CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Retained Earnings	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2012	$ 817,931	$ 426	$ 162,470	$ 37,379	$ (112,655)	$ 730,311
Beginning Balance (in shares) at Dec. 31, 2012		38,908
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued upon exercise of stock options (in shares)		11
Stock issued upon exercise of stock options	146	0	146
Tax benefit from stock option and restricted stock units	5,589		5,589
Stock upon vesting of restricted stock units (in shares)		221
Stock issued upon vesting of restricted stock units	0	2	(2)
Stock-based compensation, net of share repurchases for tax withholdings	(7,576)		(7,576)
Purchase of shares of treasury stock, Shares		(241)
Purchase of shares of treasury stock	(17,911)				(17,911)
Changes in available-for-sale securities, net of tax effect of $43 in 2014 and $(47) in 2013	(78)			(78)
Foreign currency translation	153			153
Net earnings attributable to WEX Inc.	28,689					28,689
Ending Balance at Mar. 31, 2013	826,943	428	160,627	37,454	(130,566)	759,000
Ending Balance (in shares) at Mar. 31, 2013		38,899
Beginning Balance at Dec. 31, 2013	903,297	429	168,891	(15,495)	(130,566)	879,519	519
Beginning Balance (in shares) at Dec. 31, 2013		38,987
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued upon exercise of stock options (in shares)		8
Stock issued upon exercise of stock options	105	0	105
Tax benefit from stock option and restricted stock units	1,010		1,010
Stock upon vesting of restricted stock units (in shares)		63
Stock issued upon vesting of restricted stock units		1	(1)
Stock-based compensation, net of share repurchases for tax withholdings	(883)		(883)
Purchase of shares of treasury stock, Shares		(181)
Purchase of shares of treasury stock	(16,948)				(16,948)
Changes in available-for-sale securities, net of tax effect of $43 in 2014 and $(47) in 2013	74			74
Foreign currency translation	14,003			13,999
Noncontrolling Interest, Foreign Currency Translation Adjustment							4
Net earnings attributable to WEX Inc.	36,542					36,542
Net Income (Loss) Attributable to Noncontrolling Interests, Excluding Redeemable Noncontrolling Interest							(295)
Net income	36,247
Ending Balance at Mar. 31, 2014	$ 936,905	$ 430	$ 169,122	$ (1,422)	$ (147,514)	$ 916,061	$ 228
Ending Balance (in shares) at Mar. 31, 2014		38,877