Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 28,214	$ 34,366
Adjustments to reconcile net income to cash flows provided by operating activities:
Depreciation and amortization	24,614	18,449
Stock-based compensation expense	3,295	3,733
Other non-cash items	(2,231)	611
Changes in assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(74,776)	(57,753)
Inventories, net	40,883	16,052
Prepaid expenses and other assets	6,350	10,268
Accounts payable, trade	31,878	11,581
Accrued expenses and other liabilities	(13,468)	15,278
Net cash flows provided by operating activities	44,759	52,585
Cash flows from investing activities:
Capital expenditures	(7,955)	(24,442)
Acquisitions of businesses, net of cash acquired	(95,766)	0
Other investing activities	1,972	61
Net cash flows used in investing activities	(101,749)	(24,381)
Cash flows from financing activities:
Exercise of stock-based awards, net of shares tendered for payment of taxes	(4,517)	(6,348)
Proceeds from line of credit borrowings	247,154	175,660
Repayments under line of credit borrowings	(102,330)	(182,720)
Repayments under term loan borrowings	(3,750)	0
Payment of dividends	(16,321)	(14,999)
Other financing activities	(391)	(157)
Net cash flows provided by (used in) financing activities	119,845	(28,564)
Effect of exchange rate changes on cash and cash equivalents	(215)	(251)
Net decrease in cash and cash equivalents	62,640	(611)
Cash, cash equivalents, and restricted cash at beginning of period	35,359	14,928	$ 14,928
Cash, cash equivalents, and restricted cash at end of period	97,999	14,317	$ 35,359
Supplemental disclosure of cash flow information:
Cash paid during the period for interest	5,536	2,394
Cash paid during the period for income taxes, net of refunds	(73)	59
Purchase of property and equipment in accrued expenses	$ 2,459	$ 1,202