Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net cash provided by operating activities (Note 2)	$ 1,005,061	$ 1,174,339	$ 1,100,118
Cash flows from investing activities:
Capital expenditures	(206,294)	(256,263)	(259,974)
Origination of finance receivables	(3,591,948)	(3,664,495)	(3,751,830)
Collections on finance receivables	3,228,311	3,175,031	3,136,885
Proceeds from finance receivables sold	0	312,571	0
Sales and redemptions of marketable securities	6,916	40,014	11,507
Acquisition of business	0	0	(59,910)
Other	547	411	7,474
Net cash used by investing activities	(562,468)	(392,731)	(915,848)
Cash flows from financing activities:
Proceeds from issuance of medium-term notes	893,668	1,193,396	595,386
Repayments of medium-term notes	(800,000)	(451,336)	(610,331)
Proceeds from issuance of senior unsecured notes	0	0	740,385
Proceeds from securitization debt	0	0	1,195,668
Repayments of securitization debt	(444,671)	(665,400)	(1,008,135)
Borrowings of asset-backed commercial paper	469,932	62,396	87,442
Repayments of asset-backed commercial paper	(176,227)	(71,500)	(72,727)
Net increase (decrease) in credit facilities and unsecured commercial paper	212,809	(145,812)	469,473
Net change in restricted cash	8,458	43,495	11,410
Dividends paid	(251,862)	(252,321)	(249,262)
Purchase of common stock for treasury	(465,263)	(465,341)	(1,537,020)
Excess tax benefits from share-based payments	0	2,251	3,468
Issuance of common stock under employee stock option plans	11,353	15,782	20,179
Net cash used by financing activities	(541,803)	(734,390)	(354,064)
Effect of exchange rate changes on cash and cash equivalents	26,747	(9,443)	(14,677)
Net (decrease) increase in cash and cash equivalents	(72,463)	37,775	(184,471)
Cash and cash equivalents:
Cash and cash equivalents—beginning of period	759,984	722,209	906,680
Net (decrease) increase in cash and cash equivalents	(72,463)	37,775	(184,471)
Cash and cash equivalents—end of period	$ 687,521	$ 759,984	$ 722,209