Fair Value Measurements - General Disclosures (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 1,848,073	$ 697,685
Equity securities	5,362	6,169
Loans held for sale, at fair value	39,607	25,895
U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	58,535	25,411
Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	290,766	52,342
Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	278,930	170,044
Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	124,155	1,942
Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	961,137	315,748
Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	134,550	132,198
Recurring basis
Financial assets and financial liabilities measured at fair value
Equity securities	5,362	6,169
Loans held for sale, at fair value	39,607	25,895
Recurring basis \| Derivative assets
Financial assets and financial liabilities measured at fair value
Fair value recorded in other assets	13,083	2,062
Recurring basis \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Fair value recorded in other liabilities	13,897	2,643
Recurring basis \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	58,535	25,411
Recurring basis \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	290,766	52,342
Recurring basis \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	278,930	170,044
Recurring basis \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	124,155	1,942
Recurring basis \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	961,137	315,748
Recurring basis \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	134,550	132,198
Recurring basis \| Level 1
Financial assets and financial liabilities measured at fair value
Equity securities		6,169
Recurring basis \| Level 2
Financial assets and financial liabilities measured at fair value
Equity securities	5,362
Loans held for sale, at fair value	39,607	25,895
Recurring basis \| Level 2 \| Derivative assets
Financial assets and financial liabilities measured at fair value
Fair value recorded in other assets	13,083	2,062
Recurring basis \| Level 2 \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Fair value recorded in other liabilities	13,897	2,643
Recurring basis \| Level 2 \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	58,535	25,411
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	290,766	52,342
Recurring basis \| Level 2 \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	278,930	170,044
Recurring basis \| Level 2 \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	124,155	1,942
Recurring basis \| Level 2 \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	961,137	315,748
Recurring basis \| Level 2 \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Debt securities available for sale	$ 134,550	$ 132,198

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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