Securities - Fair Value and Gross Unrealized Loss, Aggregated by Investment Category and Length of Time Individual Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
U.S. Treasury and Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 53,299	$ 8,048
Less Than 12 Months, Gross Unrealized Loss	761	10
Greater than 12 Months, Fair Value	3,469
Greater than 12 Months, Gross Unrealized Loss	9
Fair Value	56,768	8,048
Gross Unrealized Loss	770	10
Mortgage-Backed Securities-Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	240,192	47,211
Less Than 12 Months, Gross Unrealized Loss	10,593	312
Greater than 12 Months, Fair Value	20,216
Greater than 12 Months, Gross Unrealized Loss	1,139
Fair Value	260,408	47,211
Gross Unrealized Loss	11,732	312
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	8,060	2,963
Less Than 12 Months, Gross Unrealized Loss	94	10
Greater than 12 Months, Fair Value	1,322
Greater than 12 Months, Gross Unrealized Loss	6
Fair Value	9,382	2,963
Gross Unrealized Loss	100	10
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	203	367
Less Than 12 Months, Gross Unrealized Loss	2	1
Greater than 12 Months, Fair Value	98	2,950
Greater than 12 Months, Gross Unrealized Loss	2	7,571
Fair Value	301	3,317
Gross Unrealized Loss	4	7,572
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	301,754	58,589
Less Than 12 Months, Gross Unrealized Loss	11,450	333
Greater than 12 Months, Fair Value	25,105	2,950
Greater than 12 Months, Gross Unrealized Loss	1,156	7,571
Fair Value	326,859	61,539
Gross Unrealized Loss	12,606	7,904
Mutual Funds and Other Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value		12
Less Than 12 Months, Gross Unrealized Loss		1
Greater than 12 Months, Fair Value	8,785	96
Greater than 12 Months, Gross Unrealized Loss	387	123
Fair Value	8,785	108
Gross Unrealized Loss	387	124
Temporarily Impaired Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	301,754	58,601
Less Than 12 Months, Gross Unrealized Loss	11,450	334
Greater than 12 Months, Fair Value	33,890	3,046
Greater than 12 Months, Gross Unrealized Loss	1,543	7,694
Fair Value	335,644	61,647
Gross Unrealized Loss	$ 12,993	$ 8,028