Securities - Contractual Maturity of Investment Securities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]
Less than one year, Amortized Cost	$ 48,552
Due after one year through five years, Amortized Cost	83,272
Due after five years through ten years, Amortized Cost	6,231
Due after ten years, Amortized Cost	55,000
Total Amortized Cost	193,055
Less than one year, Estimated Fair Value	48,682
Due after one year through five years, Estimated Fair Value	83,289
Due after five years through ten years, Estimated Fair Value	6,169
Due after ten years, Estimated Fair Value	44,963
Total Estimated Fair Value	$ 183,103