Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net income	$ 51,427	$ 25,140	$ 35,343
Adjustments to reconcile net income to net cash flows:
Depreciation	26,511	21,604	21,559
Amortization of intangible assets	9,514	8,294	8,562
Amortization of deferred financing costs	599	802	1,366
Loss (Gain) on foreign currency, net	381	259	(395)
Amortization of inventory fair value adjustment	2,347
Accretion of debt discount, net		4,005	3,694
Loss on disposals and impairments	584	8,273	2,003
Loss on extinguishment of debt	1,797	1,989
Loss on partial settlement of pension plans	1,720
(Benefit) provision for deferred taxes	(8,012)	(2,850)	(170)
Stock based compensation	5,274	4,230	4,004
Changes in assets and liabilities:
Trade receivables	(8,103)	(4,140)	7,223
Inventories	(2,379)	2,324	6,049
Accounts payable and accrued liabilities	(2,994)	4,333	2,816
Other current assets and liabilities	(3,178)	529	(3,343)
Other operating assets and liabilities	5,093	1,849	(1,895)
Net cash (used)/provided by operating activities	80,581	76,641	86,816
Cash flows from investing activities
Purchase of property, plant and equipment	(32,826)	(18,941)	(22,906)
Proceeds from sale of property	3,221		1,201
Acquisition of Stromag and Guardian businesses, net of cash acquired	2,883	(187,967)
Net cash (used)/provided in investing activities	(26,722)	(206,908)	(21,705)
Cash flows from financing activities
Payments of debt issuance costs		(650)	(1,006)
Payments on term loan facility			(130,063)
Payments on Revolving Credit Facility	(79,536)	(31,861)	(14,998)
Dividend payments	(18,259)	(11,667)	(14,928)
Cash paid for redemption of convertible debt	(954)
Borrowing under Revolving Credit Facility	27,958	200,579	120,036
Payments of equipment, working capital notes, mortgages and other debt	(1,168)	(3,308)	(3,864)
Proceeds from equipment, working capital notes, mortgages and other debt		2,729	8,398
Shares surrendered for tax withholding	(2,089)	(1,337)	(1,182)
Purchase of non-controlling interest in Lamiflex			(878)
Purchases of common stock under share repurchase program		(4,713)	(17,298)
Net cash (used)/provided by financing activities	(74,048)	149,772	(55,783)
Effect of exchange rate changes on cash and cash equivalents	3,065	(707)	(6,511)
Net change in cash and cash equivalents	(17,124)	18,798	2,817
Cash and cash equivalents at beginning of year	69,118	50,320	47,503
Cash and cash equivalents at end of period	51,994	69,118	50,320
Cash paid during the period for:
Interest	6,921	7,161	7,237
Income taxes	23,607	10,855	15,729
Non-cash Financing and Investing:
Acquisition of property, plant and equipment included in accounts payable	222	459	$ 1,129
Conversion of convertible senior notes to common stock	$ 51,853	$ 45,286