CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities:
Net income	$ 80,459	$ 48,283	$ 46,320
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	44,099	37,847	34,054
Equity compensation expense	11,818	11,275	9,643
Deferred income taxes	17,513	7,382	3,668
Equity in undistributed income of unconsolidated joint ventures	(4,898)	(4,146)	(2,890)
Dividends received from unconsolidated joint ventures	3,529	2,757	3,463
Pension and postretirement benefits	(1,561)	(2,822)	(1,512)
Gain on the sale of property, plant and equipment	(5,329)	0	0
Loss from the disposal of property, plant and equipment	175	225	295
Asbestos-related charges	3,400	313	(256)
Impairment of assets/investments	807	0	150
Bad debt expense	(439)	1,321	1,085
Loss on disposition of a business	0	0	4,819
Proceeds from insurance related to operations	932	0	0
Changes in assets and liabilities:
Accounts receivable	(14,059)	(13,005)	8,971
Inventories	(14,208)	9,689	(10,608)
Pension and postretirement benefit contributions	(906)	(842)	(7,737)
Other current assets	(576)	1,933	(1,278)
Accounts payable and other accrued expenses	12,341	21,472	(17,632)
Other, net	5,885	(4,715)	3,367
Net cash provided by operating activities	138,982	116,967	73,922
Investing Activities:
Capital expenditures	(27,215)	(18,136)	(24,837)
Proceeds from insurance claims	1,041	275	2,682
Proceeds from the sale of property, plant and equipment, net	8,095	0	0
Other investing activities	0	0	(1,000)
Proceeds from the sale of a business	0	0	1,265
Acquisition of business, net of cash received	(60,191)	(133,943)	(158,407)
Net cash used in investing activities	(78,270)	(151,804)	(180,297)
Financing Activities:
Proceeds from long-term borrowings	0	166,000	125,000
Repayment of debt principal and long-term lease obligation	(110,689)	(103,760)	(6,641)
Line of credit issuance costs	(1,169)	0	(293)
Repurchases of capital stock	0	(7,995)	(39,993)
Proceeds from sale of capital stock, net	3,085	4,143	6,967
Payments of taxes related to net share settlement of equity awards	(5,309)	(1,377)	(2,740)
Proceeds from issuance of shares to employee stock purchase plan	895	858	727
Net cash (used in) provided by financing activities	(113,187)	57,869	83,027
Effect of exchange rate fluctuations on cash	5,867	149	(9,441)
Net (decrease) increase in cash and cash equivalents	(46,608)	23,181	(32,789)
Cash and cash equivalents at beginning of year	227,767	204,586	237,375
Cash and cash equivalents at end of year	181,159	$ 227,767	$ 204,586
Supplemental Disclosures:
Interest, net of amounts capitalized	5,787
Income taxes	$ 36,918