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Securities (Details) $ in Thousands | Sep. 30, 2015 USD ($) Position | Dec. 31, 2014 USD ($) Position
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | $ 1,043,620 | $ 1,001,718
Unrealized gains | 15,255 | 14,823
Unrealized losses | (478) | (3,370)
Estimated fair value | 1,058,397 | 1,013,171
Amortized costs of securities available for sale pledged to secure public deposits | 1,100,000 | 1,000,000
Amortized costs of securities available for sale pledged as collateral for repurchase agreements | 174,800 | 208,800
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 64,183 | 143,428
12 Months or Longer, Fair Value | 42,498 | 244,836
Total, Fair Value | 106,681 | 388,264
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | (204) | (500)
12 months or longer Unrealized Losses | (274) | (2,870)
Total Unrealized Losses | $ (478) | $ (3,370)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 25 | 59
12 Months or Longer, Number of Positions | Position | 25 | 58
Total, Number of Positions | Position | 50 | 117
Schedule of Held-to-maturity Securities [Line Items] |  |
Amortized cost | $ 470,758 | $ 454,361
Unrealized gains | 5,697 | 2,721
Unrealized losses | (1,019) | (2,088)
Estimated fair value | 475,436 | 454,994
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 16,070 | 69,566
12 Months or Longer, Fair Value | 43,127 | 48,034
Total, Fair Value | 59,197 | 117,600
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less Than 12 Months, Unrealized Losses | (68) | (165)
12 Months or Longer, Unrealized Losses | (951) | (1,923)
Total, Unrealized Losses | $ (1,019) | $ (2,088)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | Position | 12 | 112
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater Than or Equal to One Year | Position | 4 | 10
Total, Number of Positions | Position | 16 | 122
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract] |  |
Within one year | $ 4,031 |
From one to five years | 369,188 |
From five to ten years | 137,908 |
After ten years | 519,593 |
Total, Amortized Cost | 1,030,720 |
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract] |  |
Within one year | 4,058 |
From one to five years | 371,294 |
From five to ten years | 140,701 |
After ten years | 527,013 |
Total, Fair Value | 1,043,066 |
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |
Within one year | 42,420 |
From one to five years | 15,186 |
From five to ten years | 107,816 |
After ten years | 305,336 |
Amortized cost | 470,758 | $ 454,361
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] |  |
Within one year | 42,427 |
From one to five years | 15,260 |
From five to ten years | 109,043 |
After ten years | 308,706 |
Total, Fair Value | 475,436 | 454,994
US Treasury [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost |  | 23,041
Unrealized gains |  | 70
Unrealized losses |  | 0
Estimated fair value |  | 23,111
Federal Agency [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | 342,140 | 332,193
Unrealized gains | 1,245 | 327
Unrealized losses | (122) | (2,606)
Estimated fair value | 343,263 | 329,914
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 19,962 | 66,528
12 Months or Longer, Fair Value | 29,908 | 198,151
Total, Fair Value | 49,870 | 264,679
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | (30) | (226)
12 months or longer Unrealized Losses | (92) | (2,380)
Total Unrealized Losses | $ (122) | $ (2,606)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 2 | 8
12 Months or Longer, Number of Positions | Position | 3 | 16
Total, Number of Positions | Position | 5 | 24
State & Municipal [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | $ 33,140 | $ 37,035
Unrealized gains | 510 | 587
Unrealized losses | (3) | (52)
Estimated fair value | 33,647 | 37,570
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 2,957 | 8,818
12 Months or Longer, Fair Value | 0 | 1,321
Total, Fair Value | 2,957 | 10,139
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | (3) | (42)
12 months or longer Unrealized Losses | 0 | (10)
Total Unrealized Losses | $ (3) | $ (52)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 4 | 33
12 Months or Longer, Number of Positions | Position | 0 | 5
Total, Number of Positions | Position | 4 | 38
Mortgage-Backed [Member] |  |
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | $ 11,656 | $ 10,400
12 Months or Longer, Fair Value | 4,319 | 35,565
Total, Fair Value | 15,975 | 45,965
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | (109) | (36)
12 months or longer Unrealized Losses | (60) | (254)
Total Unrealized Losses | $ (169) | $ (290)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 14 | 10
12 Months or Longer, Number of Positions | Position | 16 | 31
Total, Number of Positions | Position | 30 | 41
Mortgage-backed Securities, Issued by US Government-Sponsored Enterprises [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | $ 313,840 | $ 339,190
Unrealized gains | 7,118 | 7,597
Unrealized losses | (105) | (224)
Estimated fair value | 320,853 | 346,563
Mortgage-backed Securities, Issued by US Government Agency Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | 14,293 | 17,367
Unrealized gains | 728 | 863
Unrealized losses | (64) | (66)
Estimated fair value | 14,957 | 18,164
Collateralized Mortgage Obligations [Member] |  |
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 29,608 | 57,682
12 Months or Longer, Fair Value | 4,340 | 6,598
Total, Fair Value | 33,948 | 64,280
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | (62) | (196)
12 months or longer Unrealized Losses | (22) | (74)
Total Unrealized Losses | $ (84) | $ (270)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 5 | 8
12 Months or Longer, Number of Positions | Position | 3 | 4
Total, Number of Positions | Position | 8 | 12
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | $ 296,005 | $ 199,837
Unrealized gains | 2,638 | 1,828
Unrealized losses | (63) | (234)
Estimated fair value | 298,580 | 201,431
Collateralized Mortgage Obligations, U.S. Government Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | 31,302 | 40,237
Unrealized gains | 485 | 497
Unrealized losses | (21) | (36)
Estimated fair value | 31,766 | 40,698
Other Securities [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Amortized cost | 12,900 | 12,818
Unrealized gains | 2,531 | 3,054
Unrealized losses | (100) | (152)
Estimated fair value | 15,331 | 15,720
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 0 | 0
12 Months or Longer, Fair Value | 3,931 | 3,201
Total, Fair Value | 3,931 | 3,201
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less than 12 months Unrealized Losses | 0 | 0
12 months or longer Unrealized Losses | (100) | (152)
Total Unrealized Losses | $ (100) | $ (152)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Less Than 12 Months, Number of Positions | Position | 0 | 0
12 Months or Longer, Number of Positions | Position | 3 | 2
Total, Number of Positions | Position | 3 | 2
Mortgage-Backed [Member] |  |
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | $ 9,757 |
12 Months or Longer, Fair Value | 0 |
Total, Fair Value | 9,757 |
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less Than 12 Months, Unrealized Losses | (25) |
12 Months or Longer, Unrealized Losses | 0 |
Total, Unrealized Losses | $ (25) |
Unrealized Loss Position, Number of Positions [Abstract] |  |
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | Position | 1 |
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater Than or Equal to One Year | Position | 0 |
Total, Number of Positions | Position | 1 |
Mortgage-Backed [Member] | Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Amortized cost | $ 9,782 | $ 755
Unrealized gains | 0 | 113
Unrealized losses | (25) | 0
Estimated fair value | 9,757 | 868
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |
Amortized cost | 9,782 | 755
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] |  |
Total, Fair Value | 9,757 | 868
Mortgage-Backed [Member] | Collateralized Mortgage Obligations, U.S. Government Securities [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Amortized cost | 665 |
Unrealized gains | 107 |
Unrealized losses | 0 |
Estimated fair value | 772 |
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |
Amortized cost | 665 |
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] |  |
Total, Fair Value | 772 |
State & Municipal [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Amortized cost | 177,345 | 135,978
Unrealized gains | 1,509 | 674
Unrealized losses | (43) | (123)
Estimated fair value | 178,811 | 136,529
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 6,313 | 43,514
12 Months or Longer, Fair Value | 0 | 1,619
Total, Fair Value | 6,313 | 45,133
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less Than 12 Months, Unrealized Losses | (43) | (116)
12 Months or Longer, Unrealized Losses | 0 | (7)
Total, Unrealized Losses | $ (43) | $ (123)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | Position | 11 | 110
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater Than or Equal to One Year | Position | 0 | 6
Total, Number of Positions | Position | 11 | 116
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |
Amortized cost | $ 177,345 | $ 135,978
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] |  |
Total, Fair Value | 178,811 | 136,529
Collateralized Mortgage Obligations [Member] |  |
Unrealized Loss Position, Fair Value [Abstract] |  |
Less Than 12 Months, Fair Value | 0 | 26,052
12 Months or Longer, Fair Value | 43,127 | 46,415
Total, Fair Value | 43,127 | 72,467
Unrealized Loss Position, Unrealized Losses [Abstract] |  |
Less Than 12 Months, Unrealized Losses | 0 | (49)
12 Months or Longer, Unrealized Losses | (951) | (1,916)
Total, Unrealized Losses | $ (951) | $ (1,965)
Unrealized Loss Position, Number of Positions [Abstract] |  |
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year | Position | 0 | 2
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater Than or Equal to One Year | Position | 4 | 4
Total, Number of Positions | Position | 4 | 6
Collateralized Mortgage Obligations [Member] | Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member] |  |
Schedule of Held-to-maturity Securities [Line Items] |  |
Amortized cost | $ 282,966 | $ 317,628
Unrealized gains | 4,081 | 1,934
Unrealized losses | (951) | (1,965)
Estimated fair value | 286,096 | 317,597
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] |  |
Amortized cost | 282,966 | 317,628
Held-to-maturity Securities, Debt Maturities, Fair Value [Abstract] |  |
Total, Fair Value | $ 286,096 | $ 317,597

X
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