Loans and Allowance for Credit Losses (Details 2) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Recorded investment in loans:
Loans individually evaluated for impairment	$ 33,534	$ 34,471	$ 34,848
Loans collectively evaluated for impairment	6,050,670	5,643,422	5,447,127
Net loans	6,084,204	5,677,893	5,481,975
Commercial Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	8,309	10,437	12,448
Loans collectively evaluated for impairment	1,235,875	1,190,291	1,117,594
Net loans	1,244,184	1,200,728	1,130,042
Commercial Real Estate - Income Producing Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	10,241	15,057	14,648
Loans collectively evaluated for impairment	2,888,707	2,494,460	2,536,538
Net loans	2,898,948	2,509,517	2,551,186
Commercial Real Estate - Owner Occupied Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	6,570	2,093	2,517
Loans collectively evaluated for impairment	743,010	638,777	587,910
Net loans	749,580	640,870	590,427
Real Estate Mortgage - Residential Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment		241	244
Loans collectively evaluated for impairment	109,460	152,507	154,195
Net loans	109,460	152,748	154,439
Construction Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	7,728	6,517	4,878
Loans collectively evaluated for impairment	963,593	1,052,052	937,935
Net loans	971,321	1,058,569	942,813
Home Equity Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	594		113
Loans collectively evaluated for impairment	101,304	105,096	106,743
Net loans	101,898	105,096	106,856
Other Consumer Portfolio Segment [Member]
Recorded investment in loans:
Loans individually evaluated for impairment	92	126
Loans collectively evaluated for impairment	8,721	10,239	6,212
Net loans	$ 8,813	$ 10,365	$ 6,212

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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