CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
NET INCOME	$ 58,984	$ 51,183	$ 156,569	$ 139,620
OTHER COMPREHENSIVE INCOME (LOSS)
Derivative instruments, net of tax (Note 6)	110	(1,316)	24,468	(5,440)
Available-for-sale securities, net of tax (Note 6)	87	0	87	0
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAX	197	(1,316)	24,555	(5,440)
TOTAL COMPREHENSIVE INCOME	$ 59,181	$ 49,867	$ 181,124	$ 134,180