Parent Company Financial Information (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income	$ 202,820	$ 154,244	$ 194,451
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	14,926	10,737	9,271
Net cash provided by operating activities	235,065	192,292	204,747
Cash Flows From Investing Activities
Net cash received in business combinations	154,984	0	0
Net cash used in investing activities	(2,358,360)	(1,918,785)	(865,450)
Financing Activities
Cash dividends paid	(83,790)	(95,509)	(101,911)
Repayments of Junior Subordinated Debt	35,000	0	0
Purchase and retirement of common stock	4,140	2,522	2,792
Purchase of treasury stock	0	(20,000)	(50,834)
Proceeds from exercise of stock options and employee stock purchase plan	2,350	2,028	2,025
Net cash provided by financing activities	2,294,243	2,132,586	630,789
Supplemental Information:
Stock Issued	256,061	0	0
Cash and cash equivalents at beginning of period	653,766	247,673	277,587
Cash and cash equivalents at end of period	824,714	653,766	247,673
Parent Company
Operating Activities
Net income	202,820	154,244	194,451
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(99,321)	(68,826)	(30,089)
Stock-based compensation expense	14,926	10,737	9,271
Net changes in other assets and liabilities	(1,436)	(17)	(133)
Net cash provided by operating activities	116,989	96,138	173,500
Cash Flows From Investing Activities
Net cash received in business combinations	2,173	0	0
Net cash used in investing activities	2,173	0	0
Financing Activities
Cash dividends paid	(83,841)	(96,215)	(102,265)
Repayments of Junior Subordinated Debt	35,000	0	0
Purchase and retirement of common stock	4,140	2,522	2,792
Purchase of treasury stock	0	(20,000)	(50,834)
Proceeds from exercise of stock options and employee stock purchase plan	2,350	2,028	2,025
Net cash provided by financing activities	(120,631)	(116,709)	(153,866)
Increase (decrease) in cash and cash equivalents	(1,469)	(20,571)	19,634
Supplemental Information:
Stock Issued	256,061	0	0
Cash and cash equivalents at beginning of period	7,234	27,805	8,171
Cash and cash equivalents at end of period	$ 5,765	$ 7,234	$ 27,805