Municipal Bonds With And Without Insurance (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Financial Statement Details [Line Items]
Municipal Bonds Ratings With Insurance	$ 20,582
Ratings without Insurance	20,582
AAA Rating
Financial Statement Details [Line Items]
Municipal Bonds Ratings With Insurance	4,616
AA Rating
Financial Statement Details [Line Items]
Municipal Bonds Ratings With Insurance	15,966
Ratings without Insurance	4,616
Standard & Poor's, A Rating [Member]
Financial Statement Details [Line Items]
Ratings without Insurance	14,940
Standard & Poor's, BBB Rating [Member]
Financial Statement Details [Line Items]
Ratings without Insurance	$ 1,026