Condensed Parent Company Only Financial Information - Condensed Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investments in subsidiaries, at underlying equity:
Cash in bank subsidiary	$ 23,556	$ 36,264	$ 54,020	$ 36,929
Other assets	2,066	10,906	3,849
Total assets	668,895	762,264	804,912
Liabilities and Shareholders' Equity:
Other liabilities	1,359	1,399	2,002
Total liabilities	573,944	663,117	694,158
Shareholders' equity	94,951	99,147	110,754	109,452
Total liabilities and shareholders' equity	668,895	762,264	804,912
Parent Company [Member]
Investments in subsidiaries, at underlying equity:
Bank subsidiary	91,179	94,883	106,266
Nonbank subsidiary	1	1	1
Cash in bank subsidiary	160	487	360	808
Other assets	3,611	3,937	4,288
Total assets	94,951	99,308	110,915
Liabilities and Shareholders' Equity:
Other liabilities		161	161
Total liabilities		161	161
Shareholders' equity	94,951	99,147	110,754
Total liabilities and shareholders' equity	$ 94,951	$ 99,308	$ 110,915