Recent Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017
Increase to prior year retained earnings			$ 4,141
Increase in deferred income taxes			109,404	$ 108,025
Decrease to other receivables			66,519	$ 67,137
Accounting Standards Update 2017-07 [Member]
Reclassification of income from Selling, general and administrative expenses to Other income, expense, net	$ 500	$ 1,000
Accounting Standards Update 2016-16 [Member]
Increase to prior year retained earnings			4,100
Increase in deferred income taxes			4,700
Decrease to other receivables			$ 600