Gross Unrealized Losses and Fair Value Aggregated by Investment Category and Length of Time in Continuous Unrealized Loss Position (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 12,769
Less than 12 months Unrealized Loss	146
12 months or more Fair Value	522
12 months or more Unrealized Loss	255
Total Fair Value	13,291
Total Unrealized Loss	401
Obligations of U.S. Govt Agencies
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months Fair Value
Less than 12 months Unrealized Loss
12 months or more Fair Value
12 months or more Unrealized Loss
Total Fair Value
Total Unrealized Loss
State and Municipal
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	5,665
Less than 12 months Unrealized Loss	102
12 months or more Fair Value	281
12 months or more Unrealized Loss	18
Total Fair Value	5,946
Total Unrealized Loss	120
Corporate Trust Preferred
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
12 months or more Fair Value	241
12 months or more Unrealized Loss	237
Total Fair Value	241
Total Unrealized Loss	237
Mortgage Backed
Available for Sale Securities Continuous Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	7,104
Less than 12 months Unrealized Loss	44
Total Fair Value	7,104
Total Unrealized Loss	$ 44