Quarterly Financial Data (Unaudited) - Acquisition and Integration Costs (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Combinations
Pre-tax acquisition costs	$ 9,879,000	$ 661,000	$ 540,000	$ 139,000	$ 199,000	$ 8,214,000	$ 615,000		$ 11,080,000	$ 9,167,000	$ 671,000
Tax Cuts and Jobs Act of 2017 effect on re-measurement of net deferred tax assets								$ 7,103,000			7,103,000
Banking
Business Combinations
Pre-tax acquisition costs									$ 11,080,000	$ 9,167,000
Tax Cuts and Jobs Act of 2017 effect on re-measurement of net deferred tax assets											$ 6,749,000