Share-Based Payments (Performance Share Awards (PSAs) Activity) (Details) - PSUs	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Issued | shares	360,546
RSUs
Nonvested, Beginning Balance (in shares) | shares	390,841
Granted (in shares) | shares	190,170
Vested (in shares) | shares	(159,216)
Reinvested dividend equivalents (in shares) | shares	3,029
Forfeited (in shares) | shares	(5,428)
Nonvested, Ending Balance (in shares) | shares	419,396
Weighted Average Grant Date Fair Value Per Share
Nonvested, Beginning Balance (in dollars per share) | $ / shares	$ 71.93
Granted (in dollars per share) | $ / shares	101.51
Vested (in dollars per share) | $ / shares	50.78
Reinvested dividend equivalents (in dollars per share) | $ / shares	83.04
Forfeited (in dollars per share) | $ / shares	92.32
Nonvested, Ending Balance (in dollars per share) | $ / shares	93.19
Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased | $ / shares	$ 50.27