Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income	$ 21,760	$ 25,333
Adjustments to reconcile net income to net cash provided by operations:
Depreciation	3,993	3,181
Amortization	15,557	12,144
Loss on extinguishment of debt	4,337	0
Deferred income taxes	(1,436)	1,998
Non-cash stock compensation and retirement savings plan contributions	14,160	12,452
Amortization of debt discount and issuance costs	4,345	3,480
Adjustment to fair value of contingent consideration for purchase of businesses	3,793	(310)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	3,382	(608)
Other assets	1,079	(6,706)
Accounts payable	(7,372)	(9,964)
Other liabilities	(3,979)	(3,313)
Net cash provided by operating activities	59,619	37,687
Investing Activities
Purchase of property and equipment	(3,880)	(6,466)
Capitalization of internally developed software costs	(1,245)	(867)
Purchase of businesses, net of cash acquired	(90,190)	(11,143)
Net cash used in investing activities	(95,315)	(18,476)
Financing Activities
Proceeds from issuance of 2025 convertible notes	230,000	0
Payment for 2025 convertible notes issuance costs	(7,303)	0
Purchase of 2025 convertible notes hedges	(48,944)	0
Proceeds from issuance of 2025 convertible notes warrants	22,218	0
Payments for repurchase of 2023 convertible notes	(170,720)	0
Proceeds from sale of of hedges related to 2023 convertible notes	47,338	0
Repurchase of warrants related to 2023 convertible notes	(40,699)	0
Proceeds from line of credit	28,000	0
Payments on line of credit	(28,000)	0
Payment of contingent consideration for purchase of business	(876)	(4,281)
Proceeds from the sale of stock through the Employee Stock Purchase Plan	210	130
Purchases of treasury stock	(11,112)	(19,777)
Remittance of taxes withheld as part of a net share settlement of restricted stock vesting	(4,861)	(3,982)
Net cash provided by (used in) financing activities	15,251	(27,910)
Effect of exchange rate on cash and cash equivalents	(251)	135
Change in cash and cash equivalents	(20,696)	(8,564)
Cash and cash equivalents at beginning of period	70,728	44,984
Cash and cash equivalents at end of period	50,032	36,420
Supplemental Disclosures:
Cash paid for income taxes	3,782	5,524
Cash paid for interest	3,321	3,606
Non-Cash Investing Activity:
Stock issued for purchase of businesses	8,729	1,294
Liability incurred for purchase of property and equipment	$ 500	$ 2,391