Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 1,310,330	$ 1,260,842
Short-term investments	99,828	139
Accounts receivable, less allowance for doubtful accounts of $10,187 at September 30, 2013 and $9,383 at December 31, 2012	1,027,572	1,031,376
Deferred Federal and state income taxes	12,670	12,102
Other	47,811	53,140
Total current assets	2,498,211	2,357,599
Property and equipment, less accumulated depreciation and amortization of $337,154 at September 30, 2013 and $325,595 at December 31, 2012	562,125	556,204
Goodwill	7,927	7,927
Other assets, net	30,300	32,395
Total assets	3,098,563	2,954,125
Current Liabilities:
Accounts payable	656,674	641,593
Accrued expenses, primarily salaries and related costs	183,130	178,995
Federal, state and foreign income taxes	24,175	21,970
Total current liabilities	863,979	842,558
Deferred Federal and state income taxes	53,854	78,997
Commitments and contingencies
Shareholders' Equity:
Preferred stock, none issued	0	0
Common stock, par value $.01 per share. Issued and outstanding 205,455,991 shares at September 30, 2013 and 206,392,013 shares at December 31, 2012	2,055	2,064
Additional paid-in capital	2,443	1,283
Retained earnings	2,181,317	2,018,618
Accumulated other comprehensive (loss) income	(6,236)	5,734
Total shareholders’ equity	2,179,579	2,027,699
Noncontrolling interest	1,151	4,871
Total equity	2,180,730	2,032,570
Total liabilities and equity	$ 3,098,563	$ 2,954,125