CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net (loss) income	$ (97,412)	$ 89,575	$ 69,421
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation	25,989	21,886	21,215
Amortization of intangibles	21,981	20,471	19,468
Net (gain) loss on sale of assets and business divestiture	(1,567)	(109)	(10,148)
Loss on debt extinguishment	396	165	280
Deferred income taxes	5,016	3,420	(2,976)
Stock-based compensation	4,509	9,036	10,169
Non-cash interest expense	1,112	1,045	1,745
Impairment and other, net	107,114	0	24,968
Accounts receivable	71,436	8,327	(39,539)
Inventories	21,099	(2,510)	(18,713)
Prepaid expenses and other	(2,875)	(3,809)	4,548
Accounts payable and accrued liabilities	(28,266)	(817)	32,653
Other, net	(4,398)	(396)	(620)
Net cash provided by operating activities	124,134	146,284	112,471
Cash flows from investing activities:
Capital expenditures	(20,131)	(37,645)	(34,009)
Proceeds from sale of assets and business divestiture	17,115	785	17,776
Other, net	0	0	3,060
Net cash used in investing activities	(3,016)	(36,860)	(13,173)
Cash flows from financing activities:
Proceeds from exercise of stock options	1,273	848	961
Dividends paid	(17,324)	(17,797)	(17,768)
Borrowings under revolving credit facilities	45,794	619	937
Payments under revolving credit facilities	(45,794)	(619)	(937)
Principal payments under finance lease obligations	(327)	(308)	(290)
Principal payments against senior notes	(10,000)	0	0
Borrowings under term loan credit facility, net of original issuance discount	148,500	0	0
Principal payments under term loan credit facility	(146,393)	(50,470)	(1,880)
Principal payments under industrial revenue bond	0	0	(93)
Debt issuance costs paid	(791)	(164)	(476)
Convertible senior notes repurchase	0	0	(80,200)
Stock repurchases	(18,895)	(33,707)	(58,383)
Net cash used in financing activities	(43,957)	(101,598)	(158,129)
Cash, cash equivalents, and restricted cash:
Net increase (decrease) in cash, cash equivalents, and restricted cash	77,161	7,826	(58,831)
Cash, cash equivalents, and restricted cash at beginning of period	140,516	132,690	191,521
Cash, cash equivalents, and restricted cash at end of period	217,677	140,516	132,690
Supplemental disclosures of cash flow information:
Cash paid for interest	23,411	26,234	27,386
(Refunds received) cash paid for income taxes	$ (4,670)	$ 20,379	$ 24,243