Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Cash flows from operating activities:
Net income	$ 55,487	$ 14,664	$ 30,498
Adjustments to reconcile net income to net cash provided by operating acitivites:
Depreciation	20,079	20,479	18,704
Amortization	38,469	34,830	25,175
Stock-based compensation	8,472	8,375	7,499
Deferred income taxes	(40,021)	(2,871)	2,251
Gain on sale of facility	0	(1,890)	0
Income tax benefit of stock option exercises	0	203	3,961
Excess tax benefit from stock option exercises	0	(483)	(4,081)
Loss on early extinguishment of debt	0	254	0
Increase (decrease) in cash flows from changes in assets and liabilities, net of acquired assets
Accounts receivable	(13,631)	(6,380)	(9,643)
Inventories	(3,926)	3,103	(18,581)
Accounts payable	(286)	2,094	11,508
Income taxes	4,288	(200)	(1,357)
Accrued compensation and benefits	336	(2,598)	(3,964)
Other assets	(22,401)	(23,234)	(12,005)
Other liabilities	18,700	(6,465)	952
Total operating	10,079	25,217	20,419
Net cash provided by operating activities	65,566	39,881	50,917
Cash flows from investing activities:
Payments related to business acquisitions and asset acquisitions, net of cash acquired	(16,212)	(256,450)	(9,353)
Proceeds from sale of a facility	0	5,178	0
Purchases of property, plant and equipment	(12,842)	(14,753)	(15,009)
Net cash used in investing activities	(29,054)	(266,025)	(24,362)
Cash flows from financing activities:
Excess tax benefit from stock option exercises	0	483	4,081
Payments on term loan	(8,750)	(8,750)	0
Proceeds from term loan	0	175,000	0
Payments on revolving line of credit	(157,000)	(162,347)	(112,000)
Proceeds from revolving line of credit	155,000	225,000	142,680
Payments related to distribution agreement	0	(16,667)	(16,667)
Payments on mortgage notes	(1,452)	(1,339)	(1,234)
Payments related to debt issuance costs	0	(5,556)	(1,485)
Dividends paid on common stock	(22,307)	(22,213)	(22,105)
Other, net	(372)	(1,068)	(5,892)
Net cash provided by (used in) financing activities	(34,881)	182,543	(12,622)
Effect of exchange rate changes on cash and cash equivalents	3,563	(1,475)	(7,761)
Net increase (decrease) in cash and cash equivalents	5,194	(45,076)	6,172
Cash and cash equivalents at beginning of year	27,428	72,504	66,332
Cash and cash equivalents at end of year	32,622	27,428	72,504
Non-cash investing and financing activities:
Contractual obligations for acquisition of a business	0	0	440
Dividends payable	5,592	5,566	5,542
Cash paid during the year for:
Interest	16,157	13,758	5,434
Income taxes	$ 8,869	$ 9,588	$ 10,261