Investments - Summarize Company's Other Investment Securities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Investment Securities [Line Items]
Amortized Cost	$ 118,164	$ 122,841
Gross Unrealized Gains	5,842	8,222
Gross Unrealized Losses	(1,881)	(350)
Fair Value	122,125	130,713
Mutual Fund Amortized Cost	9,901	7,501
Mutual Fund Gross Unrealized Gains	737	832
Mutual Fund Gross Unrealized Losses	(1)
Mutual Fund Fair value	10,637	8,333
Total Amortized Cost	128,065	130,342
Total Gross Unrealized Gains	6,579	9,054
Total Gross Unrealized Losses	(1,882)	(350)
Total Fair Value	132,762	139,046
U.S. Government and Agencies [Member]
Investment Securities [Line Items]
Amortized Cost	11,202	11,202
Gross Unrealized Gains	670	908
Fair Value	11,872	12,110
State [Member]
Investment Securities [Line Items]
Amortized Cost	2,986	3,994
Gross Unrealized Gains	61	117
Gross Unrealized Losses	(3)
Fair Value	3,044	4,111
Political Subdivisions [Member]
Investment Securities [Line Items]
Amortized Cost	752	753
Gross Unrealized Gains	21	37
Fair Value	773	790
Revenue and Assessment [Member]
Investment Securities [Line Items]
Amortized Cost	15,219	16,449
Gross Unrealized Gains	920	1,553
Gross Unrealized Losses	(5)	(6)
Fair Value	16,134	17,996
Corporate Bonds [Member]
Investment Securities [Line Items]
Amortized Cost	68,725	68,114
Gross Unrealized Gains	2,449	3,669
Gross Unrealized Losses	(1,854)	(246)
Fair Value	69,320	71,537
Agency Backed [Member]
Investment Securities [Line Items]
Amortized Cost	8,781	11,079
Gross Unrealized Gains	553	791
Fair Value	9,334	11,870
Non-Agency Backed - Residential [Member]
Investment Securities [Line Items]
Amortized Cost	4,642	5,098
Gross Unrealized Gains	479	472
Gross Unrealized Losses	(19)	(98)
Fair Value	5,102	5,472
Non-Agency Backed - Commercial [Member]
Investment Securities [Line Items]
Amortized Cost	4,357	4,652
Gross Unrealized Gains	496	457
Fair Value	4,853	5,109
Redeemable Preferred Stocks [Member]
Investment Securities [Line Items]
Amortized Cost	1,500	1,500
Gross Unrealized Gains	193	218
Fair Value	$ 1,693	$ 1,718