Investments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014 Individual Equity	Jun. 30, 2013
Investments Schedule [Abstract]
Individual fixed maturity held in unrealized loss position	88
Equity securities held in unrealized loss position	1
Individual fixed maturity held in unrealized loss position	26
Carrying value of investments	$ 11.1
Net realized investment gains (losses)	0.3	0.6
Impairment losses recognized	$ 1.3	$ 1.9