XML 12 R33.htm IDEA: XBRL DOCUMENT

Fair Value Measurement - Additional Information (Detail)	Mar. 31, 2013 Securities	Dec. 31, 2012 Securities
Fair Value Measurements Disclosure [Line Items]
Number of securities in unrealized loss position	18	16
Number of securities	41	38

Disclosure regarding factors used to determine that the impairment of securities categorized as held-to-maturity where cost exceeds fair value is not an other than temporary impairment (OTTI). This item contains disclosure of the number of investment positions in the held-to-maturity investments determined to be temporarily impaired.

+ References+ Details