CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 354,260	$ 286,034
Restricted cash	41,137	42,637
Marketable securities	1,960	1,851
Accounts receivable, net:
Trade	12,292	13,107
Unbilled	318,431	254,999
Other	3,258	2,178
Prepaid insurance	10,782	15,041
Other current assets	26,991	19,526
Income Taxes Receivable, Current	9,824	4,949
Total current assets	778,935	640,322
Property and equipment:
Land	6,215	5,214
Buildings and improvements	95,615	90,151
Computer hardware and software	105,060	97,311
Software development costs	60,568	51,956
Furniture, fixtures and other	42,891	38,483
Total property and equipment, gross	310,349	283,115
Accumulated depreciation and amortization	(214,690)	(202,854)
Total property and equipment, net	95,659	80,261
Other assets:
Prepaid health insurance	9,000	9,000
Deposits – health insurance	5,300	4,700
Deposits – workers’ compensation	154,215	143,938
Goodwill and other intangible assets, net	12,762	13,088
Deferred income taxes, net	4,283	14,025
Other assets	3,541	1,840
Total other assets	189,101	186,591
Total assets	1,063,695	907,174
Current liabilities:
Accounts payable	6,447	4,189
Payroll taxes and other payroll deductions payable	303,247	247,766
Accrued worksite employee payroll cost	267,402	215,214
Accrued health insurance costs	26,075	26,360
Accrued workers’ compensation costs	42,974	44,231
Accrued corporate payroll and commissions	52,595	40,761
Other accrued liabilities	27,741	22,437
Total current liabilities	726,481	600,958
Noncurrent liabilities:
Accrued workers’ compensation costs	166,493	141,291
Long-term debt	104,400	104,400
Total noncurrent liabilities	270,893	245,691
Commitments and contingencies
Stockholders’ equity:
Preferred stock, par value $0.01 per share: Shares authorized - 20,000 Shares issued and outstanding - none	0	0
Common stock, par value $0.01 per share: Shares authorized - 60,000 Shares issued - 55,489 at December 31, 2017 and 2016	555	555
Additional paid-in capital	25,337	8,962
Treasury stock, at cost – 14,009 and 13,438 at December 31, 2017 and 2016, respectively	(256,363)	(227,152)
Accumulated other comprehensive income, net of tax	(5)	(3)
Retained earnings	296,797	278,163
Total stockholders’ equity	66,321	60,525
Total liabilities and stockholders’ equity	$ 1,063,695	$ 907,174