Segment Information - Reconciliation of Adjusted Operating Income to Income Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Adjusted operating income	$ 163,590	$ 133,200	$ 470,882	$ 379,312
Stock-based compensation			24,657	22,354
Impairment charges	2,424	0	2,424	16,175
Operating income	100,688	63,723	281,961	172,056
Financing interest expense	(25,718)	(25,754)	(78,560)	(81,449)
Net foreign currency (loss) gain	(1,094)	14,611	(27,438)	33,578
Net unrealized gain (loss) on financial instruments	2,157	(150)	18,371	(849)
Income before income taxes	76,033	52,430	194,334	123,336
Fleet Solutions
Segment Reporting Information [Line Items]
Adjusted operating income	113,731	92,698	329,364	267,718
Travel and corporate solutions
Segment Reporting Information [Line Items]
Adjusted operating income	39,377	28,995	99,074	69,697
Health and Employee Benefit Solutions
Segment Reporting Information [Line Items]
Adjusted operating income	10,482	11,507	42,444	41,897
Segment reconciling items
Segment Reporting Information [Line Items]
Unallocated corporate expenses	13,414	12,935	42,378	38,056
Acquisition-related intangible amortization	33,439	38,510	103,596	114,603
Other acquisition and divestiture related items	1,536	1,006	2,792	3,380
Debt restructuring costs	317	2,519	3,798	2,519
Stock-based compensation	9,799	8,483	25,659	22,354
Restructuring and other costs	1,973	6,024	8,274	10,169
Impairment charges	$ 2,424	$ 0	$ 2,424	$ 16,175

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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This element represents interest incurred for borrowed money which was used to produce goods or render services.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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The net result for the period of deducting operating expenses from operating revenues.

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Discloses the amount charged against the accrued restructuring reserves, or earnings if not previously accrued, during the period for the specified type of restructuring cost.

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

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Adjusted operating income

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Amortization of Debt Issuance Costs, Net of Gain (Loss) on Extinguishment of Debt

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Other Acquisition And Divestiture Related Items

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