Condensed Consolidating Financial Statements of Guarantors of Senior Notes and Senior Convertible Notes Condensed Consolidating Statements of Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended																12 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
Condensed Income Statements, Captions [Line Items]
Revenues	$ 668,574		$ 609,951		$ 625,505		$ 652,352		$ 629,421		$ 581,182		$ 597,372		$ 602,506		$ 2,556,382	$ 2,410,481	$ 2,316,040
Costs and expenses	520,755		493,896		499,467		492,695		481,610		460,429		469,741		475,488		2,006,813	1,887,268	1,839,538
Gross profits	147,819		116,055		126,038		159,657		147,811		120,753		127,631		127,018		549,569	523,213	476,502
General and administrative expenses																	155,136	121,891	101,826
Losses on divestitures and impairment charges, net																	6,263	1,533	10,977
Operating income	87,995		83,296		89,114		127,765		103,806		95,176		99,689		101,118		388,170	399,789	363,699
Interest expense																	142,360	135,068	133,782
Gains (losses) on early extinguishment of debt, net																	468	(22,706)	(3,509)
Equity in subsidiaries																	0	0	0
Other (expense) income, net																	(559)	3,668	(772)
Income from continuing operations before income taxes	49,682	[1]	45,882	[1]	56,143	[1]	94,012	[1]	46,749	[1]	63,925	[1]	63,574	[1]	71,435	[1]	245,719	245,683	225,636
Benefit (provision) for income taxes	(21,130)		(18,488)		(21,708)		(35,290)		(20,365)		(22,128)		(25,935)		(23,120)		96,615	91,548	79,404
Net income	28,552		27,394		34,435		58,722		26,384		41,797		37,639		48,315		149,104	154,135	146,232
Net income attributable to noncontrolling interests	2,719		615		820		1,102		1		735		563		290		5,256	1,589	1,329
Net income attributable to common stockholders	25,833		26,779		33,615		57,620		26,383		41,062		37,076		48,025		143,848	152,546	144,903
Parent
Condensed Income Statements, Captions [Line Items]
Revenues																	0	0	0
Costs and expenses																	0	0	0
Gross profits																	0	0	0
General and administrative expenses																	30,492	2,062	1,940
Losses on divestitures and impairment charges, net																	0	0	0
Operating income																	(30,492)	(2,062)	(1,940)
Interest expense																	135,362	128,950	128,315
Gains (losses) on early extinguishment of debt, net																	0	(22,706)	(3,509)
Equity in subsidiaries																	248,784	249,803	229,536
Other (expense) income, net																	0	0	0
Income from continuing operations before income taxes																	82,930	96,085	95,772
Benefit (provision) for income taxes																	(60,918)	(56,461)	(49,131)
Net income																	143,848	152,546	144,903
Net income attributable to noncontrolling interests																	0	0	0
Net income attributable to common stockholders																	143,848	152,546	144,903
Subsidiary Issuer
Condensed Income Statements, Captions [Line Items]
Revenues																	0
Costs and expenses																	0
Gross profits																	0
General and administrative expenses																	451
Losses on divestitures and impairment charges, net																	0
Operating income																	(451)
Interest expense																	472
Gains (losses) on early extinguishment of debt, net																	0
Equity in subsidiaries																	1,068
Other (expense) income, net																	0
Income from continuing operations before income taxes																	145
Benefit (provision) for income taxes																	(360)
Net income																	505
Net income attributable to noncontrolling interests																	0
Net income attributable to common stockholders																	505
Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues																	11,349
Costs and expenses																	9,648
Gross profits																	1,701
General and administrative expenses																	0
Losses on divestitures and impairment charges, net																	0
Operating income																	1,701
Interest expense																	0
Gains (losses) on early extinguishment of debt, net																	0
Equity in subsidiaries																	0
Other (expense) income, net																	(20)
Income from continuing operations before income taxes																	1,681
Benefit (provision) for income taxes																	656
Net income																	1,025
Net income attributable to noncontrolling interests																	0
Net income attributable to common stockholders																	1,025
Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues																	2,545,033	2,410,481	2,316,040
Costs and expenses																	1,997,165	1,887,268	1,839,538
Gross profits																	547,868	523,213	476,502
General and administrative expenses																	124,193	119,829	99,886
Losses on divestitures and impairment charges, net																	6,263	1,533	10,977
Operating income																	417,412	401,851	365,639
Interest expense																	6,526	6,118	5,467
Gains (losses) on early extinguishment of debt, net																	468	0	0
Equity in subsidiaries																	0	0	0
Other (expense) income, net																	(539)	3,668	(772)
Income from continuing operations before income taxes																	410,815	399,401	359,400
Benefit (provision) for income taxes																	157,237	148,009	128,535
Net income																	253,578	251,392	230,865
Net income attributable to noncontrolling interests																	0	0	0
Net income attributable to common stockholders																	253,578	251,392	230,865
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues																	0	0	0
Costs and expenses																	0	0	0
Gross profits																	0	0	0
General and administrative expenses																	0	0	0
Losses on divestitures and impairment charges, net																	0	0	0
Operating income																	0	0	0
Interest expense																	0	0	0
Gains (losses) on early extinguishment of debt, net																	0	0	0
Equity in subsidiaries																	(249,852)	(249,803)	(229,536)
Other (expense) income, net																	0	0	0
Income from continuing operations before income taxes																	(249,852)	(249,803)	(229,536)
Benefit (provision) for income taxes																	0	0	0
Net income																	(249,852)	(249,803)	(229,536)
Net income attributable to noncontrolling interests																	5,256	1,589	1,329
Net income attributable to common stockholders																	$ (255,108)	$ (251,392)	$ (230,865)

[1] Includes (Losses) gains on divestitures and impairment charges, net, as described in Note 20.