CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 16,661	$ 19,505
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	10,377	8,652
Impairment charge	2,679	0
Amortization of marketable securities	1,029	1,279
Stock-based compensation	5,602	4,956
Deferred income taxes	2,281	1,001
Changes in operating assets and liabilities:
Restricted cash	(318)	157
Accounts receivable	(10,018)	(5,495)
Prepaid insurance	(2,122)	3,148
Other current assets	267	3,355
Other assets	(5,698)	(4,991)
Accounts payable	(1,055)	(2,212)
Payroll taxes and other payroll deductions payable	(48,852)	(46,062)
Accrued worksite employee payroll expense	22,159	14,568
Accrued health insurance costs	(8,668)	441
Accrued workers' compensation costs	797	2,382
Accrued corporate payroll, commissions and other accrued liabilities	(2,003)	(7,515)
Income taxes payable/receivable	(4,259)	4,090
Total adjustments	(37,802)	(22,246)
Net cash used in operating activities	(21,141)	(2,741)
Marketable securities:
Purchases	(45,642)	(14,818)
Proceeds from dispositions	4,564	13,401
Proceeds from maturities	4,236	0
Cash exchanged for acquisitions	0	(1,200)
Property and equipment	(6,640)	(8,331)
Net cash used in investing activities	(43,482)	(10,948)
Cash flows from financing activities:
Purchase of treasury stock	(15,122)	(11,741)
Dividends paid	(8,694)	(8,285)
Proceeds from the exercise of stock options	858	1,044
Income tax benefit from stock-based compensation	953	1,434
Other	577	619
Net cash used in financing activities	(21,428)	(16,929)
Net decrease in cash and cash equivalents	(86,051)	(30,618)
Cash and cash equivalents at beginning of period	264,544	211,208
Cash and cash equivalents at end of period	$ 178,493	$ 180,590