Deposits - Schedule of Deposits of Time Deposits Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Banking And Thrift [Abstract]
Within one year	$ 417,278	$ 375,862
After one year through two years	124,448	118,333
After two years through three years	59,889	78,492
After three years through four years	19,053	36,920
After four years through five years	13,216	17,106
Thereafter	5,185	5,046
Total	$ 639,069	$ 631,759
Within one year, Weighted average rate	65.20%	59.60%
After one year through two years, Weighted average rate	19.50%	18.70%
After two years through three years, Weighted average rate	9.40%	12.40%
After three years through four years, Weighted average rate	3.00%	5.80%
After four years through five years, Weighted average rate	2.10%	2.70%
Thereafter, Weighted average rate	0.80%	0.80%
Total, Weighted average rate	100.00%	100.00%