Securities - Investments in Pooled Trust Preferred Securities (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Investments in pooled trust preferred securities
Amortized Cost	$ 1,264,529	$ 674,104
Fair Value	1,250,777	671,488
Gross Unrealized Losses	(18,269)	(10,488)
Trust preferred securities
Investments in pooled trust preferred securities
Amortized Cost	12,359	12,442
Fair Value	10,633	$ 9,388
Gross Unrealized Losses	(1,726)
XXIII
Investments in pooled trust preferred securities
Amortized Cost	8,292
Fair Value	6,956
Gross Unrealized Losses	$ (1,336)
Issuers currently in deferral or default (percent)	16.00%
XXVI
Investments in pooled trust preferred securities
Amortized Cost	$ 4,067
Fair Value	3,677
Gross Unrealized Losses	$ (390)
Issuers currently in deferral or default (percent)	19.00%

Percentage of issuers currently in deferral or default.

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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

+ References

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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