Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 1,189,429	$ 923,735
Accounts receivable, less allowance for doubtful accounts of $12,727 at March 31, 2019 and $15,345 at December 31, 2018	1,353,725	1,581,530
Deferred contract costs	131,535	159,510
Other	54,305	70,041
Total current assets	2,728,994	2,734,816
Property and equipment, less accumulated depreciation and amortization of $457,513 at March 31, 2019 and $446,977 at December 31, 2018	500,853	504,105
Operating lease right-of-use assets	349,140	0
Goodwill	7,927	7,927
Deferred federal and state income taxes, net	37,781	40,465
Other assets, net	18,217	27,246
Total assets	3,642,912	3,314,559
Current Liabilities:
Accounts payable	768,665	902,259
Accrued expenses, primarily salaries and related costs	220,085	215,813
Contract liabilities	157,040	190,343
Current portion of operating lease liabilities	58,635	0
Federal, state and foreign income taxes	23,502	18,424
Total current liabilities	1,227,927	1,326,839
Noncurrent portion of operating lease liabilities	289,551	0
Commitments and contingencies
Shareholders' Equity:
Preferred stock, none issued	0	0
Common stock, par value $0.01 per share. Issued and outstanding 171,648 shares at March 31, 2019 and 171,582 shares at December 31, 2018	1,716	1,716
Additional paid-in capital	3,978	1,896
Retained earnings	2,222,562	2,088,707
Accumulated other comprehensive loss	(103,986)	(105,481)
Total shareholders’ equity	2,124,270	1,986,838
Noncontrolling interest	1,164	882
Total equity	2,125,434	1,987,720
Total liabilities and equity	$ 3,642,912	$ 3,314,559