Investment Securities Available for Sale (Summary Of Available For Sale Investment Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 4,085,913	$ 4,038,239
Gross Unrealized Gains	6,274	6,107
Gross Unrealized Losses	(100,555)	(57,277)
Fair Value	3,991,632	3,987,069
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	123,436	83,608
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1,359)	(934)
Fair Value	122,077	82,674
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	38,021	10,771
Gross Unrealized Gains	361	91
Gross Unrealized Losses	0	0
Fair Value	38,382	10,862
Mortgage-backed securities issued by U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	100,060	121,283
Gross Unrealized Gains	172	519
Gross Unrealized Losses	(3,027)	(1,362)
Fair Value	97,205	120,440
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,460,498	2,621,694
Gross Unrealized Gains	1,981	5,037
Gross Unrealized Losses	(63,829)	(31,105)
Fair Value	2,398,650	2,595,626
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,215,406	1,135,259
Gross Unrealized Gains	2,997	144
Gross Unrealized Losses	(29,885)	(23,404)
Fair Value	1,188,518	1,111,999
Commercial mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	131,492	45,124
Gross Unrealized Gains	613	22
Gross Unrealized Losses	(2,240)	(249)
Fair Value	129,865	44,897
State and municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		180
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		180
Corporate debt and other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,000	20,320
Gross Unrealized Gains	150	294
Gross Unrealized Losses	(215)	(223)
Fair Value	$ 16,935	$ 20,391

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

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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.

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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.

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