Share-Based Payments (Nonvested restricted stock activity) (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Dec. 31, 2019 $ / shares shares
RSUs
Nonvested, Beginning Balance (in shares) | shares	1,975,659
Granted (in shares) | shares	363,447
Vested (in shares) | shares	(829,067)
Reinvested dividend equivalents (in shares) | shares	9,091
Forfeited (in shares) | shares	(58,595)
Nonvested, Ending Balance (in shares) | shares	1,460,535
Weighted Average Grant Date Fair Value Per Share
Nonvested, Beginning Balance (in dollars per share) | $ / shares	$ 62.28
Granted (in dollars per share) | $ / shares	88.09
Vested (in dollars per share) | $ / shares	54.11
Reinvested dividend equivalents (in dollars per share) | $ / shares	63.98
Forfeited (in dollars per share) | $ / shares	72.73
Nonvested, Ending Balance (in dollars per share) | $ / shares	$ 72.93