Basis of Presentation (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Jan. 01, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net cash used in financing activities	$ (6,163)	$ (44,797)
Net cash provided by operations	$ 89,890	228,584
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net cash used in financing activities		600
Net cash provided by operations		$ 600
Accounting Standards Update 2016-09 [Member] | Retained Earnings [Member]
New Accounting Pronouncement Or Change In Accounting Principle Retrospective Adjustments [Abstract]
Net cumulative effect adjustment			$ 200
Accounting Standards Update 2016-09 [Member] | Additional Paid In Capital [Member]
New Accounting Pronouncement Or Change In Accounting Principle Retrospective Adjustments [Abstract]
Net cumulative effect adjustment			$ 200