Guarantees	6 Months Ended
Jan. 31, 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 January 31, 2013, AFSI had $28.5 million of outstanding debt, of which the Company guarantees half. The Company had no income and $0.1 million, respectively, from this equity method investment during the three months ended January 31, 2013 and 2012. For the six months ended January 31, 2013 and 2012, the Company recorded earnings of $0.7 million and $0.8 million from this equity method investment, respectively. During the three and six months ended January 31, 2013 and 2012, the Company also recorded royalty income of $1.3 million and $3.0 million, respectively, and $1.5 million and $3.2 million, respectively, related to AFSI. As of January 31, 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 January 31, 2013, there were no amounts drawn upon these letters of credit.

Guarantees

6 Months Ended

Jan. 31, 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 January 31, 2013, AFSI had $28.5 million of outstanding debt, of which the Company guarantees half. The Company had no income and $0.1 million, respectively, from this equity method investment during the three months ended January 31, 2013 and 2012. For the six months ended January 31, 2013 and 2012, the Company recorded earnings of $0.7 million and $0.8 million from this equity method investment, respectively. During the three and six months ended January 31, 2013 and 2012, the Company also recorded royalty income of $1.3 million and $3.0 million, respectively, and $1.5 million and $3.2 million, respectively, related to AFSI.

As of January 31, 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 January 31, 2013, there were no amounts drawn upon these letters of credit.