Summary of Significant Accounting Policies (Details) (USD $)	1 Months Ended	3 Months Ended
	Sep. 30, 2012	Mar. 31, 2013
Summary of Significant Accounting Policies (Textual) [Abstract]
Authorized amount from board of directors for share repurchase	$ 200,000,000
Share repurchase program effective date - current plan	Oct. 01, 2012
Share repurchase program expiry date - current plan	Dec. 31, 2014
Shares repurchased under the program		0
Customer receivables concentration | Customer receivables concentration | Energy Equipment Group
Summary of Significant Accounting Policies (Textual) [Abstract]
Number of customers for net receivables concentration		1
Net receivables percentage		14.00%