- Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 1,003,604	$ 963,808	$ 968,141	$ 1,012,103	$ 993,184	$ 953,071	$ 927,859	$ 954,809	$ 3,947,656	$ 3,828,923	$ 3,383,708
Gross Profit	381,491	358,667	381,965	399,978	376,497	341,074	345,557	351,241
Earnings (Loss) Before Income Taxes	(86,004)	51,665	56,819	70,308	82,057	53,415	49,980	66,752	92,788	252,204	239,577
Net Earnings (Loss)	$ (107,057)	$ 39,801	$ 42,650	$ 56,078	$ 61,743	$ 43,720	$ 38,501	$ 52,246	$ 31,472	$ 196,210	$ 292,536
Earnings Per Share (in dollars per share)	$ (1.60)	$ 0.59	$ 0.63	$ 0.83	$ 0.91	$ 0.64	$ 0.55	$ 0.75	$ 0.47	$ 2.84	$ 4.13
Earnings Per Share Assuming Dilution (in dollars per share)	$ (1.60)	$ 0.58	$ 0.62	$ 0.82	$ 0.89	$ 0.62	$ 0.54	$ 0.73	$ 0.46	$ 2.78	$ 4.06
Accounts Receivable, allowances	$ 76,293				$ 62,704				$ 76,293	$ 62,704	$ 46,946	$ 35,690
Progressive Leasing
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Taxes									$ 55,711	175,015	$ 140,224
Accounts Receivable, allowances					$ 67,000	$ 64,200	$ 50,000	$ 46,500		$ 67,000