CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities
Net income	$ 38,440	$ 17,600
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27,810	42,036
Deferred income taxes	(346)	1,835
Stock-based compensation	20,169	12,991
Excess tax credits received from equity incentive plan activity	(2,591)	(20,327)
Changes in operating assets and liabilities:
Restricted cash and available for sale investments	(31,409)	(21,198)
Prepaid expenses and other current assets	(5,253)	(3,201)
Workers compensation receivables	(11,374)	3,294
Other assets	438	(14,585)
Accounts payable	4,538	2,522
Prepaid income taxes	386	27,574
Accrued corporate wages and other current liabilities	4,548	9,103
Workers compensation and other liabilities	33,856	47,419
Worksite employee related assets	525,841	768,010
Worksite employee related liabilities	(526,945)	(768,552)
Net cash provided by operating activities	78,108	104,521
Investing activities
Acquisitions of businesses	(300)	(4,750)
Purchases of restricted investments	(14,959)	(14,989)
Proceeds from maturities of restricted investments	25,790	1,275
Purchase of property and equipment	(27,942)	(14,747)
Net cash used in investing activities	(17,411)	(33,211)
Financing activities
Proceeds from issuance of notes payable	57,978	0
Payments for extinguishment of debt	(57,563)	0
Payment of debt issuance costs	(1,376)	0
Repayment of notes payable and capital leases	27,506	40,493
Proceeds from issuance of common stock on exercised options	3,584	6,464
Proceeds from issuance of common stock on employee stock purchase plan	2,304	2,723
Repurchase of common stock	(43,747)	(48,364)
Awards effectively repurchased for required employee withholding taxes	(2,672)	(576)
Excess tax credits received from equity incentive plan activity	2,591	20,327
Tax credit received for deductible IPO transaction costs	0	822
Net cash used in financing activities	(66,407)	(59,097)
Effect of exchange rate changes on cash and cash equivalents	90	(239)
Net increase in cash and cash equivalents	(5,620)	11,974
Cash and cash equivalents at beginning of period	166,178	134,341
Cash and cash equivalents at end of period	160,558	146,315
Supplemental disclosures of cash flow information
Cash paid for interest	11,651	11,378
Cash paid for income taxes, net	27,650	1,467
Supplemental schedule of noncash investing and financing activities
Payable for purchase of property and equipment	$ 1,363	$ 68