Securities Available for Sale - Securities Available for Sale by Contractual Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized cost	$ 21,111
Due after one year through five years, Amortized cost	77,832
Due after five years through ten years, Amortized cost	0
Due after ten years, Amortized cost	3,019
Securities available for sale, Amortized cost	1,162,332	1,235,330
Due in one year or less, Fair value	21,188
Due after one year through five years, Fair value	78,119
Due after five years through ten years, Fair value	0
Due after ten years, Fair value	2,867
Securities available for sale, at fair value	1,157,594	1,264,002
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized cost	1,060,013	1,134,647
Securities available for sale, at fair value	1,054,974	1,162,325
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, Amortized cost	357	307
Securities available for sale, at fair value	$ 446	$ 344