Condensed Consolidating Financial Statements of Guarantors of Senior Notes and Senior Convertible Notes Condensed Consolidating Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	$ 384,709	$ 369,246	$ 388,112
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	113,084	115,628	118,375
Acquisitions, net of cash acquired	1,057,122	65,463	99,570
Proceeds from divestitures and sales of property and equipment	13,072	9,953	24,529
Other	(341)	3,816	(3,159)
Distributions from subsidiaries	0	0	0
Net Cash Provided by (Used in) Investing Activities	(1,156,793)	(174,954)	(190,257)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	1,055,000	227,507	85,000
Debt issuance costs	36,064	4,500	0
Payments of debt	91,836	1,145	22,774
Early extinguishment of debt	80	202,140	43,194
Principal payments on capital leases	26,280	25,760	23,030
Proceeds from exercise of stock options	6,309	18,389	8,227
Purchase of Company common stock	1,708	186,766	197,302
Payments of dividends	57,229	60,296	44,795
Purchase of noncontrolling interest	23,333	3,000	0
Other	336	6,199	(798)
Distributions to parent	0	0	0
Net Cash Provided by (Used in) Financing Activities	825,115	(231,512)	(238,666)
Effect of foreign currency	(866)	1,359	(1,466)
Net increase (decrease) in cash and cash equivalents	52,165	(35,861)	(42,277)
Cash and cash equivalents at beginning of period	92,708	128,569	170,846
Cash and cash equivalents at end of period	144,873	92,708	128,569
Parent
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	(147,355)	(126,547)	(125,067)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	0	0	0
Acquisitions, net of cash acquired	1,165,350	0	0
Proceeds from divestitures and sales of property and equipment	0	0	0
Other	0	0	0
Distributions from subsidiaries	437,742	340,260	337,131
Net Cash Provided by (Used in) Investing Activities	(727,608)	340,260	337,131
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	1,055,000	221,600	85,000
Debt issuance costs	36,064	4,500	0
Payments of debt	91,265	0	20,000
Early extinguishment of debt	80	202,140	43,194
Principal payments on capital leases	0	0	0
Proceeds from exercise of stock options	6,309	18,389	8,227
Purchase of Company common stock	1,708	186,766	197,302
Payments of dividends	57,229	60,296	44,795
Purchase of noncontrolling interest
Other	0	0	0
Distributions to parent	0	0	0
Net Cash Provided by (Used in) Financing Activities	874,963	(213,713)	(212,064)
Effect of foreign currency	0		0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Subsidiary Issuer
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	(25,024)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	0
Acquisitions, net of cash acquired	114,875
Proceeds from divestitures and sales of property and equipment	0
Other	0
Distributions from subsidiaries	0
Net Cash Provided by (Used in) Investing Activities	114,875
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	0
Debt issuance costs	0
Payments of debt	0
Early extinguishment of debt	0
Principal payments on capital leases	0
Proceeds from exercise of stock options	0
Purchase of Company common stock	0
Payments of dividends	0
Purchase of noncontrolling interest
Other	0
Distributions to parent	(36,308)
Net Cash Provided by (Used in) Financing Activities	(36,308)
Effect of foreign currency	0
Net increase (decrease) in cash and cash equivalents	53,543
Cash and cash equivalents at beginning of period	0
Cash and cash equivalents at end of period	53,543
Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	1,737
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	0
Acquisitions, net of cash acquired	1,898
Proceeds from divestitures and sales of property and equipment	0
Other	0
Distributions from subsidiaries	0
Net Cash Provided by (Used in) Investing Activities	1,898
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	0
Debt issuance costs	0
Payments of debt	0
Early extinguishment of debt	0
Principal payments on capital leases	0
Proceeds from exercise of stock options	0
Purchase of Company common stock	0
Payments of dividends	0
Purchase of noncontrolling interest
Other	0
Distributions to parent	(1,737)
Net Cash Provided by (Used in) Financing Activities	(1,737)
Effect of foreign currency	0
Net increase (decrease) in cash and cash equivalents	1,898
Cash and cash equivalents at beginning of period	0
Cash and cash equivalents at end of period	1,898
Non-Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	555,351	495,793	513,179
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	113,084	115,628	118,375
Acquisitions, net of cash acquired	8,545	65,463	99,570
Proceeds from divestitures and sales of property and equipment	13,072	9,953	24,529
Other	(341)	3,816	(3,159)
Distributions from subsidiaries	0	0	0
Net Cash Provided by (Used in) Investing Activities	(108,216)	(174,954)	(190,257)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	0	5,907	0
Debt issuance costs	0	0	0
Payments of debt	571	1,145	2,774
Early extinguishment of debt	0	0	0
Principal payments on capital leases	26,280	25,760	23,030
Proceeds from exercise of stock options	0	0	0
Purchase of Company common stock	0	0	0
Payments of dividends	0	0	0
Purchase of noncontrolling interest	23,333	3,000
Other	336	6,199	(798)
Distributions to parent	(399,697)	(340,260)	(337,131)
Net Cash Provided by (Used in) Financing Activities	(449,545)	(358,059)	(363,733)
Effect of foreign currency	(866)	1,359	(1,466)
Net increase (decrease) in cash and cash equivalents	(3,276)	(35,861)	(42,277)
Cash and cash equivalents at beginning of period	92,708	128,569	170,846
Cash and cash equivalents at end of period	89,432	92,708	128,569
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	0	0	0
Net Cash Provided by (Used in) Investing Activities [Abstract]
Capital expenditures	0	0	0
Acquisitions, net of cash acquired	0	0	0
Proceeds from divestitures and sales of property and equipment	0	0	0
Other	0	0	0
Distributions from subsidiaries	(437,742)	(340,260)	(337,131)
Net Cash Provided by (Used in) Investing Activities	(437,742)	(340,260)	(337,131)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from issuance of long-term debt	0	0	0
Debt issuance costs	0	0	0
Payments of debt	0	0	0
Early extinguishment of debt	0	0	0
Principal payments on capital leases	0	0	0
Proceeds from exercise of stock options	0	0	0
Purchase of Company common stock	0	0	0
Payments of dividends	0	0	0
Purchase of noncontrolling interest
Other	0	0	0
Distributions to parent	437,742	340,260	337,131
Net Cash Provided by (Used in) Financing Activities	437,742	340,260	337,131
Effect of foreign currency	0		0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0