Fair Value Measurements - Fair Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
Securities available for sale, at fair value	$ 1,290,613	$ 1,250,777
Derivative instruments	61	1,620
Mortgage loans held for sale in loans held for sale	318,272	219,848
Financial liabilities:
Derivative instruments	9,974	6,768
Trust preferred securities
Financial assets:
Securities available for sale, at fair value	9,986	10,633
Other debt securities
Financial assets:
Securities available for sale, at fair value	56,365	43,927
Level 1
Financial assets:
Securities available for sale, at fair value	0	0
Derivative instruments	0	0
Financial liabilities:
Derivative instruments	0	0
Level 2
Financial assets:
Securities available for sale, at fair value	1,280,627	1,240,144
Derivative instruments	8,498	6,519
Financial liabilities:
Derivative instruments	10,000	8,388
Level 3
Financial assets:
Securities available for sale, at fair value	9,986	10,633
Derivative instruments	0	0
Financial liabilities:
Derivative instruments	0	0
Recurring
Financial assets:
Securities available for sale, at fair value	1,290,613	1,250,777
Derivative instruments	8,498	6,519
Mortgage loans held for sale in loans held for sale	318,272	219,848
Total financial assets	1,617,383	1,477,144
Financial liabilities:
Derivative instruments	10,000	8,388
Recurring \| Trust preferred securities
Financial assets:
Securities available for sale, at fair value	9,986	10,633
Recurring \| Other debt securities
Financial assets:
Securities available for sale, at fair value	1,280,627	1,240,144
Recurring \| Level 1
Financial assets:
Securities available for sale, at fair value	0	0
Derivative instruments	0	0
Mortgage loans held for sale in loans held for sale	0	0
Total financial assets	0	0
Financial liabilities:
Derivative instruments	0	0
Recurring \| Level 1 \| Trust preferred securities
Financial assets:
Securities available for sale, at fair value	0	0
Recurring \| Level 1 \| Other debt securities
Financial assets:
Securities available for sale, at fair value	0	0
Recurring \| Level 2
Financial assets:
Securities available for sale, at fair value	1,280,627	1,240,144
Derivative instruments	8,498	6,519
Mortgage loans held for sale in loans held for sale	318,272	219,848
Total financial assets	1,607,397	1,466,511
Financial liabilities:
Derivative instruments	10,000	8,388
Recurring \| Level 2 \| Trust preferred securities
Financial assets:
Securities available for sale, at fair value	0	0
Recurring \| Level 2 \| Other debt securities
Financial assets:
Securities available for sale, at fair value	1,280,627	1,240,144
Recurring \| Level 3
Financial assets:
Securities available for sale, at fair value	9,986	10,633
Derivative instruments	0	0
Mortgage loans held for sale in loans held for sale	0	0
Total financial assets	9,986	10,633
Financial liabilities:
Derivative instruments	0	0
Recurring \| Level 3 \| Trust preferred securities
Financial assets:
Securities available for sale, at fair value	9,986	10,633
Recurring \| Level 3 \| Other debt securities
Financial assets:
Securities available for sale, at fair value	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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