Business Segments - Business Segment Net Sales and Income Before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue from External Customer [Line Items]
Net sales	$ 77,055	$ 64,433	$ 69,938	$ 69,624	$ 77,154	$ 72,190	$ 69,956	$ 73,605	$ 281,050	$ 292,905	$ 344,816
Long-Lived Assets	249,055				269,797				249,055	269,797	279,463
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									27,180	15,167	34,727
Capital Expenditures									11,805	9,668	15,780
Depreciation Expense									11,342	10,661	10,153
Identifiable Assets	502,673				533,179				502,673	533,179	531,632
Heat Exchange Coils [Member]
Revenue from External Customer [Line Items]
Net sales									42,364	44,477	41,845
Centrifugal Pumps [Member]
Revenue from External Customer [Line Items]
Net sales									32,341	30,551	28,602
Air Handling Systems [Member]
Revenue from External Customer [Line Items]
Net sales									19,059	28,407	25,989
Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									281,050	292,905	344,816
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									38,881	25,682	46,916
Corporate Costs, Including Other Income (Expense) [Member]
Revenue from External Customer [Line Items]
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									(11,701)	(10,515)	(12,189)
Capital Expenditures									32	3	62
Depreciation Expense									66	68	67
Identifiable Assets	70,684				78,350				70,684	78,350	70,829
U.S. [Member]
Revenue from External Customer [Line Items]
Net sales									134,695	143,579	148,629
Long-Lived Assets	213,332				228,177				213,332	228,177	238,927
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									26,137	14,707	30,190
Foreign [Member]
Revenue from External Customer [Line Items]
Net sales									146,355	149,326	196,187
Long-Lived Assets	35,723				41,620				35,723	41,620	40,536
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									1,043	460	4,537
Forged and Cast Rolls [Member]
Revenue from External Customer [Line Items]
Net sales									187,286	189,470	248,380
Forged and Cast Rolls [Member] | Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									187,286	189,470	248,380
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									13,936	18,415	38,761
Capital Expenditures									11,016	8,867	15,108
Depreciation Expense									9,976	9,282	8,712
Identifiable Assets	263,012				268,489				263,012	268,489	265,340
Air and Liquid Processing [Member] | Operating Segments [Member]
Revenue from External Customer [Line Items]
Net sales									93,764	103,435	96,436
Income Before Income Taxes and Equity Losses in Chinese Joint Venture									24,945	7,267	8,155
Capital Expenditures									757	798	610
Depreciation Expense									1,300	1,311	1,374
Identifiable Assets	$ 168,977				$ 186,340				$ 168,977	$ 186,340	$ 195,463