Guarantees	9 Months Ended
Apr. 30, 2018
Guarantees [Abstract]
Guarantees	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, 2018, AFSI had $33.5 million of outstanding debt, of which the Company guarantees half. In addition, during the three months ended April 30, 2018 and 2017, the Company recorded earnings from this equity method investment of $0.6 million and $0.7 million, respectively. The Company recorded $1.1 million and $1.6 million of earnings from this equity method investment during the nine months ended April 30, 2018 and 2017, respectively. During the three months ended April 30, 2018 and 2017, the Company recorded royalty income related to AFSI of $1.7 million and $1.6 million, respectively, in other income, net. During the nine months ended April 30, 2018 and 2017, the Company recorded royalty income related to AFSI of $5.3 million and $4.3 million, respectively, in other income, net. As of April 30, 2018 and July 31, 2017, the Company had a contingent liability for standby letters of credit totaling $8.2 million and $10.5 million, respectively, 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 contract terms as detailed in each letter of credit. As of April 30, 2018 and July 31, 2017, there were no amounts drawn upon these letters of credit.

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, 2018, AFSI had $33.5 million of outstanding debt, of which the Company guarantees half. In addition, during the three months ended April 30, 2018 and 2017, the Company recorded earnings from this equity method investment of $0.6 million and $0.7 million, respectively. The Company recorded $1.1 million and $1.6 million of earnings from this equity method investment during the nine months ended April 30, 2018 and 2017, respectively. During the three months ended April 30, 2018 and 2017, the Company recorded royalty income related to AFSI of $1.7 million and $1.6 million, respectively, in other income, net. During the nine months ended April 30, 2018 and 2017, the Company recorded royalty income related to AFSI of $5.3 million and $4.3 million, respectively, in other income, net.

As of April 30, 2018 and July 31, 2017, the Company had a contingent liability for standby letters of credit totaling $8.2 million and $10.5 million, respectively, 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 contract terms as detailed in each letter of credit. As of April 30, 2018 and July 31, 2017, there were no amounts drawn upon these letters of credit.