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Fair Value Measurements (Details 3) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
ASSETS |  |  |  |
Debt Securities, Held-to-maturity |  | $ 797,359 |  | $ 611,490
Held to Maturity, Fair Value, Total |  | 808,656 |  | 603,640
Loans, net of allowance for loan losses(b) |  | 8,884,827 |  | 6,841,901
Federal Home Loan Bank Stock |  | 26,085 |  | 15,683
Bank Owned Life Insurance |  | 197,292 |  | 160,456
LIABILITIES |  |  |  |
Federal Home Loan Bank borrowings(f) |  | 277,671 |  | 147,806
Long-term Debt |  | 74,879 | [1] | 0
Long-term Debt, Fair Value | [1] | 72,426 |  |
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust |  | 62,847 |  | 76,173
Subordinated Debt |  | 84,305 |  | 34,728
Deposits [Member] |  |  |  |
LIABILITIES |  |  |  |
Time certificates of deposits(f) | [2] | 7,862,856 |  | 6,716,017
Accrued Liabilities, Fair Value Disclosure | [2] | 7,862,856 |  | 6,716,017
Time certificates of deposits(f) |  |  |  |
LIABILITIES |  |  |  |
Time certificates of deposits(f) | [1] | 1,445,059 |  | 711,103
Accrued Liabilities, Fair Value Disclosure | [1] | 1,441,990 |  | 703,728
Federal Home Loan Bank borrowings(f) |  |  |  |
LIABILITIES |  |  |  |
Federal Home Loan Bank borrowings(f) | [1] | 277,671 |  | 147,806
Federal Home Loan Bank Borrowings, Fair Value Disclosure | [1] | 277,554 |  | 147,603
Junior subordinated debentures(g) |  |  |  |
LIABILITIES |  |  |  |
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust | [3] | 62,847 |  | 76,173
Accrued Liabilities, Fair Value Disclosure | [3] | 64,586 |  | 73,827
Subordinated debentures(f) |  |  |  |
LIABILITIES |  |  |  |
Subordinated Debt | [1] | 84,305 |  | 34,728
Accrued Liabilities, Fair Value Disclosure | [1] | 87,963 |  | 32,509
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term Debt [Member] |  |  |  |
LIABILITIES |  |  |  |
Long-term Debt, Fair Value | [1] | 0 |  |
Significant Other Observable Inputs (Level 2) | Deposits [Member] |  |  |  |
LIABILITIES |  |  |  |
Accrued Liabilities, Fair Value Disclosure | [2] | 7,862,856 |  | 6,716,017
Significant Other Observable Inputs (Level 2) | Time certificates of deposits(f) |  |  |  |
LIABILITIES |  |  |  |
Accrued Liabilities, Fair Value Disclosure | [1] | 1,441,990 |  | 703,728
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings(f) |  |  |  |
LIABILITIES |  |  |  |
Federal Home Loan Bank Borrowings, Fair Value Disclosure | [1] | 277,554 |  |
Accrued Liabilities, Fair Value Disclosure | [1] |  |  | 147,603
Significant Other Observable Inputs (Level 2) | Long-term Debt [Member] |  |  |  |
LIABILITIES |  |  |  |
Long-term Debt, Fair Value | [1] | 72,426 |  |
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures(g) |  |  |  |
LIABILITIES |  |  |  |
Accrued Liabilities, Fair Value Disclosure | [3] | 64,586 |  | 73,827
Significant Unobservable Inputs (Level 3) | Long-term Debt [Member] |  |  |  |
LIABILITIES |  |  |  |
Long-term Debt, Fair Value | [1] | 0 |  |
Significant Unobservable Inputs (Level 3) | Subordinated debentures(f) |  |  |  |
LIABILITIES |  |  |  |
Accrued Liabilities, Fair Value Disclosure | [1] | 87,963 |  | 32,509
U.S. Government agency securities |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 12,833 |  |
Held to Maturity, Fair Value, Total | [4] | 12,963 |  |
U.S. Government agency securities | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 12,963 |  |
U.S. Treasury securities |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 1,003 |  | 1,004
Held to Maturity, Fair Value, Total | [4] | 1,024 |  | 1,015
U.S. Treasury securities | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 1,024 |  | 1,015
Agency mortgage-backed securities |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 423,825 |  | 252,484
Held to Maturity, Fair Value, Total | [4] | 431,267 |  | 250,928
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 431,267 |  | 250,928
Agency collateralized mortgage obligations |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 324,441 |  | 332,775
Held to Maturity, Fair Value, Total | [4] | 327,718 |  | 326,724
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 327,718 |  | 326,724
Single issuer trust preferred securities issued by banks |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 1,500 |  | 1,500
Held to Maturity, Fair Value, Total | [4] | 1,490 |  | 1,490
Single issuer trust preferred securities issued by banks | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 1,490 |  | 1,490
Small Business Administration Pooled Securities [Member] |  |  |  |
ASSETS |  |  |  |
Debt Securities, Held-to-maturity | [4] | 33,757 |  | 23,727
Held to Maturity, Fair Value, Total | [4] | 34,194 |  | 23,483
Small Business Administration Pooled Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 0 |  | 0
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 34,194 |  | 23,483
Small Business Administration Pooled Securities [Member] | Significant Unobservable Inputs (Level 3) |  |  |  |
ASSETS |  |  |  |
Held to Maturity, Fair Value, Total | [4] | 0 |  | 0
Loans, net of allowance for loan losses(b) |  |  |  |
ASSETS |  |  |  |
Loans, net of allowance for loan losses(b) | [5] | 8,858,356 |  | 6,812,792
Loans Receivable, Fair Value Disclosure | [5] | 8,719,439 |  | 6,635,209
Loans, net of allowance for loan losses(b) | Significant Unobservable Inputs (Level 3) |  |  |  |
ASSETS |  |  |  |
Loans Receivable, Fair Value Disclosure | [5] | 8,719,439 |  | 6,635,209
Investment in Federal Home Loan Bank Stock [Member] |  |  |  |
ASSETS |  |  |  |
Federal Home Loan Bank Stock | [6] | 26,085 |  | 15,683
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 26,085 |  | 15,683
Investment in Federal Home Loan Bank Stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |  |
ASSETS |  |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 0 |  | 0
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 26,085 |  | 15,683
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3) |  |  |  |
ASSETS |  |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 0 |  | 0
Cash Surrender Value [Member] |  |  |  |
ASSETS |  |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 197,292 |  | 160,456
Bank Owned Life Insurance | [7] | 197,292 |  | 160,456
Cash Surrender Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |  |
ASSETS |  |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 0 |  | 0
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2) |  |  |  |
ASSETS |  |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 197,292 |  | 160,456
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3) |  |  |  |
ASSETS |  |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | $ 0 |  | $ 0
[1] | Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.
[2] | Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date.
[3] | Fair value was determined based upon market prices of securities with similar terms and maturities.
[4] | The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis.
[5] | Fair value of loans is measured using the exit price valuation method, determined primarily by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows, while incorporating liquidity and credit assumptions. Additionally, this amount excludes collateral dependent impaired loans, which are deemed to be marked to fair value on a nonrecurring basis.
[6] | FHLB stock has no quoted market value and is carried at cost, therefore the carrying amount approximates fair value.
[7] | Cash surrender value of life insurance is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore carrying amount approximates fair value.

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