Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
OPERATING ACTIVITIES:
Net income	$ 40,237	$ 24,844
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other	12,480	11,971
Stock-based compensation expense	3,878	3,588
Amortization of debt discount and deferred issuance costs	217	602
Accretion of interest on deferred consideration	1,895	2,343
Change in deferred tax assets and liabilities	78	0
Changes in assets and liabilities:
Accounts receivable	(7,737)	(10,682)
Inventories	(602)	682
Prepaid expenses and other current and non-current assets	321	3,995
Accounts payable	6,639	1,802
Accrued payroll and related expenses	(2,860)	(6,969)
Other current and non-current liabilities	6,634	721
Net cash provided by operating activities:	61,180	32,897
INVESTING ACTIVITIES:
Acquisitions of property, equipment and intangibles	(5,884)	(4,993)
Net cash used for investing activities:	(5,884)	(4,993)
FINANCING ACTIVITIES:
Proceeds from issuance of common stock	2,805	6,847
Payments on Revolving Credit Facility	(112)	(38)
Payments on finance lease obligation	0	(20,000)
Repurchases of common stock	(1,954)	(1,476)
Payments of acquisition contingent consideration	(34)	(12)
Net cash provided by (used for) financing activities:	705	(14,679)
Effect of exchange rates on cash	(6)	18
Net increase in cash and cash equivalents	55,995	13,243
Cash and cash equivalents, beginning of period	52,775	43,695
Cash and cash equivalents, end of period	108,770	56,938
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Purchase of property, equipment and intangibles by incurring current liabilities	860	1,728
Reduction of other current liabilities upon issuance of restricted share units	$ 767	$ 1,970