Income Taxes (Schedule of Income Tax Expense) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal									$ 11,876	$ 14,102	$ 14,529
State									1,241	1,206	1,289
Total									13,117	15,308	15,818
Deferred:
Change in federal corporate income tax rate(1)									0	0	14,263
Federal									1,230	(2,541)	4,117
Deferred State and Local Income Tax Expense (Benefit)									29	(61)	(320)
Deferred Income Tax Expense (Benefit)									1,259	(2,602)	18,060
Income tax expense	$ 3,921	$ 3,696	$ 3,275	$ 3,484	$ 3,502	$ 3,238	$ 2,887	$ 3,079	$ 14,376	$ 12,706	$ 33,878