Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES
Net (Loss) Earnings Including Noncontrolling Interest	$ (6,205)	$ 46,614	$ 32,088
Adjustments to Reconcile Net (Loss) Earnings to Net Cash Provided by Operating Activities:
Depreciation	26,199	17,891	16,550
Amortization of Intangible Assets	17,054	409	1,481
Amortization of Debt Issuance Costs	1,779	0	0
Debt Issuance Cost Charges Related to Short-Term Financing	6,200	0	0
Fair Value Step-Up Adjustment to Acquired Inventory	7,245	0	0
Impairment of Long-Lived Assets	0	0	11,199
Deferred Income Taxes	(6,095)	(1,172)	(1,129)
Share-Based Compensation Expense	5,891	3,875	8,222
Allowance for Doubtful Accounts and Returns	1,602	468	1,089
Loss on Sale of Business	0	149	0
Other, Net	364	(345)	(100)
Changes in Operating Assets and Liabilities, Net of Assets Acquired:
Receivables, Net	(14,381)	(9,278)	4,547
Inventories	(2,898)	23	(10,190)
Accounts Payable	10,849	(3,904)	(10,455)
Employee Compensation and Benefits	(7,780)	124	716
Other Current Liabilities	14,560	(185)	(402)
Income Taxes	285	5,427	(4,283)
Other Assets and Liabilities	(495)	(2,218)	(4,101)
Net Cash Provided by Operating Activities	54,174	57,878	45,232
INVESTING ACTIVITIES
Purchases of Property, Plant and Equipment	(20,437)	(26,526)	(24,780)
Proceeds from Disposals of Property, Plant and Equipment	2,511	615	336
Proceeds from Principal Payments Received on Long-Term Note Receivable	667	0	0
Issuance of Long-Term Note Receivable	(1,500)	(2,000)	0
Acquisitions of Businesses, Net of Cash Acquired	(354,073)	(12,933)	0
Purchase of Intangible Asset	(2,500)	0	0
Proceeds from Sale of Business	0	285	1,185
(Increase) Decrease in Restricted Cash	(92)	116	(322)
Net Cash Used in Investing Activities	(375,424)	(40,443)	(23,581)
FINANCING ACTIVITIES
Proceeds from Short-Term Debt	303,000	0	0
Repayments of Short-Term Debt	(303,000)	0	0
Proceeds from Issuance of Long-Term Debt	440,000	15,000	0
Payments of Long-Term Debt	(96,248)	(3,460)	(3,445)
Payments of Debt Issuance Costs	(16,482)	0	0
Change in Capital Lease Obligations	311	0	0
Purchases of Common Stock	0	(12,762)	(45,998)
Proceeds from Issuances of Common Stock	6,875	5,271	1,677
Excess Tax Benefit on Stock Plans	0	686	859
Purchase of Noncontrolling Owner Interest	(30)	0	0
Dividends Paid	(14,953)	(14,293)	(14,498)
Net Cash Provided by (Used in) Financing Activities	319,473	(9,558)	(61,405)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	2,142	(1,144)	(1,908)
NET INCREASE IN CASH AND CASH EQUIVALENTS	365	6,733	(41,662)
Cash and Cash Equivalents at Beginning of Year	58,033	51,300	92,962
CASH AND CASH EQUIVALENTS AT END OF YEAR	58,398	58,033	51,300
Cash Paid During the Year for:
Income Taxes	13,542	14,172	23,421
Interest	14,228	1,135	1,167
Supplemental Non-Cash Investing and Financing Activities:
Long-Term Note Receivable from Sale of Business	0	5,489	0
Capital Expenditures in Accounts Payable	$ 2,167	$ 2,045	$ 1,830