Employee Benefit Plans - Stock Option Activity (Details) - Officer and Employee Plans [Member] - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Number
Shares, Outstanding at Beginning of Period	717,524	817,414
Shares, Exercised	(505,712)	(89,556)
Shares, Forfeited	(24,496)	(10,334)
Shares, Outstanding at End of Period	187,316	717,524
Weighted Average Exercisable Price
Weighted Average Exercisable Price, Outstanding at Beginning of Period (in dollars per share)	$ 10.57	$ 10.62
Weighted Average Exercisable Price Exercised (in dollars per share)	9.64	8.98
Weighted Average Exercisable Price Forfeited (in dollars per share)	19.90	28.49
Weighted Average Exercisable Price, Outstanding at End of Period (in dollars per share)	$ 11.85	$ 10.57