Other Borrowings and Notes Payable (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Feb. 23, 2016
Debt Instrument [Line Items]
Line of Credit, Current			$ 20,000,000
Securities sold under customer repurchase agreements	$ 221,450,000	$ 253,674,000
Total	221,450,000	253,674,000
Amount withdrawn	2,000,000	0
Other Borrowings
Debt Instrument [Line Items]
Maximum balance outstanding at any month-end	231,450,000	253,674,000
Average balance during the year	$ 170,963,000	$ 220,807,000
Average interest rate during the year	0.41%	0.21%
Average interest rate at December 31	0.49%	0.25%
Line of Credit
Debt Instrument [Line Items]
Maximum balance outstanding at any month-end	$ 2,000,000	$ 10,000,000
Average balance during the year	$ 22,000	$ 822,000
Average interest rate during the year	4.63%	3.50%
Average interest rate at December 31	4.63%	0.00%
Remaining borrowing capacity	$ 989,400,000
Aggregate of pledge secured by certain eligible loans	1,170,300,000
Amount withdrawn	$ 0