Investment Securities (Tables)
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12 Months Ended |
Dec. 31, 2013
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Investments, Debt and Equity Securities [Abstract] |
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Amortized Cost and Approximate Fair Values of Investment Securities |
The amortized cost and approximate fair values of investment securities are summarized as follows: | | | | | | | | | | | | | | December 31, 2013 | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Estimated Fair Value | Available-for-Sale | | | | | Obligations of U.S. government agencies | $ | 774,055 |
| $ | 1,432 |
| $ | (12,249 | ) | $ | 763,238 |
| U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | 1,197,295 |
| 11,905 |
| (25,147 | ) | 1,184,053 |
| Private mortgage-backed securities | 407 |
| 9 |
| (1 | ) | 415 |
| Total | $ | 1,971,757 |
| $ | 13,346 |
| $ | (37,397 | ) | $ | 1,947,706 |
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| | | | | | | | | | | | | | December 31, 2013 | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Estimated Fair Value | Held-to Maturity | | | | | State, county and municipal securities | $ | 185,818 |
| $ | 4,043 |
| $ | (2,049 | ) | $ | 187,812 |
| Corporate securities | 18,019 |
| 103 |
| (8 | ) | 18,114 |
| Total | $ | 203,837 |
| $ | 4,146 |
| $ | (2,057 | ) | $ | 205,926 |
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Gross gains of $49 and gross losses of $48 were realized on the disposition of available-for-sale securities in 2013. | | | | | | | | | | | | | | December 31, 2012 | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Estimated Fair Value | Available-for-Sale | | | | | Obligations of U.S. government agencies | $ | 751,501 |
| $ | 3,518 |
| $ | (163 | ) | $ | 754,856 |
| U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | 1,214,377 |
| 27,000 |
| (1,526 | ) | 1,239,851 |
| Private mortgage-backed securities | 539 |
| 13 |
| (1 | ) | 551 |
| Total | $ | 1,966,417 |
| $ | 30,531 |
| $ | (1,690 | ) | $ | 1,995,258 |
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| | | | | | | | | | | | | | December 31, 2012 | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Estimated Fair Value | Held-to Maturity | | | | | State, county and municipal securities | $ | 192,875 |
| $ | 10,835 |
| $ | (176 | ) | $ | 203,534 |
| Corporate securities | 14,975 |
| 64 |
| (13 | ) | $ | 15,026 |
| Other securities | 373 |
| — |
| — |
| 373 |
| Total | $ | 208,223 |
| $ | 10,899 |
| $ | (189 | ) | $ | 218,933 |
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Gross Unrealized Losses and Fair Values of Investment Securities |
The following table shows the gross unrealized losses and fair values of investment securities, aggregated by investment category, and the length of time individual investment securities have been in a continuous unrealized loss position, as of December 31, 2013 and 2012. | | | | | | | | | | | | | | | | | | | | | Less than 12 Months | 12 Months or More | Total | December 31, 2013 | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Available-for-Sale | | | | | | | Obligations of U.S. government agencies | $ | 458,385 |
| $ | (10,355 | ) | $ | 59,362 |
| $ | (1,894 | ) | $ | 517,747 |
| $ | (12,249 | ) | U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | 634,199 |
| (17,273 | ) | 166,930 |
| (7,874 | ) | 801,129 |
| (25,147 | ) | Private mortgage-backed securities | — |
| — |
| 104 |
| (1 | ) | 104 |
| (1 | ) | Total | $ | 1,092,584 |
| $ | (27,628 | ) | $ | 226,396 |
| $ | (9,769 | ) | $ | 1,318,980 |
| $ | (37,397 | ) |
| | | | | | | | | | | | | | | | | | | | | Less than 12 Months | 12 Months or More | Total | December 31, 2013 | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Held-to-Maturity | | | | | | | State, county and municipal securities | $ | 37,550 |
| $ | (1,319 | ) | $ | 14,296 |
| $ | (730 | ) | $ | 51,846 |
| $ | (2,049 | ) | Corporate securities | 7,294 |
| (8 | ) | — |
| — |
| 7,294 |
| (8 | ) | Total | $ | 44,844 |
| (1,327 | ) | 14,296 |
| (730 | ) | 59,140 |
| (2,057 | ) |
| | | | | | | | | | | | | | | | | | | | | Less than 12 Months | 12 Months or More | Total | December 31, 2012 | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Available-for-Sale | | | | | | | Obligations of U.S. government agencies | $ | 93,982 |
| $ | (163 | ) | $ | — |
| $ | — |
| $ | 93,982 |
| $ | (163 | ) | U.S. agency residential mortgage-backed securities & collateralized mortgage obligations | 250,198 |
| (1,526 | ) | — |
| — |
| 250,198 |
| (1,526 | ) | Private mortgage-backed securities | — |
| — |
| 137 |
| (1 | ) | 137 |
| (1 | ) | Total | $ | 344,180 |
| $ | (1,689 | ) | $ | 137 |
| $ | (1 | ) | $ | 344,317 |
| $ | (1,690 | ) |
| | | | | | | | | | | | | | | | | | | | | Less than 12 Months | 12 Months or More | Total | December 31, 2012 | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Fair Value | Gross Unrealized Losses | Held-to-Maturity | | | | | | | State, county and municipal securities | $ | 19,389 |
| $ | (168 | ) | $ | 557 |
| $ | (8 | ) | $ | 19,946 |
| $ | (176 | ) | Corporate securities | $ | 9,312 |
| $ | (13 | ) | $ | — |
| $ | — |
| $ | 9,312 |
| $ | (13 | ) | Total | $ | 28,701 |
| (181 | ) | 557 |
| (8 | ) | 29,258 |
| (189 | ) |
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Maturities of Investment Securities |
All other investment securities maturities are shown at contractual maturity dates. | | | | | | | | | | | | | | | | Available-for-Sale | | Held-to-Maturity | December 31, 2013 | Amortized Cost | Estimated Fair Value | | Amortized Cost | Estimated Fair Value | Within one year | $ | 263,280 |
| $ | 261,054 |
| | $ | 4,190 |
| $ | 4,244 |
| After one year but within five years | 1,223,138 |
| 1,211,243 |
| | 57,860 |
| 58,494 |
| After five years but within ten years | 401,500 |
| 392,496 |
| | 87,703 |
| 89,168 |
| After ten years | 83,839 |
| 82,913 |
| | 54,084 |
| 54,020 |
| Total | $ | 1,971,757 |
| $ | 1,947,706 |
| | $ | 203,837 |
| $ | 205,926 |
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