Stockholders' Equity (Share-Based Payments - Options and Stock Appreciation Rights Outstanding) (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Shares/Awards [Roll Forward]
Options Outstanding, Shares, Beginning Balance (in shares)	18,018
Options Outstanding, Shares, Exercised (in shares)	(18,018)
Options Outstanding, Shares, Forfeited (in shares)	0
Options Outstanding, Shares, Granted (in shares)	0
Options Outstanding, Shares, Expired (in shares)	0
Options Outstanding, Shares, Ending Balance (in shares)	0
Weighted-Average Exercise Price [Roll Forward]
Options Outstanding, Weighted-Average Exercise Price, Beginning Balance (usd per share) | $ / shares	$ 242.07
Options Outstanding, Weighted-Average Exercise Price, Exercised (usd per share) | $ / shares	242.07
Options Outstanding, Weighted-Average Exercise Price, Forfeited (usd per share) | $ / shares	0
Options Outstanding, Weighted-Average Exercise Price, Expired (usd per share) | $ / shares	0
Options Outstanding, Weighted-Average Exercise Price, Granted (usd per share) | $ / shares	0
Options Outstanding, Weighted-Average Exercise Price, Ending Balance (usd per share) | $ / shares	$ 0
Shares Available For Grant
Shares Available For Grant, Beginning Balance (in shares)	291,000
Shares Available For Grant, Exercised (in shares)	0
Shares Available For Grant, Forfeited (in shares)	0
Shares Available For Grant, Expired (in shares)	0
Shares Available For Grant, Granted (in shares)	0
Shares Available For Grant, Ending Balance (in shares)	291,000