Common Stock (Schedule of Stock Option Exercise Prices) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Amount Outstanding (in shares) | shares	507
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 21.37
Options Exercisable, Amount Exercisable (in shares) | shares	507
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 21.37
0.01-5.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	0.01
Range of exercise prices, maximum (in dollars per share)	$ 5.00
Options Outstanding, Amount Outstanding (in shares) | shares	100
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 2 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 3.38
Options Exercisable, Amount Exercisable (in shares) | shares	100
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 3.38
5.01-10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	5.01
Range of exercise prices, maximum (in dollars per share)	$ 10.00
Options Outstanding, Amount Outstanding (in shares) | shares	169
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 2 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.32
Options Exercisable, Amount Exercisable (in shares) | shares	169
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 8.32
10.01-15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	10.01
Range of exercise prices, maximum (in dollars per share)	$ 15.00
Options Outstanding, Amount Outstanding (in shares) | shares	12
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 1 month
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 14.50
Options Exercisable, Amount Exercisable (in shares) | shares	12
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.50
15.01-20.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	15.01
Range of exercise prices, maximum (in dollars per share)	$ 20.00
Options Outstanding, Amount Outstanding (in shares) | shares	12
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2 years 10 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.22
Options Exercisable, Amount Exercisable (in shares) | shares	12
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.22
25.01-30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	25.01
Range of exercise prices, maximum (in dollars per share)	$ 30.00
Options Outstanding, Amount Outstanding (in shares) | shares	27
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3 years 2 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 26.01
Options Exercisable, Amount Exercisable (in shares) | shares	27
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 26.01
30.01-35.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	30.01
Range of exercise prices, maximum (in dollars per share)	$ 35.00
Options Outstanding, Amount Outstanding (in shares) | shares	62
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	4 years 2 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 31.49
Options Exercisable, Amount Exercisable (in shares) | shares	62
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 31.49
40.01-45.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	40.01
Range of exercise prices, maximum (in dollars per share)	$ 45.00
Options Outstanding, Amount Outstanding (in shares) | shares	51
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	5 years 1 month
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 41.25
Options Exercisable, Amount Exercisable (in shares) | shares	51
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 41.25
50.01-55.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of exercise prices, minimum (in dollars per share)	50.01
Range of exercise prices, maximum (in dollars per share)	$ 55.00
Options Outstanding, Amount Outstanding (in shares) | shares	74
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	6 years 2 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 53.78
Options Exercisable, Amount Exercisable (in shares) | shares	74
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 53.78