Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
ASSETS
Other current assets	$ 110,403	$ (992)	$ 108,220
Total current assets	697,646	(992)	654,172
Operating lease right-of-use assets	80,594	83,707	0
Total long-term assets	983,322	83,707	883,177
TOTAL ASSETS	1,680,968	82,715	1,537,349
LIABILITIES
Accrued liabilities	229,127	13,776	260,683
Total current liabilities	689,619	13,776	770,444
Long-term operating lease liabilities	68,955	68,939	0
Total long-term liabilities	939,479	68,939	776,138
TOTAL LIABILITIES	1,629,098	82,715	1,546,582
Lease obligation liabilities	82,887
Straight-line lease liabilities	82,564		84,826
Stranded tax effects	1,700
Accounting Standards Update 2016-02
ASSETS
Other current assets		107,228	1,000
Total current assets		653,180
Operating lease right-of-use assets	83,700	83,707
Total long-term assets		966,884
TOTAL ASSETS		1,620,064
LIABILITIES
Accrued liabilities		274,459
Total current liabilities		784,220
Long-term operating lease liabilities		68,939
Total long-term liabilities		845,077
TOTAL LIABILITIES		$ 1,629,297
Lease obligation liabilities	$ 86,700
Straight-line lease liabilities			$ 4,000