Securities - Summaries of Fair Values and Unrealized Losses of Securities, Segregated by Length of Impairment (Detail) (USD $) | Jun. 30, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified | Security | Security |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | 15 | 54 |
Number of available for sale securities, Greater than 1 year | 29 | 14 |
Number of available for sale securities | 44 | 68 |
Securities Available For Sale, Less than 12 Months, Fair Value | $236,060 | $734,257 |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | -1,263 | -26,101 |
Securities Available For Sale, 12 Months or More, Fair Value | 364,659 | 48,144 |
Securities Available For Sale, 12 Months or More, Unrealized Losses | -13,194 | -13,194 |
Securities Available For Sale, Fair Value, Total | 600,719 | 782,401 |
Securities Available For Sale, Unrealized Losses, Total | -14,457 | -39,295 |
Number of held to maturity securities | 60 | 80 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 115,779 | 669,220 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -403 | -24,379 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | 365,291 | 15,674 |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | -11,209 | -711 |
Securities Held To Maturity, Fair Value, Total | 481,070 | 684,894 |
Securities Held To Maturity, Unrealized Losses, Total | -11,612 | -25,090 |
Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 23 | 78 |
Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 37 | 2 |
U.S. Government-Sponsored Entities [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | 2 | 17 |
Number of available for sale securities, Greater than 1 year | 8 | ' |
Number of available for sale securities | 10 | 17 |
Securities Available For Sale, Less than 12 Months, Fair Value | 25,647 | 232,962 |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | -38 | -5,904 |
Securities Available For Sale, 12 Months or More, Fair Value | 113,891 | ' |
Securities Available For Sale, 12 Months or More, Unrealized Losses | -2,097 | ' |
Securities Available For Sale, Fair Value, Total | 139,538 | 232,962 |
Securities Available For Sale, Unrealized Losses, Total | -2,135 | -5,904 |
Number of held to maturity securities | 5 | 3 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 30,103 | 24,513 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -14 | -530 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | 39,330 | 14,378 |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | -706 | -621 |
Securities Held To Maturity, Fair Value, Total | 69,433 | 38,891 |
Securities Held To Maturity, Unrealized Losses, Total | -720 | -1,151 |
U.S. Government-Sponsored Entities [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 2 | 2 |
U.S. Government-Sponsored Entities [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 3 | 1 |
Agency Mortgage-Backed Securities [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | 2 | 9 |
Number of available for sale securities, Greater than 1 year | ' | ' |
Number of available for sale securities | 2 | 9 |
Securities Available For Sale, Less than 12 Months, Fair Value | 29,988 | 108,284 |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | -28 | -1,303 |
Securities Available For Sale, 12 Months or More, Fair Value | ' | ' |
Securities Available For Sale, 12 Months or More, Unrealized Losses | ' | ' |
Securities Available For Sale, Fair Value, Total | 29,988 | 108,284 |
Securities Available For Sale, Unrealized Losses, Total | -28 | -1,303 |
Number of held to maturity securities | 9 | 25 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 13,788 | 308,864 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -8 | -5,942 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | 87,376 | 1,296 |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | -690 | -90 |
Securities Held To Maturity, Fair Value, Total | 101,164 | 310,160 |
Securities Held To Maturity, Unrealized Losses, Total | -698 | -6,032 |
Agency Mortgage-Backed Securities [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 1 | 24 |
Agency Mortgage-Backed Securities [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 8 | 1 |
Agency Collateralized Mortgage Obligations [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | 10 | 26 |
Number of available for sale securities, Greater than 1 year | 16 | 2 |
Number of available for sale securities | 26 | 28 |
Securities Available For Sale, Less than 12 Months, Fair Value | 178,355 | 389,989 |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | -1,187 | -18,644 |
Securities Available For Sale, 12 Months or More, Fair Value | 243,377 | 34,229 |
Securities Available For Sale, 12 Months or More, Unrealized Losses | -10,413 | -2,150 |
Securities Available For Sale, Fair Value, Total | 421,732 | 424,218 |
Securities Available For Sale, Unrealized Losses, Total | -11,600 | -20,794 |
Number of held to maturity securities | 20 | 21 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 50,237 | 301,312 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -281 | -15,844 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | 224,392 | ' |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | -9,497 | ' |
Securities Held To Maturity, Fair Value, Total | 274,629 | 301,312 |
Securities Held To Maturity, Unrealized Losses, Total | -9,778 | -15,844 |
Agency Collateralized Mortgage Obligations [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 4 | 21 |
Agency Collateralized Mortgage Obligations [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 16 | ' |
Commercial Mortgage-Backed Securities [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | ' | 1 |
Securities Held To Maturity, Less than 12 Months, Fair Value | ' | 984 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | ' | -37 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | ' | ' |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | ' | ' |
Securities Held To Maturity, Fair Value, Total | ' | 984 |
Securities Held To Maturity, Unrealized Losses, Total | ' | -37 |
Commercial Mortgage-Backed Securities [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | ' | 1 |
Commercial Mortgage-Backed Securities [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | ' | ' |
States of the U.S. and Political Subdivisions [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | 1 | 2 |
Number of available for sale securities, Greater than 1 year | 1 | ' |
Number of available for sale securities | 2 | 2 |
Securities Available For Sale, Less than 12 Months, Fair Value | 2,070 | 3,022 |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | -10 | -250 |
Securities Available For Sale, 12 Months or More, Fair Value | 1,128 | ' |
Securities Available For Sale, 12 Months or More, Unrealized Losses | -64 | ' |
Securities Available For Sale, Fair Value, Total | 3,198 | 3,022 |
Securities Available For Sale, Unrealized Losses, Total | -74 | -250 |
Number of held to maturity securities | 23 | 27 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 18,846 | 31,537 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -93 | -2,022 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | 14,193 | ' |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | -316 | ' |
Securities Held To Maturity, Fair Value, Total | 33,039 | 31,537 |
Securities Held To Maturity, Unrealized Losses, Total | -409 | -2,022 |
States of the U.S. and Political Subdivisions [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 13 | 27 |
States of the U.S. and Political Subdivisions [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 10 | ' |
Other Securities [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | ' | ' |
Number of available for sale securities, Greater than 1 year | 4 | 4 |
Number of available for sale securities | 4 | 4 |
Securities Available For Sale, Less than 12 Months, Fair Value | ' | ' |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | ' | ' |
Securities Available For Sale, 12 Months or More, Fair Value | 6,263 | 5,950 |
Securities Available For Sale, 12 Months or More, Unrealized Losses | -620 | -929 |
Securities Available For Sale, Fair Value, Total | 6,263 | 5,950 |
Securities Available For Sale, Unrealized Losses, Total | -620 | -929 |
Collateralized Debt Obligations [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of available for sale securities, Less than 1 year | ' | ' |
Number of available for sale securities, Greater than 1 year | ' | 8 |
Number of available for sale securities | ' | 8 |
Securities Available For Sale, Less than 12 Months, Fair Value | ' | ' |
Securities Available For Sale, Less than 12 Months, Unrealized Losses | ' | ' |
Securities Available For Sale, 12 Months or More, Fair Value | ' | 7,965 |
Securities Available For Sale, 12 Months or More, Unrealized Losses | ' | -10,115 |
Securities Available For Sale, Fair Value, Total | ' | 7,965 |
Securities Available For Sale, Unrealized Losses, Total | ' | -10,115 |
Non-Agency Collateralized Mortgage Obligations [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 3 | 3 |
Securities Held To Maturity, Less than 12 Months, Fair Value | 2,805 | 2,010 |
Securities Held To Maturity, Less than 12 Months, Unrealized Losses | -7 | -4 |
Securities Held To Maturity, Greater than 12 Months, Fair Value | ' | ' |
Securities Held To Maturity, Greater than 12 Months, Unrealized Losses | ' | ' |
Securities Held To Maturity, Fair Value, Total | 2,805 | 2,010 |
Securities Held To Maturity, Unrealized Losses, Total | ($7) | ($4) |
Non-Agency Collateralized Mortgage Obligations [Member] | Less than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | 3 | 3 |
Non-Agency Collateralized Mortgage Obligations [Member] | Greater than 12 Months [Member] | ' | ' |
Schedule Of Securities [Line Items] | ' | ' |
Number of held to maturity securities | ' | ' |