Participation in the U.S. Treasury Troubled Asset Relief Program - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended		9 Months Ended
	Jul. 03, 2012	Jan. 23, 2009	Sep. 30, 2013	Sep. 05, 2012
Equity [Abstract]
Sale to U.S. Treasury of newly-issued non-voting preferred shares		23,184
Liquidation preference as per securities purchase agreement		$ 1,000
Warrant sold to purchase common shares as per securities purchase agreement		469,312
Warrant exercise price per common share		7.41
Term of Warrant			10 years
Cumulative dividend rate per annum on liquidation preference, first five years			5.00%
Cumulative dividend rate per annum on liquidation preference, after five years			9.00%
Sale of Preferred Shares to investors	23,184
Aggregate purchase price of warrant				$ 563