Recent Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income tax benefit	$ (7,514)	$ (7,138)
Increase to prior year retained earnings	4,141
Increase in deferred income taxes	117,425		$ 108,025
Decrease to other receivables	66,117		$ 67,137
Accounting Standards Update 2017-07 [Member]
Reclassification of income from Selling, general and administrative expenses to Other income, expense, net		$ 500
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