Goodwill and Other Intangible Assets (Goodwill And Other Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Finite-lived Intangible Assets [Roll Forward]
Other intangible assets, gross	$ 113,471		$ 113,471		$ 113,471	$ 113,471
Other intangible assets, accumulated amortization	(79,963)		(79,963)		(76,585)	(67,963)
Other intangible assets, amortization	(1,689)	$ (2,328)	(3,378)	$ (4,888)	(8,622)
Other intangible assets, net	$ 33,508		$ 33,508		$ 36,886	$ 45,508