Financial Statement Presentation - Additional Information (Detail) $ in Millions	Nov. 17, 2017 USD ($)
Scout Investments Inc [Member]
Consideration received on sale of stock of subsidiaries	$ 172.5

Cash received on stock transaction after deduction of issuance costs.

No definition available.

Name:	us-gaap_SaleOfStockConsiderationReceivedOnTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration