Guarantees	9 Months Ended
Apr. 30, 2013
Guarantees [Abstract]
Guarantees	Note I – Guarantees The Company and Caterpillar Inc. equally own the shares of Advanced Filtration Systems Inc. (AFSI), an unconsolidated joint venture, and guarantee certain debt of the joint venture. As of April 30, 2013, AFSI had $30.8 million of outstanding debt, of which the Company guarantees half. The Company had earnings of $0.7 million and $0.6 million, respectively, from this equity method investment during the three months ended April 30, 2013 and 2012. For the nine months ended April 30, 2013 and 2012, the Company recorded earnings of $1.4 million from this equity method investment. During the three and nine months ended April 30, 2013 and 2012, the Company also recorded royalty income of $1.4 million and $4.4 million, respectively, and $1.4 million and $4.6 million, respectively, related to AFSI. As of April 30, 2013, the Company had a contingent liability for standby letters of credit totaling $13.2 million that have been issued and are outstanding. The letters of credit guarantee payment to third parties in the event the Company is in breach of insurance contract terms as detailed in each letter of credit. At April 30, 2013, there were no amounts drawn upon these letters of credit.

Guarantees

9 Months Ended

Apr. 30, 2013

Note I – Guarantees

The Company and Caterpillar Inc. equally own the shares of Advanced Filtration Systems Inc. (AFSI), an unconsolidated joint venture, and guarantee certain debt of the joint venture. As of April 30, 2013, AFSI had $30.8 million of outstanding debt, of which the Company guarantees half. The Company had earnings of $0.7 million and $0.6 million, respectively, from this equity method investment during the three months ended April 30, 2013 and 2012. For the nine months ended April 30, 2013 and 2012, the Company recorded earnings of $1.4 million from this equity method investment. During the three and nine months ended April 30, 2013 and 2012, the Company also recorded royalty income of $1.4 million and $4.4 million, respectively, and $1.4 million and $4.6 million, respectively, related to AFSI.

As of April 30, 2013, the Company had a contingent liability for standby letters of credit totaling $13.2 million that have been issued and are outstanding. The letters of credit guarantee payment to third parties in the event the Company is in breach of insurance contract terms as detailed in each letter of credit. At April 30, 2013, there were no amounts drawn upon these letters of credit.