Securities (Securities Available for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 3,210,615	$ 2,763,321
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	12,799	8,480
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(55,966)	(34,050)
Securities available for sale	3,167,448	2,737,751
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,222,521	1,752,236
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	9,236	1,815
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(43,467)	(27,326)
Securities available for sale	2,188,290	1,726,725
State and Municipal Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	579,755	593,940
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	2,328	6,023
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(7,760)	(3,959)
Securities available for sale	574,323	596,004
U.S. Government Agency and Government-Sponsored Enterprise Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	408,088	416,894
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	1,235	642
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(4,736)	(2,762)
Securities available for sale	404,587	414,774
US Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	251	251
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(3)	(3)
Securities available for sale	$ 248	$ 248

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

No definition available.

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

+ Details

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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