Investment Securities (Summary of Amortized Cost and Fair Value of Available-for-Sale Investment Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investment Securities Available-for-Sale
Amortized Cost	$ 1,256,721	$ 556,636
Unrealized Gains	1,566	1,468
Unrealized Losses	23,323	4,373
Available-for-sale, at fair value	1,234,964	553,731
U.S. Treasury securities
Investment Securities Available-for-Sale
Amortized Cost	5,788	5,773
Unrealized Gains	5	0
Unrealized Losses	0	8
Available-for-sale, at fair value	5,793	5,765
Government sponsored agencies
Investment Securities Available-for-Sale
Amortized Cost	216,890	195,711
Unrealized Gains	189	78
Unrealized Losses	2,068	800
Available-for-sale, at fair value	215,011	194,989
State and political subdivisions
Investment Securities Available-for-Sale
Amortized Cost	311,704	14,731
Unrealized Gains	163	395
Unrealized Losses	11,779	6
Available-for-sale, at fair value	300,088	15,120
Residential mortgage-backed securities
Investment Securities Available-for-Sale
Amortized Cost	276,162	189,452
Unrealized Gains	112	538
Unrealized Losses	3,992	2,222
Available-for-sale, at fair value	272,282	187,768
Collateralized mortgage obligations
Investment Securities Available-for-Sale
Amortized Cost	323,965	133,256
Unrealized Gains	63	111
Unrealized Losses	4,003	1,137
Available-for-sale, at fair value	320,025	132,230
Corporate bonds
Investment Securities Available-for-Sale
Amortized Cost	90,859	14,825
Unrealized Gains	16	2
Unrealized Losses	1,401	200
Available-for-sale, at fair value	89,474	14,627
Preferred stock and trust preferred securities
Investment Securities Available-for-Sale
Amortized Cost	31,353	2,888
Unrealized Gains	1,018	344
Unrealized Losses	80	0
Available-for-sale, at fair value	$ 32,291	$ 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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