Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Revenues, net	$ 220,869	$ 171,820	$ 414,520	$ 317,985
Expenses:
Merchant commissions	19,555	17,651	33,416	28,044
Processing	32,010	27,014	61,953	52,593
Selling	13,386	10,274	25,090	20,449
General and administrative	30,954	23,824	60,215	47,647
Depreciation and amortization	15,890	11,609	30,519	23,329
Operating income	109,074	81,448	203,327	145,923
Other (income) expense, net	(6)	(66)	286	522
Interest expense, net	3,756	2,818	7,204	6,381
Total other expense	3,750	2,752	7,490	6,903
Income before taxes	105,324	78,696	195,837	139,020
Provision for income taxes	32,225	24,295	58,076	42,540
Net income	$ 73,099	$ 54,401	$ 137,761	$ 96,480
Earnings per share:
Basic earnings per share	$ 0.90	$ 0.65	$ 1.69	$ 1.16
Diluted earnings per share	$ 0.87	$ 0.63	$ 1.64	$ 1.13
Weighted average shares outstanding:
Basic weighted average shares outstanding	81,573	83,294	81,398	82,929
Diluted weighted average shares outstanding	84,461	85,737	84,212	85,451