CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 28,004	$ 32,032	$ 40,402
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	21,387	21,064	18,250
Total Impairments - Goodwill, Intangibles and Assets	3,687	6,021	4,191
Amortization of marketable securities	1,891	2,119	2,295
Stock-based compensation	11,053	11,103	9,814
Deferred income taxes	(1,733)	(2,288)	(5,743)
Changes in operating assets and liabilities, net of acquisitions:
Restricted cash	7,888	(4,779)	(2,412)
Accounts receivable	34,893	(19,623)	(19,453)
Prepaid insurance	(10,663)	4,982	5,680
Other current assets	(5,596)	(2,402)	1,837
Other assets	(32,013)	(18,091)	(12,991)
Accounts payable	1,996	(982)	(1,425)
Payroll taxes and other payroll deductions payable	10,737	(12,930)	9,922
Accrued worksite employee payroll expense	18,595	23,731	19,753
Accrued health insurance costs	13,226	(8,839)	4,515
Accrued workers’ compensation costs	15,805	7,815	7,418
Accrued corporate payroll, commissions and other accrued liabilities	18,517	556	2,353
Income taxes payable/receivable	4,039	(4,825)	6,392
Total adjustments	113,709	2,632	50,396
Net cash provided by operating activities	141,713	34,664	90,798
Marketable securities:
Purchases	(69,578)	(54,756)	(30,680)
Proceeds from maturities	28,494	15,201	32,619
Proceeds from dispositions	56,880	8,026	35,891
Investments and acquisitions, net of cash acquired	0	0	(2,410)
Property and equipment:
Purchases	(19,124)	(11,562)	(17,631)
Proceeds from dispositions	122	57	69
Net cash provided by (used in) investing activities	(3,206)	(43,034)	17,858
Cash flows from financing activities:
Purchase of treasury stock	(20,769)	(17,229)	(13,773)
Repurchase of common stock	0	0	(3,162)
Payments of Ordinary Dividends, Common Stock	(69,493)	(17,386)	(42,728)
Proceeds from the exercise of stock options	279	1,448	2,249
Income tax benefit from stock-based compensation	889	1,621	2,316
Other	1,288	1,127	(222)
Net cash used in financing activities	(87,806)	(30,419)	(55,320)
Net increase (decrease) in cash and cash equivalents	50,701	(38,789)	53,336
Cash and cash equivalents at beginning of year	225,755	264,544	211,208
Cash and cash equivalents at end of year	276,456	225,755	264,544
Supplemental disclosures:
Cash paid for income taxes, net	$ 16,429	$ 27,191	$ 24,924