QUARTERLY DATA (UNAUDITED) (Details) (USD $)	3 Months Ended								12 Months Ended			3 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Change in Tax Benefits	Jul. 30, 2012 Secured Senior Notes 2016 Senior Notes
Quarterly [Line Items]
Revenues	$ 879,430,000	$ 907,535,000	$ 860,528,000	$ 862,163,000	$ 558,962,000	$ 533,806,000	$ 523,118,000	$ 572,022,000	$ 3,509,656,000	$ 2,187,908,000	$ 1,984,136,000
Cost of revenues	645,164,000	647,119,000	614,326,000	636,024,000	399,743,000	372,940,000	367,623,000	400,315,000	2,542,633,000	1,540,621,000	1,379,991,000
Gross profit	234,266,000	260,416,000	246,202,000	226,139,000	159,219,000	160,866,000	155,495,000	171,707,000
Income from operations	58,877,000	73,608,000	53,243,000	34,828,000	36,231,000	56,739,000	47,533,000	61,701,000	220,556,000	202,204,000	217,665,000
Other income (expense)	(325,000)	(150,000)	1,655,000	525,000	(337,000)	(91,000)	(75,000)	(299,000)	1,705,000	(802,000)	6,402,000
Net income	26,801,000	35,361,000	22,902,000	10,502,000	61,874,000	12,359,000	23,426,000	32,015,000	95,566,000	129,674,000	127,252,000
Basic income per share (in dollars per share)	$ 0.44	$ 0.58	$ 0.38	$ 0.17	$ 1.11	$ 0.23	$ 0.44	$ 0.60	$ 1.58	$ 2.41	$ 2.40
Diluted income per share (in dollars per share)	$ 0.44	$ 0.58	$ 0.38	$ 0.17	$ 1.11	$ 0.23	$ 0.44	$ 0.60	$ 1.57	$ 2.40	$ 2.39
Loss on early extinguishment of debt									0	26,385,000	0
Long-term Debt, Gross													520,000,000
Unrecognized Tax Benefits, Period Increase (Decrease)												$ (52,400,000)