Loans and Allowance for Credit Losses (Details 1) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for Credit Losses, beginning balance	$ 61,047	$ 56,536	$ 59,074	$ 52,687
Loans charged-off	(593)	(1,993)	(2,266)	(5,398)
Recoveries of loans previously charged-off	592	33	1,275	356
Net loans (charged-off) recoveries	(1)	(1,960)	(991)	(5,042)
Provision for credit losses	1,921	2,288	4,884	9,219
Allowance for Credit Losses, ending balance	62,967	56,864	62,967	56,864
Individually evaluated for impairment					$ 8,700	$ 4,471
Collectively evaluated for impairment					54,267	52,393
Balance	62,967	56,536	62,967	56,864	62,967	56,864
Commercial Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	14,225	13,386	14,700	11,563
Loans charged-off	(522)	(109)	(659)	(2,802)
Recoveries of loans previously charged-off	407	7	675	93
Net loans (charged-off) recoveries	(115)	(102)	16	(2,709)
Provision for credit losses	(2,266)	(523)	(2,872)	3,907
Allowance for Credit Losses, ending balance	11,844	12,761	11,844	12,761
Individually evaluated for impairment					3,246	1,997
Collectively evaluated for impairment					8,598	10,764
Balance	11,844	12,761	11,844	12,761	11,844	12,761
Commercial Real Estate - Income Producing Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	23,308	19,072	21,105	14,122
Loans charged-off		(1,751)	(1,470)	(2,342)
Recoveries of loans previously charged-off	30	10	80	14
Net loans (charged-off) recoveries	30	(1,741)	(1,390)	(2,328)
Provision for credit losses	(963)	3,178	2,660	8,715
Allowance for Credit Losses, ending balance	22,375	20,509	22,375	20,509
Individually evaluated for impairment					1,378	1,714
Collectively evaluated for impairment					20,997	18,795
Balance	22,375	20,509	22,375	20,509	22,375	20,509
Commercial Real Estate - Owner Occupied Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	4,189	4,202	4,010	3,279
Recoveries of loans previously charged-off			2	2
Net loans (charged-off) recoveries			2	2
Provision for credit losses	1,273	59	1,450	980
Allowance for Credit Losses, ending balance	5,462	4,261	5,462	4,261
Individually evaluated for impairment					1,005	360
Collectively evaluated for impairment					4,457	3,901
Balance	5,462	4,261	5,462	4,261	5,462	4,261
Real Estate Mortgage - Residential Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	1,081	1,061	1,284	1,268
Recoveries of loans previously charged-off	2	2	5	5
Net loans (charged-off) recoveries	2	2	5	5
Provision for credit losses	(126)	47	(332)	(163)
Allowance for Credit Losses, ending balance	957	1,110	957	1,110
Collectively evaluated for impairment					957	1,110
Balance	957	1,110	957	1,110	957	1,110
Construction Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	16,727	17,024	16,487	21,088
Loans charged-off	(39)		(39)
Recoveries of loans previously charged-off	146	3	491	207
Net loans (charged-off) recoveries	107	3	452	207
Provision for credit losses	4,052	(513)	3,947	(4,781)
Allowance for Credit Losses, ending balance	20,886	16,514	20,886	16,514
Individually evaluated for impairment					2,900	300
Collectively evaluated for impairment					17,986	16,214
Balance	20,886	16,514	16,487	21,088	20,886	16,514
Home Equity Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	1,216	1,556	1,328	1,292
Loans charged-off		(121)		(217)
Recoveries of loans previously charged-off	1	3	4	11
Net loans (charged-off) recoveries	1	(118)	4	(206)
Provision for credit losses	(120)	(69)	(235)	283
Allowance for Credit Losses, ending balance	1,097	1,369	1,097	1,369
Individually evaluated for impairment					90
Collectively evaluated for impairment					1,007	1,369
Balance	1,097	1,369	1,097	1,369	1,097	1,369
Other Consumer Portfolio Segment [Member]
Allowance for Credit Losses, beginning balance	301	235	160	75
Loans charged-off	(32)	(12)	(98)	(37)
Recoveries of loans previously charged-off	6	8	18	24
Net loans (charged-off) recoveries	(26)	(4)	(80)	(13)
Provision for credit losses	71	109	266	278
Allowance for Credit Losses, ending balance	346	340	346	340
Individually evaluated for impairment					81	100
Collectively evaluated for impairment					265	240
Balance	$ 346	$ 340	$ 346	$ 340	$ 346	$ 340

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of other addition (reduction) in allowance reserve for credit loss.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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