Subsequent Event - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	1 Months Ended
	Jun. 30, 2013	Jul. 12, 2013 Subsequent event	Jul. 12, 2013 Subsequent event Minimum	Jul. 12, 2013 Subsequent event Maximum
Subsequent Event [Line Items]
Future capital contributions period after March 18, 2013			120 days	165 days
Future capital contributions amount by company	$ 3.5	$ 3.5