CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 37,657		$ 35,513
Other Comprehensive Gain (Loss) - Net of Tax:
Unrealized Gain (Loss) on Available-for-Sale Securities	62	[1]	(274)	[1]
Unrealized Gain on Derivatives - Other	8	[1]	7	[1]
Other Comprehensive Gain (Loss) - Net of Tax	70	[1]	(267)	[1]
Comprehensive Income	$ 37,727		$ 35,246

[1] Determined using a combined statutory tax rate of 41% .