial statements. The reconciliation between the income tax computed by applying the U.S. federal statutory rate and the reported effective tax rate on income from continuing operations is as follows: Year ended December 31, 2017 2016 2015 Federal statutory rate 35.0 % 35.0 % 35.0 % State income taxes (net of federal income tax benefit) 2.0 1.1 2.5 Foreign income tax rate differential (0.6 ) (4.4 ) 1.4 Revaluation of deferred tax assets for foreign and state tax rate changes, net 0.4 (0.9 ) 0.7 Research and development credit — (0.5 ) 0.2 Release of tax reserves — (4.9 ) — Withholding taxes 0.2 0.3 — 2017 Tax Act (33.9 ) — — Domestic production exclusions — — (1.8 ) Change in valuation allowance 5.8 2.3 1.6 Nondeductible expenses 0.9 3.4 0.3 Incremental tax benefit from share-based compensation awards (0.9 ) — — Other 2.0 2.6 0.8 Effective tax rate 10.9 % 34.0 % 40.7 % Our effective tax rate was 10.9 percent for 2017 as compared to 34.0 percent for 2016 . The decline in our tax rate is primarily due the reduction of our net deferred tax liabilities resulting from the change in federal corporate income tax rate to 21 percent from 35 percent effective January 1, 2018 as part of the 2017 Tax Act, partly offset by the increase in valuation allowance. Our effective tax rate was 34.0 percent for 2016 as compared to 40.7 percent for 2015. The change in our tax rate reflects a shift in jurisdictional profitability between 2015 and 2016. Increased profits in 2016 within tax jurisdictions with tax rates lower than the United States resulted in a reduction to our effective tax rate. Our 2016 tax rate reflects the release of certain historical foreign reserve positions in Australia, primarily driven by a lapse of statute, as well as a reduction in our domestic production activities deduction as a result of lower taxable income in the United States. The tax effects of temporary differences in the recognition of income and expense for tax and financial reporting purposes that give rise to significant portions of the deferred tax assets and the deferred tax liabilities are presented below: December 31, 2017 2016 Deferred assets related to: Reserve for credit losses $ 6,562 $ 7,122 Tax credit carryforwards 1,283 5,178 Stock-based compensation, net 9,858 12,729 Net operating loss carry forwards 54,700 56,501 Accruals 7,355 18,985 Deferred financing costs — 5,420 Other — 164 Total 79,758 106,099 Deferred tax liabilities related to: Other liabilities 2,060 643 Deferred financing costs 7,219 — Property, equipment and capitalized software 22,315 32,759 Intangibles 141,908 118,695 Investment in partnership — 94,354 Total 173,502 246,451 Valuation allowance 17,787 5,620 Deferred income taxes, net $ (111,531 ) $ (145,972 ) Net deferred tax (liabilities) assets by jurisdiction are as follows: December 31, 2017 2016 United States $ (116,229 ) $ (148,389 ) Australia (945 ) (2,020 ) United Kingdom 7,315 6,474 New Zealand 188 183 The Netherlands 249 206 Brazil (1,073 ) (2,497 ) Canada (1,036 ) 71 Deferred income taxes, net $ (111,531 ) $ (145,972 ) The 2017 decrease in our net deferred tax liabilities resulted from the change in federal corporate income tax rate to 21 percent from 35 percent effective January 1, 2018 as part of 2017 Tax Act, partly offset by current year activity. The Company also recorded $34,462 as a reduction to net deferred tax liabilities related to the finalization of purchase price accounting of the EFS acquisition. At December 31, 2017, the Company changed the tax structure of EFS to convert the limited liability company from a partnership to an entity disregarded as separate from its owners for federal tax purposes. Accordingly, investment in partnership deferred tax liability was allocated to the deferred tax liabilities and assets related to the underlying assets, primarily intangibles. The Company had approximately $294,318 of post apportionment state, $112,688 of federal and $77,622 of foreign net operating loss carry forwards at December 31, 2017 and approximately $211,010 of post apportionment state, $103,739 of federal and $54,062 of foreign net operating loss carry forwards at December 31, 2016 . The U.S. losses expire at various times through 2037 . Foreign losses in Brazil and the UK have indefinite carry forward periods. At December 31, 2017, the Company maintained valuation allowances for the following items: (i) acquired and certain net operating losses in the UK (ii) Evolution1’s equity investment in its minority-owned subsidiaries, (iii) state tax credits, and (iv) certain net operating losses and estimated non-deductible expenses. In each case, the Company has determined it is not likely that the benefits will be utilized. No other valuation allowances have been established for any other deferred tax assets as the Company believes it is more likely than not that its deferred tax assets will be utilized within the carry forward periods. During 2017 and 2016 , the Company recorded tax expense of $12,167 and $2,000 , respectively, for net increases to the valuation allowance. The substantial majority of the 2017 increase in valuation allowance was related to the state net operating losses for our parent company’s separate state filings. At December 31, 2017 , the Company had $4,859 of unrecognized tax benefits, net of federal income tax benefit, of which $3,944 , if fully recognized, would decrease our effective tax rate. No significant changes to the existing unrecognized tax benefits are expected within the next 12 months. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. The Company recorded tax expense of $12 and $263 for interest and penalties related to uncertain tax positions for the years ended December 31, 2017 and December 21, 2015, respectively while a tax benefit of $2,251 was recorded for the year ended December 21, 2016. As of December 31, 2017 and 2016, the Company had no material amounts accrued for interest and penalties related to unrecognized tax benefits. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits excluding interest and penalties is as follows: Year ended December 31, 2017 2016 2015 Beginning balance $ 4,960 $ 4,776 $ 4,856 Increases related to prior year tax positions 1,332 4,960 431 Decreases related to prior year tax positions, due to foreign currency exchange — — (511 ) Decreases related to prior year tax positions — (431 ) — Settlements (1,255 ) — — Lapse of statute — (4,345 ) — Ending balance $ 5,037 $ 4,960 $ 4,776 The Company’s primary tax jurisdictions are the United States, Australia and the United Kingdom. The Company or one of its subsidiaries files income tax returns in the United States federal jurisdiction and various state and foreign jurisdictions, where required. In the normal course of business, the Company is no longer subject to income tax examination after the Internal Revenue Service statute of limitations of three years. The Internal Revenue Service is currently in the process of examining the Company’s US federal income tax returns for 2010 through 2015. The Company is currently appealing adjustments proposed by the Internal Revenue Service in connection with the ongoing audits. The Company is also subject to an ongoing examination in New Zealand by Inland Revenue for calendar tax years 2013, 2014 and 2015, but no adjustments have been proposed, and the Company believes its position does not warrant a reserve.

Tax Receivable Agreement

Tax Receivable Agreement	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax Receivable Agreement	15. Tax Receivable Agreement As a consequence of the Company’s separation from its former parent company in 2005, the tax basis of the Company’s net tangible and intangible assets increased (the “Tax Basis Increase”). The Tax Basis Increase reduced the amount of tax that the Company would pay in the future to the extent the Company generated taxable income in sufficient amounts. The Company was contractually obligated, pursuant to its 2005 Tax Receivable Agreement with the Company’s former parent company (Cendant Corporation), to remit 85 percent of any such cash savings. Pursuant to the Separation and Distribution Agreement dated as of July 27, 2006, by and among Cendant Corporation (now known as Avis Budget Group, Inc. or “Avis”), Realogy Corporation (“Realogy”), Wyndham Worldwide Corporation (“Wyndham”) and Travelport Inc., Realogy acquired from Cendant the right to receive 62.5 percent of the payments by WEX Inc. to Cendant and Wyndham acquired from Cendant the right to receive 37.5 percent of the payments by WEX Inc. to Cendant under the 2005 Tax Receivable Agreement. On June 26, 2009, the Company entered into a Tax Receivable Prepayment Agreement with Realogy, pursuant to which the Company paid Realogy $51,000 , net of bank fees and legal expenses, as prepayment in full to settle the remaining obligations to Realogy under the 2005 Tax Receivable Agreement. In connection with the Tax Receivable Prepayment Agreement with Realogy, the Company entered into a Ratification Agreement on June 26, 2009 (the “Ratification Agreement”) with Avis, Realogy and Wyndham which amended the 2005 Tax Receivable Agreement to require the Company to pay 31.875 percent of the future tax savings related to the Tax Basis Increase to Wyndham. The estimated amount of future payments owed to Wyndham is reflected as amounts due under tax receivable agreement on the consolidated balance sheets. The estimate is dependent upon future statutory tax rates and the Company’s ability to generate sufficient taxable income adequate to cover the tax depreciation, amortization and interest expense associated with the Tax Basis Increase. Estimated blended tax rates are impacted by a number of factors including tax law changes, statutory tax rate changes, state apportionment and state filing combinations. The Company regularly reviews its estimated blended tax rates and projections of future taxable earnings to determine whether changes in the estimated liability are required. Any changes to the estimated future payments due to changes in estimated blended tax rates are recorded in the consolidated statements of income as non-cash adjustments related to tax receivable agreement. There has been a reassessment of the projected blended tax rates for each period presented. For the year ended December 31, 2017 , the net future benefits decreased, primarily as a result of the decline in Federal statutory tax rate as part of the 2017 Tax Act, which decreased the associated liability to Wyndham, resulting in a $15,259 offset to non-operating expense. In addition, the liability decreased due to payments of $11,769 made during the year ended December 31, 2017. For the year ended December 31, 2016, the net future benefits increased, which increased the associated liability to Wyndham, resulting in a charge to non-operating expense of $563 . In addition, the liability decreased due to payments of $10,797 made during the year ended December 31, 2016. For the year ended December 31, 2015, the net future benefits decreased, which decreased the associated liability to Wyndham, resulting in a $2,145 offset to non-operating expense.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Benefit Plans	16. Employee Benefit Plans The Company sponsors a 401(k) retirement and savings plan. Eligible employees may participate in the plan immediately. The Company’s employees who are at least 18 years of age, have worked at least 1,000 hours in the past year, and have completed one year of service are eligible for Company matching contributions in the plan. The Company matches 100 percent of each employee’s contributions up to a maximum of 6 percent of each employee’s eligible compensation. All contributions vest immediately. WEX Inc. has the right to discontinue the plan at any time. Contributions to the plan are voluntary. The Company contributed $6,710 , $5,297 and $4,571 in matching funds to the plan for the years ended December 31, 2017 , 2016 and 2015 , respectively. During 2016, the Company acquired EFS, which as of the date of the acquisition had its own employee savings plan (“the EFS Plan”). As of December 31, 2016, the EFS Plan was merged with the existing WEX plan, and the existing WEX plan recorded a receivable for the amount of net assets available for benefits expected to be received from the EFS Plan. On February 1, 2017, the WEX plan received net assets available for benefits totaling $15,159 in a transfer from the EFS Plan. On January 1, 2017, EFS employees became eligible to participate in the existing WEX plan. During 2014, the Company acquired Evolution1 which, as of the date of the acquisition, had its own employee savings plan, (“the Evolution1 Plan”). As of December 31, 2014, the Evolution1 Plan was merged with the existing WEX plan, and the existing plan recorded a receivable for the amount of net assets available for benefits it expected to receive from the Evolution1 Plan. Net assets available for benefits totaling $21,739 were received by the plan on January 2, 2015, in a transfer from the Evolution1 Plan. On January 1, 2015, Evolution1 employees became eligible to participate in the existing WEX plan. The Company also sponsors a defined contribution plan for certain employees designated by the Company. Participants may elect to defer receipt of designated percentages or amounts of their compensation. The Company maintains a grantor’s trust to hold the assets under the Company’s defined contribution plan. The obligation related to the defined contribution plan totaled $6,798 and $5,673 at December 31, 2017 and 2016 , respectively, and are included in other liabilities on the consolidated balance sheets. The assets held in trust are designated as trading securities and, as such, these trading securities are to be recorded at fair value with any changes recorded currently to earnings. The aggregate market value of the securities within the trust was $6,798 and $5,673 at December 31, 2017 and 2016 , respectively, and are included in other assets on the consolidated balance sheets. The Company has defined benefit pension plans in Germany and Norway. The total net unfunded status for the Company’s foreign defined benefit pension plans was $291 and $5,979 as of December 31, 2017 and 2016 , respectively, recognized as accrued expenses in the consolidated balance sheets. The Company will measure these plan obligations on an annual basis. The change in fair value to the defined benefit pension plans is recorded through the consolidated statements of income. The expense under each of these defined benefit pension plans for 2017 and 2016 was not material to the consolidated financial statements.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value	17. Fair Value The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis and the related hierarchy levels: December 31, Fair Value Hierarchy 2017 2016 Assets: Mortgage-backed securities 2 $ 305 $ 490 Asset-backed securities 2 345 648 Municipal bonds 2 534 682 Fixed-income mutual fund 1 22,174 21,705 Available-for-sale securities 23,358 23,525 Executive deferred compensation plan trust (a) 1 6,798 5,673 Interest rate swaps (a) 2 15,919 12,908 Liabilities: Interest rate swaps (b) 2 $ 1,697 $ — (a) The fair value is recorded in other assets. (b) The fair value is recorded in other liabilities. We did not have any transfers between Level 1, Level 2 or Level 3 of the fair value hierarchy during the years ended December 31, 2017 and 2016 . See Note 1, Summary of Significant Accounting Policies for a description of the levels of the fair value hierarchy. Available-For-Sale Securities When available, the Company uses quoted market prices to determine the fair value of available-for-sale securities; such inputs are classified as Level 1 of the fair-value hierarchy. These securities primarily consist of an open-ended mutual fund which is invested in fixed-income securities and is held in order to satisfy the regulatory requirements of WEX Bank. For mortgage-backed and asset-backed debt securities and bonds, the Company generally uses quoted prices for recent trading activity of assets with similar characteristics to the debt security or bond being valued. The securities and bonds priced using such methods are generally valued using Level 2 inputs. Executive Deferred Compensation Plan Trust The obligations related to the deferred compensation plan trust are classified as Level 1 in the fair value hierarchy because the fair value is determined using quoted prices for identical instruments in active markets. Interest Rate Swaps The Company determines the fair value of its interest rate swaps based on the discounted cash flows of the difference between the projected fixed payments on the swaps and the implied floating payments using the current LIBOR curve, which are Level 2 inputs of the fair value hierarchy. Notes Outstanding On January 30, 2013, the Company completed an offering in an aggregate principal amount of $400,000 of 4.750 percent senior notes due February 1, 2023, with interest payable semiannually. The Notes outstanding have a fair value of $410,000 and $390,000 as of December 31, 2017 and December 31, 2016, respectively. The fair value is based on market rates for the issuance of our debt. The Company determined the fair value of its Notes outstanding is classified as Level 2 in the fair value hierarchy. 2016 Credit Agreement The Company determines the fair value of the amount outstanding under its 2016 Credit Agreement based on the market rates for the issuance of the Company's debt which are Level 2 inputs in the fair value hierarchy. As of both December 31, 2017 and 2016, the carrying value of the 2016 Credit Agreement approximated its fair value.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	18. Commitments and Contingencies Litigation On August 11, 2016, the Company was sued in the Circuit Court of St. Charles County, Missouri, in a putative class action alleging the Company improperly sent unauthorized facsimile advertisements in violation of the Telephone Consumer Protection Act, 47 U.S.C. § 227 (the “TCPA”). The named plaintiff sought to represent a nationwide class of recipients of unauthorized facsimile advertisements from the Company (collectively, the "Plaintiffs") and requested statutory damages for each facsimile advertisement. The Plaintiffs further alleged that the opt-out notice of the faxes did not meet the criteria set forth in the TCPA or its underlying regulations. The Company removed the case to the United States District Court for the Eastern District of Missouri on September 15, 2016. On October 14, 2016, the Company filed an answer denying liability and stating the facsimile advertisement at issue was sent by FleetOne, LLC, the Company’s wholly-owned subsidiary. On May 10, 2017, the parties agreed to a settlement in principle to resolve the class claims, which was preliminarily approved by the court on October 6, 2017. The court entered its final judgment approving the settlement agreement on January 19, 2018. The settlement amount is not material to the Company's financial position, results of operations, cash flows or liquidity. In addition, from time to time, we are subject to legal proceedings and claims in the ordinary course of business. As of the date of this filing, the current estimate of a reasonably possible loss contingency from all legal proceedings is not material to the Company's consolidated financial position, results of operations, cash flows or liquidity. Extension of Credit to Customers The Company had aggregate unused commitments of approximately $6,300,000 and $5,400,000 at December 31, 2017 and 2016 , respectively, related to payment processing services, primarily related to commitments to extend credit to customers and customers of strategic relationships as part of the Company’s established lending product agreements. Many of these commitments are not expected to be used; therefore, total unused credit available to customers and customers of strategic relationships does not represent future cash requirements. The Company can increase or decrease its customers’ credit lines at its discretion at any time, subject to limited notice requirements in some instances. These amounts are not recorded on the consolidated balance sheets. Operating Leases The Company leases office space and equipment under non-cancelable operating lease agreements that expire at various dates through 2026. In addition, the Company rents office equipment under agreements that may be canceled at any time. Rental expense related to office space, equipment, and vehicle leases amounted to $15,471 , $15,104 and $11,310 for the years ended December 31, 2017 , 2016 and 2015 , respectively. These amounts were included in occupancy and equipment on the consolidated statements of income. The Company leases information technology hardware and software under agreements that may be terminated by the Company at any time. Lease and rental expense related to information technology hardware and software leases totaled $8,765 , $12,875 and $11,288 for the years ended December 31, 2017 , 2016 and 2015 , respectively. These amounts were included in technology leasing and support on the consolidated statements of income. Future minimum lease payments under non-cancelable operating leases are as follows: 2018 $ 13,559 2019 9,903 2020 8,532 2021 8,093 2022 6,734 Thereafter 10,214 Total minimum lease payments $ 57,035 Minimum Volume Purchase Commitments One of the Company's subsidiaries is required to purchase a minimum amount of fuel from suppliers on an annual basis through 2024. Should the Company fail to meet these minimum volume commitments, a penalty will be assessed as defined under the contracts. Starting in 2020, annual volume commitments reset based on prior year volume purchased. If the Company does not purchase fuel under these commitments after December 31, 2017 , it would incur total penalties through 2019 totaling $362,856 . During the year ended December 31, 2017 , the Company incurred $1,217 in shortfall penalties under these contracts. During the years ended December 31, 2016 and 2015 , the Company did not incur material shortfall penalties under these contracts. The Company considers the associated risk of loss to be remote based on current operations.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Loss	19. Accumulated Other Comprehensive Loss A reconciliation of accumulated other comprehensive loss for the years ended December 31, 2017 and 2016 , is as follows: 2017 2016 Unrealized Losses on Available- for-Sale Securities Foreign Currency Items Unrealized Losses on Available- for-Sale Securities Foreign Currency Items Beginning balance $ (463 ) $ (122,376 ) $ (212 ) $ (103,239 ) Other comprehensive loss (5 ) 32,049 (251 ) (19,137 ) Ending balance $ (468 ) $ (90,327 ) $ (463 ) $ (122,376 ) No significant amounts were reclassified from accumulated other comprehensive loss in the periods presented. The change in foreign currency items is primarily due to the foreign currency translation of non-cash assets such as goodwill and other intangible assets related to the Company's foreign subsidiaries. The total tax effect on foreign currency translation adjustments was $4,851 and $5,416 as of December 31, 2017 and 2016 , respectively.

Dividend Restrictions

Dividend Restrictions	12 Months Ended
	Dec. 31, 2017
Disclosure of Restrictions on Dividends, Loans and Advances Disclosure [Abstract]
Dividend Restrictions	20. Dividend Restrictions The Company has certain restrictions on the dividends it may pay under its revolving credit agreement, including pro forma compliance with a ratio of consolidated funded indebtedness to consolidated EBITDA of 2.50 :1.00 for the most recent period of four fiscal quarters. However, if the Company's leverage ratio does not exceed 5.25 through September 30, 2017, 5.00 through September 30, 2018, 4.50 through September 30, 2019, or 4.00 from December 31, 2019 and thereafter, after execution of a restricted payment, the Company may pay $50,000 per annum for restricted payments, including dividends, of which 100% of unused amounts may be carried over into subsequent years. The Company has not declared any dividends on its common stock since it commenced trading on the NYSE on February 16, 2005. Dividends paid by WEX Bank have provided a substantial part of the Company’s operating funds and for the foreseeable future it is anticipated that dividends paid by WEX Bank will continue to be a source of operating funds to the Company. Capital adequacy requirements serve to limit the amount of dividends that may be paid by WEX Bank. WEX Bank is chartered under the laws of the State of Utah and the FDIC insures its deposits. Under Utah law, WEX Bank may only pay a dividend out of net profits after it has (i) provided for all expenses, losses, interest and taxes accrued or due from WEX Bank and (ii) transferred to a surplus fund 10 percent of its net profits before dividends for the period covered by the dividend, until the surplus reaches 100 percent of its capital stock. For purposes of these Utah dividend limitations, WEX Bank’s capital stock is $5,250 and its capital surplus exceeds 100 percent of capital stock. Under FDIC regulations, WEX Bank may not pay any dividend if, following the payment of the dividend, WEX Bank would be “undercapitalized,” as defined under the Federal Deposit Insurance Act and applicable regulations. The FDIC also has the authority to prohibit WEX Bank from engaging in business practices that the FDIC considers to be unsafe or unsound, which, depending on the financial condition of WEX Bank, could include the payment of dividends. WEX Bank complied with the aforementioned dividend restrictions for each of the years ended December 31, 2017 , 2016 and 2015 .

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	21. Stock-Based Compensation In 2010, the Company adopted the WEX Inc. 2010 Equity Incentive Plan (the “Plan”), which replaced the Company’s 2005 Equity and Incentive Plan. In May 2015, the Company adopted the 2015 Section 162(m) Performance Incentive Plan (collectively the “Plans”). The Plans, which are stockholder-approved, permit the grant of stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based or cash-based awards to non-employee directors, officers, employees, advisors or consultants. The Plans permit the Company to grant a total number of shares which is the sum of; (i) 3,800 shares of common stock; (ii) plus such additional number of shares of common stock (up to 1,596 ) that were reserved for issuance under the Company’s Amended and Restated 2005 Equity and Incentive Plan (the “Prior Plan”) that remained available for grant under the Prior Plan at the time the 2010 Plan was adopted. There were 1,617,334 units of common stock available for grant for future equity-incentive compensation awards under the Plan at December 31, 2017 . On December 31, 2017 , the Company had four stock-based compensation award types, which are described below. The compensation cost that has been charged against income for these programs totals $30,487 , $19,742 and $12,420 for 2017 , 2016 and 2015 , respectively. The associated tax benefit related to these costs was $7,347 , $7,200 and $4,542 , for 2017 , 2016 and 2015 , respectively. Restricted Stock Units The Company periodically grants restricted stock units (“RSUs”), which represent a right to receive a specific number of shares of the Company's common stock at a specified date, to non-employee directors and certain employees. RSUs granted to non-employee directors vest 12 months from the date of grant, or upon termination of board service if the director elects to defer receipt. RSUs issued to certain employees generally vest evenly over up to three years and provide for accelerated vesting if there is a change of control (as defined in the Plan). The fair value of each RSU award is based on the closing market price of the Company’s stock on the day of grant as reported by the New York Stock Exchange (“NYSE”). The following is a summary of RSU activity during the year ended December 31, 2017 : Restricted Stock Units Units Weighted- Average Grant- Date Fair Value Outstanding at January 1, 2017 206 $ 88.78 Granted 111 105.64 Shares released, including 26 shares withheld for tax (a) (86 ) 84.51 Forfeited (58 ) 98.98 Outstanding at December 31, 2017 173 $ 98.31 (a) The Company withholds shares of common stock to pay the minimum required statutory taxes due upon RSU vesting. Cash is then remitted by the Company to the appropriate taxing authority. As of December 31, 2017 , there was $9,613 of total unrecognized compensation cost related to RSUs. That cost is expected to be recognized over a weighted-average period of 1.3 years . The total grant-date fair value of RSUs granted was $11,700 , $18,826 and $7,846 during 2017 , 2016 and 2015 , respectively. The total fair value of RSUs that vested during 2017 , 2016 and 2015 was $7,310 , $3,648 and $4,521 , respectively. Performance-Based Restricted Stock Units The Company periodically grants performance-based restricted stock units (“PBRSUs”) to employees. A PBRSU is a right to receive stock based on the achievement of both performance goals and continued employment during the vesting period. In a PBRSU, the number of shares earned varies based upon meeting certain performance goals. PBRSU awards generally have performance goals spanning one to three years, depending on the nature of the performance goal. The fair value of each PBRSU award is based on the closing market price of the Company’s stock on the grant date as reported by the NYSE. The following is a summary of PBRSU activity during the year ended December 31, 2017 : Performance-Based Restricted Stock Units Shares Weighted- Average Grant-Date Fair Value Outstanding at January 1, 2017 310 $ 84.83 Granted 185 105.15 Forfeited (27 ) 85.31 Vested, including 64 shares withheld for tax (a) (174 ) 91.92 Performance adjustment 20 89.85 Outstanding at December 31, 2017 314 $ 93.18 (a) The Company withholds shares of common stock to pay the minimum required statutory taxes due upon PBRSU vesting. Cash is then remitted by the Company to the appropriate taxing authority. As of December 31, 2017 , there was $13,430 of unrecognized compensation cost related to the PBRSUs that is expected to be recognized over a weighted-average period of 1.9 years. The total grant-date fair value of PBRSUs granted during 2017 , 2016 and 2015 was $15,014 , $15,921 and $6,860 , respectively. The total fair value of PBRSUs that vested during 2017 , 2016 and 2015 was $15,948 , $4,858 and $2,035 , respectively. Stock Options Market Performance-Based Stock Options In May 2017, the Company granted market performance-based stock options with a contractual term of ten years to members of senior management. The options contain a market condition that begins operating on the third anniversary of the grant date, requiring the closing price of the Company's stock to meet or exceed certain price thresholds for twenty consecutive trading days (“Stock Price Hurdle”) in order for shares to vest. In addition, award recipients must be continually employed from the grant date until such date that the Stock Price Hurdle is satisfied in order for shares to vest. To the extent both the service condition and the Stock Price Hurdles are not met by the end of a defined measurement period, these options will be canceled. The grant date fair value of these options was estimated on the date of the grant using a Monte-Carlo simulation model used to simulate a distribution of future stock price paths based on historical volatility levels. The table below summarizes the assumptions used to calculate the fair value: Exercise price $ 99.69 Expected stock price volatility 31.14 % Risk-free interest rate 2.18 % Weighted average fair value of performance options granted $ 28.69 The Company will expense these options on a graded basis over the derived service period of approximately three years regardless of whether the market condition is satisfied. Upon satisfaction of a Stock Price Hurdle, any unrecognized compensation expense for that specific tranche will be accelerated. Service-Based Stock Options Stock options granted to certain officers and employees under the Plan generally become exercisable over three years (with approximately 33 percent of the total grant vesting each year on the anniversary of the grant date) and expire 10 years from the date of grant. Based on the Company's lack of historical option exercise experience and granting of stock options with "plain vanilla” characteristics, the Company uses the simplified method to estimate the expected term of its employee stock options. The fair value of each option award is estimated on the grant date using the following assumptions and a Black-Scholes-Merton option-pricing model. The expected term assumption as it relates to the valuation of the options represents the period of time that options granted are expected to be outstanding. The Company also estimates expected volatilities that are based on implied volatilities from traded options on the Company's stock, historical volatility of the Company’s stock, and other factors. The option-pricing model includes a risk-free interest rate for the period matching the expected term of the option and is based on the U.S. Treasury yield curve in effect at the time of the grant. The dividend yield used in the option-pricing model is the calculated yield on the Company’s stock at the time of the grant. The table below summarizes the assumptions used to calculate the fair value by year of grant: 2017 2016 2015 Weighted average expected life (in years) 6.0 6.0 6.0 Weighted average exercise price $ 104.95 $ 77.20 $ 103.40 Weighted average volatility 30.67 % 31.93 % 30.46 % Weighted average risk-free rate 2.13 % 1.62 % 1.73 % Weighted average fair value $ 35.58 $ 26.14 $ 33.93 The following is a summary of all stock option activity during the year ended December 31, 2017 : Stock Options Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2017 180 $ 81.90 Granted 682 100.72 Exercised (12 ) 59.43 Forfeited (16 ) 78.96 Outstanding at December 31, 2017 834 $ 97.70 9.07 $ 36,302 Exercisable on December 31, 2017 66 $ 88.90 7.77 $ 3,452 Vested and expected to vest at December 31, 2017 760 $ 98.45 9.18 $ 32,529 As of December 31, 2017 , there was $17,077 of total unrecognized compensation cost related to options. That cost is expected to be recognized over a weighted-average period of 1.2 years. The total intrinsic value of options exercised during the years ended December 31, 2017 , 2016 and 2015 was $642 , $1,712 and $216 , respectively. The total grant-date fair value of options granted during 2017 , 2016 and 2015 was $20,516 , $3,297 , and $1,855 , respectively. Deferred Stock Units Non-employee directors may elect to defer their cash fees and RSUs in the form of deferred stock units ("DSUs"). The Company previously granted non-employee directors fully vested RSUs. These awards were fully vested upon grant and are distributed as common stock on the date which is 200 days immediately following the date upon which such director’s service as a member of the Company’s Board of Directors terminates for any reason. There were approximately 94 and 101 DSUs outstanding as of December 31, 2017 and 2016 , respectively. Unvested DSUs as of December 31, 2017 and 2016 were not material.

Impairment and Restructuring Ac

Impairment and Restructuring Activities	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Impairment and Restructuring Activities	22. Impairment and Restructuring Activities Impairment Charges and Asset Write-Offs Following the acquisition of AOC in the fourth quarter of 2017, the Company reevaluated software currently under development for payment processing within our Travel and Corporate Solutions segment. From this, we determined the developed technology obtained in the AOC acquisition more closely aligns with our technological strategy. As result, approximately $22,000 of software under development was determined to have no future benefit and therefore impaired during the year ended December 31, 2017. We also impaired approximately $6,000 of computer software within the Fleet Solutions segment in 2017 as a result of our ongoing platform consolidation strategy, designed to ensure we continue to deliver superior technology to our customers. During the year ended December 31, 2017, the Company executed a vendor contract amendment based on a strategic decision to in-source certain previously outsourced technology functions. As a result of this action, the Company determined that approximately $16,000 of prepaid services had no future benefit and were therefore written off within the Fleet Solutions segment during the same period. Restructuring In the first quarter of 2015, the Company commenced a restructuring initiative (the “2015 Restructuring Initiative”) as a result of its global review of operations. The review of operations identified certain initiatives to further streamline the business, to improve the Company's efficiency, and to globalize the Company's operations, all with an objective to improve scale and increase profitability going forward. The Company continued its efforts to improve its overall operational efficiency and began a second restructuring initiative (the “2016 Restructuring Initiative”) during the second quarter of 2016. In connection with the EFS acquisition, the Company initiated a restructuring program in the third quarter of 2016 (the “Acquisition Integration Restructuring Initiative”). The restructuring expenses related to these initiatives primarily consist of employee costs and office closure costs directly associated with the respective programs. The Company has determined the amount of expenses related to these initiatives is probable and reasonably estimable. As such, it has recorded the impact on the consolidated statements of income and in accrued expenses on the consolidated balance sheets. Restructuring charges incurred to date under these initiatives were $24,479 as of December 31, 2017. The balances under these initiatives are expected to be paid through 2018. Based on current plans, which are subject to change, the amount of additional restructuring costs that the Company expects to incur is immaterial. The following table presents the Company's 2015 Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 5,231 $ 7,249 Restructuring charges 1 2,642 2,182 Reserve release (77 ) (816 ) Cash paid (4,020 ) (3,921 ) Other 2 (1,158 ) (166 ) Impact of foreign currency translation 62 703 Balance, end of year $ 2,680 $ 5,231 1 Primarily consists of employee costs. 2 In 2017, the liability was transferred to the 2016 Restructuring Initiative. The following table presents the Company's 2016 Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 3,662 $ — Restructuring charges 1 285 3,506 Reserve release (1,590 ) — Cash paid (3,479 ) (4 ) Other 2 1,158 166 Impact of foreign currency translation 702 (6 ) Balance, end of year $ 738 $ 3,662 1 Primarily consists of employee costs. 2 In 2017, the liability was transferred from the 2015 Restructuring Initiative. The following table presents the Company's Acquisition Integration Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 1,764 $ — Restructuring charges 1 6,121 2,614 Reserve release (242 ) — Cash paid (2,650 ) (850 ) Other 107 — Impact of foreign currency translation (7 ) — Balance, end of year $ 5,093 $ 1,764 1 Primarily consists of office closure costs. The following table presents the Company's total restructuring liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 10,657 $ 7,249 Restructuring charges 9,048 8,302 Reserve release (1,909 ) (816 ) Cash paid (10,149 ) (4,775 ) Other 107 — Impact of foreign currency translation 757 697 Balance, end of year $ 8,511 $ 10,657

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	23. Segment Information Operating segments are defined as components of an enterprise about which separate financial information is available and is evaluated regularly by the chief operating decision maker (“CODM”) in deciding how to allocate resources and assess performance. The Company's CODM is its Chief Executive Officer. The operating segments are aggregated into the three reportable segments described below. • Fleet Solutions provides customers with payment and transaction processing services specifically designed for the needs of commercial and government fleets. This segment also provides information management services to these fleet customers. • Travel and Corporate Solutions focuses on the complex payment environment of business-to-business payments, providing customers with payment processing solutions for their corporate payment and transaction monitoring needs. • Health and Employee Benefit Solutions provides healthcare payment products and SaaS consumer directed platforms, as well as payroll related benefits to customers. During the third quarter of 2017, the Company revised its operating segment measurement from adjusted pre-tax income to adjusted operating income. The Company no longer allocates financing interest expense to our operating segments as management believes this item can obscure underlying business trends. As such, we believe adjusted operating income reflects an enhanced measurement of segment profitability. Segment results for the years ended December 31, 2016 and 2015 have been revised to reflect this change in operating segment measurement. Adjusted operating income adjusts operating income to exclude: (i) acquisition and divestiture related items (including acquisition-related intangible amortization); (ii) stock-based compensation; (iii) restructuring and other costs; (iv) gains on divestitures; (v) debt restructuring costs (vi) reserves for regulatory penalties, (vii) impairment charges and asset write-offs. For the year ended December 31, 2016, adjusted operating income excluded a vendor settlement. The accounting policies of the reportable segments are generally the same as those described in the summary of significant accounting policies. Assets are not allocated to the segments for internal reporting purposes. The following tables present the Company’s reportable segment results on an adjusted operating income basis for the years ended December 31, 2017 , 2016 and 2015 : Year Ended December 31, 2017 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 360,158 $ 158,660 $ 50,348 $ 569,166 Account servicing revenue 165,083 7,531 103,956 276,570 Finance fee revenue 159,336 760 27,486 187,582 Other revenue 138,389 57,096 21,745 217,230 Total revenue $ 822,966 $ 224,047 $ 203,535 $ 1,250,548 Depreciation and amortization $ 143,301 $ 17,703 $ 42,720 $ 203,724 Adjusted operating income $ 297,322 $ 117,432 $ 50,718 $ 465,472 Year Ended December 31, 2016 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 297,900 $ 175,762 $ 46,957 $ 520,619 Account servicing revenue 127,106 1,247 82,660 211,013 Finance fee revenue 124,725 643 13,572 138,940 Other revenue 92,330 37,595 17,963 147,888 Total revenue $ 642,061 $ 215,247 $ 161,152 $ 1,018,460 Depreciation and amortization $ 100,860 $ 6,187 $ 34,604 $ 141,651 Adjusted operating income $ 215,424 $ 104,531 $ 43,118 $ 363,073 Year Ended December 31, 2015 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 305,855 $ 151,311 $ 38,703 $ 495,869 Account servicing revenue 100,850 1,930 53,912 156,692 Finance fee revenue 83,554 326 5,113 88,993 Other revenue 57,419 41,852 13,812 113,083 Total revenue $ 547,678 $ 195,419 $ 111,540 $ 854,637 Depreciation and amortization $ 54,453 $ 2,999 $ 25,625 $ 83,077 Adjusted operating income $ 186,731 $ 87,380 $ 28,576 $ 302,687 No one customer accounted for more than 10 percent of the total consolidated revenue in 2017, 2016 or 2015. The following table presents the Company's interest income by segment for the years ended December 31, 2017 , 2016 and 2015 : 2017 2016 2015 Fleet Solutions $ 3,681 $ 3,053 $ 1,704 Travel and Corporate Solutions 717 498 348 Health and Employee Benefit Solutions 27,507 13,581 5,116 Total interest income $ 31,905 $ 17,132 $ 7,168 The following table reconciles adjusted operating income to income before income taxes: Year ended December 31, 2017 2016 2015 Fleet Solutions $ 297,322 $ 215,424 $ 186,731 Travel and Corporate Solutions 117,432 104,531 87,380 Health and Employee Benefit Solutions 50,718 43,118 28,576 Adjusted operating income $ 465,472 $ 363,073 $ 302,687 Acquisition-related intangible amortization (153,810 ) (97,829 ) (47,792 ) Other acquisition and divestiture related items (5,000 ) (20,879 ) (4,137 ) Stock-based compensation (30,487 ) (19,742 ) (12,420 ) Restructuring and other costs (11,129 ) (13,995 ) (9,010 ) Impairment charges and asset write-offs (44,171 ) — — Gain on divestiture 20,958 — 1,215 Vendor settlement — (15,500 ) — Debt restructuring (2,563 ) — — Regulatory reserve — — (1,750 ) Operating income $ 239,270 $ 195,128 $ 228,793 Financing interest expense (107,067 ) (113,418 ) (46,189 ) Net foreign currency gain (loss) 29,919 (7,665 ) (5,689 ) Net unrealized gains on interest rate swap agreements 1,314 12,908 — Net realized and unrealized gains on fuel price derivatives — 711 5,848 Non-cash adjustments related to tax receivable agreement 15,259 (563 ) 2,145 Income before income taxes $ 178,695 $ 87,101 $ 184,908 Geographic Data Revenue by principal geographic area, based on the country in which the sale originated, was as follows: Year ended December 31, 2017 2016 2015 United States $ 1,037,322 $ 839,917 $ 691,088 Australia 62,030 53,068 50,387 Other international 1 151,196 125,475 113,162 Total revenues $ 1,250,548 $ 1,018,460 $ 854,637 1 No single country, other than the United States and Australia, made up more than 5 percent of total revenues for any of the years presented. Net property, equipment and capitalized software are subject to geographic risks because they are generally difficult to move and relatively illiquid. Net property, equipment and capitalized software by principal geographic area was as follows: Year ended December 31, 2017 2016 2015 United States $ 148,490 $ 146,165 $ 79,265 Australia 5,432 5,493 5,445 Other international 9,986 15,620 53,875 Net property, equipment and capitalized software $ 163,908 $ 167,278 $ 138,585

Supplementary Regulatory Capita

Supplementary Regulatory Capital Disclosure	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Supplementary Regulatory Capital Disclosure	24. Supplementary Regulatory Capital Disclosure The Company's subsidiary, WEX Bank is subject to various regulatory capital requirements administered by the FDIC and the Utah Department of Financial Institutions. Failure to meet minimum capital requirements can initiate certain mandatory, and possible additional discretionary, actions by regulators that, if undertaken, could have a direct material effect on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, WEX Bank must meet specific capital guidelines that involve quantitative measures of WEX Bank’s assets, liabilities, and certain off-balance-sheet items as calculated under regulatory accounting practices. WEX Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Quantitative measures established by regulation to ensure capital adequacy require WEX Bank to maintain minimum amounts and ratios as defined in the regulations. As of December 31, 2017 and December 31, 2016 , the most recent FDIC exam report categorized WEX Bank as “well capitalized” under the regulatory framework for prompt corrective action. There are no conditions or events subsequent to that examination report that management believes have changed WEX Bank’s capital rating. The following table presents WEX Bank's actual and regulatory minimum capital amounts and ratios: Actual Amount Ratio Minimum for Capital Adequacy Purposes Amount Ratio Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio December 31, 2017 Total Capital to risk-weighted assets $ 316,129 13.38 % $ 188,991 8.00 % $ 236,239 10.00 % Tier 1 Capital to average assets 304,555 12.50 % 97,452 4.00 % 121,815 5.00 % Common equity to risk-weighted assets 304,555 12.89 % 106,308 4.50 % 153,555 6.50 % Tier 1 Capital to risk-weighted assets $ 304,555 12.89 % $ 141,743 6.00 % $ 188,991 8.00 % December 31, 2016 Total Capital to risk-weighted assets $ 228,402 12.59 % $ 145,182 8.00 % $ 181,477 10.00 % Tier 1 Capital to average assets 214,847 11.10 % 77,413 4.00 % 96,767 5.00 % Common equity to risk-weighted assets 214,847 11.84 % 81,665 4.50 % 117,961 6.50 % Tier 1 Capital to risk-weighted assets $ 214,847 11.84 % $ 108,887 6.00 % $ 145,183 8.00 %

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	25. Subsequent Event On January 17, 2018, the Company further repriced the secured term loans under the 2016 Credit Agreement, which reduced the applicable interest rate margin for the Company’s tranche B term loans by 50 basis points for both LIBOR borrowings and base rate borrowings, increased the outstanding amounts on these tranche B term loans from $1.182 billion to $1.335 billion , and made certain other changes to the 2016 Credit Agreement, including increasing the maximum consolidated leverage ratio for the period of December 31, 2018 through September 30, 2019 and upon the occurrence of an acquisition meeting certain specified criteria, permitting the incurrence of unsecured indebtedness as long as the Company is in pro forma compliance with the financial covenants, resetting the six month soft call period for a repricing of the tranche B term loans and resetting and amending the test for incremental loans. Following the repricing, the applicable interest rate margin for the tranche B term loans was set at 2.25% for LIBOR borrowings and 1.25% for base rate borrowings. The Company incurred approximately $6 million of expenses upon the closing of this repricing.

Quarterly Financial Results (Un

Quarterly Financial Results (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Results (Unaudited)	26. Quarterly Financial Results (Unaudited) Summarized quarterly results for the years ended December 31, 2017 and 2016 , are as follows: Three months ended March 31 June 30 September 30 December 31 2017 Total revenues $ 291,357 $ 303,884 $ 324,002 $ 331,305 Operating income $ 60,752 $ 47,581 $ 63,723 $ 67,214 Net earnings attributable to shareholders (a) $ 29,401 $ 17,090 $ 33,971 $ 79,804 Earnings per share: (a) Basic $ 0.69 $ 0.40 $ 0.79 $ 1.86 Diluted $ 0.68 $ 0.40 $ 0.79 $ 1.85 2016 Total revenues (b) $ 205,928 $ 233,936 $ 287,756 $ 290,840 Operating income (b) $ 41,127 $ 51,635 $ 54,568 $ 47,798 Net earnings attributable to shareholders (b) $ 23,086 $ 12,567 $ 19,696 $ 5,288 Earnings per share: (b) Basic $ 0.60 $ 0.32 $ 0.46 $ 0.12 Diluted $ 0.59 $ 0.32 $ 0.46 $ 0.12 (a) The three months ended December 31, 2017 includes a tax benefit of approximately $60 million as a result of the 2017 Tax Act. (b) Results for three months ended September 30, 2016 and December 31, 2016 include the operations of EFS and the issuance of approximately 4,000 shares of common stock for the acquisition of EFS on July 1, 2016. Basic and diluted net income per share are computed independently for each quarter presented. Therefore, the sum of quarterly basic and diluted net income per share information may not equal annual basic and diluted net income per share.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Business Description	Business Description WEX Inc. (“Company”, "we" or "our”) is a provider of corporate card payment solutions. The Company provides products and services that meet the needs of businesses in various geographic regions including North and South America, Asia Pacific and Europe. The Company’s Fleet Solutions, Travel and Corporate Solutions, and Health and Employee Benefit Solutions segments provide their customers with security and control for complex payments across a wide spectrum of business sectors. The Company markets its products and services directly, as well as through strategic relationships which include major oil companies, fuel retailers, vehicle maintenance providers, online travel agencies and health partners.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements of the Company for the years ended December 31, 2017 , 2016 and 2015 , include the accounts of the Company and its wholly and majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The Company rounds amounts in the consolidated financial statements to thousands and calculates all percentages and per-share data from underlying whole-dollar amounts. Thus, certain amounts may not foot, crossfoot, or recalculate based on reported numbers due to rounding.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The Company prepares its consolidated financial statements in conformity with GAAP and with the Rules and Regulations of the SEC, specifically Regulation S-X and the instructions to Form 10-K. These principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenue and expenses during the period. Actual results could differ from those estimates and those differences may be material.
Cash and Cash Equivalents	Cash and Cash Equivalents Highly liquid investments with remaining maturities at the time of purchase of three months or less (that are readily convertible to cash) are considered to be cash equivalents and are stated at cost, which approximates fair value. Cash equivalents include federal funds sold, which are unsecured short-term investments entered into with financial institutions.
Restricted Cash	Restricted Cash Restricted cash represents funds collected from individuals or employers on behalf of our customers that are to be remitted to third parties or funds required to be maintained on hand under certain vendor agreements. This restricted cash, which is not available to fund the Company’s operations, totaled $18,866 and $22,412 as of December 31, 2017 and 2016 , respectively, and is classified in other assets on the Company’s consolidated balance sheets. We maintain an offsetting liability against restricted cash collected and remitted on behalf of our customers.
Accounts Receivable, Net of Allowances	Accounts Receivable, Net of Allowances Accounts receivable is stated at net realizable value. The balance includes a reserve for credit losses which reflects management’s estimate of uncollectable balances resulting from credit and fraud losses. Management has consistently considered its portfolio of charge card receivables as a large group of smaller balance accounts that it has collectively evaluated for impairment. The reserve for credit losses is established based on the determination of the amount of expected credit losses inherent in the accounts receivable as of the reporting date. Management reviews delinquency reports, historical collection rates, changes in customer payment patterns, economic trends, geography and other information in order to make judgments as to probable credit losses. Management also uses historical charge off experience to determine the amount of losses inherent in accounts receivable at the reporting date. Assumptions regarding probable credit losses are reviewed periodically and may be impacted by actual performance of accounts receivable and changes in any of the factors discussed above. The balance also includes a reserve for waived finance fees, which is used to maintain customer goodwill and recorded against the late fee revenue recognized.
Available-for-sale Securities	Available-for-sale Securities The Company records certain investments as available-for-sale securities. Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of tax, reported on the consolidated balance sheets in accumulated other comprehensive loss. Realized gains and losses and declines in fair value determined to be other-than-temporary are included in non-operating expenses. The cost basis of securities is based on the specific identification method. Interest and dividends earned on securities classified as available-for-sale are included in other revenue. Available-for-sale securities held by the Company were purchased and are held by WEX Bank in order to meet the requirements of the Community Reinvestment Act.
Derivatives	Derivatives From time to time, the Company utilizes derivative instruments as part of its overall strategy to manage its exposure to fluctuations in fuel prices and to reduce the impact of interest and foreign currency exchange rate volatility. The Company's derivative instruments are recorded at fair value on the consolidated balance sheets . The Company’s derivative instruments have not been designated as hedges; therefore, both realized and unrealized gains and losses are recognized in earnings. For the purposes of cash flow presentation, realized and unrealized gains or losses are included within cash flows from operating activities.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Replacements, renewals and improvements are capitalized and costs for repair and maintenance are expensed as incurred. Depreciation is primarily computed using the straight-line method over the estimated useful lives shown below. Below are the estimated useful lives for assets placed in service during 2017 and beyond: Estimated Useful Lives Furniture, fixtures and equipment 3 to 5 years Internal-use computer software 1.5 to 7 years Computer software 3 years Leasehold improvements (a) up to 5 years (a) Leasehold improvements are primarily depreciated using the straight-line method over the lesser of the useful life of the asset or the remaining lease term.
Capitalized Software	Capitalized Software The Company develops software that is used to provide processing and information management services to customers. A significant portion of the Company’s capital expenditures is devoted to the development of such internal-use computer software. Costs incurred during the preliminary project stage are expensed as incurred. Software development costs are capitalized during the application development stage. Capitalization begins when the preliminary project stage is complete, as well as when management authorizes and commits to the funding of the project. Capitalization of costs ceases when the software is ready for its intended use. Costs related to maintenance of internal-use software are expensed as incurred. Software development costs are amortized using the straight-line method over the estimated useful life of the software.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The Company classifies intangible assets in the following three categories: (1) intangible assets with definite lives subject to amortization, (2) intangible assets with indefinite lives not subject to amortization and (3) goodwill. The Company tests intangible assets with definite lives for impairment if conditions exist that indicate the carrying value may not be recoverable. Such conditions may include a reduction in operating cash flow or a dramatic change in the manner in which the asset is intended to be used. The Company records an impairment charge when the carrying value of the definite-lived intangible asset is not recoverable from the undiscounted cash flows generated from the use of the asset. Intangible assets with indefinite lives and goodwill are not amortized. The Company tests these intangible assets and goodwill for impairment at least annually or more frequently if facts or circumstances indicate that such intangible assets or goodwill might be impaired. All goodwill and intangible assets are assigned to reporting units, which are one level below the Company’s operating segments. The Company performs impairment tests at the reporting unit level. Such impairment tests include comparing the fair value of the respective reporting unit with its carrying value, including goodwill. The Company uses both discounted cash flow analyses and comparable company pricing multiples to determine the fair value of our reporting units. Such analyses are corroborated using market analytics. Certain assumptions are used in determining the fair value, including assumptions about future cash flows and terminal values. When appropriate, the Company considers the assumptions that it believes hypothetical marketplace participants would use in estimating future cash flows. In addition, an appropriate discount rate is used, based on the Company’s cost of capital or reporting unit-specific economic factors. When the fair value is less than the carrying value of the intangible assets or the reporting unit, the Company records an impairment charge to reduce the carrying value of the assets to the reporting unit's implied fair value. The Company's annual goodwill and intangible asset impairment tests performed as of October 1, 2017 , 2016 and 2015 did not identify any impairment. Intangible assets that are deemed to have definite lives are amortized over their useful lives, which is the period of time that the asset is expected to contribute directly or indirectly to future cash flows. The Company determines the useful lives of its identifiable intangible assets after considering the specific facts and circumstances related to each intangible asset. The factors that management considers when determining useful lives include the contractual term of agreements, the history of the asset, the Company’s long-term strategy for the use of the asset, any laws or other local regulations which could impact the useful life of the asset and other economic factors, including competition and specific market conditions. An evaluation of the remaining useful lives of the definite-lived intangible assets is performed periodically to determine if any change is warranted.
Impairment and Disposals of Assets	Impairment and Disposals of Assets Long-lived assets are tested for impairment whenever facts or circumstances, such as a reduction in operating cash flow or a dramatic change in the manner the asset is intended to be used, indicate the carrying amount of the asset may not be recoverable. The Company compares the estimated undiscounted future cash flows associated with these assets or operations to their carrying value to determine if a write-down to fair value is required. During 2017, the Company impaired certain software currently under development for payment processing and prepaid services related to technology outsourcing as these items were determined to have no future benefit. See Note 22 , Impairment and Restructuring Activities , for further discussion. The Company did not recognize any significant impairment expense on the Company’s assets during the years ended December 31, 2016 and 2015 . Disposals in the ordinary course of business are recorded in occupancy and equipment in the consolidated statements of income.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company holds mortgage-backed securities, fixed-income securities, derivatives (see Note 11 , Derivative Instruments ) and certain other financial instruments that are carried at fair value. The Company determines fair value based upon quoted prices when available or through the use of alternative approaches, such as model pricing, when market quotes are not readily accessible or available. Various factors are considered in determining the fair value of the Company’s obligations, including: closing exchange or over-the-counter market price quotations; time value and volatility factors underlying options and derivatives; price activity for equivalent instruments; and the Company’s own-credit standing. These valuation techniques may be based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs create the following fair value hierarchy: • Level 1 – Quoted prices for identical instruments in active markets. • Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable. • Level 3 – Instruments whose significant value drivers are unobservable. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The carrying values of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses, and other liabilities approximate their respective fair values due to the short-term nature of such instruments. The carrying values of certificates of deposit, interest-bearing money market deposits and borrowed federal funds approximate their respective fair values as the interest rates on these financial instruments are variable market-based rates. All other financial instruments are reflected at fair value on the consolidated balance sheets. Available-For-Sale Securities When available, the Company uses quoted market prices to determine the fair value of available-for-sale securities; such inputs are classified as Level 1 of the fair-value hierarchy. These securities primarily consist of an open-ended mutual fund which is invested in fixed-income securities and is held in order to satisfy the regulatory requirements of WEX Bank. For mortgage-backed and asset-backed debt securities and bonds, the Company generally uses quoted prices for recent trading activity of assets with similar characteristics to the debt security or bond being valued. The securities and bonds priced using such methods are generally valued using Level 2 inputs. Executive Deferred Compensation Plan Trust The obligations related to the deferred compensation plan trust are classified as Level 1 in the fair value hierarchy because the fair value is determined using quoted prices for identical instruments in active markets.
Revenue Recognition	Revenue Recognition The majority of the Company’s revenues are comprised of transaction-based fees, which are generally calculated based on measures such as (i) percentage of dollar value of volume processed; (ii) number of transactions processed; or (iii) some combination thereof. The Company has entered into agreements with major oil companies, fuel retailers, vehicle maintenance providers, online travel agencies and health partners which provide products and/or services to the Company’s customers. These agreements specify that a transaction is deemed to be captured when the Company has validated that the transaction has no errors and has accepted and posted the data to the Company’s records. The Company recognizes revenues when persuasive evidence of an arrangement exists, the products and services have been provided to the client, the sales price is fixed or determinable and collectability is reasonably assured. The Company generally records revenue net of costs based on the following criteria: (i) the Company is not the primary obligor in the arrangement; (ii) the Company has no inventory risk; (iii) the Company does not have reasonable latitude with respect to establishing the price for the product; (iv) the Company does not make any changes to the product or have any involvement in the product specifications; and, (v) the amount the Company earns for its services is fixed, within a limited range. The Company enters into contracts with certain large customers or strategic relationships that provide for fee rebates tied to performance milestones. Rebates are recorded as a reduction in revenue in the same period that revenue is earned or performance occurs. Rebates and incentives are calculated based on estimated performance and the terms of the related business agreements. A description of the major components of revenue are as follows: Payment Processing Revenue . Revenue consists of transaction fees as well as interchange income: • Fleet transaction fees are assessed to major oil companies, fuel retailers and vehicle maintenance providers. We extend short-term credit to the fleet customer and pay the purchase price for the fleet customer’s transaction, less the payment processing fees we retain, to the merchant. We collect the total purchase price from the fleet customer. The fee charged is generally based upon a percentage of the total transaction amount; however, it may also be based on a fixed amount charged per transaction or on a combination of both measures. The Company records revenue at the time the transaction is captured. • In Europe, our fleet payment processing revenue is specifically derived from the difference between the negotiated price of the fuel from the supplier and the agreed upon price paid by the fleets. • Interchange income is earned from the Company’s suite of card products in the Fleet Solutions and Health and Employee Benefit Solutions segments, as well as on our virtual card technology. Interchange income is a fee paid by a merchant bank to the card-issuing bank through the interchange network. Interchange fees are set by the credit card providers. The Company recognizes interchange income as earned. With regard to fleet and travel payment processing revenue, the Company is generally responsible for the collection of the total transaction amount from the customer and the payment to the merchant of their sales amount, net of the payment processing revenue earned by the Company, and as such, recognizes revenue net of the cost of the underlying products and services. As a consequence, the Company’s accounts receivable and accounts payable related to its payment processing revenues are reflective of the total transaction amount processed by the Company, not the Company’s revenue. Account Servicing Revenue . In our Fleet Solutions segment, account servicing revenue is primarily comprised of monthly fees based on vehicles serviced. These fees are primarily in return for providing monthly vehicle data reports. In our Health and Employee Benefit Solutions segment, we also recognize account servicing fees for the per-participant per-month fee charged per consumer on our healthcare financial technology platform. Account servicing revenue is recognized monthly, as the Company fulfills its contractual service obligations. Finance Fees . The Company earns revenue by assessing monthly finance fees on accounts with overdue balances. These fees are recognized as revenue at the time the fees are assessed. The finance fee is calculated using a stated late fee rate based on the entire balance outstanding from the customer or a minimum, whichever is higher. On occasion, these fees are waived to maintain customer goodwill. The Company’s established reserve for such waived amounts is estimated and offset against the late fee revenue recognized. These waived fees amounted to approximately $16,900 , $10,900 and $6,000 in 2017 , 2016 and 2015 , respectively. The Company engages in factoring, the purchase of accounts receivable from a third party at a discount. Revenue earned in this transaction is recorded in finance fees. We also recognize fees for interest associated with the Company’s fuel desk product and revenue earned on the Company’s foreign salary advance product. Other . The Company earns transaction fees, which are principally based on the number of transactions processed; however, the fees may be a percentage of the total transaction amount. These fees are recognized at the time the transaction is captured. The Company assesses fees for providing ancillary services, such as information products and services, professional services and marketing services. Other revenues also include international settlement fees, fees for overnight shipping, certain customized electronic reporting and customer contact services provided on behalf of certain of the Company’s customers. Service related revenues are recognized in the period that the work is performed. Interest and dividends earned on investments in available-for-sale securities are included in other revenues. Such income is recognized in the period that it is earned. The Company sells telematics devices as part of its WEX Telematics program. The Company recognizes revenue from these sales when the customer has accepted delivery of the product and collectability of the sales amount is reasonably assured. From time to time the Company enters into agreements with suppliers, partners and customers and offers incentives to establish access to new channels, enter new market segments and expand the use and acceptance of WEX products and services. As part of these agreements the Company may agree to pay an up-front bonus or fee. The Company capitalizes these payments within other assets in the consolidated balance sheets and amortizes each monthly, generally on a straight-line basis against the related revenue earned throughout the life of the agreement.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes the fair value of all stock-based payments to employees in its financial statements. The Company estimates the fair value of service-based stock option awards and market performance-based stock option awards on the grant date using a Black-Scholes-Merton valuation model and a Monte Carlo simulation model, respectively. The fair value of Restricted Stock Units (“RSUs”), including Performance Based Restricted Stock Units (“PBRSUs”), is determined and fixed on the grant date based on the Company's stock price. Stock-based compensation expense is net of estimated forfeitures and is recorded over each award's requisite service period. The Company uses the straight-line methodology for recognizing the expense associated with service-based stock options and RSU grants and a graded-vesting methodology for the expense recognition of market performance-based stock options and PBRSUs. Stock-based compensation is recorded in salary and other personnel expense in the consolidated statements of income.
Advertising Costs	Advertising Costs Advertising and marketing costs are expensed in the period incurred.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which the associated temporary differences became deductible. A valuation allowance is established for those jurisdictions in which deferred tax assets realization is deemed less than more likely than not. Current accounting guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. This accounting guidance also provides guidance on derecognition, classification, interest and penalties, accounting in the interim periods, disclosure, and transition. Penalties and interest related to uncertain tax positions are recognized as a component of income tax expense. To the extent penalties and interest are not assessed with respect to uncertain tax positions, amounts accrued are reduced and reflected as a reduction of the overall income tax provision.
Earnings per Share	Earnings per Share Basic earnings per share is computed by dividing net earnings attributable to shareholders by the weighted average number of shares of common stock and vested deferred stock units (“DSUs”) outstanding during the year. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and assumed issuance of unvested RSUs and DSUs and unvested PBRSUs for which the performance condition has been met as of the date of determination using the treasury stock method unless the effect is anti-dilutive. The treasury stock method assumes that proceeds, including cash received from the exercise of employee stock options and the total unrecognized compensation expense for unvested share-based compensation awards, would be used to purchase the Company's common stock at the average market price during the period. Prior to the January 2017 adoption of ASU 2016-09, the treasury stock method also included excess tax benefits in its proceeds calculation.
Foreign Currency Movement	Foreign Currency Movement The financial statements of the Company’s foreign subsidiaries, where the local currency is the functional currency, are Realized and unrealized gains and losses on foreign currency transactions as well as the re-measurement of the Company's cash, receivable and payable balances that are denominated in foreign currencies, are recorded directly in net foreign currency gain (loss) in the consolidated statements of income. However, gains or losses resulting from intercompany transactions where repayment is not anticipated for the foreseeable future are not recognized in the consolidated statements of income. In these situations, the gains or losses are deferred and included as a component of accumulated other comprehensive loss. In addition, gains and losses associated with the Company's foreign currency exchange derivatives are recorded in net foreign currency gain (loss) in the consolidated statements of income.
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Accumulated other comprehensive loss includes unrealized gains and losses on available-for-sale securities and foreign currency translation adjustments pertaining to the net investment in foreign operations. Amounts are recognized net of tax to the extent applicable. Realized gains or losses on securities transactions are classified as non-operating in the consolidated statements of income.
Recent Accounting Pronouncements	Standard Description Date/Method of Adoption Effect on financial statements or other significant matters Adopted During the Year Ended December 31, 2017 Accounting Standards Update (“ASU”) 2016-09 Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting This standard simplifies several aspects of accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, statutory tax withholding requirements, and classification in the statement of cash flows. January 1, 2017 Prior to the adoption of this guidance, the Company used the "with and without" method to determine when excess tax benefits were realized. As a result of certain US net operating loss carryforwards, excess tax benefits to date have not reduced taxes paid and therefore were not previously recognized in our financial statements. This standard required prospective recognition of all the tax effects related to share-based payments in the income statement. The impact of adoption was recorded as a cumulative effect adjustment to retained earnings of $261. For the year ended December 31, 2017, the Company recognized approximately $1,600 of excess tax benefits within our income tax provision. The Company has elected to prospectively classify these excess tax benefits as cash flows from operating activities effective January 1, 2017. The Company will continue to estimate the number of awards expected to vest, rather than electing to account for forfeitures as they occur. Adoption of this standard has not impacted the Company's minimum statutory tax withholding practices. ASU 2017-09 Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting This standard clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as a modification. Under the new guidance, an entity will not apply modification accounting to a share-based payment award if there is no change to the award’s fair value, vesting conditions and classification as an equity or liability instrument. The Company elected to early adopt this standard effective July 1, 2017. The adoption has not impacted the Company's consolidated financial statements and related disclosures. Not Yet Adopted as of December 31, 2017 ASU 2016-18 Statement of Cash Flows (Topic 230): Restricted Cash This standard clarifies the classification and presentation of restricted cash in the statement of cash flows. The statement of cash flows must explain the change during the period in the total of cash and cash equivalents and amounts described as restricted cash or cash equivalents. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years, and requires retrospective application to all periods presented. Early adoption is permitted. Upon adoption, restricted cash will be included in cash and restricted cash equivalents when reconciling the beginning of year and end of year amounts presented on the consolidated statements of cash flows. Restricted cash totaled $18,866 and $22,412 as of December 31, 2017 and 2016, respectively, and is recorded in other assets on the consolidated balance sheets. ASU 2016-13 Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses will be based on historical experience, current conditions, and reasonable and supportable forecasts that impact the collectability of the reported amount. The standard is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2016-02 Leases (Topic 842) This standard increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Certain qualitative and quantitative disclosures are required. The standard is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period. When transitioning, the standard requires leases to be recognized and measured at the beginning of the earliest period presented using a modified retrospective approach. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. ASU 2016-01 Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities This standard requires equity investments, except those accounted for under the equity method of accounting, or those that result in consolidation of the investee, to be measured at fair value with changes in fair value recognized in net income. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is evaluating the impact the pronouncement will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2014-09 Revenue from Contracts with Customers (Topic 606) This standard supersedes most existing revenue recognition guidance under GAAP. The new revenue recognition standard requires entities to recognize revenue for 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. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted this standard on January 1, 2018. The guidance permits two methods of adoption: full retrospective approach, which requires an entity to restate each prior period that is reported in the financial statements and modified retrospective approach, which requires a cumulative adjustment to retained earnings as of the effective date, without restatement of prior period amounts. The Company adopted the standard using the modified retrospective method. Topic 606 does not apply to rights or obligations associated with financial instruments (e.g. interest income), including the Company’s finance fee and interest income from banking relationships and cardholders. In addition, fees associated with cardholder arrangements are outside the scope of Topic 606. As a result of detailed analysis, management has determined that approximately 30 percent of consolidated revenues for the year ended December 31, 2017 are outside the scope of Topic 606. The Company’s revenue from discount and interchange, transaction processing and certain fees is within the scope of Topic 606. FASB and its Transition Resource Group have issued clarifications on various aspects of ASU 2014-09. The Company has determined there will be two significant changes in the classification on our consolidated statement of income which will impact reported total revenues and operating expenses but have no impact on income from operations. • Certain amounts paid to partners in our Fleet Solutions and Travel and Corporate Solutions segments have been determined to fall under the cost to obtain a contract guidance. As a result, these amounts, which were previously presented net of revenues, will be reflected as a selling expense going forward. Based on 2017 results, this change would have increased both reported revenues and expenses by approximately $52,000. • Network fees paid to Visa and MasterCard by all three of our segments, which have previously been presented within service fees expense, will be presented net of revenue going forward. Based on 2017 results, this change would have reduced both reported revenues and expenses by approximately $24,000. The majority of network fee expenses are incurred by our Travel and Corporate Solutions segment. • Under the new guidance certain costs to obtain a contract, such as sales commissions are to be capitalized and amortized over the life of the contract, with a practical expedient available for contracts under one year in duration. We have evaluated our worldwide sales commission structure and determined that the vast majority of commission expense will continue to be expensed. In 2017, we incurred approximately $1,000 of sales commissions which meet the criteria for capitalization under the new guidance. Except for the items mentioned above, we have determined that the timing and measurement of revenue associated with the Company’s transaction processing services, including discount and interchange and other transaction processing fees, will not be significantly impacted by the new standard. As such, we estimate that applying the modified retrospective method to outstanding contracts as of our January 1, 2018 implementation date will have an immaterial cumulative effect on the opening balance of 2018 retained earnings. The Company has implemented changes to its accounting policies, business processes and internal controls to support the recognition, measurement and disclosure requirements under the new standard.
Investments	The Company reviews its investments to identify and evaluate indications of possible impairment. Factors considered in determining whether a loss is temporary include the length of time and extent to which the fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. Substantially all of the Company’s fixed income securities are rated investment grade or better.
Derivatives Activity	The Company is exposed to certain market risks relating to its ongoing business operations. From time to time, the Company enters into derivative instrument arrangements to manage various risks including interest rate risk, foreign exchange risk, and commodity price risk. None of these derivative instruments qualify for hedge accounting treatment.

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Estimated Useful Lives	Below are the estimated useful lives for assets placed in service during 2017 and beyond: Estimated Useful Lives Furniture, fixtures and equipment 3 to 5 years Internal-use computer software 1.5 to 7 years Computer software 3 years Leasehold improvements (a) up to 5 years (a) Leasehold improvements are primarily depreciated using the straight-line method over the lesser of the useful life of the asset or the remaining lease term.
Schedule of Internal-Use Software	Below are the amounts of internal-use software capitalized and amortized: Year ended December 31, 2017 2016 2015 Amounts capitalized for internal-use computer software (including work-in-process) $ 50,682 $ 55,379 $ 52,218 Amounts expensed for amortization of internal-use computer software $ 32,582 $ 27,581 $ 20,316
Schedule of Net Earnings Attributable to Shareholders and Reconciliation of Basic and Diluted Shares	The following table summarizes net earnings attributable to shareholders and reconciles basic and diluted shares outstanding used in the earnings per share computations: Year ended December 31, 2017 2016 2015 Net earnings attributable to shareholders $ 160,266 $ 60,637 $ 101,904 Weighted average common shares outstanding – Basic 42,977 40,809 38,771 Dilutive impact of share based compensation awards 128 105 72 Weighted average common shares outstanding – Diluted 43,105 40,914 38,843

Recent Accounting Pronounceme38

Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following table provides a brief description of recent accounting pronouncements that could have a material effect on our financial statements: Standard Description Date/Method of Adoption Effect on financial statements or other significant matters Adopted During the Year Ended December 31, 2017 Accounting Standards Update (“ASU”) 2016-09 Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting This standard simplifies several aspects of accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, statutory tax withholding requirements, and classification in the statement of cash flows. January 1, 2017 Prior to the adoption of this guidance, the Company used the "with and without" method to determine when excess tax benefits were realized. As a result of certain US net operating loss carryforwards, excess tax benefits to date have not reduced taxes paid and therefore were not previously recognized in our financial statements. This standard required prospective recognition of all the tax effects related to share-based payments in the income statement. The impact of adoption was recorded as a cumulative effect adjustment to retained earnings of $261. For the year ended December 31, 2017, the Company recognized approximately $1,600 of excess tax benefits within our income tax provision. The Company has elected to prospectively classify these excess tax benefits as cash flows from operating activities effective January 1, 2017. The Company will continue to estimate the number of awards expected to vest, rather than electing to account for forfeitures as they occur. Adoption of this standard has not impacted the Company's minimum statutory tax withholding practices. ASU 2017-09 Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting This standard clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as a modification. Under the new guidance, an entity will not apply modification accounting to a share-based payment award if there is no change to the award’s fair value, vesting conditions and classification as an equity or liability instrument. The Company elected to early adopt this standard effective July 1, 2017. The adoption has not impacted the Company's consolidated financial statements and related disclosures. Not Yet Adopted as of December 31, 2017 ASU 2016-18 Statement of Cash Flows (Topic 230): Restricted Cash This standard clarifies the classification and presentation of restricted cash in the statement of cash flows. The statement of cash flows must explain the change during the period in the total of cash and cash equivalents and amounts described as restricted cash or cash equivalents. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within those fiscal years, and requires retrospective application to all periods presented. Early adoption is permitted. Upon adoption, restricted cash will be included in cash and restricted cash equivalents when reconciling the beginning of year and end of year amounts presented on the consolidated statements of cash flows. Restricted cash totaled $18,866 and $22,412 as of December 31, 2017 and 2016, respectively, and is recorded in other assets on the consolidated balance sheets. ASU 2016-13 Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments This standard requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses will be based on historical experience, current conditions, and reasonable and supportable forecasts that impact the collectability of the reported amount. The standard is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those fiscal years. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2016-02 Leases (Topic 842) This standard increases transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Certain qualitative and quantitative disclosures are required. The standard is effective for annual reporting periods beginning after December 15, 2018, including interim periods within that reporting period. When transitioning, the standard requires leases to be recognized and measured at the beginning of the earliest period presented using a modified retrospective approach. The Company is evaluating the impact the standard will have on the consolidated financial statements and related disclosures. ASU 2016-01 Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities This standard requires equity investments, except those accounted for under the equity method of accounting, or those that result in consolidation of the investee, to be measured at fair value with changes in fair value recognized in net income. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is evaluating the impact the pronouncement will have on the consolidated financial statements and related disclosures. Standard Description Date/Method of Adoption Effect on financial statements or other significant matters ASU 2014-09 Revenue from Contracts with Customers (Topic 606) This standard supersedes most existing revenue recognition guidance under GAAP. The new revenue recognition standard requires entities to recognize revenue for 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. In addition, the standard requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted this standard on January 1, 2018. The guidance permits two methods of adoption: full retrospective approach, which requires an entity to restate each prior period that is reported in the financial statements and modified retrospective approach, which requires a cumulative adjustment to retained earnings as of the effective date, without restatement of prior period amounts. The Company adopted the standard using the modified retrospective method. Topic 606 does not apply to rights or obligations associated with financial instruments (e.g. interest income), including the Company’s finance fee and interest income from banking relationships and cardholders. In addition, fees associated with cardholder arrangements are outside the scope of Topic 606. As a result of detailed analysis, management has determined that approximately 30 percent of consolidated revenues for the year ended December 31, 2017 are outside the scope of Topic 606. The Company’s revenue from discount and interchange, transaction processing and certain fees is within the scope of Topic 606. FASB and its Transition Resource Group have issued clarifications on various aspects of ASU 2014-09. The Company has determined there will be two significant changes in the classification on our consolidated statement of income which will impact reported total revenues and operating expenses but have no impact on income from operations. • Certain amounts paid to partners in our Fleet Solutions and Travel and Corporate Solutions segments have been determined to fall under the cost to obtain a contract guidance. As a result, these amounts, which were previously presented net of revenues, will be reflected as a selling expense going forward. Based on 2017 results, this change would have increased both reported revenues and expenses by approximately $52,000. • Network fees paid to Visa and MasterCard by all three of our segments, which have previously been presented within service fees expense, will be presented net of revenue going forward. Based on 2017 results, this change would have reduced both reported revenues and expenses by approximately $24,000. The majority of network fee expenses are incurred by our Travel and Corporate Solutions segment. • Under the new guidance certain costs to obtain a contract, such as sales commissions are to be capitalized and amortized over the life of the contract, with a practical expedient available for contracts under one year in duration. We have evaluated our worldwide sales commission structure and determined that the vast majority of commission expense will continue to be expensed. In 2017, we incurred approximately $1,000 of sales commissions which meet the criteria for capitalization under the new guidance. Except for the items mentioned above, we have determined that the timing and measurement of revenue associated with the Company’s transaction processing services, including discount and interchange and other transaction processing fees, will not be significantly impacted by the new standard. As such, we estimate that applying the modified retrospective method to outstanding contracts as of our January 1, 2018 implementation date will have an immaterial cumulative effect on the opening balance of 2018 retained earnings. The Company has implemented changes to its accounting policies, business processes and internal controls to support the recognition, measurement and disclosure requirements under the new standard.

Business Acquisitions and Oth39

Business Acquisitions and Other Intangible Assets Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following is a summary of the final allocation of the purchase price to the assets and liabilities acquired: Consideration paid (net of cash acquired) $ 80,677 Less: Accounts receivable 1,594 Other tangible assets and liabilities, net 314 Acquired software and developed technology (a) 10,300 Customer relationships (b) 27,700 Trade name (c) 1,500 Recorded goodwill $ 39,269 (a) Weighted average life – 5.0 years . (b) Weighted average life – 7.6 years . (c) Weighted average life – 8.1 years (a) (b) (c) The weighted average life of these amortized intangible assets is 6.9 years . The following represents the components and final allocation of the purchase price: As Reported December 31, 2016 Measurement Period Adjustments As Reported, Final Total consideration, net of cash acquired $ 1,444,235 $ — $ 1,444,235 Less: Accounts receivable 162,684 — 162,684 Property and equipment 2,387 1 2,388 Customer relationships (a)(b) 842,700 (1,300 ) 841,400 Developed technologies (a)(c) 32,120 — 32,120 Trademarks and trade names (a)(d) 13,700 — 13,700 Deferred income tax assets 34,992 6,352 41,344 Other assets — 739 739 Accounts payable (153,777 ) 248 (153,529 ) Accrued expenses (128,267 ) 9,361 (118,906 ) Deferred income tax liabilities (91,194 ) 28,071 (63,123 ) Recorded goodwill (a) $ 728,890 $ (43,472 ) $ 685,418 (a) $1,235,331 in goodwill and other intangible assets recorded from this business combination were allocated to our Fleet Solutions segment, the remaining $337,307 was allocated to our Travel and Corporate Solutions segment. (b) Weighted average life – 8.1 years . (c) Weighted average life – 2.0 years . (d) Weighted average life – 7.7 years . (b) (c) (d) The weighted average life of these amortized intangible assets is 7.9 years . The following is a summary of the preliminary allocation of the purchase price to the assets and liabilities acquired: As Reported December 31, 2017 Total consideration $ 129,828 Less: Cash 15,546 Accounts receivable 4,171 Property and equipment 2,530 Customer relationships (a) 15,000 Developed technologies (b) 24,100 Trademarks and trade names (c) 1,460 Other liabilities (685 ) Recorded goodwill $ 67,706 (a) Weighted average life – 8.9 years . (b) Weighted average life – 3.4 years . (c) Weighted average life – 4.0 years . (a) (b) (c) The weighted average life of these amortized intangible assets is 5.4 years .
Business Acquisition, Pro Forma Information	The following represents unaudited pro forma operational results as if the acquisition had occurred as of January 1, 2015: Year Ended December 31, 2016 2015 Total revenues $ 1,089,880 $ 994,619 Net earnings attributable to shareholders $ 42,821 $ 36,763 Pro forma net income attributable to shareholders per common share: Basic $ 1.00 $ 0.86 Diluted $ 1.00 $ 0.86

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Schedule of Concentration of Credit Risk	The following table presents the outstanding balance of accounts receivable that are less than 60 days past due, in each case as a percentage of total trade accounts receivable: December 31, Delinquency Status 2017 2016 29 days or less past due 95 % 93 % 59 days or less past due 97 % 98 %
Changes in Reserves for Credit Losses Related to Accounts Receivable	The following table presents changes in the accounts receivable allowances: Year ended December 31, 2017 2016 2015 Balance, beginning of year $ 21,454 $ 14,672 $ 14,627 Provision for credit losses 1 61,148 33,348 22,825 Charges to other accounts 2 16,869 10,166 6,155 Charge-offs (77,229 ) (43,309 ) (33,885 ) Recoveries of amounts previously charged-off 7,526 6,201 5,202 Currency translation 439 376 (252 ) Balance, end of year $ 30,207 $ 21,454 $ 14,672 1 During 2017, the majority of the increase relates to higher incidences of magnetic stripe card skimming fraud. 2 The Company earns revenue by assessing monthly finance fees on accounts with overdue balances. These fees are recognized as revenue at the time the fees are assessed. The finance fee is calculated using the greater of a minimum charge or a stated late fee rate multiplied by the outstanding balance that is subject to a late fee charge. On occasion, these fees are waived to maintain customer goodwill. Charges to other accounts represents the offset against the late fee revenue recognized when the Company establishes a reserve for such waived amounts.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available-For-Sale Securities	The Company’s available-for-sale securities as of December 31, 2017 and 2016 , are presented below: Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (a) 2017 Mortgage-backed securities $ 325 $ 4 $ 24 $ 305 Asset-backed securities 350 — 5 345 Municipal bonds 539 1 6 534 Equity securities (b) 22,888 — 714 22,174 Total available-for-sale securities $ 24,102 $ 5 $ 749 $ 23,358 2016 Mortgage-backed securities $ 498 $ 15 $ 23 $ 490 Asset-backed securities 650 — 2 648 Municipal bonds 697 1 16 682 Equity securities (b) 22,414 — 709 21,705 Total available-for-sale securities $ 24,259 $ 16 $ 750 $ 23,525 (a) The Company’s techniques used to measure the fair value of its investments are discussed in Note 17 , Fair Value . (b) Excludes $6,798 and $5,673 in equity securities designated as trading as of December 31, 2017 and 2016 , respectively, included in other assets on the consolidated balance sheets. See Note 16 , Employee Benefit Plans for additional information.
Maturity Dates Of Available-For-Sale Securities	The maturity dates of the Company’s available-for-sale securities are as follows: December 31, 2017 2016 Cost Fair Value Cost Fair Value Due after 1 year through year 5 $ — $ — $ 165 $ 165 Due after 5 years through year 10 390 385 529 529 Due after 10 years 499 494 653 636 Mortgage-backed securities with original maturities of 30 years 325 305 498 490 Equity securities with no maturity dates 22,888 22,174 22,414 21,705 Total $ 24,102 $ 23,358 $ 24,259 $ 23,525

Property, Equipment and Capit42

Property, Equipment and Capitalized Software, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Schedule Of Property, Equipment And Capitalized Software, Net	Property, equipment and capitalized software, net consist of the following: December 31, 2017 2016 Furniture, fixtures and equipment $ 75,015 $ 69,513 Computer software 308,362 254,163 Software under development 21,452 49,922 Leasehold improvements 23,248 21,257 Capital leases 759 759 Total 428,836 395,614 Less: accumulated depreciation and amortization (264,928 ) (228,336 ) Total property, equipment and capitalized software, net $ 163,908 $ 167,278

Goodwill and Other Intangible43

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill	The changes in goodwill during the period January 1 to December 31, 2017 were as follows: Fleet Solutions Segment Travel and Corporate Solutions Segment Health and Employee Benefit Solutions Segment Total Gross goodwill, January 1, 2017 $ 1,293,138 $ 202,771 $ 353,722 $ 1,849,631 Acquisition adjustments for EFS (37,296 ) (6,176 ) — (43,472 ) Acquisition of AOC — 67,706 — 67,706 Divestiture of Telapoint (4,469 ) — — (4,469 ) Impact of foreign currency translation 18,345 740 (214 ) 18,871 Gross goodwill, December 31, 2017 1,269,718 265,041 353,508 1,888,267 Accumulated impairment, January 1, 2017 (855 ) (10,335 ) — (11,190 ) Impact of foreign currency translation (72 ) (873 ) — (945 ) Accumulated impairment, December 31, 2017 $ (927 ) $ (11,208 ) $ — $ (12,135 ) Net goodwill, January 1, 2017 $ 1,292,283 $ 192,436 $ 353,722 $ 1,838,441 Net goodwill, December 31, 2017 $ 1,268,791 $ 253,833 $ 353,508 $ 1,876,132 The changes in goodwill during the period January 1 to December 31, 2016 were as follows: Fleet Solutions Segment Travel and Corporate Solutions Segment Health and Employee Benefit Solutions Total Gross goodwill, January 1, 2016 $ 735,770 $ 38,134 $ 350,321 $ 1,124,225 Acquisition of EFS 561,119 167,771 — 728,890 Acquisition adjustments — — 502 502 Impact of foreign currency translation (3,751 ) (3,134 ) 2,899 (3,986 ) Gross goodwill, December 31, 2016 1,293,138 202,771 353,722 1,849,631 Accumulated impairment, January 1, 2016 (867 ) (10,480 ) — (11,347 ) Impact of foreign currency translation 12 145 — 157 Accumulated impairment, December 31, 2016 $ (855 ) $ (10,335 ) $ — $ (11,190 ) Net goodwill, January 1, 2016 $ 734,903 $ 27,654 $ 350,321 $ 1,112,878 Net goodwill, December 31, 2016 $ 1,292,283 $ 192,436 $ 353,722 $ 1,838,441
Changes in Other Intangible Assets
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table presents the estimated amortization expense related to the definite-lived intangible assets listed above for each of the next five fiscal years: 2018 $ 141,583 2019 127,393 2020 116,164 2021 100,367 2022 $ 89,267
Other Intangible Assets	Other intangible assets consist of the following: December 31, 2017 December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Definite-lived intangible assets Acquired software and developed technology $ 203,861 $ (96,197 ) $ 107,664 $ 187,499 $ (69,483 ) $ 118,016 Customer relationships 1,257,232 (269,216 ) 988,016 1,247,624 (167,301 ) 1,080,323 Licensing agreements 34,546 (15,029 ) 19,517 30,760 (9,126 ) 21,634 Non-compete agreement — — — 4,000 — 4,000 Patent 2,581 (2,076 ) 505 2,380 (1,724 ) 656 Trade name 44,079 (10,309 ) 33,770 41,029 (6,508 ) 34,521 $ 1,542,299 $ (392,827 ) $ 1,149,472 $ 1,513,292 $ (254,142 ) $ 1,259,150 Indefinite-lived intangible assets Trademarks, trade names and brand names 4,575 6,318 Total $ 1,154,047 $ 1,265,468

Accounts Payable (Tables)

Accounts Payable (Tables)	12 Months Ended
	Dec. 31, 2017
Payables and Accruals [Abstract]
Schedule Of Accounts Payable	Accounts payable consists of: December 31, 2017 2016 Merchant payables $ 720,553 $ 520,058 Other payables 90,809 97,060 Accounts payable $ 811,362 $ 617,118

Deposits, Borrowed Federal Fu45

Deposits, Borrowed Federal Funds and Other Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Schedule of Deposits	The following table presents information about deposits: December 31, 2017 2016 Certificates of deposit with maturities within 1 year $ 630,879 $ 517,524 Certificates of deposit with maturities greater than 1 year and less than 5 years 306,865 208,048 Interest-bearing money market deposits 285,899 325,464 Customer deposits 70,211 67,787 Total deposits $ 1,293,854 $ 1,118,823 Weighted average cost of funds on certificates of deposit outstanding 1.51 % 0.96 % Weighted average cost of interest-bearing money market deposits 1.49 % 0.76 %
Schedule of Average Interest Rates	The following table presents the average interest rates and balances for deposits, borrowed federal funds and other debt: Year ended December 31, 2017 2016 2015 Average interest rate: Deposits 1.22 % 0.94 % 0.65 % Borrowed federal funds 1.24 % 0.69 % 0.39 % Interest-bearing money market deposits 1.12 % 0.50 % 0.25 % WEX Latin America debt 21.21 % 19.70 % 15.21 % Participation agreement 3.46 % 2.94 % 2.57 %

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The notional amounts, fixed and variable interest rates and maturities of the interest rate swap agreements are as follows: Tranche A Tranche B Tranche C Tranche D Tranche E Notional amount at inception $300,000 $200,000 $400,000 $150,000 $250,000 Amortization N/A N/A 5% annually N/A N/A Maturity date 12/30/2022 12/30/2022 12/31/2020 12/31/2020 12/31/2018 Fixed interest rate 2.204% 2.212% 1.108% 1.125% 0.896%
Foreign Currency Swap	The following table summarizes the contracts related to the Company's foreign currency swaps, which settle in U.S. dollars at various dates within 5 days after year-end: Aggregate Notional Amount December 31, 2017 2016 Australian dollar A$ 5,000 A$ 15,000
Changes in Fair Value of Fuel Price Derivatives	The following table summarizes the changes in fair value of the fuel price derivatives which have been recorded on the consolidated statements of income: Year ended December 31, 2016 2015 Realized gains $ 5,718 $ 41,810 Change in unrealized fuel price derivatives (5,007 ) (35,962 ) Net realized and unrealized gains on fuel price derivatives $ 711 $ 5,848
Location and Amounts of Derivative Fair Values	The following table presents information on the location and amounts of derivative fair values on the consolidated balance sheets, which are recorded at fair value: Asset Derivatives Liability Derivatives December 31, 2017 December 31, 2016 December 31, 2017 December 31, 2016 Derivatives Not Designated as Hedging Instruments Balance Fair Balance Fair Balance Fair Balance Fair Interest rate swaps Other assets $ 15,919 Other assets $ 12,908 Other liabilities $ 1,697 Other liabilities $ — Foreign currency contracts Accounts receivable $ — Accounts receivable $ 29 Accounts payable $ — Accounts payable $ —
Location and Amounts of Derivative Gains and Losses	The following table presents information on the location and amounts of derivative gains and losses: Derivatives Not Designated as Hedging Instruments Location of Gain Recognized in Amount of Gain (Loss) Recognized in December 31, 2017 2016 2015 Foreign currency contracts Net foreign currency gain $ — $ 59 $ 27,236 Interest rate swap agreements - unrealized portion Net unrealized gains on interest rate swap agreements $ 1,314 $ 12,908 $ — Interest rate swap agreements - realized portion Financing interest income $ 214 $ — $ — Commodity contracts Net realized and unrealized gains on fuel price derivatives $ — $ 711 $ 5,848

Financing Debt (Tables)

Financing Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Outstanding Borrowings	The following table summarizes the Company's outstanding borrowings under the agreements outlined below: Year ended December 31, 2017 2016 Revolving line-of-credit facility $ 136,535 $ — Term loans 1,602,875 1,637,625 Revolving line-of-credit facility and term loans (a) $ 1,739,410 $ 1,637,625 Unamortized debt issuance costs (32,346 ) (38,334 ) Revolving line-of-credit facility and term loans, net $ 1,707,064 $ 1,599,291 Notes outstanding (a) $ 400,000 $ 400,000 Unamortized debt issuance costs (3,731 ) (4,466 ) Notes outstanding, net $ 396,269 $ 395,534 (a) See Note 17, Fair Value for more information regarding the Company's 2016 Credit Agreement and notes outstanding.
Summary of Annual Principal Payments	The table below summarizes the Company's annual principal payments on its term loans under the 2016 Credit Agreement for each of the next five years: 2018 $ 34,750 2019 34,750 2020 34,750 2021 364,625 2022 $ 12,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Components Of Income Before Income Taxes	Income (losses) before income taxes consisted of the following: Year ended December 31, 2017 2016 2015 United States $ 149,344 $ 32,622 $ 203,692 Foreign 29,351 54,479 (18,784 ) Total $ 178,695 $ 87,101 $ 184,908
Components Of Income Tax Expense (Benefit)	Income taxes from continuing operations consisted of the following for the years ended December 31: United States State Foreign Total 2017 Current $ 2,253 $ 3,687 $ 14,473 $ 20,413 Deferred $ (11,234 ) $ 13,280 $ (2,934 ) (888 ) Income taxes $ 19,525 2016 Current $ (1,232 ) $ 3,033 $ 8,325 $ 10,126 Deferred $ 21,565 $ (5,106 ) $ 3,040 19,499 Income taxes $ 29,625 2015 Current $ 22,570 $ 4,288 $ 9,173 $ 36,031 Deferred $ 37,553 $ 5,631 $ (3,919 ) 39,265 Income taxes $ 75,296
Reconciliation Of Provision Of Income Taxes	The reconciliation between the income tax computed by applying the U.S. federal statutory rate and the reported effective tax rate on income from continuing operations is as follows: Year ended December 31, 2017 2016 2015 Federal statutory rate 35.0 % 35.0 % 35.0 % State income taxes (net of federal income tax benefit) 2.0 1.1 2.5 Foreign income tax rate differential (0.6 ) (4.4 ) 1.4 Revaluation of deferred tax assets for foreign and state tax rate changes, net 0.4 (0.9 ) 0.7 Research and development credit — (0.5 ) 0.2 Release of tax reserves — (4.9 ) — Withholding taxes 0.2 0.3 — 2017 Tax Act (33.9 ) — — Domestic production exclusions — — (1.8 ) Change in valuation allowance 5.8 2.3 1.6 Nondeductible expenses 0.9 3.4 0.3 Incremental tax benefit from share-based compensation awards (0.9 ) — — Other 2.0 2.6 0.8 Effective tax rate 10.9 % 34.0 % 40.7 %
Deferred Tax Assets And Liabilities	The tax effects of temporary differences in the recognition of income and expense for tax and financial reporting purposes that give rise to significant portions of the deferred tax assets and the deferred tax liabilities are presented below: December 31, 2017 2016 Deferred assets related to: Reserve for credit losses $ 6,562 $ 7,122 Tax credit carryforwards 1,283 5,178 Stock-based compensation, net 9,858 12,729 Net operating loss carry forwards 54,700 56,501 Accruals 7,355 18,985 Deferred financing costs — 5,420 Other — 164 Total 79,758 106,099 Deferred tax liabilities related to: Other liabilities 2,060 643 Deferred financing costs 7,219 — Property, equipment and capitalized software 22,315 32,759 Intangibles 141,908 118,695 Investment in partnership — 94,354 Total 173,502 246,451 Valuation allowance 17,787 5,620 Deferred income taxes, net $ (111,531 ) $ (145,972 )
Net Deferred Tax Assets By Jurisdiction	Net deferred tax (liabilities) assets by jurisdiction are as follows: December 31, 2017 2016 United States $ (116,229 ) $ (148,389 ) Australia (945 ) (2,020 ) United Kingdom 7,315 6,474 New Zealand 188 183 The Netherlands 249 206 Brazil (1,073 ) (2,497 ) Canada (1,036 ) 71 Deferred income taxes, net $ (111,531 ) $ (145,972 )
Reconciliation Of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits excluding interest and penalties is as follows: Year ended December 31, 2017 2016 2015 Beginning balance $ 4,960 $ 4,776 $ 4,856 Increases related to prior year tax positions 1,332 4,960 431 Decreases related to prior year tax positions, due to foreign currency exchange — — (511 ) Decreases related to prior year tax positions — (431 ) — Settlements (1,255 ) — — Lapse of statute — (4,345 ) — Ending balance $ 5,037 $ 4,960 $ 4,776

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Assets And Liabilities Measured At Fair Value	The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis and the related hierarchy levels: December 31, Fair Value Hierarchy 2017 2016 Assets: Mortgage-backed securities 2 $ 305 $ 490 Asset-backed securities 2 345 648 Municipal bonds 2 534 682 Fixed-income mutual fund 1 22,174 21,705 Available-for-sale securities 23,358 23,525 Executive deferred compensation plan trust (a) 1 6,798 5,673 Interest rate swaps (a) 2 15,919 12,908 Liabilities: Interest rate swaps (b) 2 $ 1,697 $ — (a) The fair value is recorded in other assets. (b) The fair value is recorded in other liabilities

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	Future minimum lease payments under non-cancelable operating leases are as follows: 2018 $ 13,559 2019 9,903 2020 8,532 2021 8,093 2022 6,734 Thereafter 10,214 Total minimum lease payments $ 57,035

Accumulated Other Comprehensi51

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	A reconciliation of accumulated other comprehensive loss for the years ended December 31, 2017 and 2016 , is as follows: 2017 2016 Unrealized Losses on Available- for-Sale Securities Foreign Currency Items Unrealized Losses on Available- for-Sale Securities Foreign Currency Items Beginning balance $ (463 ) $ (122,376 ) $ (212 ) $ (103,239 ) Other comprehensive loss (5 ) 32,049 (251 ) (19,137 ) Ending balance $ (468 ) $ (90,327 ) $ (463 ) $ (122,376 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule Of Restricted Stock Units	The following is a summary of RSU activity during the year ended December 31, 2017 : Restricted Stock Units Units Weighted- Average Grant- Date Fair Value Outstanding at January 1, 2017 206 $ 88.78 Granted 111 105.64 Shares released, including 26 shares withheld for tax (a) (86 ) 84.51 Forfeited (58 ) 98.98 Outstanding at December 31, 2017 173 $ 98.31 (a) The Company withholds shares of common stock to pay the minimum required statutory taxes due upon RSU vesting. Cash is then remitted by the Company to the appropriate taxing authority.
Schedule Of Performance Based Restricted Stock Units	The following is a summary of PBRSU activity during the year ended December 31, 2017 : Performance-Based Restricted Stock Units Shares Weighted- Average Grant-Date Fair Value Outstanding at January 1, 2017 310 $ 84.83 Granted 185 105.15 Forfeited (27 ) 85.31 Vested, including 64 shares withheld for tax (a) (174 ) 91.92 Performance adjustment 20 89.85 Outstanding at December 31, 2017 314 $ 93.18 (a) The Company withholds shares of common stock to pay the minimum required statutory taxes due upon PBRSU vesting. Cash is then remitted by the Company to the appropriate taxing authority.
Schedule Of Assumptions Used	The table below summarizes the assumptions used to calculate the fair value: Exercise price $ 99.69 Expected stock price volatility 31.14 % Risk-free interest rate 2.18 % Weighted average fair value of performance options granted $ 28.69 The table below summarizes the assumptions used to calculate the fair value by year of grant: 2017 2016 2015 Weighted average expected life (in years) 6.0 6.0 6.0 Weighted average exercise price $ 104.95 $ 77.20 $ 103.40 Weighted average volatility 30.67 % 31.93 % 30.46 % Weighted average risk-free rate 2.13 % 1.62 % 1.73 % Weighted average fair value $ 35.58 $ 26.14 $ 33.93
Schedule Of Stock Option Activity	The following is a summary of all stock option activity during the year ended December 31, 2017 : Stock Options Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2017 180 $ 81.90 Granted 682 100.72 Exercised (12 ) 59.43 Forfeited (16 ) 78.96 Outstanding at December 31, 2017 834 $ 97.70 9.07 $ 36,302 Exercisable on December 31, 2017 66 $ 88.90 7.77 $ 3,452 Vested and expected to vest at December 31, 2017 760 $ 98.45 9.18 $ 32,529

Impairment and Restructuring 53

Impairment and Restructuring Activities (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The following table presents the Company's 2015 Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 5,231 $ 7,249 Restructuring charges 1 2,642 2,182 Reserve release (77 ) (816 ) Cash paid (4,020 ) (3,921 ) Other 2 (1,158 ) (166 ) Impact of foreign currency translation 62 703 Balance, end of year $ 2,680 $ 5,231 1 Primarily consists of employee costs. 2 In 2017, the liability was transferred to the 2016 Restructuring Initiative. The following table presents the Company's 2016 Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 3,662 $ — Restructuring charges 1 285 3,506 Reserve release (1,590 ) — Cash paid (3,479 ) (4 ) Other 2 1,158 166 Impact of foreign currency translation 702 (6 ) Balance, end of year $ 738 $ 3,662 1 Primarily consists of employee costs. 2 In 2017, the liability was transferred from the 2015 Restructuring Initiative. The following table presents the Company's Acquisition Integration Restructuring Initiative liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 1,764 $ — Restructuring charges 1 6,121 2,614 Reserve release (242 ) — Cash paid (2,650 ) (850 ) Other 107 — Impact of foreign currency translation (7 ) — Balance, end of year $ 5,093 $ 1,764 1 Primarily consists of office closure costs. The following table presents the Company's total restructuring liability: Years Ended December 31, 2017 2016 Balance, beginning of year $ 10,657 $ 7,249 Restructuring charges 9,048 8,302 Reserve release (1,909 ) (816 ) Cash paid (10,149 ) (4,775 ) Other 107 — Impact of foreign currency translation 757 697 Balance, end of year $ 8,511 $ 10,657

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Reportable Segment Results	The following tables present the Company’s reportable segment results on an adjusted operating income basis for the years ended December 31, 2017 , 2016 and 2015 : Year Ended December 31, 2017 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 360,158 $ 158,660 $ 50,348 $ 569,166 Account servicing revenue 165,083 7,531 103,956 276,570 Finance fee revenue 159,336 760 27,486 187,582 Other revenue 138,389 57,096 21,745 217,230 Total revenue $ 822,966 $ 224,047 $ 203,535 $ 1,250,548 Depreciation and amortization $ 143,301 $ 17,703 $ 42,720 $ 203,724 Adjusted operating income $ 297,322 $ 117,432 $ 50,718 $ 465,472 Year Ended December 31, 2016 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 297,900 $ 175,762 $ 46,957 $ 520,619 Account servicing revenue 127,106 1,247 82,660 211,013 Finance fee revenue 124,725 643 13,572 138,940 Other revenue 92,330 37,595 17,963 147,888 Total revenue $ 642,061 $ 215,247 $ 161,152 $ 1,018,460 Depreciation and amortization $ 100,860 $ 6,187 $ 34,604 $ 141,651 Adjusted operating income $ 215,424 $ 104,531 $ 43,118 $ 363,073 Year Ended December 31, 2015 Fleet Solutions Travel and Corporate Solutions Health and Employee Benefit Solutions Total Payment processing revenue $ 305,855 $ 151,311 $ 38,703 $ 495,869 Account servicing revenue 100,850 1,930 53,912 156,692 Finance fee revenue 83,554 326 5,113 88,993 Other revenue 57,419 41,852 13,812 113,083 Total revenue $ 547,678 $ 195,419 $ 111,540 $ 854,637 Depreciation and amortization $ 54,453 $ 2,999 $ 25,625 $ 83,077 Adjusted operating income $ 186,731 $ 87,380 $ 28,576 $ 302,687
Interest Income	The following table presents the Company's interest income by segment for the years ended December 31, 2017 , 2016 and 2015 : 2017 2016 2015 Fleet Solutions $ 3,681 $ 3,053 $ 1,704 Travel and Corporate Solutions 717 498 348 Health and Employee Benefit Solutions 27,507 13,581 5,116 Total interest income $ 31,905 $ 17,132 $ 7,168
Reconciliation Of Adjusted Net Income To Net Income	The following table reconciles adjusted operating income to income before income taxes: Year ended December 31, 2017 2016 2015 Fleet Solutions $ 297,322 $ 215,424 $ 186,731 Travel and Corporate Solutions 117,432 104,531 87,380 Health and Employee Benefit Solutions 50,718 43,118 28,576 Adjusted operating income $ 465,472 $ 363,073 $ 302,687 Acquisition-related intangible amortization (153,810 ) (97,829 ) (47,792 ) Other acquisition and divestiture related items (5,000 ) (20,879 ) (4,137 ) Stock-based compensation (30,487 ) (19,742 ) (12,420 ) Restructuring and other costs (11,129 ) (13,995 ) (9,010 ) Impairment charges and asset write-offs (44,171 ) — — Gain on divestiture 20,958 — 1,215 Vendor settlement — (15,500 ) — Debt restructuring (2,563 ) — — Regulatory reserve — — (1,750 ) Operating income $ 239,270 $ 195,128 $ 228,793 Financing interest expense (107,067 ) (113,418 ) (46,189 ) Net foreign currency gain (loss) 29,919 (7,665 ) (5,689 ) Net unrealized gains on interest rate swap agreements 1,314 12,908 — Net realized and unrealized gains on fuel price derivatives — 711 5,848 Non-cash adjustments related to tax receivable agreement 15,259 (563 ) 2,145 Income before income taxes $ 178,695 $ 87,101 $ 184,908
Schedule Of Revenue By Geographic Data	Revenue by principal geographic area, based on the country in which the sale originated, was as follows: Year ended December 31, 2017 2016 2015 United States $ 1,037,322 $ 839,917 $ 691,088 Australia 62,030 53,068 50,387 Other international 1 151,196 125,475 113,162 Total revenues $ 1,250,548 $ 1,018,460 $ 854,637 1 No single country, other than the United States and Australia, made up more than 5 percent of total revenues for any of the years presented. Net property, equipment and capitalized software are subject to geographic risks because they are generally difficult to move and relatively illiquid. Net property, equipment and capitalized software by principal geographic area was as follows: Year ended December 31, 2017 2016 2015 United States $ 148,490 $ 146,165 $ 79,265 Australia 5,432 5,493 5,445 Other international 9,986 15,620 53,875 Net property, equipment and capitalized software $ 163,908 $ 167,278 $ 138,585

Supplementary Regulatory Capi55

Supplementary Regulatory Capital Disclosure (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following table presents WEX Bank's actual and regulatory minimum capital amounts and ratios: Actual Amount Ratio Minimum for Capital Adequacy Purposes Amount Ratio Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio December 31, 2017 Total Capital to risk-weighted assets $ 316,129 13.38 % $ 188,991 8.00 % $ 236,239 10.00 % Tier 1 Capital to average assets 304,555 12.50 % 97,452 4.00 % 121,815 5.00 % Common equity to risk-weighted assets 304,555 12.89 % 106,308 4.50 % 153,555 6.50 % Tier 1 Capital to risk-weighted assets $ 304,555 12.89 % $ 141,743 6.00 % $ 188,991 8.00 % December 31, 2016 Total Capital to risk-weighted assets $ 228,402 12.59 % $ 145,182 8.00 % $ 181,477 10.00 % Tier 1 Capital to average assets 214,847 11.10 % 77,413 4.00 % 96,767 5.00 % Common equity to risk-weighted assets 214,847 11.84 % 81,665 4.50 % 117,961 6.50 % Tier 1 Capital to risk-weighted assets $ 214,847 11.84 % $ 108,887 6.00 % $ 145,183 8.00 %

Quarterly Financial Results (56

Quarterly Financial Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary Of Quarterly Financial Results	Summarized quarterly results for the years ended December 31, 2017 and 2016 , are as follows: Three months ended March 31 June 30 September 30 December 31 2017 Total revenues $ 291,357 $ 303,884 $ 324,002 $ 331,305 Operating income $ 60,752 $ 47,581 $ 63,723 $ 67,214 Net earnings attributable to shareholders (a) $ 29,401 $ 17,090 $ 33,971 $ 79,804 Earnings per share: (a) Basic $ 0.69 $ 0.40 $ 0.79 $ 1.86 Diluted $ 0.68 $ 0.40 $ 0.79 $ 1.85 2016 Total revenues (b) $ 205,928 $ 233,936 $ 287,756 $ 290,840 Operating income (b) $ 41,127 $ 51,635 $ 54,568 $ 47,798 Net earnings attributable to shareholders (b) $ 23,086 $ 12,567 $ 19,696 $ 5,288 Earnings per share: (b) Basic $ 0.60 $ 0.32 $ 0.46 $ 0.12 Diluted $ 0.59 $ 0.32 $ 0.46 $ 0.12 (a) The three months ended December 31, 2017 includes a tax benefit of approximately $60 million as a result of the 2017 Tax Act. (b) Results for three months ended September 30, 2016 and December 31, 2016 include the operations of EFS and the issuance of approximately 4,000 shares of common stock for the acquisition of EFS on July 1, 2016.

Summary of Significant Accoun57

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Restricted cash	$ 18,866	$ 22,412
Impairment charges and asset write-offs	44,171	0	$ 0
Offset of waived finance fees	16,900	10,900	6,000
Advertising expense	$ 17,141	$ 14,864	$ 12,891

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2017
Furniture, fixtures and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	3 years
Furniture, fixtures and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	5 years
Internal-use computer software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	1 year 6 months
Internal-use computer software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	7 years
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	3 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment useful lives	5 years

Summary of Significant Accoun59

Summary of Significant Accounting Policies - Summary of Capitalized Software (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Amounts capitalized for internal-use computer software (including work-in-process)	$ 50,682	$ 55,379	$ 52,218
Amounts expensed for amortization of internal-use computer software	$ 32,582	$ 27,581	$ 20,316

Summary of Significant Accoun60

Summary of Significant Accounting Policies - Weighted Average Common Shares Outstanding Used to Calculate Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Net earnings attributable to shareholders	$ 160,266	$ 60,637	$ 101,904
Weighted average common shares outstanding – Basic (in shares)	42,977	40,809	38,771
Dilutive impact of share based compensation awards (in shares)	128	105	72
Weighted average common shares outstanding – Diluted (in shares)	43,105	40,914	38,843

Recent Accounting Pronounceme61

Recent Accounting Pronouncements (Details) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment	[1]					$ 261					$ 261
Effect of excess tax benefits related to share-based payments										$ 1,600
Restricted cash		$ 18,886				22,412				18,886	22,412
Revenues		331,305	$ 324,002	$ 303,884	$ 291,357	290,840	$ 287,756	$ 233,936	$ 205,928	1,250,548	1,018,460	$ 854,637
Operating expenses										$ 1,011,278	$ 823,332	625,844
Number of Operating Segments | segment										3
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of consolidated revenue not affected by new accounting pronouncement											30.00%
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment	[1]					261					$ 261
Retained Earnings | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment						$ 261					261
Travel and Corporate Solutions
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues										$ 224,047	$ 215,247	$ 195,419
Pro Forma | Fleet Solutions And Travel And Corporate Solutions | 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]
Revenues										52,000
Operating expenses										52,000
Pro Forma | Travel and Corporate Solutions | 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]
Revenues										(24,000)
Operating expenses										(24,000)
Pro Forma | Sales Commission | 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]
Sales commissions		$ 1,000								$ 1,000
[1]	Includes the impact of modified retrospective transition as part of the Company's ASU 2016-09 adoption to recognize previously disallowed excess tax benefits that increased a net operating loss.

Business Acquisitions and Oth62

Business Acquisitions and Other Intangible Assets Acquisitions - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Expenses related to acquisitions	$ 956	$ 19,168	$ 342

Business Acquisitions and Oth63

Business Acquisitions and Other Intangible Assets Acquisitions - Summary of AOC Acquisition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Oct. 18, 2017	Dec. 31, 2016	Dec. 31, 2015
Less:
Recorded goodwill	$ 1,876,132		$ 1,838,441	$ 1,112,878
AOC Acquisition
Business Acquisition [Line Items]
Total consideration		$ 129,828
Less:
Cash	15,546
Accounts receivable	4,171
Property and equipment	2,530
Other liabilities	685
Recorded goodwill	$ 67,706
Weighted average life	5 years 4 months 24 days
Total revenues	$ 6,685
Net loss before taxes	620
Customer relationships | AOC Acquisition
Less:
Intangible assets	$ 15,000
Weighted average life	8 years 10 months 24 days
Developed technologies | AOC Acquisition
Less:
Intangible assets	$ 24,100
Weighted average life	3 years 4 months 24 days
Trademarks and Trade names | AOC Acquisition
Less:
Intangible assets	$ 1,460
Weighted average life	4 years

Business Acquisitions and Oth64

Business Acquisitions and Other Intangible Assets Acquisitions - Summary of EFS Acquisition (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 01, 2016	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Consideration transferred, shares, amount			$ 0	$ 354,953	$ 0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Recorded goodwill				502
Recorded goodwill			1,876,132	1,838,441	1,112,878
Fleet solutions
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Recorded goodwill				0
Recorded goodwill			1,268,791	1,292,283	734,903
Travel and Corporate Solutions
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Recorded goodwill				0
Recorded goodwill			253,833	192,436	27,654
Electronic Funds Source LLC
Business Acquisition [Line Items]
Consideration transferred, shares (in shares)	4,012,000
Consideration transferred, shares, amount	$ 355,000
Percent of ownership interest acquired	9.40%
Payments to acquire businesses	$ 1,182,000
Consideration transferred	1,444,000
Cash	$ 93,000
Direct ownership in the limited liability company	49.50%
Direct ownership held by other corporation	50.50%
Goodwill, expected tax deductible amount			557,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Total consideration		$ 1,444,235		1,444,235
Accounts receivable		162,684		162,684
Property and equipment		2,388		2,387
Deferred income tax assets		41,344		34,992
Other assets		739		0
Accounts payable		(153,529)		(153,777)
Accrued expenses		(118,906)		(128,267)
Deferred income tax liabilities		(63,123)		(91,194)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Consideration paid, net of cash acquired		0
Accounts receivable		0
Property and equipment		1
Deferred income tax assets		6,352
Other assets		739
Accounts payable		248
Accrued expenses		9,361
Deferred income tax liabilities		28,071
Recorded goodwill		(43,472)	(43,472)
Recorded goodwill		685,418		728,890
Weighted average life	7 years 10 months 24 days
Unaudited pro forma operational results
Total revenues				1,089,880	994,619
Net earnings attributable to shareholders				$ 42,821	$ 36,763
Pro forma net income attributable to WEX Inc. per common share:
Basic (in dollars per share)				$ 1	$ 0.86
Diluted (in dollars per share)				$ 1	$ 0.86
Electronic Funds Source LLC | Fleet solutions
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Recorded goodwill			(37,296)
Recorded goodwill	$ 1,235,331
Total revenues				$ 83,300
Net loss before taxes				5,800
Electronic Funds Source LLC | Travel and Corporate Solutions
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Recorded goodwill			$ (6,176)
Recorded goodwill	$ 337,307
Electronic Funds Source LLC | Acquisition-related Costs
Unaudited pro forma operational results
Net earnings attributable to shareholders					$ (19,168)
Electronic Funds Source LLC | Extinguishment of Debt Related Expense
Unaudited pro forma operational results
Net earnings attributable to shareholders					$ (7,074)
Electronic Funds Source LLC | Customer relationships
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets		841,400		842,700
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Intangible assets		(1,300)
Weighted average life	8 years 1 month 6 days
Electronic Funds Source LLC | Developed technologies
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets		32,120		32,120
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Intangible assets		0
Weighted average life	2 years
Electronic Funds Source LLC | Trademarks and Trade names
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Intangible assets		13,700		$ 13,700
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Intangible assets		$ 0
Weighted average life	7 years 8 months 12 days

Business Acquisitions and Oth65

Business Acquisitions and Other Intangible Assets Acquisitions - Summary of Benaissance Acquisition (Details) - USD ($) $ in Thousands	Nov. 18, 2015	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Consideration paid (net of cash acquired)			$ 114,282	$ 1,089,282	$ 80,677
Less:
Recorded goodwill		$ 1,112,878	$ 1,876,132	$ 1,838,441	$ 1,112,878
Benaissance
Business Acquisition [Line Items]
Consideration transferred	$ 80,677
Revenues		2,085
Net income		$ 399
Consideration paid (net of cash acquired)	80,677
Less:
Accounts receivable	1,594
Other tangible assets and liabilities, net	314
Recorded goodwill	$ 39,269
Weighted average life	6 years 10 months 24 days
Benaissance | Acquired software and developed technology
Less:
Finite-lived intangible assets	$ 10,300
Weighted average life	5 years
Benaissance | Customer relationships
Less:
Finite-lived intangible assets	$ 27,700
Weighted average life	7 years 7 months 6 days
Benaissance | Trade name
Less:
Finite-lived intangible assets	$ 1,500
Weighted average life	8 years 1 month 6 days

Business Acquisitions and Oth66

Business Acquisitions and Other Intangible Assets Acquisitions - Summary of UNIK Acquisition (Details) - Unik Financial Services $ in Thousands	Aug. 31, 2015USD ($)
Business Acquisition [Line Items]
Percent of ownership interest acquired	49.00%
Purchase of redeemable non-controlling interest	$ 46,018

Divestitures (Details)

Divestitures (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations - USD ($) $ in Thousands	Jan. 07, 2015	Dec. 31, 2017
Telapoint
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net assets disposed of		$ 8,942
Consideration received		29,900
Pre-tax book gain on disposal		$ 20,958
Rapid Paycard
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 20,000
Pre-tax book gain on disposal	$ 1,215

Accounts Receivable - Additiona

Accounts Receivable - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivable payments terms (in days)	30 days
Threshold period past due for write-off of trade accounts receivable (in days)	150 days
Accounts receivable | Customer Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of outstanding receivables		10.00%
Revolving line-of-credit facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables with revolving credit balances	$ 12,200	$ 3,400
29 days or less past due | Accounts receivable | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of outstanding receivables	95.00%	93.00%
59 days or less past due | Accounts receivable | Credit Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of outstanding receivables	97.00%	98.00%
Customer One | Accounts receivable | Customer Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of outstanding receivables	10.00%	11.00%

Accounts Receivable - Changes i

Accounts Receivable - Changes in Reserves for Credit Losses Related to Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts Receivable [Rollforward]
Balance, beginning of year	$ 21,454	$ 14,672	$ 14,627
Provision for credit losses	61,148	33,348	22,825
Charges to other accounts	16,869	10,166	6,155
Charge-offs	(77,229)	(43,309)	(33,885)
Recoveries of amounts previously charged-off	7,526	6,201	5,202
Currency translation	439	376	(252)
Balance, end of year	$ 30,207	$ 21,454	$ 14,672

Investments - Available-For-Sal

Investments - Available-For-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 24,102	$ 24,259
Gross Unrealized Gains	5	16
Gross Unrealized Losses	749	750
Fair Value	23,358	23,525
Equity securities designated as trading	6,798	5,673
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Cost	325	498
Gross Unrealized Gains	4	15
Gross Unrealized Losses	24	23
Fair Value	305	490
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Cost	350	650
Gross Unrealized Gains	0	0
Gross Unrealized Losses	5	2
Fair Value	345	648
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	539	697
Gross Unrealized Gains	1	1
Gross Unrealized Losses	6	16
Fair Value	534	682
Fixed-income mutual fund
Schedule of Available-for-sale Securities [Line Items]
Cost	22,888	22,414
Gross Unrealized Gains	0	0
Gross Unrealized Losses	714	709
Fair Value	$ 22,174	$ 21,705

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Maturities of available-for-sale securities	$ 631	$ 495	$ 594

Investments - Maturity Dates Of

Investments - Maturity Dates Of Available-For-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Cost
Due after 1 year through year 5	$ 0	$ 165
Due after 5 years through year 10	390	529
Due after 10 years	499	653
Mortgage-backed securities with original maturities of 30 years	325	498
Equity securities with no maturity dates	22,888	22,414
Total	24,102	24,259
Fair Value
Due after 1 year through year 5	0	165
Due after 5 years through year 10	385	529
Due after 10 years	494	636
Mortgage-backed securities with original maturities of 30 years	305	490
Equity securities with no maturity dates	22,174	21,705
Total	$ 23,358	$ 23,525

Property, Equipment and Capit73

Property, Equipment and Capitalized Software, Net - Schedule Of Property, Equipment And Capitalized Software, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	$ 428,836	$ 395,614
Less: accumulated depreciation and amortization	(264,928)	(228,336)
Total property, equipment and capitalized software, net	163,908	167,278	$ 138,585
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	75,015	69,513
Computer software
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	308,362	254,163
Software under development
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	21,452	49,922
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	23,248	21,257
Capital leases
Property, Plant and Equipment [Line Items]
Property, equipment and capitalized software, gross	$ 759	$ 759

Property, Equipment and Capit74

Property, Equipment and Capitalized Software, Net - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation	$ 49,913,000	$ 43,821,000	$ 35,285,000
Impairment charges	$ 28,000,000	$ 0	$ 0

Goodwill and Other Intangible75

Goodwill and Other Intangible Assets - Schedule of Changes In Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Gross goodwill, beginning of period	$ 1,849,631	$ 1,849,631	$ 1,124,225
Acquisition adjustments			502
Acquisition			728,890
Divestiture of Telapoint		(4,469)
Impact of foreign currency translation		18,871	3,986
Gross goodwill, end of period		1,888,267	1,849,631
Accumulated impairment, beginning of period	(11,190)	(11,190)	(11,347)
Impact of foreign currency translation		(945)	(157)
Accumulated impairment, end of period		(12,135)	(11,190)
Net goodwill, beginning of period	1,838,441	1,838,441	1,112,878
Net goodwill, end of period		1,876,132	1,838,441
Fleet solutions
Goodwill [Roll Forward]
Gross goodwill, beginning of period	1,293,138	1,293,138	735,770
Acquisition adjustments			0
Acquisition			561,119
Divestiture of Telapoint		(4,469)
Impact of foreign currency translation		18,345	3,751
Gross goodwill, end of period		1,269,718	1,293,138
Accumulated impairment, beginning of period	(855)	(855)	(867)
Impact of foreign currency translation		(72)	(12)
Accumulated impairment, end of period		(927)	(855)
Net goodwill, beginning of period	1,292,283	1,292,283	734,903
Net goodwill, end of period		1,268,791	1,292,283
Travel and Corporate Solutions
Goodwill [Roll Forward]
Gross goodwill, beginning of period	202,771	202,771	38,134
Acquisition adjustments			0
Acquisition			167,771
Divestiture of Telapoint		0
Impact of foreign currency translation		740	3,134
Gross goodwill, end of period		265,041	202,771
Accumulated impairment, beginning of period	(10,335)	(10,335)	(10,480)
Impact of foreign currency translation		(873)	(145)
Accumulated impairment, end of period		(11,208)	(10,335)
Net goodwill, beginning of period	192,436	192,436	27,654
Net goodwill, end of period		253,833	192,436
Health and Employee Benefit Solutions
Goodwill [Roll Forward]
Gross goodwill, beginning of period	353,722	353,722	350,321
Acquisition adjustments			502
Acquisition			0
Divestiture of Telapoint		0
Impact of foreign currency translation		(214)	(2,899)
Gross goodwill, end of period		353,508	353,722
Accumulated impairment, beginning of period	0	0	0
Impact of foreign currency translation		0	0
Accumulated impairment, end of period		0	0
Net goodwill, beginning of period	353,722	353,722	350,321
Net goodwill, end of period		353,508	353,722
Electronic Funds Source LLC
Goodwill [Roll Forward]
Acquisition adjustments	(43,472)	(43,472)
Net goodwill, beginning of period	728,890	728,890
Net goodwill, end of period	$ 685,418		$ 728,890
Electronic Funds Source LLC | Fleet solutions
Goodwill [Roll Forward]
Acquisition adjustments		(37,296)
Electronic Funds Source LLC | Travel and Corporate Solutions
Goodwill [Roll Forward]
Acquisition adjustments		(6,176)
Electronic Funds Source LLC | Health and Employee Benefit Solutions
Goodwill [Roll Forward]
Acquisition adjustments		0
AOC Acquisition
Goodwill [Roll Forward]
Acquisition		67,706
Net goodwill, end of period		67,706
AOC Acquisition | Fleet solutions
Goodwill [Roll Forward]
Acquisition		0
AOC Acquisition | Travel and Corporate Solutions
Goodwill [Roll Forward]
Acquisition		67,706
AOC Acquisition | Health and Employee Benefit Solutions
Goodwill [Roll Forward]
Acquisition		$ 0

Goodwill and Other Intangible76

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,542,299,000	$ 1,513,292,000
Accumulated Amortization	(392,827,000)	(254,142,000)
Net Carrying Amount	1,149,472,000	1,259,150,000
Net Carrying Amount, Total	1,154,047,000	1,265,468,000
Amortization expense	153,811	97,829	$ 47,792
Acquired software and developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	203,861,000	187,499,000
Accumulated Amortization	(96,197,000)	(69,483,000)
Net Carrying Amount	107,664,000	118,016,000
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,257,232,000	1,247,624,000
Accumulated Amortization	(269,216,000)	(167,301,000)
Net Carrying Amount	988,016,000	1,080,323,000
Licensing agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	34,546,000	30,760,000
Accumulated Amortization	(15,029,000)	(9,126,000)
Net Carrying Amount	19,517,000	21,634,000
Non-compete agreement
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	0	4,000,000
Accumulated Amortization	0	0
Net Carrying Amount	0	4,000,000
Patent
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,581,000	2,380,000
Accumulated Amortization	(2,076,000)	(1,724,000)
Net Carrying Amount	505,000	656,000
Trade name
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	44,079,000	41,029,000
Accumulated Amortization	(10,309,000)	(6,508,000)
Net Carrying Amount	33,770,000	34,521,000
Trademarks, trade names and brand names
Finite-Lived Intangible Assets [Line Items]
Trademarks, trade names and brand names, Net Carrying Amount	$ 4,575,000	$ 6,318,000

Goodwill and Other Intangible77

Goodwill and Other Intangible Assets - Estimated Amortization Expense (Details) $ in Thousands	Dec. 31, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 141,583
2,019	127,393
2,020	116,164
2,021	100,367
2,022	$ 89,267

Accounts Payable (Details)

Accounts Payable (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Merchant payables	$ 720,553	$ 520,058
Other payables	90,809	97,060
Accounts payable	$ 811,362	$ 617,118

Deposits, Borrowed Federal Fu79

Deposits, Borrowed Federal Funds and Other Debt - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Certificates of deposit, denominations ($250 or less)	$ 250,000
Federal funds lines-of-credit	400,000,000	$ 250,000,000
Debt outstanding	0	0
Participation Agreement
Debt Instrument [Line Items]
Increase in funding capacity	90,000
Debt instrument, aggregate principal amount	185,000
Debt balance	$ 185,000,000	95,000,000
Participation Agreement | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate margin	2.25%
Loan Participations and Assignments Maturing May 2018
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount	$ 85,000,000
Loan Participations and Assignments Maturing December 2021
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount	50,000,000
Loan Participations and Assignments Maturing On Demand
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount	50,000,000
WEX Brazil
Debt Instrument [Line Items]
Debt outstanding	9,747,000	$ 30,755,000
Interest-bearing Deposits
Debt Instrument [Line Items]
Interest-bearing money market deposits, denominations	$ 250,000
Minimum
Debt Instrument [Line Items]
Certificates of deposit, maturities range	3 months
Certificates of deposit, fixed interest rates range	1.00%
Maximum
Debt Instrument [Line Items]
Certificates of deposit, maturities range	3 years
Certificates of deposit, fixed interest rates range	2.15%

Deposits, Borrowed Federal Fu80

Deposits, Borrowed Federal Funds and Other Debt - Schedule of Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Certificates of deposit with maturities within 1 year	$ 630,879	$ 517,524
Certificates of deposit with maturities greater than 1 year and less than 5 years	306,865	208,048
Interest-bearing money market deposits	285,899	325,464
Customer deposits	70,211	67,787
Total deposits	$ 1,293,854	$ 1,118,823
Weighted average cost of funds on certificates of deposit outstanding	1.51%	0.96%
Weighted average cost of interest-bearing money market deposits	1.49%	0.76%

Deposits, Borrowed Federal Fu81

Deposits, Borrowed Federal Funds and Other Debt - Average Interest Rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Deposits	1.22%	0.94%	0.65%
Borrowed federal funds	1.24%	0.69%	0.39%
Interest-bearing money market deposits	1.12%	0.50%	0.25%
Participation Agreement
Debt Instrument [Line Items]
Participation agreement	3.46%	2.94%	2.57%
WEX Brazil
Debt Instrument [Line Items]
WEX Latin America debt	21.21%	19.70%	15.21%

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)
Derivative [Line Items]
Revolving line-of-credit facility and term loans, net	$ 1,707,064	$ 1,599,291
Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements | contract	5
Borrowings under derivative agreements	$ 1,300,000
Interest rate swaps | Minimum
Derivative [Line Items]
Fixed rate variable interest	0.896%
Interest rate swaps | Maximum
Derivative [Line Items]
Fixed rate variable interest	2.212%
Foreign Currency Swap
Derivative [Line Items]
Derivative settlement term	5 days

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Notional Amounts (Details) - Derivatives not designated as hedging instruments - USD ($)	Dec. 31, 2017	Nov. 30, 2016
Tranche A
Derivative [Line Items]
Notional amount at inception	$ 300,000,000
Fixed interest rate	2.204%
Tranche B
Derivative [Line Items]
Notional amount at inception	$ 200,000,000
Fixed interest rate	2.212%
Tranche C
Derivative [Line Items]
Notional amount at inception	$ 400,000,000
Amortization		5.00%
Fixed interest rate	1.108%
Tranche D
Derivative [Line Items]
Notional amount at inception	$ 150,000,000
Fixed interest rate	1.125%
Tranche E
Derivative [Line Items]
Notional amount at inception	$ 250,000,000
Fixed interest rate	0.896%

Derivative Instruments - Forwar

Derivative Instruments - Forward Currency Swap (Details) - AUD	Dec. 31, 2017	Dec. 31, 2016
Foreign Currency Swap | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional amount at inception	AUD 5,000,000	AUD 15,000,000

Derivative Instruments - Summar

Derivative Instruments - Summary of Changes in Fair Value (Details) - Fuel - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Realized gains (losses)	$ 5,718	$ 41,810
Change in unrealized fuel price derivatives	(5,007)	(35,962)
Net realized and unrealized gains (losses) on derivative instruments	$ 711	$ 5,848

Derivative Instruments - Locati

Derivative Instruments - Location and Amounts of Derivative Fair Values in Condensed Consolidated Balance Sheets (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other assets | Interest rate swaps
Derivative [Line Items]
Asset Derivatives, Fair Value	$ 15,919	$ 12,908
Other liabilities | Interest rate swaps
Derivative [Line Items]
Liability Derivatives, Fair Value	1,697	0
Accounts receivable | Foreign currency contracts
Derivative [Line Items]
Asset Derivatives, Fair Value	0	29
Accounts payable | Foreign currency contracts
Derivative [Line Items]
Liability Derivatives, Fair Value	$ 0	$ 0

Derivative Instruments - Loca87

Derivative Instruments - Location and Amounts of Derivative Gains and Losses in Condensed Consolidated Statements of Income (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign currency contracts | Net foreign currency gain
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ 0	$ 59	$ 27,236
Interest rate swaps | Net unrealized gains on interest rate swap agreements
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	1,314	12,908	0
Interest rate swaps | Financing interest income
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	214	0	0
Commodity contracts | Net realized and unrealized gains on fuel price derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative	$ 0	$ 711	$ 5,848

Off-Balance Sheet Arrangement88

Off-Balance Sheet Arrangements Off-Balance Sheet Arrangements (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
WEX Europe Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of receivables sold	$ 574,400
Loss on factoring	3,700
Amount of factored receivables	61,800
Factored receivables in excess of established credit limit	3,700
WEX Latin America
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of receivables sold	16,300
Loss on factoring	$ 800

Financing Debt - Summary of Out

Financing Debt - Summary of Outstanding Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Line of Credit | 2016 Credit Agreement
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,739,410	$ 1,637,625
Unamortized debt issuance costs	(32,346)	(38,334)
Long-term debt, net	1,707,064	1,599,291
Revolving line-of-credit facility | Line of Credit | 2016 Credit Agreement
Debt Instrument [Line Items]
Long-term debt, gross	136,535	0
Term loans | Line of Credit | 2016 Credit Agreement
Debt Instrument [Line Items]
Long-term debt, gross	1,602,875	1,637,625
Senior Notes
Debt Instrument [Line Items]
Long-term debt, gross	400,000	400,000
Unamortized debt issuance costs	(3,731)	(4,466)
Long-term debt, net	$ 396,269	$ 395,534

Financing Debt - Additional Inf

Financing Debt - Additional Information (Details) - USD ($)

Jul. 03, 2017

Jul. 01, 2016

Apr. 07, 2016

Jan. 30, 2013

Sep. 30, 2016

Jun. 30, 2016

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Oct. 30, 2017

Jun. 30, 2017

Jan. 31, 2016

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 400,000,000

$ 250,000,000

Current borrowing capacity

406,000,000

Revolving line-of-credit facility and term loans, net

1,707,064,000

1,599,291,000

Permitted securitization transactions

$ 350,000,000

Percentage of principal amount Company must offer to repurchase

101.00%

Notes outstanding, net

396,269,000

395,534,000

Receivables transferred to the investment fund

150,235,000

97,417,000

Securitization facility

126,901,000

84,323,000

Ticking fees expensed

0

30,045,000

$ 0

Pledged receivables held as collateral

343,800,000

Electronic Funds Source LLC

Debt Instrument [Line Items]

Revolving line-of-credit facility and term loans, net

$ 2,125,000,000

Electronic Funds Source LLC | Interest Expense

Debt Instrument [Line Items]

Commitment fee amount

30,045,000

Minimum | Electronic Funds Source LLC

Debt Instrument [Line Items]

Commitment fee amount

$ 7,874,000

Maximum | Electronic Funds Source LLC | Interest Expense

Debt Instrument [Line Items]

Commitment fee amount

$ 22,171,000

Interest Rate Option Two | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

1.00%

Interest Rate Option Two | Federal Fund Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

0.50%

Senior Notes Redeemed During 12 Months Beginning February 1, 2018

Debt Instrument [Line Items]

Redemption price as percentage of principal amount

102.375%

Senior Notes Redeemed During 12 Months Beginning February 1, 2019

Debt Instrument [Line Items]

Redemption price as percentage of principal amount

101.583%

Senior Notes Redeemed During 12 Months Beginning February 1, 2020

Debt Instrument [Line Items]

Redemption price as percentage of principal amount

100.792%

Senior Notes Redeemed During 12 Months Beginning February 1, 2021

Debt Instrument [Line Items]

Redemption price as percentage of principal amount

100.00%

Senior Notes Redeemed Prior To February 1, 2018

Debt Instrument [Line Items]

Redemption price as percentage of principal amount

100.00%

Federal Reserve Bank

Debt Instrument [Line Items]

Revolving line-of-credit facility and term loans, net

0

Revolving line-of-credit facility | Federal Reserve Bank

Debt Instrument [Line Items]

Current borrowing capacity

277,326,000

Revolving line-of-credit facility | Letter of Credit | 2011 Credit Agreement

Debt Instrument [Line Items]

Revolving line-of-credit facility and term loans, net

$ 27,500,000

$ 13,300,000

2016 Credit Agreement

Debt Instrument [Line Items]

Weighted average effective interest rate (as a percent)

4.20%

4.20%

Amount allowed for exclusion of certain corporate cash balances

$ 75,000,000

Debt instrument, cash proceeds from assets sales required to be used towards debt repayment, percent

100.00%

Debt instrument. cash proceeds from other debts required to be used towards debt repayment, percent

100.00%

Debt issuance costs

$ 49,810,000

$ 49,810,000

Debt issuance discount

12,000,000

2016 Credit Agreement | Minimum

Debt Instrument [Line Items]

Commitment fee percentage

0.30%

2016 Credit Agreement | Maximum

Debt Instrument [Line Items]

Commitment fee percentage

0.50%

0.45%

2016 Credit Agreement | Interest Rate Option One | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

2.75%

2016 Credit Agreement | Interest Rate Option One | Eurocurrency Rate | Minimum

Debt Instrument [Line Items]

Margin on variable rate, percent

1.75%

2016 Credit Agreement | Interest Rate Option One | Eurocurrency Rate | Maximum

Debt Instrument [Line Items]

Margin on variable rate, percent

3.25%

2016 Credit Agreement | Interest Rate Option Two | Eurocurrency Rate | Minimum

Debt Instrument [Line Items]

Margin on variable rate, percent

0.75%

2016 Credit Agreement | Interest Rate Option Two | Eurocurrency Rate | Maximum

Debt Instrument [Line Items]

Margin on variable rate, percent

2.25%

1.75%

2016 Credit Agreement | Revolving line-of-credit facility

Debt Instrument [Line Items]

Additional borrowing capacity added

$ 100,000,000

Current borrowing capacity

$ 570,000,000

2016 Credit Agreement Tranche A

Debt Instrument [Line Items]

Debt instrument, quarterly payment, percent of original principal amount

1.25%

Interest coverage ratio (no less than)

3.25

Indebtedness to EBITDA Ratio (no more than)

5.40

2016 Credit Agreement Tranche A | December 31, 2016

Debt Instrument [Line Items]

Indebtedness to EBITDA Ratio (no more than)

5.25

2016 Credit Agreement Tranche A | December 31, 2017

Debt Instrument [Line Items]

Indebtedness to EBITDA Ratio (no more than)

5

2016 Credit Agreement Tranche A | December 31, 2018

Debt Instrument [Line Items]

Indebtedness to EBITDA Ratio (no more than)

4.25

2016 Credit Agreement Tranche A | December 31, 2019

Debt Instrument [Line Items]

Indebtedness to EBITDA Ratio (no more than)

4

2016 Credit Agreement Tranche A | Interest Rate Option One | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

2.25%

Reduction in basis points

0.50%

2016 Credit Agreement Tranche A | Interest Rate Option One | Eurocurrency Rate | Minimum

Debt Instrument [Line Items]

Margin on variable rate, percent

1.75%

2016 Credit Agreement Tranche A | Interest Rate Option One | Eurocurrency Rate | Maximum

Debt Instrument [Line Items]

Margin on variable rate, percent

2.75%

2016 Credit Agreement Tranche A | Interest Rate Option Two | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

1.25%

2016 Credit Agreement Tranche A | Interest Rate Option Two | Eurocurrency Rate | Minimum

Debt Instrument [Line Items]

Margin on variable rate, percent

0.75%

2016 Credit Agreement Tranche A | Interest Rate Option Two | Eurocurrency Rate | Maximum

Debt Instrument [Line Items]

Margin on variable rate, percent

1.75%

2016 Credit Agreement Tranche A | Revolving line-of-credit facility

Debt Instrument [Line Items]

Current borrowing capacity

1,025,000,000

2016 Credit Agreement Tranche B

Debt Instrument [Line Items]

Debt instrument unamortized discount, percent

1.00%

Debt instrument, excess of cash required to be used for debt repayment

50.00%

Debt instrument, conditions for prepayment, maximum period following effective date

6 months

Debt instrument, loan prepayment premium, percent

1.00%

Debt instrument, quarterly payment, percent of original principal amount

0.25%

2016 Credit Agreement Tranche B | Leverage Ratio One

Debt Instrument [Line Items]

Debt instrument, excess of cash required to be used for debt repayment

25.00%

2016 Credit Agreement Tranche B | Leverage Ratio Two

Debt Instrument [Line Items]

Debt instrument, excess of cash required to be used for debt repayment

0.00%

2016 Credit Agreement Tranche B | Interest Rate Option One | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

2.75%

Reduction in basis points

0.75%

Debt instrument, interest rate, floor

0.00%

2016 Credit Agreement Tranche B | Interest Rate Option Two | Eurocurrency Rate | Minimum

Debt Instrument [Line Items]

Interest rate, stated percentage

2.25%

2016 Credit Agreement Tranche B | Revolving line-of-credit facility

Debt Instrument [Line Items]

Current borrowing capacity

1,200,000,000

2014 Credit Agreement

Debt Instrument [Line Items]

Ticking fees expensed

$ 5,056,000

Loss on debt extinguishment

$ 2,018,000

2014 Credit Agreement | Revolving line-of-credit facility

Debt Instrument [Line Items]

Revolving line-of-credit facility and term loans, net

$ 282,639,000

2014 Credit Agreement | Revolving line-of-credit facility | Eurocurrency Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

2.00%

2014 Credit Agreement | Revolving line-of-credit facility | London Interbank Offered Rate (LIBOR)

Debt Instrument [Line Items]

Margin on variable rate, percent

2.00%

2014 Credit Agreement | Revolving line-of-credit facility | Prime Rate

Debt Instrument [Line Items]

Margin on variable rate, percent

1.00%

2014 Credit Agreement | Credit Facility and Term Loans

Debt Instrument [Line Items]

Revolving line-of-credit facility and term loans, net

$ 445,000,000

2014 Credit Agreement | Credit Facility and Term Loans | London Interbank Offered Rate (LIBOR)

Debt Instrument [Line Items]

Margin on variable rate, percent

2.00%

Senior Notes

Debt Instrument [Line Items]

Interest rate, stated percentage

4.75%

Issue price of principal amount (as a percent)

100.00%

Notes outstanding, net

$ 400,000,000

$ 400,000,000

Securitization Facility

Debt Instrument [Line Items]

Securitization facility, percentage of receivables used as collateral

85.00%

Interest rate during period, percent

2.53%

2.65%

Securitization facility

$ 90,000,000

$ 78,600,000

European Securitization Facility

Debt Instrument [Line Items]

Securitized debt

$ 17,900,000

$ 5,700,000

Interest rate during period, percent

1.11%

0.95%

Debt instrument, term

5 years

WEX Latin America | WEX Latin America Securitization Facility

Debt Instrument [Line Items]

Receivables transferred to the investment fund

$ 49,100,000

Cash proceeds from receivable securitization

43,800,000

Discount recognized on securitization

5,300,000

Servicing fee income from securitization

3,000,000

Securitized debt

$ 19,000,000

Term loans | 2016 Credit Agreement Tranche A | Line of Credit

Debt Instrument [Line Items]

Debt instrument, face amount

455,000

Term loans | 2016 Credit Agreement Tranche B | Line of Credit

Debt Instrument [Line Items]

Debt instrument, face amount

1,200,000

Revolving line-of-credit facility | 2016 Credit Agreement | Line of Credit

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 570,000

Financing Debt - Summary of Ann

Financing Debt - Summary of Annual Principal Payments (Details) $ in Thousands	Dec. 31, 2017USD ($)
Debt Disclosure [Abstract]
2,018	$ 34,750
2,019	34,750
2,020	34,750
2,021	364,625
2,022	$ 12,000

Income Taxes - Components Of In

Income Taxes - Components Of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States	$ 149,344	$ 32,622	$ 203,692
Foreign	29,351	54,479	(18,784)
Income before income taxes	$ 178,695	$ 87,101	$ 184,908

Income Taxes - Components Of 93

Income Taxes - Components Of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current, United States	$ 2,253	$ (1,232)	$ 22,570
Deferred, United States	(11,234)	21,565	37,553
Current, State and Local	3,687	3,033	4,288
Deferred, State and Local	13,280	(5,106)	5,631
Current, Foreign	14,473	8,325	9,173
Deferred, Foreign	(2,934)	3,040	(3,919)
Current, Total	20,413	10,126	36,031
Deferred, Total	(888)	19,499	39,265
Income taxes	$ 19,525	$ 29,625	$ 75,296

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
2017 Tax Act, income tax benefit	$ 60,636,000
Tax benefit from remeasurement of deferred tax assets and liabilities		$ 62,488,000
Non-cash adjustments related to tax receivable agreement		15,259,000	$ 0	$ 0
Adjustment to receivable agreement, unrecognized income tax expense		5,726,000
Income tax expense, transition tax		9,098,000
Reversal of net deferred tax liabilities		1,520,000
Undistributed Earnings of Foreign Subsidiaries	58,675,000	$ 58,675,000	$ 25,824,000
Effective tax rate		10.90%	34.00%	40.70%
Tax expense related to valuation allowance		$ 12,167,000	$ 2,000,000
Unrecognized tax benefits, net	4,859,000	4,859,000
Unrecognized tax benefits that, if recognized, would impact effective tax rate	3,944,000	3,944,000
Interest and penalties related to uncertain tax positions		12,000	(2,251,000)	$ 263,000
Accrued penalties and interest related to uncertain tax positions	0	0	0
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Operating loss carry forwards	294,318,000	294,318,000	211,010,000
Domestic Tax Authority
Income Tax Contingency [Line Items]
Operating loss carry forwards	112,688,000	112,688,000	103,739,000
Foreign Tax Authority
Income Tax Contingency [Line Items]
Operating loss carry forwards	$ 77,622,000	77,622,000	$ 54,062,000
Electronic Funds Source LLC
Income Tax Contingency [Line Items]
Deferred tax liabilities related to finalization of purchase price accounting		$ 34,462,000

Income Taxes - Reconciliation O

Income Taxes - Reconciliation Of Provision Of Income Taxes (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal statutory rate	35.00%	35.00%	35.00%
State income taxes (net of federal income tax benefit)	2.00%	1.10%	2.50%
Foreign income tax rate differential	(0.60%)	(4.40%)	1.40%
Revaluation of deferred tax assets for foreign and state tax rate changes, net	0.40%	(0.90%)	0.70%
Research and development credit	(0.00%)	(0.50%)	0.20%
Release of tax reserves	0.00%	(4.90%)	0.00%
Withholding taxes	0.20%	0.30%	0.00%
2017 Tax Act	(33.90%)	0.00%	0.00%
Domestic production exclusions	(0.00%)	(0.00%)	(1.80%)
Change in valuation allowance	5.80%	2.30%	1.60%
Nondeductible expenses	0.90%	3.40%	0.30%
Incremental tax benefit from share-based compensation awards	(0.90%)	0.00%	0.00%
Other	2.00%	2.60%	0.80%
Effective tax rate	10.90%	34.00%	40.70%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred assets related to:
Reserve for credit losses	$ 6,562	$ 7,122
Tax credit carryforwards	1,283	5,178
Stock-based compensation, net	9,858	12,729
Net operating loss carry forwards	54,700	56,501
Accruals	7,355	18,985
Deferred financing costs	0	5,420
Other	0	164
Total	79,758	106,099
Deferred tax liabilities related to:
Other liabilities	2,060	643
Deferred financing costs	7,219	0
Property, equipment and capitalized software	22,315	32,759
Intangibles	141,908	118,695
Investment in partnership	0	94,354
Total	173,502	246,451
Valuation allowance	17,787	5,620
Deferred income taxes, net	$ (111,531)	$ (145,972)

Income Taxes - Net Deferred Tax

Income Taxes - Net Deferred Tax Assets By Jurisdiction (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Deferred tax liabilities	$ (111,531)	$ (145,972)
United States
Income Tax Contingency [Line Items]
Deferred tax liabilities	(116,229)	(148,389)
Australia
Income Tax Contingency [Line Items]
Deferred tax liabilities	(945)	(2,020)
United Kingdom
Income Tax Contingency [Line Items]
Deferred tax assets	7,315	6,474
New Zealand
Income Tax Contingency [Line Items]
Deferred tax assets	188	183
The Netherlands
Income Tax Contingency [Line Items]
Deferred tax assets	249	206
Brazil
Income Tax Contingency [Line Items]
Deferred tax liabilities	(1,073)	(2,497)
Canada
Income Tax Contingency [Line Items]
Deferred tax assets		$ 71
Deferred tax liabilities	$ (1,036)

Income Taxes - Reconciliation98

Income Taxes - Reconciliation Of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 4,960	$ 4,776	$ 4,856
Increases related to prior year tax positions	1,332	4,960	431
Decreases related to prior year tax positions, due to foreign currency exchange	0	0	(511)
Decreases related to prior year tax positions	0	(431)	0
Settlements	(1,255)	0	0
Lapse of statute	0	(4,345)	0
Ending balance	$ 5,037	$ 4,960	$ 4,776

Tax Receivable Agreement - Addi

Tax Receivable Agreement - Additional Information (Details) - USD ($) $ in Thousands	Jun. 26, 2009	Jul. 27, 2006	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2005
Income Tax Holiday [Line Items]
Percentage of remittance of cash savings						85.00%
Pursuant of tax receivable prepayment to third party	$ 51,000
Charge to non-operating expense			$ (15,259)	$ (563)	$ (2,145)
Payments for tax receivable agreement			$ 11,769	$ 10,797
Realogy Corporation
Income Tax Holiday [Line Items]
Acquired right to receive percentage of payment		62.50%
Wyndham Worldwide Corporation
Income Tax Holiday [Line Items]
Acquired right to receive percentage of payment		37.50%
Percentage of right to receive payments under ratification agreement	31.875%

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands	Feb. 01, 2017	Jan. 02, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Eligible age to participate			18 years
Hours worked to be eligible to participate (at least)			1000 hours
Eligible year of service for Company matching contributions			1 year
Company matching percentage of each employee's contributions to maximum employee eligible compensation			100.00%
Maximum percentage of employee eligible compensation to the plan			6.00%
Contributions by company			$ 6,710	$ 5,297	$ 4,571
Obligation related to defined contribution plan			6,798	5,673
Aggregate market value of the securities			6,798	5,673
Electronic Funds Source LLC
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets received from acquisition	$ 15,159
Evolution1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets received from acquisition		$ 21,739
ESSO Portfolio
Defined Benefit Plan Disclosure [Line Items]
Total net unfunded status of defined benefit pension plan			291	5,979
Expense under defined benefit pension plans			$ 0	$ 0

Fair Value - Assets and Liabili

Fair Value - Assets and Liabilities Measured at Fair Value and Related Hierarchy Levels (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets:
Available-for-sale securities	$ 23,358	$ 23,525
Significant Other Observable Inputs (Level 2) | Interest rate swaps
Assets:
Derivative asset	15,919	12,908
Liabilities:
Interest rate swaps	1,697	0
Significant Other Observable Inputs (Level 2) | Mortgage-backed securities
Assets:
Available-for-sale securities	305	490
Significant Other Observable Inputs (Level 2) | Asset-backed securities
Assets:
Available-for-sale securities	345	648
Significant Other Observable Inputs (Level 2) | Municipal bonds
Assets:
Available-for-sale securities	534	682
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Executive deferred compensation plan trust	6,798	5,673
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed-income mutual fund
Assets:
Available-for-sale securities	$ 22,174	$ 21,705

Fair Value - Additional Informa

Fair Value - Additional Information (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Jan. 30, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Notes outstanding, net	$ 396,269,000	$ 395,534,000
Fair value of notes	$ 410,000,000	390,000,000
Senior Notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Notes outstanding, net		$ 400,000,000	$ 400,000,000
Interest rate, stated percentage			4.75%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Unused commitments to extend credit	$ 6,300,000,000	$ 5,400,000,000
Minimum volume purchase commitments	362,856,000
Purchase Commitments, Shortfall Penalties Incurred	1,217,000	0	$ 0
Office space, equipment, and vehicle
Loss Contingencies [Line Items]
Rent expense	15,471,000	15,104,000	11,310,000
Technology Hardware and Software
Loss Contingencies [Line Items]
Rent expense	$ 8,765,000	$ 12,875,000	$ 11,288,000

Commitments and Contingencie104

Commitments and Contingencies - Future Minimum Lease Payments Under Non-Cancelable Operating and Capital Leases (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Operating
2,018	$ 13,559
2,019	9,903
2,020	8,532
2,021	8,093
2,022	6,734
Thereafter	10,214
Total minimum lease payments	$ 57,035

Accumulated Other Comprehens105

Accumulated Other Comprehensive Loss - Reconciliation of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 1,505,747	$ 1,095,681
Ending balance	1,720,558	1,505,747
Unrealized Losses on Available- for-Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(463)	(212)
Other comprehensive loss	(5)	(251)
Ending balance	(468)	(463)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(122,376)	(103,239)
Other comprehensive loss	32,049	(19,137)
Ending balance	$ (90,327)	$ (122,376)

Accumulated Other Comprehens106

Accumulated Other Comprehensive Loss - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification amounts from accumulated other comprehensive loss	$ 0	$ 0
Unrealized Losses on Available- for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), tax	$ 4,851	$ 5,416

Dividend Restrictions - Additio

Dividend Restrictions - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Ratio of funded indebtedness to EBITDA (no more than)	2.50
Maximum restricted payments, including dividends, per annum	$ 50,000,000
Percentage of eligible carry over of unused restricted dividend payments	100.00%
Percentage of transfer to surplus fund	10.00%
Required percentage of surplus to capital stock	100.00%
Capital stock	$ 5,250,000
Capital surplus as percent of capital stock	100.00%
September 30, 2017
Debt Instrument [Line Items]
Ratio of funded indebtedness to EBITDA (no more than)	5.25
September 30, 2018
Debt Instrument [Line Items]
Ratio of funded indebtedness to EBITDA (no more than)	5
September 30, 2019
Debt Instrument [Line Items]
Ratio of funded indebtedness to EBITDA (no more than)	4.5
December 31, 2019 and thereafter
Debt Instrument [Line Items]
Ratio of funded indebtedness to EBITDA (no more than)	4

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) $ in Thousands	1 Months Ended		12 Months Ended
	May 31, 2017	May 31, 2015shares	Dec. 31, 2017USD ($)dayawardshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares		3,800,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized (in shares) | shares		1,596,000
Number of stock-based compensation plans | award			4
Total stock-based compensation cost recognized			$ 30,487	$ 19,742	$ 12,420
Tax benefit from stock option and restricted stock units			7,347	7,200	4,542
Shares exercised, total intrinsic value			642	1,712	216
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost			$ 9,613
Compensation cost expected recognition weighted average period (in years)			1 year 3 months 18 days
Shares granted fair value			$ 11,700	18,826	7,846
Shares vested fair value			$ 7,310	$ 3,648	4,521
Deferred stock units (in shares) | shares			173,000	206,000
Performance Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost			$ 13,430
Compensation cost expected recognition weighted average period (in years)			1 year 10 months 24 days
Shares vested fair value			$ 15,948	$ 4,858	2,035
Performance Based Restricted Stock Units | Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units (in shares) | shares			314,000	310,000
Performance Based Restricted Stock Units | Units at Target
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted fair value			$ 15,014	$ 15,921	6,860
Performance Based Restricted Stock Units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance goals tracking period			1 year
Performance Based Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance goals tracking period			3 years
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Derived service period			3 years
Expiration period	10 years
Number of consecutive trading days | day			20
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
Total unrecognized compensation cost			$ 17,077
Compensation cost expected recognition weighted average period (in years)			1 year 2 months 12 days
Expiration period			10 years
Grant date fair value of shares			$ 20,516	$ 3,297	$ 1,855
Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units (in shares) | shares			94,000	101,000
Common Stock Issued
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units of common stock available for grant | shares			1,617,334
Non-Employee Directors And Certain Employees | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			12 months
Certain Employees | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			3 years
First anniversary | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			33.00%
Second anniversary | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			33.33%
Third anniversary | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage			33.33%

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Restricted Stock Units (Details) - Restricted Stock Units (RSUs) shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Units
Balance at beginning of period (in shares)	206
Granted (in shares)	111
Vested (in shares)	(86)
Forfeited (in shares)	(58)
Balance at end of period (in shares)	173
Restricted shares withheld for tax	26
Weighted- Average Grant- Date Fair Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 88.78
Granted (in dollars per share) | $ / shares	105.64
Vested (in dollars per share) | $ / shares	84.51
Forfeited (in dollars per share) | $ / shares	98.98
Balance at end of period (in dollars per share) | $ / shares	$ 98.31

Stock-Based Compensation - S110

Stock-Based Compensation - Schedule of Performance Based Restricted Stock Units (Details) - Performance Based Restricted Stock Units shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Units
Restricted shares withheld for tax	64
Weighted- Average Grant-Date Fair Value
Balance at beginning of period (in dollars per share) | $ / shares	$ 84.83
Granted (in dollars per share) | $ / shares	105.15
Forfeited (in dollars per share) | $ / shares	85.31
Vested (in dollars per share) | $ / shares	91.92
Performance adjustment (in dollars per share) | $ / shares	89.85
Balance at end of period (in dollars per share) | $ / shares	$ 93.18
Shares
Units
Balance at beginning of period (in shares)	310
Granted (in shares)	185
Forfeited (in shares)	(27)
Vested (in shares)	(174)
Performance adjustment (in shares)	20
Balance at end of period (in shares)	314

Stock-Based Compensation - S111

Stock-Based Compensation - Schedule of Assumptions Used (Details) - $ / shares	Mar. 20, 2017	Mar. 15, 2016	Mar. 15, 2015	Dec. 31, 2017	Dec. 31, 2016
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in dollars per share)				$ 99.69
Expected stock price volatility				31.14%
Weighted average risk-free rate				2.18%
Weighted average fair value (in dollars per share)				$ 28.69
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free rate	2.13%	1.62%	1.73%
Weighted average fair value (in dollars per share)	$ 35.58	$ 26.14	$ 33.93
Weighted average expected life (in years)	6 years	6 years	6 years
Weighted average exercise price (in dollars per share)	$ 104.95	$ 77.20	$ 103.40	$ 97.70	$ 81.90
Weighted average volatility (as a percent)	30.67%	31.93%	30.46%

Stock-Based Compensation - S112

Stock-Based Compensation - Schedule of Stock Option Activity (Details) - Stock Option $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Shares
Shares, Beginning balance outstanding (in shares) | shares	180
Shares, Granted (in shares) | shares	682
Shares, Exercised (in shares) | shares	(12)
Shares, Forfeited (in shares) | shares	(16)
Shares, Ending balance outstanding (in shares) | shares	834
Shares, Exercisable (in shares) | shares	66
Share, Expected to vest (in shares) | shares	760
Weighted- Average Exercise Price
Weighted-Average Exercise Price, Beginning balance outstanding (in dollars per share) | $ / shares	$ 81.90
Weighted-Average Exercise Price, Granted (in dollars per share) | $ / shares	100.72
Weighted-Average Exercise Price, Exercised (in dollars per share) | $ / shares	59.43
Weighted-Average Exercise Price, Forfeited or expired (in dollars per share) | $ / shares	78.96
Weighted-Average Exercise Price, Ending balance outstanding (in dollars per share) | $ / shares	97.70
Exercisable (in dollars per share) | $ / shares	88.90
Expected to vest (in dollars per share) | $ / shares	$ 98.45
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term, Outstanding	9 years 26 days
Weighted average remaining contractual term, Exercisable	7 years 9 months 7 days
Weighted average remaining contractual term, expected to vest	9 years 2 months 6 days
Aggregate Intrinsic Value, Outstanding | $	$ 36,302
Aggregate Intrinsic Value, Exercisable | $	3,452
Aggregate Intrinsic Value, Expected to vest | $	$ 32,529

Impairment and Restructuring113

Impairment and Restructuring Activities - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Impairment of software under development		$ 28,000,000	$ 0	$ 0
Impairment charges and asset write-offs		44,171,000	$ 0	$ 0
Restructuring charges incurred to date	$ 24,479,000	24,479,000
Software and Software Development Costs
Restructuring Cost and Reserve [Line Items]
Computer software impairment	6,000,000
Fleet solutions
Restructuring Cost and Reserve [Line Items]
Impairment charges and asset write-offs		$ 16,000,000
Software under development | Travel and Corporate Solutions
Restructuring Cost and Reserve [Line Items]
Impairment of software under development	$ 22,000,000

Impairment and Restructuring114

Impairment and Restructuring Activities - Summary of Restructuring Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring Reserve [Roll Forward]
Balance, beginning of year	$ 10,657	$ 7,249
Restructuring charges	9,048	8,302
Reserve release	(1,909)	(816)
Cash paid	(10,149)	(4,775)
Other	107	0
Impact of foreign currency translation	757	697
Balance, end of year	8,511	10,657
2015 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance, beginning of year	5,231	7,249
Restructuring charges	2,642	2,182
Reserve release	77	816
Cash paid	(4,020)	(3,921)
Other	(1,158)	(166)
Impact of foreign currency translation	62	703
Balance, end of year	2,680	5,231
2016 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance, beginning of year	3,662	0
Restructuring charges	285	3,506
Reserve release	(1,590)	0
Cash paid	(3,479)	(4)
Other	1,158	166
Impact of foreign currency translation	702	(6)
Balance, end of year	738	3,662
Acquisition Integration Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance, beginning of year	1,764	0
Restructuring charges	6,121	2,614
Reserve release	(242)	0
Cash paid	(2,650)	(850)
Other	107	0
Impact of foreign currency translation	(7)	0
Balance, end of year	$ 5,093	$ 1,764

Segment Information - Additiona

Segment Information - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017reportable_segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information - Reportabl

Segment Information - Reportable Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting, Revenue Reconciling Item [Line Items]
Payment processing revenue									$ 569,166	$ 520,619	$ 495,869
Account servicing revenue									276,570	211,012	156,693
Finance fee revenue									187,582	138,940	88,993
Other revenue									217,230	147,889	113,082
Total revenues	$ 331,305	$ 324,002	$ 303,884	$ 291,357	$ 290,840	$ 287,756	$ 233,936	$ 205,928	1,250,548	1,018,460	854,637
Depreciation and amortization									203,724	141,651	83,077
Adjusted operating income									465,472	363,073	302,687
Fleet solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Payment processing revenue									360,158	297,900	305,855
Account servicing revenue									165,083	127,106	100,850
Finance fee revenue									159,336	124,725	83,554
Other revenue									138,389	92,330	57,419
Total revenues									822,966	642,061	547,678
Depreciation and amortization									143,301	100,860	54,453
Adjusted operating income									297,322	215,424	186,731
Travel and corporate solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Payment processing revenue									158,660	175,762	151,311
Account servicing revenue									7,531	1,247	1,930
Finance fee revenue									760	643	326
Other revenue									57,096	37,595	41,852
Total revenues									224,047	215,247	195,419
Depreciation and amortization									17,703	6,187	2,999
Adjusted operating income									117,432	104,531	87,380
Health and Employee Benefit Solutions
Segment Reporting, Revenue Reconciling Item [Line Items]
Payment processing revenue									50,348	46,957	38,703
Account servicing revenue									103,956	82,660	53,912
Finance fee revenue									27,486	13,572	5,113
Other revenue									21,745	17,963	13,812
Total revenues									203,535	161,152	111,540
Depreciation and amortization									42,720	34,604	25,625
Adjusted operating income									$ 50,718	$ 43,118	$ 28,576

Segment Information - Interest

Segment Information - Interest Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total interest income	$ 31,905	$ 17,132	$ 7,168
Fleet solutions
Segment Reporting Information [Line Items]
Total interest income	3,681	3,053	1,704
Travel and Corporate Solutions
Segment Reporting Information [Line Items]
Total interest income	717	498	348
Health and Employee Benefit Solutions
Segment Reporting Information [Line Items]
Total interest income	$ 27,507	$ 13,581	$ 5,116

Segment Information - Reconcili

Segment Information - Reconciliation of Adjusted Net Income to Net Income (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating income									$ 465,472,000	$ 363,073,000	$ 302,687,000
Acquisition-related intangible amortization									(153,811)	(97,829)	(47,792)
Stock-based compensation									(30,487,000)	(19,742,000)	(12,420,000)
Restructuring and other costs									(9,048,000)	(8,302,000)
Impairment charges and asset write-offs									(44,171,000)	0	0
Gain on divestiture									20,958,000	0	1,215,000
Operating income	$ 67,214,000	$ 63,723,000	$ 47,581,000	$ 60,752,000	$ 47,798,000	$ 54,568,000	$ 51,635,000	$ 41,127,000	239,270,000	195,128,000	228,793,000
Financing interest expense									(107,067,000)	(113,418,000)	(46,189,000)
Net foreign currency gain (loss)									(29,919,000)	7,665,000	5,689,000
Net unrealized gains on interest rate swap agreements									1,314,000	12,908,000	0
Net realized and unrealized gains on fuel price derivatives									0	711,000	5,848,000
Non-cash adjustments related to tax receivable agreement									(15,259,000)	563,000	(2,145,000)
Income before income taxes									178,695,000	87,101,000	184,908,000
Segment Reconciling Items
Segment Reporting Information [Line Items]
Acquisition-related intangible amortization									(153,810,000)	(97,829,000)	(47,792,000)
Other acquisition and divestiture related items									(5,000,000)	(20,879,000)	(4,137,000)
Stock-based compensation									(30,487,000)	(19,742,000)	(12,420,000)
Restructuring and other costs									(11,129,000)	(13,995,000)	(9,010,000)
Impairment charges and asset write-offs									(44,171,000)	0	0
Gain on divestiture									20,958,000	0	1,215,000
Vendor settlement									0	(15,500,000)	0
Debt restructuring									(2,563,000)	0	0
Regulatory reserve									0	0	(1,750,000)
Fleet solutions
Segment Reporting Information [Line Items]
Operating income									297,322,000	215,424,000	186,731,000
Impairment charges and asset write-offs									(16,000,000)
Travel and Corporate Solutions
Segment Reporting Information [Line Items]
Operating income									117,432,000	104,531,000	87,380,000
Health and Employee Benefit Solutions
Segment Reporting Information [Line Items]
Operating income									$ 50,718,000	$ 43,118,000	$ 28,576,000

Segment Information - Schedule

Segment Information - Schedule Of Revenue By Geographic Data (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 331,305	$ 324,002	$ 303,884	$ 291,357	$ 290,840	$ 287,756	$ 233,936	$ 205,928	$ 1,250,548	$ 1,018,460	$ 854,637
Net property, equipment and capitalized software	163,908				167,278				163,908	167,278	138,585
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									1,037,322	839,917	691,088
Net property, equipment and capitalized software	148,490				146,165				148,490	146,165	79,265
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									62,030	53,068	50,387
Net property, equipment and capitalized software	5,432				5,493				5,432	5,493	5,445
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									151,196	125,475	113,162
Net property, equipment and capitalized software	$ 9,986				$ 15,620				$ 9,986	$ 15,620	$ 53,875

Supplementary Regulatory Cap120

Supplementary Regulatory Capital Disclosure - Actual and Regulatory Minimum Capital Amounts and Ratios (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Total Capital to risk-weighted assets, Actual Amount	$ 316,129	$ 228,402
Total Capital to risk-weighted assets, Ratio	13.38%	12.59%
Total Capital to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 188,991	$ 145,182
Total Capital to risk-weighted assets, Ratio	8.00%	8.00%
Total Capital to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 236,239	$ 181,477
Total Capital to risk-weighted assets, Ratio	10.00%	10.00%
Tier 1 Capital to average assets, Actual Amount	$ 304,555	$ 214,847
Tier 1 Capital to average assets, Ratio	12.50%	11.10%
Tier 1 Capital to average assets, Minimum for Capital Adequacy Purposes Amount	$ 97,452	$ 77,413
Tier 1 Capital to average assets, Ratio	4.00%	4.00%
Tier 1 Capital to average assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 121,815	$ 96,767
Tier 1 Capital to average assets, Ratio	5.00%	5.00%
Common equity to risk-weighted assets, Actual Amount	$ 304,555	$ 214,847
Common equity to risk-weighted assets, Ratio	12.89%	11.84%
Common equity to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 106,308	$ 81,665
Common equity to risk-weighted assets, Ratio	4.50%	4.50%
Common equity to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 153,555	$ 117,961
Common equity to risk-weighted assets, Ratio	6.50%	6.50%
Tier 1 Capital to risk-weighted assets, Actual Amount	$ 304,555	$ 214,847
Tier 1 Capital to risk-weighted assets, Ratio	12.89%	11.84%
Tier 1 Capital to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 141,743	$ 108,887
Tier 1 Capital to risk-weighted assets, Ratio	6.00%	6.00%
Tier 1 Capital to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 188,991	$ 145,183
Tier 1 Capital to risk-weighted assets, Ratio	8.00%	8.00%

Subsequent Event (Details)

Subsequent Event (Details) - Line of Credit - Term loans - 2016 Credit Agreement - Subsequent Event - USD ($) $ in Millions	Jan. 17, 2018	Jan. 16, 2018
Subsequent Event [Line Items]
Long-term debt	$ 1,335	$ 1,182
Debt issuance costs	$ 6
London Interbank Offered Rate (LIBOR)
Subsequent Event [Line Items]
Reduction in basis points	0.50%
Margin on variable rate, percent	2.25%
Base Rate
Subsequent Event [Line Items]
Reduction in basis points	50.00%
Margin on variable rate, percent	1.25%

Quarterly Financial Results 122

Quarterly Financial Results (Unaudited) - Summary Of Quarterly Financial Results (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Total revenues	$ 331,305	$ 324,002	$ 303,884	$ 291,357	$ 290,840	$ 287,756	$ 233,936	$ 205,928	$ 1,250,548	$ 1,018,460	$ 854,637
Operating income	67,214	63,723	47,581	60,752	47,798	54,568	51,635	41,127	239,270	195,128	228,793
Net earnings attributable to shareholders	$ 79,804	$ 33,971	$ 17,090	$ 29,401	$ 5,288	$ 19,696	$ 12,567	$ 23,086	$ 160,266	$ 60,637	$ 111,317
Earnings per share:(b)
Basic (in dollars per share)	$ 1.86	$ 0.79	$ 0.40	$ 0.69	$ 0.12	$ 0.46	$ 0.32	$ 0.60	$ 3.73	$ 1.49	$ 2.63
Diluted (in dollars per share)	$ 1.85	$ 0.79	$ 0.40	$ 0.68	$ 0.12	$ 0.46	$ 0.32	$ 0.59	$ 3.72	$ 1.48	$ 2.62
2017 Tax Act, income tax benefit	$ 60,636
Electronic Funds Source LLC
Earnings per share:(b)
Stock issued for purchase of EFS (in shares)					4,000	4,000