Long-Term Debt (Subordinated Convertible Notes and Terms) (Details) - Subordinated Convertible Notes Due 2029 [Member]	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Debt Instrument [Line Items]
Debt instrument, beginning date	Aug. 31, 2029
Conversion price per share | $ / shares	$ 36.75
Conversion, shares per $1,000 principal amount of notes	27.2109
Principal amount of notes | $	$ 1,000
Common stock covered under note hedges	11,686,075
Make-Whole [Member]
Debt Instrument [Line Items]
Common stock covered under note hedges	14,315,419
Any Calendar Quarted after March 31, 2010 [Member]
Debt Instrument [Line Items]
Closing price as percent	130.00%
Consecutive trading days	30 days
Contingent, conversion price | $ / shares	$ 47.78
Any Calendar Quarted after March 31, 2010 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Trading days	20 days
On or After November 15, 2019 [Member]
Debt Instrument [Line Items]
Closing price as percent	150.00%
Consecutive trading days	30 days
On or After November 15, 2019 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Trading days	20 days
During Any Five Business Days [Member]
Debt Instrument [Line Items]
Closing price as percent	98.00%
During Any Five Business Days [Member] | Minimum [Member]
Debt Instrument [Line Items]
Trading days	5 days