Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 1,020,854	$ 1,051,099
Accounts receivable, less allowance for doubtful accounts of $12,272 at June 30, 2018 and $12,858 at December 31, 2017	1,337,716	1,414,741
Deferred contract costs	136,133	0
Other	69,438	75,612
Total current assets	2,564,141	2,541,452
Property and equipment, less accumulated depreciation and amortization of $435,159 at June 30, 2018 and $420,282 at December 31, 2017	515,547	525,203
Goodwill	7,927	7,927
Deferred Federal and state income taxes, net	16,779	13,207
Other assets, net	28,438	29,219
Total assets	3,132,832	3,117,008
Current Liabilities:
Accounts payable	832,011	866,305
Accrued expenses, primarily salaries and related costs	227,148	206,320
Contract liabilities	161,870	0
Federal, state and foreign income taxes	19,244	20,494
Total current liabilities	1,240,273	1,093,119
Noncurrent Federal income taxes payable	0	29,516
Commitments and contingencies
Shareholders' Equity:
Preferred stock, none issued	0	0
Common stock, par value $0.01 per share. Issued and outstanding 173,577 shares at June 30, 2018 and 176,374 shares at December 31, 2017	1,736	1,764
Additional paid-in capital	1,607	546
Retained earnings	1,977,121	2,063,512
Accumulated other comprehensive loss	(90,712)	(73,964)
Total shareholders’ equity	1,889,752	1,991,858
Noncontrolling interest	2,807	2,515
Total equity	1,892,559	1,994,373
Total liabilities and equity	$ 3,132,832	$ 3,117,008