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Derivative Financial Instruments (Detail) - Nondesignated | Mar. 31, 2017 USD ($)
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Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | $ 1,784,118,000 |
Interest rate lock commitments |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 289,118,000 |
Treasury Options |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 370,000,000 |
Eurodollar Futures |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 50,000,000 |
Interest Rate Swap |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 350,000,000 |
Forward commitments to sell loans/mortgage-backed securities |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 410,000,000 |
Forward commitments to buy loans/mortgage-backed securities |  |
Derivatives, Fair Value [Line Items] |  |
Derivative financial instruments held, notional amount | 315,000,000 |
Other assets |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 5,378,000 | [1]
Other assets | Interest rate lock commitments |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 2,449,000 | [1]
Other assets | Treasury Options |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 86,000 | [1]
Other assets | Eurodollar Futures |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 23,000 | [1]
Other assets | Interest Rate Swap |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 710,000 | [1]
Other assets | Forward commitments to sell loans/mortgage-backed securities |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 32,000 | [1]
Other assets | Forward commitments to buy loans/mortgage-backed securities |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Gain | 2,078,000 | [1]
Other liabilities |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Loss | 8,921,000 | [1]
Other liabilities | Treasury Options |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Loss | 205,000 | [1]
Other liabilities | Eurodollar Futures |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Loss | 9,000 | [1]
Other liabilities | Interest Rate Swap |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Loss | 6,219,000 | [1]
Other liabilities | Forward commitments to sell loans/mortgage-backed securities |  |
Derivatives, Fair Value [Line Items] |  |
Unrealized Loss | $ 2,488,000 | [1]
[1] | Derivatives in a net gain position are recorded as "Other assets" and derivatives in a net loss position are recorded as "Other liabilities" in the Consolidated Statements of Condition.

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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