SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)(Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected quarterly financial information
Total revenues	$ 1,541,153	$ 2,269,903	$ 1,680,238	$ 1,302,012	$ 1,190,640	$ 1,706,310	$ 1,326,759	$ 1,037,247	$ 6,793,306	$ 5,260,956	$ 4,355,610
Gross profit	1,333,301	1,989,065	1,383,855	1,009,665	939,750	1,396,501	1,004,142	743,288	5,715,886	4,083,681	3,079,880
Net income	378,077	832,989	437,440	244,292	289,595	599,973	352,654	181,816	1,892,798	1,424,037	1,059,131
Net income applicable to common stockholders	$ 378,077	$ 832,989	$ 437,326	$ 244,271	$ 288,663	$ 596,586	$ 352,347	$ 181,970	$ 1,892,663	$ 1,419,566	$ 1,056,371
Net income applicable to common stockholders per basic common share (in dollars per share)	$ 7.32	$ 16.22	$ 8.62	$ 4.89	$ 5.79	$ 11.97	$ 7.07	$ 3.65	$ 37.17	$ 28.48	$ 21.27
Net income applicable to common stockholders per diluted common share (in dollars per share)	$ 7.14	$ 15.72	$ 8.39	$ 4.76	$ 5.63	$ 11.66	$ 6.88	$ 3.54	$ 36.11	$ 27.66	$ 20.63