Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (12,946)	$ 32,281	$ (6,148)
Adjustments to reconcile net income (loss) to net cash provided by operations:
Goodwill impairment	11,422	0	0
Depreciation and amortization	47,144	45,899	39,757
Stock-based compensation expense	11,640	10,361	10,843
Provision for deferred income taxes	(4,250)	236	(10,350)
Net provision for doubtful accounts	1,792	2,849	1,481
Loss on sale of a business	0	0	21,983
Gain on sale of assets	(10,801)	(1,821)	(5,478)
Gain on insurance recovery	0	(606)	0
Amortization of original issue discount and debt issuance costs	6,188	5,510	5,345
Change in assets and liabilities:
(Increase) decrease in receivables	40,182	(7,388)	(73,722)
(Increase) decrease in inventories	699	(30,352)	(15,097)
(Increase) decrease in other assets	(1,032)	1,055	986
Increase (decrease) in accounts payable	(8,318)	2,449	14,153
Increase (decrease) in accrued liabilities and other	(9,434)	2,930	54,628
Net cash provided by operating activities	72,286	63,403	38,381
Cash flows from investing activities:
Capital expenditures	(44,806)	(45,141)	(31,371)
Business acquisitions, net of cash acquired	(18,692)	(249)	(44,750)
Proceeds from sale of property, plant and equipment	13,734	2,612	7,747
Proceeds from insurance property claim	0	1,000	0
Refund of proceeds from sale of a business	0	(13,974)	0
Net cash used in investing activities	(49,764)	(55,752)	(68,374)
Cash flows from financing activities:
Borrowings on lines of credit	327,983	347,613	176,267
Payments on lines of credit	(335,613)	(352,582)	(93,700)
Payment on 2017 Convertible Notes	0	0	(83,252)
Debt issuance costs	(1,214)	(149)	(955)
Proceeds from employee stock plans	1,314	3,874	2,424
Purchases of treasury stock	(21,737)	(3,870)	(3,239)
Other financing activities	(259)	601	165
Net cash used in financing activities	(29,526)	(4,513)	(2,290)
Effect of exchange rate changes on cash	(399)	(4,332)	2,444
Net decrease in cash, cash equivalents, and restricted cash	(7,403)	(1,194)	(29,839)
Cash, cash equivalents, and restricted cash at beginning of year	64,266	65,460	95,299
Cash, cash equivalents, and restricted cash at end of year	$ 56,863	$ 64,266	$ 65,460