Business Segments - Business Segment Net Sales and (Loss) Income Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Net sales	$ 74,587	$ 65,409	$ 69,949	$ 62,913	$ 77,055	$ 64,433	$ 69,938	$ 69,624	$ 272,858	$ 281,050	$ 292,905
Long-Lived Assets	284,098				249,055				284,098	249,055	269,797
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									(892)	27,180	15,167
Capital Expenditures									13,309	11,805	9,668
Depreciation Expense									11,818	11,342	10,661
Identifiable Assets	536,409				502,673				536,409	502,673	533,179
Heat Exchange Coils [Member]
Revenue from External Customer [Line Items]
Net sales									39,109	42,364	44,477
Centrifugal Pumps [Member]
Revenue from External Customer [Line Items]
Net sales									32,983	32,341	30,551
Air Handling Systems [Member]
Revenue from External Customer [Line Items]
Net sales									21,378	19,059	28,407
Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									272,858	281,050	292,905
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									8,602	38,881	25,682
Corporate Costs, Including Other Income (Expense) [Member]
Revenue from External Customer [Line Items]
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									(9,494)	(11,701)	(10,515)
Capital Expenditures									69	32	3
Depreciation Expense									71	66	68
Identifiable Assets	78,507				70,684				78,507	70,684	78,350
U.S. [Member]
Revenue from External Customer [Line Items]
Net sales									143,493	134,695	143,579
Long-Lived Assets	252,739				213,332				252,739	213,332	228,177
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									(1,471)	26,137	14,707
Foreign [Member]
Revenue from External Customer [Line Items]
Net sales									129,365	146,355	149,326
Long-Lived Assets	31,359				35,723				31,359	35,723	41,620
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									579	1,043	460
Forged and Cast Engineered Products [Member]
Revenue from External Customer [Line Items]
Net sales									179,388	187,286	189,470
Forged and Cast Engineered Products [Member] | Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									179,388	187,286	189,470
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									4,380	13,936	18,415
Capital Expenditures									12,884	11,016	8,867
Depreciation Expense									10,303	9,976	9,282
Identifiable Assets	260,384				263,012				260,384	263,012	268,489
Air and Liquid Processing [Member] | Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									93,470	93,764	103,435
(Loss) Income Before Income Taxes and Equity Losses in Chinese Joint Venture									4,222	24,945	7,267
Capital Expenditures									356	757	798
Depreciation Expense									1,444	1,300	1,311
Identifiable Assets	$ 197,518				$ 168,977				$ 197,518	$ 168,977	$ 186,340