Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net earnings	$ 46,532	$ 14,448	$ 34,380
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	22,514	20,674	18,992
Stock-based compensation	5,256	4,184	2,738
Pension and other post-retirement plan expense (income)	422	11,570	(1,599)
Deferred income taxes	(1,008)	16,710	10,297
Gain (Loss) on Disposition of Property Plant Equipment	0	(708)	11,450
Gain (Loss) on Foreign Currency Derivatives Recorded in Earnings, Net	(82)	94	(36)
Changes in assets and liabilities, net of acquisitions and divestitures:
Accounts receivable	(9,877)	(5,198)	(7,120)
Inventories	(7,521)	(5,404)	(2,290)
Other assets	(2,675)	(1,531)	(289)
Accounts payable	5,113	5,387	537
Accrued Salaries and Benefits	2,349	(1,666)	1,876
Accrued expenses	(3,795)	28	451
Income taxes payable	1,564	(4,555)	966
Other liabilities	258	(2,918)	(52)
Pension and other post-retirement plans	(382)	(319)	(303)
Total adjustments	11,620	43,600	12,822
Net cash provided by operating activities	58,152	58,048	47,202
Cash flows from investing activities:
Capital expenditures	(28,488)	(18,094)	(20,500)
Proceeds from sale of assets	3	541	12,296
Payment for acquisitions, net of cash acquired	0	(19,121)	(73,063)
Net cash used in investing activities	(28,485)	(36,674)	(81,267)
Cash flows from financing activities:
Payments of long-term debt	(1,060,100)	(1,518,200)	(2,458,400)
Proceeds from borrowings of long-term debt	1,033,800	1,505,400	2,456,800
Payments of short-term notes payable	0	(1,150)	0
Purchase of treasury stock	(9,440)	0	0
Dividends paid	(5,285)	(5,260)	(5,234)
Payments Related to Tax Withholding for Share-based Compensation	(1,468)	(1,604)	(1,809)
Net cash used in financing activities	(42,493)	(20,814)	(8,643)
Effect of exchange rate on cash and cash equivalents	187	(793)	(415)
Net decrease in cash and cash equivalents	(12,639)	(233)	(43,123)
Cash and cash equivalents at beginning of year	113,572	113,805	156,928
Cash and cash equivalents at end of year	100,933	113,572	113,805
Supplemental cash flow information:
Cash paid for interest	1,582	2,130	2,939
Cash paid for income taxes, net	9,916	10,884	10,471
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Notes Issued	0	0	1,006
Capital Expenditures Incurred but Not yet Paid	$ 4,312	$ 5,914	$ 3,214