Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income	$ 62,560	$ 33,675	$ 23,448
Loss from discontinued operations	(405)	(44)	(28)
Income from continuing operations	62,965	33,719	23,476
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	21,690	24,114	30,548
Intangible asset impairment	247	10,175	4,863
Loss on sale of business	0	(8,763)	0
Stock compensation expense	7,122	6,373	3,891
Net gain on sale of assets	(123)	(42)	(6,431)
Exit activity (recoveries) costs, non-cash	(1,877)	7,530	8,504
Benefit of deferred income taxes	(7,105)	(4,893)	(2,051)
Other, net	2,118	1,934	4,759
Changes in operating assets and liabilities (excluding the effects of acquisitions):
Accounts receivable	(21,806)	37,828	(17,215)
Inventories	870	11,782	22,271
Other current assets and other assets	(2,629)	2,511	759
Accounts payable	11,332	(17,060)	(5,157)
Accrued expenses and other non-current liabilities	(2,734)	1,253	19,004
Net cash provided by operating activities	70,070	123,987	87,221
Cash Flows from Investing Activities
Purchases of property, plant, and equipment	(11,399)	(10,779)	(12,373)
Acquisitions, net of cash acquired	(18,494)	(23,412)	(140,621)
Net proceeds from sale of property and equipment	13,096	953	26,500
Net proceeds from sale of business	0	8,250	0
Other, net	0	1,118	1,154
Net cash used in investing activities	(16,797)	(23,870)	(125,340)
Cash Flows from Financing Activities
Long-term debt payments	(400)	(400)	(73,642)
Proceeds from long-term debt	0	0	73,242
Payment of debt issuance costs	0	(54)	(1,166)
Purchase of treasury stock at market prices	(2,872)	(1,539)	(956)
Net proceeds from issuance of common stock	674	3,341	1,801
Net cash (used in) provided by financing activities	(2,598)	1,348	(721)
Effect of exchange rate changes on cash	1,428	(146)	(2,912)
Net increase (decrease) in cash and cash equivalents	52,103	101,319	(41,752)
Cash and cash equivalents at beginning of year	170,177	68,858	110,610
Cash and cash equivalents at end of year	$ 222,280	$ 170,177	$ 68,858