Securities (Amortized Cost and Fair Value of Securities Available for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 2,562,000	$ 2,086,745
Securities Available for Sale, Gross Unrealized Gains	11,195	20,120
Securities Available for Sale, Gross Unrealized Losses	56,287	13,461
Securities Available for Sale, Fair Value	2,516,908	2,093,404
U.S. Treasury And Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	56,751	135
Securities Available for Sale, Gross Unrealized Losses	1,923	1
Securities Available for Sale, Fair Value	54,828	134
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	253,228	39,410
Securities Available for Sale, Gross Unrealized Gains	113	235
Securities Available for Sale, Gross Unrealized Losses	11,186	38
Securities Available for Sale, Fair Value	242,155	39,607
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	1,620,191	1,750,168
Securities Available for Sale, Gross Unrealized Gains	10,592	19,387
Securities Available for Sale, Gross Unrealized Losses	19,428	11,182
Securities Available for Sale, Fair Value	1,611,355	1,758,373
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	425,750
Securities Available for Sale, Gross Unrealized Losses	23,159
Securities Available for Sale, Fair Value	402,591
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	202,580	291,085
Securities Available for Sale, Gross Unrealized Gains	490	140
Securities Available for Sale, Gross Unrealized Losses	591	2,192
Securities Available for Sale, Fair Value	202,479	289,033
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	3,500	3,500
Securities Available for Sale, Fair Value	$ 3,500	3,500
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost		2,447
Securities Available for Sale, Gross Unrealized Gains		358
Securities Available for Sale, Gross Unrealized Losses		48
Securities Available for Sale, Fair Value		$ 2,757

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

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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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
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