CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities:
Net income	$ 222,198	$ 225,355	$ 163,133
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	62,107	62,997	64,017
Stock-based compensation expense	19,062	16,445	14,809
Other Operating Activities, Cash Flow Statement	(11,175)	(3,652)	25
Interest related to uncertain tax positions	800	200	100
Deferred income taxes	13,205	9,137	(50,396)
Changes in assets and liabilities
Increase (Decrease) in Accounts Receivable	11,453	(22,934)	(112,977)
Inventories, net	(47,297)	(8,702)	(119,002)
Increase (Decrease) in Other Operating Assets	(28,785)	(4,239)	(2,829)
Accounts payable	(23,505)	(9,193)	(102,870)
Accrued payroll and benefit costs	(39,081)	18,777	24,679
Other current and noncurrent liabilities	(825)	(5,656)	64,793
Net cash provided by operating activities	224,367	296,721	149,122
Investing Activities:
Capital expenditures	(44,067)	(36,210)	(21,507)
Acquisition payments, net of cash acquired	(27,597)	0	0
Proceeds from sale of assets	16,795	12,461	6,766
Payments for (Proceeds from) Other Investing Activities	(5,931)	(10,393)	9,446
Net cash used in investing activities	(60,800)	(34,142)	(5,295)
Financing Activities:
Proceeds from (Repayments of) Short-term Debt	(29,780)	(1,454)	11,789
Proceeds from issuance of long-term debt	1,305,421	1,193,067	1,504,636
Repayments of long-term debt	(1,217,434)	(1,318,470)	(1,556,636)
Repurchase of common stock	(153,049)	(127,169)	(106,792)
Payment for Contingent Consideration Liability, Financing Activities	(11,401)	0	0
Increase (Decrease) in Book Overdrafts	204	(19,857)	8,199
Proceeds from (Payments for) Other Financing Activities	3,727	1,211	2,392
Net cash provided (used) by financing activities	(109,766)	(275,094)	(141,196)
Effect of exchange rate on cash and cash equivalents	758	(9,095)	5,191
Net change in cash and cash equivalents	54,559	(21,610)	7,822
Cash and cash equivalents at the beginning of period	96,343	117,953	110,131
Cash and cash equivalents at the end of period	150,902	96,343	117,953
Supplemental disclosures:
Interest Paid, Excluding Capitalized Interest, Operating Activities	65,275	64,702	63,795
Cash paid for taxes	64,531	61,983	65,117
Non-cash investing and financing activities:
Payments to Acquire Equipment on Lease	$ 1,341	$ 437	$ 552