Unaudited Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenues, net	$ 667,381	$ 525,146	$ 1,276,004	$ 1,186,239
Expenses:
Processing	122,294	121,290	238,722	354,993
Selling	63,225	42,374	115,307	98,233
General and administrative	115,008	86,739	223,370	192,849
Depreciation and amortization	69,218	62,162	134,947	126,638
Other operating, net	24	(230)	81	(268)
Operating income	297,612	212,811	563,577	413,794
Investment gain	0	(33,709)	(9)	(31,338)
Other expense (income), net	408	2,480	2,151	(6,886)
Interest expense, net	34,685	32,412	63,236	68,091
Total other expense	35,093	1,183	65,378	29,867
Income before income taxes	262,519	211,628	498,199	383,927
Provision for income taxes	66,272	53,140	117,713	78,379
Net income	$ 196,247	$ 158,488	$ 380,486	$ 305,548
Earnings per share:
Basic earnings per share (in dollars per share)	$ 2.36	$ 1.89	$ 4.57	$ 3.62
Diluted earnings per share (in dollars per share)	$ 2.30	$ 1.83	$ 4.45	$ 3.50
Weighted average shares outstanding:
Basic (in shares)	83,141	83,895	83,307	84,399
Diluted (in shares)	85,295	86,570	85,528	87,380