Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 51,254	$ 148,969
Cumulative effect adjustment of new accounting standards	0	(1,541)
Other Comprehensive Income (Loss):
Net unrealized gain on derivatives	0	1,379
Reclassification adjustment of derivatives and designated hedges into net income	219	3,633
Retirement liability adjustment	288	271
Total	69	(1,983)
Comprehensive Income	51,323	145,445
Comprehensive Income Attributable to Noncontrolling Interests	(1,588)	(2,145)
Comprehensive Income Adjusted for Noncontrolling Interests	$ 49,735	$ 143,300