Adoption of New Accounting Standards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Adoption of New Accounting Standards
Cumulative effect	$ 140,520,000	$ 127,431,000
Salaries and employee benefits	(42,003,000)	(43,597,000)	$ (42,345,000)
Noninterest income - Other	$ 2,880,000	3,888,000	3,895,000
ASU 2014-09 | Adjustment
Adoption of New Accounting Standards
Cumulative effect				$ 0
ASU 2017-07 | Adjustment
Adoption of New Accounting Standards
Salaries and employee benefits		493,000	420,000
Noninterest income - Other		$ 493,000	$ 420,000