Investments (Gross Unrealized Losses and Fair Value by Length of Time of Available-For-Sale Securities) (Detail) $ in Thousands	Jun. 30, 2015 USD ($) Securities	Dec. 31, 2014 USD ($) Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 222,219	$ 253,226
Less than 12 months	856	122
More than 12 months	3,004	5,748
Total Unrealized Losses	$ 3,860	$ 5,870
Available-for-Sale Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities | Securities	35	37
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 108,274	$ 141,679
Less than 12 months	605	60
More than 12 months	1,079	2,758
Total Unrealized Losses	$ 1,684	$ 2,818
U.S. Government Agencies | Available-for-Sale Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities | Securities	10	14
State and municipal
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 1,410	$ 1,409
Less than 12 months	1	4
More than 12 months	0	0
Total Unrealized Losses	$ 1	$ 4
State and municipal | Available-for-Sale Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities | Securities	2	2
Mortgage-Backed
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 111,424	$ 108,902
Less than 12 months	250	58
More than 12 months	1,832	2,878
Total Unrealized Losses	$ 2,082	$ 2,936
Mortgage-Backed | Available-for-Sale Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities | Securities	22	20
Trust Preferred
Schedule Of Available For Sale Securities [Line Items]
Fair Value	$ 1,111	$ 1,236
Less than 12 months	0	0
More than 12 months	93	112
Total Unrealized Losses	$ 93	$ 112
Trust Preferred | Available-for-Sale Securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities | Securities	1	1