Parent Company Financial Statements (Statement of Income) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income:
Total revenues	[1]									$ 226,886	$ 200,494	$ 194,404
Expenses:
Interest on junior subordinated debentures										641	980	869
Legal and professional fees										3,747	2,535	2,427
Change in fair value of contingent consideration										0	0	(187)
Income before income taxes		$ 24,080	$ 23,453	$ 26,587	$ 15,040	$ 19,857	$ 24,050	$ 21,935	$ 22,337	89,160	88,179	86,692
Income tax benefit		(5,514)	(5,131)	(5,547)	(3,139)	(4,321)	(5,236)	(4,662)	(4,842)	(19,331)	(19,061)	(18,260)
Net income		$ 18,566	$ 18,322	$ 21,040	$ 11,901	$ 15,536	$ 18,814	$ 17,273	$ 17,495	69,829	69,118	68,432
Parent Company [Member]
Income:
Total revenues										43,156	36,823	32,418
Expenses:
Interest on junior subordinated debentures										641	980	869
Legal and professional fees										210	147	187
Change in fair value of contingent consideration										0	0	(187)
Other										349	337	324
Total expenses										1,200	1,464	1,193
Income before income taxes										41,956	35,359	31,225
Income tax benefit										248	301	284
Income before equity in undistributed earnings of subsidiaries										42,204	35,660	31,509
Net income										69,829	69,118	68,432
Bank [Member]
Income:
Dividends from subsidiaries										43,139	36,796	32,394
Expenses:
Equity in undistributed earnings (losses) of subsidiaries										27,603	33,445	36,876
Non-bank [Member]
Income:
Dividends from subsidiaries										17	27	24
Expenses:
Equity in undistributed earnings (losses) of subsidiaries										$ 22	$ 13	$ 47

[1] As reported in the Consolidated Statements of Income.