Fair Value Measurements Financial Instruments, Quantitative Information (Details)	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Time deposits [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.03%	0.03%	0.02%
Contractual Yield, Maximum	9.64%	9.65%	9.65%
Repricing (in years)	1 year 347 days	2 years 37 days	1 year 350 days
Discount Rate, Minimum	1.86%	1.37%	1.57%
Discount Rate, Maximum	2.18%	1.66%	2.00%
Other borrowings [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.25%	0.25%
Contractual Yield, Maximum	6.25%	3.81%	3.50%
Repricing (in years)	7 days	7 days	1 day
Discount Rate, Minimum	1.06%	0.29%	0.55%
Discount Rate, Maximum	3.70%	2.99%	3.22%
Subordinated debentures [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	5.38%	5.38%	5.38%
Contractual Yield, Maximum	5.38%	5.38%	5.38%
Repricing (in years)	16 years 310 days	18 years 135 days	16 years 314 days
Discount Rate, Minimum	4.96%	5.38%	6.11%
Discount Rate, Maximum	4.96%	5.38%	6.11%
Commercial | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.38%	0.38%
Contractual Yield, Maximum	30.00%	30.00%	30.00%
Repricing (in years)	226 days	252 days	256 days
Discount Rate, Minimum	0.78%	0.54%	0.64%
Discount Rate, Maximum	4.59%	3.93%	4.60%
Commercial real estate | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.38%	0.38%	0.38%
Contractual Yield, Maximum	18.00%	18.00%	18.00%
Repricing (in years)	282 days	263 days	259 days
Discount Rate, Minimum	1.04%	0.80%	0.94%
Discount Rate, Maximum	4.38%	3.90%	4.27%
Residential mortgage | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	1.74%	1.74%	1.74%
Contractual Yield, Maximum	18.00%	18.00%	18.00%
Repricing (in years)	2 years 44 days	1 year 347 days	2 years 99 days
Discount Rate, Minimum	1.79%	1.57%	1.71%
Discount Rate, Maximum	4.09%	3.55%	4.26%
Personal | Loans Receivable [Member]
Fair Value Inputs, Financial Instruments, Quantitative Information [Line Items]
Contractual Yield, Minimum	0.25%	0.25%	0.25%
Contractual Yield, Maximum	21.00%	21.00%	21.00%
Repricing (in years)	88 days	128 days	146 days
Discount Rate, Minimum	0.55%	0.75%	1.03%
Discount Rate, Maximum	4.78%	4.15%	4.59%