Employee Benefit Plans - Annual Retirement Plan Expense Assumptions (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.55%		5.08%
Long-term rate of return on plan assets			5.25%
Increase in compensation levels			2.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.01%
Long-term rate of return on plan assets	4.50%	4.10%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.53%
Long-term rate of return on plan assets	4.65%	6.10%