Stock-Based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares outstanding, beginning balance (in shares)	15,081
Shares exercised (in shares)	(14,231)
Shares expired (in shares)	(350)
Shares forfeited (in shares)	(500)
Shares outstanding, ending balance (in shares)	0
Shares exercisable (in shares)	0
Weighted average exercise price outstanding, beginning balance (in dollar per share) | $ / shares	$ 27.70
Weighted average exercise price exercised (in dollars per share) | $ / shares	27.70
Weighted average exercise price expired (in dollars per share) | $ / shares	27.70
Weighted average exercise price forfeited (in dollars per share) | $ / shares	27.70
Weighted average exercise price outstanding, ending balance (in dollars per share) | $ / shares	$ 0.00
Aggregate intrinsic value outstanding, beginning balance | $	$ 0
Aggregate intrinsic value exercised | $	134
Aggregate intrinsic value outstanding, ending balance | $	0
Aggregate intrinsic value exercisable | $	$ 0