INVESTMENTS - Summary of Investment Securities by Estimated Maturity (Detail) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Held-to-Maturity Amortized Cost
Due in one year or less	$ 292
Due after one year through five years	1,370
Due after five years through ten years	211
Due after ten years	851
Total	2,724	17,406
Held-to-Maturity Market Value
Due in one year or less	296
Due after one year through five years	1,442
Due after five years through ten years	245
Due after ten years	970
Held-to-Maturity Market Value	2,953	18,066
Available-for-Sale Amortized Cost
Due in one year or less	24,616
Due after one year through five years	933,066
Due after five years through ten years	82,340
Due after ten years	52,626
Total	1,092,648	904,546
Available-for-Sale Market Value
Due in one year or less	24,889
Due after one year through five years	955,663
Due after five years through ten years	85,706
Due after ten years	53,921
Available-for-Sale Market Value	$ 1,120,179	$ 919,110