Securities (Available-for-sale Securities, Debt Maturities) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Amortized Cost
Due in 1 year or less	$ 30,248
Due in 1 to 5 years	51,947
Due in 5 to 10 years	137,983
Due after 10 years	193,998
Total debt securities	414,176
Mortgage and asset-backed securities	2,061,358
Equity securities with a readily determinable fair value, cost	17,086
Amortized Cost	2,492,620
Estimated Fair Value
Due in 1 year or less	30,163
Due in 1 to 5 years	51,120
Due in 5 to 10 years	135,423
Due after 10 years	190,219
Total debt securities	406,925
Mortgage and asset-backed securities	2,026,698
Equity securities with a readily determinable fair value, fair value	17,086
Total investment securities	$ 2,450,709

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27198-111563

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75019621&loc=d3e62586-112803