Consolidated Statements of Operations (USD $)
In Thousands, except Per Share data, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Income Statement [Abstract]      
Revenue $ 21,581,890 $ 14,780,094 $ 9,940,120
Cost of revenue 20,221,837 13,654,449 9,206,744
Gross profit 1,360,053 1,125,645 733,376
Expenses:      
Selling, general and administrative 518,351 440,759 369,492
Depreciation of property and equipment 59,486 37,926 16,749
Amortization of intangible assets 213,220 203,192 130,116
Total expenses 791,057 681,877 516,357
Operating income 568,996 443,768 217,019
Interest and other expense, net 61,088 41,626 26,682
Income before income taxes 507,908 402,142 190,337
Income tax expense 134,186 103,403 69,316
Net income 373,722 298,739 121,021
Less net income attributable to non-controlling interest 56,429 36,569 4,363
Net income attributable to the Company $ 317,293 $ 262,170 $ 116,658
Earnings per share attributable to the Company:      
Basic (in dollars per share) $ 1.53 $ 1.27 $ 0.70
Diluted (in dollars per share) $ 1.53 $ 1.27 $ 0.70