CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net Income		$ 68,069	$ 53,577
Other Comprehensive Income, Net of Tax:
Unrealized Gain on Available-for-Sale Securities	[1]	49	88
Unrealized Gain on Derivatives - Other	[1]	51	8
Other Comprehensive Loss of Affiliated Companies	[1]	0	(95)
Other Comprehensive Income - Net of Tax	[1]	100	1
Comprehensive Income		$ 68,169	$ 53,578

[1] Determined using a combined average statutory tax rate of 40%.