Loans (Summary of Impaired Loans by Classes of Loans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	$ 71,284	$ 44,383
Unpaid Principal Balance	81,808	45,151
Related Valuation Allowance	8,762	6,389
Average Annual Recorded Investment	37,464	33,090	$ 25,556
Interest Income Recognized While on Impaired Status	1,285	1,312	1,252
Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	32,129	85,020
Unpaid Principal Balance	38,794	101,393
Related Valuation Allowance	0	0
Average Annual Recorded Investment	73,864	87,093	90,563
Interest Income Recognized While on Impaired Status	2,601	2,577	2,306
Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	106,869	129,403
Unpaid Principal Balance	124,058	146,544
Related Valuation Allowance	8,762	6,389
Average Annual Recorded Investment	113,446	120,183	116,119
Interest Income Recognized While on Impaired Status	3,886	3,889	3,558
Commercial Loan | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	28,925	18,898
Unpaid Principal Balance	33,209	19,426
Related Valuation Allowance	3,128	5,700
Average Annual Recorded Investment	7,829	9,511	2,117
Interest Income Recognized While on Impaired Status	0	0	0
Commercial Loan | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	7,435	27,304
Unpaid Principal Balance	11,153	32,395
Related Valuation Allowance	0	0
Average Annual Recorded Investment	29,559	27,778	32,895
Interest Income Recognized While on Impaired Status	1,343	1,005	961
Commercial Loan | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	36,360	46,202
Unpaid Principal Balance	44,362	51,821
Related Valuation Allowance	3,128	5,700
Average Annual Recorded Investment	37,388	37,289	35,012
Interest Income Recognized While on Impaired Status	1,343	1,005	961
Commercial real estate | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	21,318	4,448
Unpaid Principal Balance	27,558	4,688
Related Valuation Allowance	2,102	497
Average Annual Recorded Investment	5,658	2,918	3,699
Interest Income Recognized While on Impaired Status	0	0	0
Commercial real estate | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	20,588	48,747
Unpaid Principal Balance	23,535	59,949
Related Valuation Allowance	0	0
Average Annual Recorded Investment	41,646	50,079	46,344
Interest Income Recognized While on Impaired Status	1,236	1,547	1,342
Commercial real estate | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	41,906	53,195
Unpaid Principal Balance	51,093	64,637
Related Valuation Allowance	2,102	497
Average Annual Recorded Investment	47,304	52,997	50,043
Interest Income Recognized While on Impaired Status	1,236	1,547	1,342
Real estate construction and land development | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	177
Unpaid Principal Balance	177
Related Valuation Allowance	4
Average Annual Recorded Investment	19	0	0
Interest Income Recognized While on Impaired Status	0	0	0
Real estate construction and land development | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	80	982
Unpaid Principal Balance	80	1,062
Related Valuation Allowance	0	0
Average Annual Recorded Investment	585	889	1,831
Interest Income Recognized While on Impaired Status	22	25	3
Real estate construction and land development | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	257	982
Unpaid Principal Balance	257	1,062
Related Valuation Allowance	4	0
Average Annual Recorded Investment	604	889	1,831
Interest Income Recognized While on Impaired Status	22	25	3
Residential mortgage | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	20,864	21,037
Unpaid Principal Balance	20,864	21,037
Related Valuation Allowance	3,528	192
Average Annual Recorded Investment	23,958	20,661	19,740
Interest Income Recognized While on Impaired Status	1,285	1,312	1,252
Residential mortgage | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	3,252	5,557
Unpaid Principal Balance	3,252	5,557
Related Valuation Allowance	0	0
Average Annual Recorded Investment	1,519	6,027	6,783
Interest Income Recognized While on Impaired Status	0	0	0
Residential mortgage | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	24,116	26,594
Unpaid Principal Balance	24,116	26,594
Related Valuation Allowance	3,528	192
Average Annual Recorded Investment	25,477	26,688	26,523
Interest Income Recognized While on Impaired Status	1,285	1,312	1,252
Consumer installment | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	879
Unpaid Principal Balance	879
Related Valuation Allowance	240
Average Annual Recorded Investment	359	0	0
Interest Income Recognized While on Impaired Status	0	0	0
Consumer installment | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	0	451
Unpaid Principal Balance	0	451
Related Valuation Allowance	0	0
Average Annual Recorded Investment	0	448	592
Interest Income Recognized While on Impaired Status	0	0	0
Consumer installment | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	879	451
Unpaid Principal Balance	879	451
Related Valuation Allowance	0	0
Average Annual Recorded Investment	359	448	592
Interest Income Recognized While on Impaired Status	0	0	0
Home equity | Impaired loans with a valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	2,577
Unpaid Principal Balance	2,577
Related Valuation Allowance	390
Average Annual Recorded Investment	1,759	0	0
Interest Income Recognized While on Impaired Status	0	0	0
Home equity | Impaired loans with no valuation allowance
Schedule of Impaired loans by classes
Recorded Investment	774	1,979
Unpaid Principal Balance	774	1,979
Related Valuation Allowance	0	0
Average Annual Recorded Investment	555	1,872	2,118
Interest Income Recognized While on Impaired Status	0	0	0
Home equity | Total Impaired Loans
Schedule of Impaired loans by classes
Recorded Investment	3,351	1,979
Unpaid Principal Balance	3,351	1,979
Related Valuation Allowance	0	0
Average Annual Recorded Investment	2,314	1,872	2,118
Interest Income Recognized While on Impaired Status	$ 0	$ 0	$ 0