Fair Value Measurements - General Disclosures (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 1,765,945	$ 1,648,257
Equity securities	4,936	5,952
Loans held for sale, at fair value	89,943	68,699
U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	45,394	51,737
Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	90,574	163,000
Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	284,747	268,291
Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	245,421	139,287
Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,000,857	921,966
Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	98,952	103,976
Recurring basis
Financial assets and financial liabilities measured at fair value
Equity securities	4,936	5,952
Loans held for sale, at fair value	89,943	68,699
Recurring basis \| Derivative assets
Financial assets and financial liabilities measured at fair value
Fair value recorded in other assets	40,978	13,400
Recurring basis \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Fair value recorded in other liabilities	46,600	14,821
Recurring basis \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	45,394	51,737
Recurring basis \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	90,574	163,000
Recurring basis \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	284,747	268,291
Recurring basis \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	245,421	139,287
Recurring basis \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,000,857	921,966
Recurring basis \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	98,952	103,976
Recurring basis \| Level 2
Financial assets and financial liabilities measured at fair value
Equity securities	4,936	5,952
Loans held for sale, at fair value	89,943	68,699
Recurring basis \| Level 2 \| Derivative assets
Financial assets and financial liabilities measured at fair value
Fair value recorded in other assets	40,978	13,400
Recurring basis \| Level 2 \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Fair value recorded in other liabilities	46,600	14,821
Recurring basis \| Level 2 \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	45,394	51,737
Recurring basis \| Level 2 \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	90,574	163,000
Recurring basis \| Level 2 \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	284,747	268,291
Recurring basis \| Level 2 \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	245,421	139,287
Recurring basis \| Level 2 \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	1,000,857	921,966
Recurring basis \| Level 2 \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 98,952	$ 103,976

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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