CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities
Net income	$ 36,080	$ 28,577
Adjustments to reconcile net income to net cash provided by (used for) operating activities:
Fair value change of fuel price derivatives	(2,823)	5,882
Stock-based compensation	2,423	2,406
Depreciation, amortization and impairment	15,612	15,156
Deferred taxes	10,066	9,021
Provision for credit losses	9,090	3,756
Loss on disposal of property, equipment and capitalized software	338	63
Changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable	(271,782)	(228,297)
Other assets	(8,455)	(2,971)
Accounts payable	131,448	190,068
Accrued expenses	(6,499)	2,984
Income taxes	5,708	776
Other liabilities	1,038	1,145
Net cash (used for) provided by operating activities	(77,756)	28,566
Cash flows from investing activities
Purchases of property, equipment and capitalized software	(11,382)	(5,560)
Purchases of available-for-sale securities	(70)	(65)
Maturities of available-for-sale securities	93	502
Net cash used for investing activities	(11,359)	(5,123)
Cash flows from financing activities
Excess tax benefits from equity instrument share-based payment arrangements	1,010	5,589
Repurchase of share-based awards to satisfy tax withholdings	(3,306)	(9,985)
Proceeds from stock option exercises	104	146
Net change in deposits	101,288	135,276
Net change in borrowed federal funds	0	(48,400)
Other financing debt	3,429	787
Loan origination fee	0	(12,023)
Borrowings on notes outstanding	0	400,000
Net activity on 2011 revolving line-of-credit	0	(438,500)
Purchase of shares of treasury stock	(16,948)	(17,911)
Net cash provided by financing activities	81,827	128,729
Effect of exchange rate changes on cash and cash equivalents	574	(114)
Net change in cash and cash equivalents	(6,714)	152,058
Cash and cash equivalents, beginning of period	361,486	197,662
Cash and cash equivalents, end of period	354,772	349,720
Supplemental cash flow information
Interest paid	13,262	4,351
Income taxes paid	4,041	1,226
2011 term loan
Cash flows from financing activities
Net activity on term loan	0	(182,500)
2013 term loan
Cash flows from financing activities
Net activity on term loan	$ (3,750)	$ 296,250