CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 178,493	$ 264,544
Restricted cash	47,467	47,149
Marketable securities	52,686	16,904
Accounts receivable, net:
Trade	2,743	6,931
Unbilled	194,985	181,040
Other	2,676	2,415
Prepaid insurance	17,742	15,620
Other current assets	9,384	9,651
Deferred income taxes	4,125	7,211
Total current assets	510,301	551,465
Property and equipment:
Land	4,115	4,115
Buildings and improvements	68,695	68,583
Computer hardware and software	84,102	81,140
Software development costs	37,184	35,866
Furniture and fixtures	36,828	36,717
Aircraft	35,879	35,879
Total property and equipment, gross	266,803	262,300
Accumulated depreciation and amortization	(175,593)	(168,358)
Total property and equipment, net	91,210	93,942
Other assets:
Prepaid health insurance	9,000	9,000
Deposits - health insurance	3,000	3,000
Deposits - workers' compensation	69,947	64,201
Goodwill and other intangible assets, net	22,775	23,775
Other assets	2,085	4,817
Total other assets	106,807	104,793
Total assets	708,318	750,200
Current liabilities:
Accounts payable	2,605	3,660
Payroll taxes and other payroll deductions payable	129,682	178,534
Accrued worksite employee payroll cost	172,229	150,070
Accrued health insurance costs	5,274	13,942
Accrued workers' compensation costs	50,281	49,484
Accrued corporate payroll and commissions	17,265	23,537
Other accrued liabilities	14,415	12,478
Income tax payable	39	4,054
Total current liabilities	391,790	435,759
Noncurrent liabilities:
Accrued workers' compensation costs	66,868	64,536
Deferred income taxes	8,183	9,000
Total noncurrent liabilities	75,051	73,536
Commitments and contingencies
Stockholders' equity:
Common stock	308	308
Additional paid-in capital	134,349	133,207
Treasury stock, at cost	(142,468)	(133,950)
Accumulated other comprehensive income (loss), net of tax	(3)	16
Retained earnings	249,291	241,324
Total stockholders' equity	241,477	240,905
Total liabilities and stockholders’ equity	$ 708,318	$ 750,200