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	$ 89,575	$ 69,421	$ 111,422
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	21,886	21,215	18,012
Amortization of intangibles	20,471	19,468	17,041
Net gain on sale of property, plant and equipment	(109)	(10,148)	(8,046)
Loss on debt extinguishment	165	280	799
Deferred income taxes	3,420	(2,976)	(14,682)
Stock-based compensation	9,036	10,169	10,429
Non-cash interest expense	1,045	1,745	2,258
Impairment of goodwill and other assets	0	24,968	0
Accounts receivable	8,327	(39,539)	31,943
Inventories	(2,510)	(18,713)	(13,158)
Prepaid expenses and other	(3,809)	4,548	(2,014)
Accounts payable and accrued liabilities	(817)	32,653	(963)
Other, net	(396)	(620)	(8,662)
Net cash provided by operating activities	146,284	112,471	144,379
Cash flows from investing activities
Capital expenditures	(37,645)	(34,009)	(26,056)
Proceeds from sale of property, plant and equipment	785	17,776	10,860
Acquisitions, net of cash acquired	0	0	(323,487)
Other, net	0	3,060	6,443
Net cash used in investing activities	(36,860)	(13,173)	(332,240)
Cash flows from financing activities
Proceeds from exercise of stock options	848	961	5,790
Borrowings under senior notes	0	0	325,000
Dividends paid	(17,797)	(17,768)	(15,315)
Borrowings under revolving credit facilities	619	937	713
Payments under revolving credit facilities	(619)	(937)	(713)
Principal payments under finance lease obligations	(308)	(290)	(600)
Proceeds from issuance of term loan credit facility	0	0	377,519
Principal payments under term loan credit facility	(50,470)	(1,880)	(386,577)
Principal payments under industrial revenue bond	0	(93)	(583)
Debt issuance costs paid	(164)	(476)	(6,783)
Convertible senior notes repurchase	0	(80,200)	(8,045)
Stock repurchase	(33,707)	(58,383)	(74,491)
Net cash (used in) provided by financing activities	(101,598)	(158,129)	215,915
Cash and cash equivalents:
Net increase (decrease) in cash, cash equivalents, and restricted cash	7,826	(58,831)	28,054
Cash, cash equivalents, and restricted cash at beginning of year	132,690	191,521	163,467
Cash, cash equivalents, and restricted cash at end of year	140,516	132,690	191,521
Supplemental disclosures of cash flow information:
Cash paid for interest	26,234	27,386	9,479
Cash paid for income taxes	$ 20,379	$ 24,243	$ 41,391