Income Taxes (Summary Of Income Tax Expense) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal									$ 16,846	$ 20,090	$ 20,100
State									2,413	1,436	1,166
Total current tax expense									19,259	21,526	21,266
Total deferred tax expense									(1,244)	14,909	3,817
Income tax expense	$ 2,646	$ 5,606	$ 5,358	$ 4,405	$ 14,972	$ 7,003	$ 6,812	$ 7,647	$ 18,015	$ 36,435	$ 25,083