BMO Related Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Distribution and administration expenses	$ 0.5	$ 2.1	$ 3.0
Maximum [Member]
Related Party Transaction [Line Items]
Accounts payable, related parties	$ 0.1	$ 0.1

Amount for accounts payable to related parties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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