Agreement and Plan of Merger - Additional Information (Detail) (Met-Pro Corporation [Member], USD $) In Millions, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Apr. 22, 2013
Met-Pro Corporation [Member]
Merger Agreement [Line Items]
Purchase price of acquired entity		$ 210
Purchase price per share of acquired entity		$ 13.75
Number of trading period considered for computing share price of reporting entity	15 days
Percentage of shares exchanged for cash of acquired entity	53.00%
Percentage of shares exchanged for stock of acquired entity	47.00%
Obligated to pay termination fee	6.7
Reverse termination fee	10.4
Commitment letter, date	Apr. 21, 2013
Senior secured amortizing term loan facility aggregate principal amount	65
Senior secured revolving credit facility for loans and letters of credit aggregate principal amount	60
Senior Credit Facilities may increased	30
Minimum borrowing by the Company	10
Anticipated senior secured revolving credit facilities	90
Aggregate Senior Credit Facilities	$ 155
Percentage of shareholder voted in favor of business acquisition transaction	26.00%