Stockholders' Equity Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 28, 2016	Jan. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	18,904	18,904	0
Treasury Stock, Value, Acquired, Cost Method	$ 75,569	$ 85	$ 64,512
2016 Share Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired	1,100,000
Treasury Stock, Value, Acquired, Cost Method	$ 75,600
Treasury Stock Acquired, Average Cost Per Share	$ 65.74
Stock Repurchase Program, Authorized Amount					$ 100,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased					5,000,000
Share Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 125,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased				3,000,000