Investment Securities (Summary of Amortized Cost and Fair Value of Available-For-Sale Investment Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Available-for-sale Securities
Amortized Cost	$ 1,301,257	$ 556,636
Unrealized Gains	4,323	1,468
Unrealized Losses	2,199	4,373
Available-for-sale, at fair value	1,303,381	553,731
US Treasury securities [Member]
Available-for-sale Securities
Amortized Cost	5,784	5,773
Unrealized Gains	17	0
Unrealized Losses	0	8
Available-for-sale, at fair value	5,801	5,765
Government sponsored agencies [Member]
Available-for-sale Securities
Amortized Cost	223,917	195,711
Unrealized Gains	535	78
Unrealized Losses	414	800
Available-for-sale, at fair value	224,038	194,989
State and political subdivisions [Member]
Available-for-sale Securities
Amortized Cost	306,196	14,731
Unrealized Gains	384	395
Unrealized Losses	1,043	6
Available-for-sale, at fair value	305,537	15,120
Residential mortgage-backed securities [Member]
Available-for-sale Securities
Amortized Cost	301,194	189,452
Unrealized Gains	2,206	538
Unrealized Losses	2	2,222
Available-for-sale, at fair value	303,398	187,768
Collateralized mortgage obligations [Member]
Available-for-sale Securities
Amortized Cost	343,502	133,256
Unrealized Gains	629	111
Unrealized Losses	392	1,137
Available-for-sale, at fair value	343,739	132,230
Corporate bonds [Member]
Available-for-sale Securities
Amortized Cost	96,283	14,825
Unrealized Gains	37	2
Unrealized Losses	235	200
Available-for-sale, at fair value	96,085	14,627
Preferred stock and trust preferred securities[Member]
Available-for-sale Securities
Amortized Cost	24,381	2,888
Unrealized Gains	515	344
Unrealized Losses	113	0
Available-for-sale, at fair value	$ 24,783	$ 3,232

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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

+ References

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=51813488&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=27724398&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=49167202&loc=d3e26610-111562

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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