CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows provided by Operating Activities:
Net income	$ 39,469	$ 60,145
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,335	10,184
Provision for doubtful accounts	3,276	181
Stock-based compensation expense	1,866	1,259
Deferred income taxes		10
Loss on disposal of fixed assets	13	114
Changes in assets and liabilities:
Accounts receivable	(42,610)	(31,390)
Inventories	(10,023)	(6,883)
Prepaid expenses, income tax receivables and other current assets	43	3,702
Other non-current assets	(719)	319
Accounts payable	48,736	(3,167)
Accrued expenses and other liabilities	(3,987)	5,548
Net cash provided by operating activities	46,399	40,022
Cash Flows used in Investing Activities:
Purchases of equipment	(9,611)	(20,621)
Net cash used in investing activities	(9,611)	(20,621)
Cash Flows used in Financing Activities:
Purchase of treasury shares	(10,222)	(4,363)
Dividend payments	(8,427)	(8,452)
Issuance of stock under Employee Stock Purchase Plan	536	609
Payments of payroll taxes on stock-based compensation through shares withheld	(684)	(409)
Net cash used in financing activities	(18,797)	(12,615)
Increase in cash and cash equivalents	17,991	6,786
Cash and cash equivalents, beginning of period	90,060	91,703
Cash and cash equivalents, end of period	108,051	98,489
Non-cash Investing and Financing Activities:
Accrued capital expenditures	248	1,684
Supplemental Cash Flow Information:
Income taxes paid	$ 13,798	$ 18,972