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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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Net Increase or Decrease in balance of noncontrolling interest in the subsidiary during the reporting period.

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Redeemable Non-Controlling Interest - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended
	Mar. 05, 2019	Mar. 31, 2020	Mar. 31, 2019
Noncontrolling Interest [Line Items]
Adjustment to redeemable non-controlling interest to reflect WEX Health at fair value			$ 0
Accretion of non-controlling interest			0
Additional Paid-in Capital
Noncontrolling Interest [Line Items]
Adjustment to redeemable non-controlling interest to reflect WEX Health at fair value			$ (41,400)
Discovery Benefits
Noncontrolling Interest [Line Items]
Ownership percentage by noncontrolling interest	4.90%
Accretion of non-controlling interest		$ (2,624)
Discovery Benefits \| Additional Paid-in Capital
Noncontrolling Interest [Line Items]
Adjustment to redeemable non-controlling interest to reflect WEX Health at fair value	$ 41,400
Discovery Benefits \| Non–Controlling Interest
Noncontrolling Interest [Line Items]
Adjustment to redeemable non-controlling interest to reflect WEX Health at fair value	$ 41,400
Discovery Benefits \| Maximum
Noncontrolling Interest [Line Items]
Call rights, exercise period		7 years