Business Acquisitions and Investments (Details 1) (USD $) In Thousands, unless otherwise specified			0 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2013	Dec. 01, 2012	May 08, 2013 Modular [Member]	May 09, 2012 Modular [Member]	Aug. 31, 2013 Modular [Member]	Sep. 01, 2012 Modular [Member]	Aug. 31, 2013 Modular [Member]	Sep. 01, 2012 Modular [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition				May 09, 2012
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Business Acquisition, Name of Acquired Entity				Modular Engineering Company Pty Ltd.
Business Acquisition, Base Purchase Price Excluding Cash Acquired				$ 7,875
Payments to Acquire Businesses, Gross			1,530	5,237
Business Acquisition, Description of Acquired Entity				a manufacturer of pressure vessels, process and storage tanks and other natural gas filtration products and distributor of aftermarket elements
Business Combination, Reason for Business Combination				acquisition of Modular gave the Company first-fit manufacturing capabilities in Western Australia, as well as a platform for aftermarket growth throughout the region
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets				2,552
Business Acquisition, Purchase Price Allocation, Goodwill Amount	240,686	241,924		5,339
Net Sales since acquisition date					2,012	2,941	5,639	3,513
Operating Profit (Loss) since acquisition date					$ (395)	$ 197	$ (1,362)	$ 229