Goodwill and Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Schedule Of Goodwill And Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 1,500	$ 2,100	$ 183,754
Goodwill	60,071		60,071
Non-Life Run-Off Segment [Member]
Schedule Of Goodwill And Intangible Assets [Line Items]
Goodwill	21,200		21,200
Active Underwriting [Member]
Schedule Of Goodwill And Intangible Assets [Line Items]
Goodwill	$ 38,900		$ 38,900
Minimum [Member]
Schedule Of Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets amortization period	10 years
Maximum [Member]
Schedule Of Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets amortization period	15 years