Summary of Carrying Amount and Estimated Fair Value of Held-to-Maturity Debt Securities and Amortized Cost and Estimated Fair Value of Available-for-Sale Debt Securities by Contractual Maturity (Parenthetical) (Detail) (Other Debt Securities, USD $)	Dec. 31, 2013
Investments Classified by Contractual Maturity Date [Line Items]
Due after ten years	$ 101,584,000	[1]
Pooled trust preferred securities
Investments Classified by Contractual Maturity Date [Line Items]
Due after ten years	$ 410,000

[1] Includes corporate bonds and capital trust notes. Included in capital trust notes are $410,000 of pooled trust preferred securities held to maturity, all of which are due after ten years. The remaining capital trust notes consist of single-issue trust preferred securities.