Stockholders' Equity (Stock Rollforward) (Details) - shares		9 Months Ended
	Feb. 27, 2020	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stock by Class [Roll Forward]
Common stock, beginning of period		21,156,143
Treasury stock, beginning of period		504,182
Changes related to deferred compensation plan for Boards of Directors:
Common shares issued under compensation plan for Boards of Directors		(3,680)	(3,200)
Common stock, end of period		21,184,157
Treasury stock, end of period		1,515,624
Performance Shares [Member]
Changes related to deferred compensation plan for Boards of Directors:
Common shares issued under compensation plan for Boards of Directors		(9,395)
Restricted Stock, Shares Issued Net of Shares for Tax Withholdings		6,127
Common Shares
Increase (Decrease) in Stock by Class [Roll Forward]
Common stock, beginning of period		21,156,143
Changes related to stock-based compensation awards:
Cancellation of restricted common shares		0
Changes related to deferred compensation plan for Boards of Directors:
Common shares issued under dividend reinvestment plan		28,014
Common stock, end of period		21,184,157
Treasury Stock
Increase (Decrease) in Stock by Class [Roll Forward]
Treasury stock, beginning of period		504,182
Changes related to stock-based compensation awards:
Release of restricted common shares		27,391
Cancellation of restricted common shares		13,445
Grant of common shares		(101,202)
Changes related to deferred compensation plan for Boards of Directors:
Purchase of treasury stock		8,632
Disbursed out of treasury stock		(2,362)
Stock Repurchased During Period, Shares	6,300,000	1,119,752
Common shares issued under compensation plan for Boards of Directors		(9,615)
Common shares issued under employee stock purchase plan		14,990
Treasury stock, end of period		1,515,624
Restricted Shares | Treasury Stock
Changes related to stock-based compensation awards:
Grant of common shares		(23,482)