Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income	$ 52,812	$ 57,265	$ 41,749
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	58,106	52,974	56,575
Amortization	9,355	7,140	7,717
Change in other noncurrent liabilities	(6,504)	2,159	(12,246)
Change in deferred taxes and other liabilities	5,889	(29,517)	1,521
Provision for write-off of property, plant and equipment	2,778	867	1,915
Fair value adjustment on available-for-sale assets		3,212
Gain on disposition or involuntary conversion of assets		(1,056)	(1,126)
Excess tax benefit of options exercised	(150)	(624)	(201)
Non-cash interest expense	564
Write-off of pension liability adjustment due to settlement	51	103	8,331
Compensation and benefits paid or payable in Class A Common Stock	2,433	1,707	1,384
Changes in operating assets and liabilities that provide/(use) cash, net of impact of business acquisition:
Accounts receivable	(12,697)	(404)	(6,564)
Inventories	(12,520)	(8,277)	(744)
Prepaid expenses and other current assets	(2,595)	1,253	1,318
Income taxes prepaid and receivable	(2,206)	(3,156)	2,566
Contract receivable	(14,045)
Accounts payable	2,108	(6,001)	640
Accrued liabilities	1,312	2,081	(11,042)
Income taxes payable	1,398	9,072	1,535
Other, net	(6,571)	7,139	(9,132)
Net cash provided by operating activities	79,518	95,937	84,196
Investing Activities
Purchase of business, net of cash acquired	(187,000)
Purchases of property, plant and equipment	(71,244)	(48,622)	(58,224)
Purchased software	(2,248)	(1,973)	(649)
Proceeds from sale or involuntary conversion of assets	6,939	2,797	1,126
Net cash used in investing activities	(253,553)	(47,798)	(57,747)
Financing Activities
Proceeds from borrowings	235,907	95,126	13,396
Principal payments on debt	(34,356)	(102,215)	(45,124)
Debt acquisition costs	(1,771)	(1,673)
Swap termination payment	(5,175)
Proceeds from options exercised	517	1,897	773
Excess tax benefit of options exercised	150	624	201
Dividends paid	(21,812)	(21,088)	(19,729)
Net cash provided by/(used in) financing activities	173,460	(27,329)	(50,483)
Effect of exchange rate changes on cash and cash equivalents	(2,796)	(15,499)	(18,830)
(Decrease)/increase in cash and cash equivalents	(3,371)	5,311	(42,864)
Cash and cash equivalents at beginning of year	185,113	179,802	222,666
Cash and cash equivalents at end of year	$ 181,742	$ 185,113	$ 179,802