Condensed Consolidating Financial Statements Condensed Consolidating Statement Of Cash Flows (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	$ 138,378,000	$ 106,489,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(11,886,000)	(27,922,000)
Proceeds from sales of assets	15,612,000	0
Equity method investments	(14,362,000)	(3,761,000)
Purchases of investments, employee benefit plans	(1,520,000)	(1,845,000)
Proceeds from sales of investments, employee benefit plans	966,000	4,052,000
Issuance of mezzanine and other notes receivable	(3,340,000)	0
Collections of mezzanine and other notes receivable	9,832,000	224,000
Other items, net	(592,000)	(578,000)
Net cash provided (used) in investing activities	(5,290,000)	(29,830,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility	0	(27,500,000)
Principal payments on long-term debt	(7,110,000)	(6,158,000)
Proceeds from the issuance of long-term debt	226,000	3,360,000
Purchases of treasury stock	(23,757,000)	(3,684,000)
Dividends paid	(32,767,000)	(22,026,000)
Excess tax benefits from stock-based compensation	2,297,000	1,216,000
Proceeds from exercise of stock options	4,984,000	6,677,000
Net cash provided (used) by financing activities	(56,127,000)	(48,115,000)
Net change in cash and cash equivalents	76,961,000	28,544,000
Effect of foreign exchange rate changes on cash and cash equivalents	(364,000)	(1,583,000)
Cash and cash equivalents at beginning of period	167,795,000	134,177,000
Cash and cash equivalents at end of period	244,392,000	161,138,000
Parent [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	111,851,000	60,070,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(5,138,000)	(4,083,000)
Proceeds from sales of assets	27,000
Equity method investments	0	0
Purchases of investments, employee benefit plans	0	0
Proceeds from sales of investments, employee benefit plans	0	0
Issuance of mezzanine and other notes receivable	(3,340,000)
Collections of mezzanine and other notes receivable	9,832,000	224,000
Advances to and investments in affiliates	(1,000,000)	(1,000,000)
Other items, net	(446,000)	(578,000)
Net cash provided (used) in investing activities	(65,000)	(5,437,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility		(27,500,000)
Principal payments on long-term debt	(6,563,000)	(5,625,000)
Proceeds from the issuance of long-term debt	0	0
Proceeds from contributions from affiliates	0	0
Purchases of treasury stock	(23,757,000)	(3,684,000)
Dividends paid	(32,767,000)	(22,026,000)
Excess tax benefits from stock-based compensation	289,000	26,000
Proceeds from exercise of stock options	4,984,000	6,677,000
Net cash provided (used) by financing activities	(57,814,000)	(52,132,000)
Net change in cash and cash equivalents	53,972,000	2,501,000
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	9,785,000	8,420,000
Cash and cash equivalents at end of period	63,757,000	10,921,000
Guarantor Subsidiaries [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	2,866,000	20,198,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(6,378,000)	(23,662,000)
Proceeds from sales of assets	15,585,000
Equity method investments	(8,800,000)	(1,481,000)
Purchases of investments, employee benefit plans	(1,520,000)	(1,845,000)
Proceeds from sales of investments, employee benefit plans	966,000	4,052,000
Issuance of mezzanine and other notes receivable	0
Collections of mezzanine and other notes receivable	0	0
Advances to and investments in affiliates	(4,740,000)	(1,280,000)
Other items, net	(146,000)	0
Net cash provided (used) in investing activities	(5,033,000)	(24,216,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility		0
Principal payments on long-term debt	(523,000)	(502,000)
Proceeds from the issuance of long-term debt	176,000	3,360,000
Proceeds from contributions from affiliates	0	0
Purchases of treasury stock	0	0
Dividends paid	0	0
Excess tax benefits from stock-based compensation	2,008,000	1,190,000
Proceeds from exercise of stock options	0	0
Net cash provided (used) by financing activities	1,661,000	4,048,000
Net change in cash and cash equivalents	(506,000)	30,000
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	569,000	407,000
Cash and cash equivalents at end of period	63,000	437,000
Non-Guarantor Subsidiaries [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	24,318,000	26,221,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(370,000)	(177,000)
Proceeds from sales of assets	0
Equity method investments	(5,562,000)	(2,280,000)
Purchases of investments, employee benefit plans	0	0
Proceeds from sales of investments, employee benefit plans	0	0
Issuance of mezzanine and other notes receivable	0
Collections of mezzanine and other notes receivable	0	0
Advances to and investments in affiliates	0	0
Other items, net	0	0
Net cash provided (used) in investing activities	(5,932,000)	(2,457,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility		0
Principal payments on long-term debt	(24,000)	(31,000)
Proceeds from the issuance of long-term debt	50,000	0
Proceeds from contributions from affiliates	5,740,000	2,280,000
Purchases of treasury stock	0	0
Dividends paid	(657,000)	0
Excess tax benefits from stock-based compensation	0	0
Proceeds from exercise of stock options	0	0
Net cash provided (used) by financing activities	5,109,000	2,249,000
Net change in cash and cash equivalents	23,495,000	26,013,000
Effect of foreign exchange rate changes on cash and cash equivalents	(364,000)	(1,583,000)
Cash and cash equivalents at beginning of period	157,441,000	125,350,000
Cash and cash equivalents at end of period	180,572,000	149,780,000
Eliminations [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	(657,000)	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	0	0
Proceeds from sales of assets	0
Equity method investments	0	0
Purchases of investments, employee benefit plans	0	0
Proceeds from sales of investments, employee benefit plans	0	0
Issuance of mezzanine and other notes receivable	0
Collections of mezzanine and other notes receivable	0	0
Advances to and investments in affiliates	5,740,000	2,280,000
Other items, net	0	0
Net cash provided (used) in investing activities	5,740,000	2,280,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility		0
Principal payments on long-term debt	0	0
Proceeds from the issuance of long-term debt	0	0
Proceeds from contributions from affiliates	(5,740,000)	(2,280,000)
Purchases of treasury stock	0	0
Dividends paid	657,000	0
Excess tax benefits from stock-based compensation	0	0
Proceeds from exercise of stock options	0	0
Net cash provided (used) by financing activities	(5,083,000)	(2,280,000)
Net change in cash and cash equivalents	0	0
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Consolidated [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	138,378,000	106,489,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(11,886,000)	(27,922,000)
Proceeds from sales of assets	15,612,000
Equity method investments	(14,362,000)	(3,761,000)
Purchases of investments, employee benefit plans	(1,520,000)	(1,845,000)
Proceeds from sales of investments, employee benefit plans	966,000	4,052,000
Issuance of mezzanine and other notes receivable	(3,340,000)
Collections of mezzanine and other notes receivable	9,832,000	224,000
Advances to and investments in affiliates	0	0
Other items, net	(592,000)	(578,000)
Net cash provided (used) in investing activities	(5,290,000)	(29,830,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net repayments pursuant to revolving credit facility		(27,500,000)
Principal payments on long-term debt	(7,110,000)	(6,158,000)
Proceeds from the issuance of long-term debt	226,000	3,360,000
Proceeds from contributions from affiliates	0	0
Purchases of treasury stock	(23,757,000)	(3,684,000)
Dividends paid	(32,767,000)	(22,026,000)
Excess tax benefits from stock-based compensation	2,297,000	1,216,000
Proceeds from exercise of stock options	4,984,000	6,677,000
Net cash provided (used) by financing activities	(56,127,000)	(48,115,000)
Net change in cash and cash equivalents	76,961,000	28,544,000
Effect of foreign exchange rate changes on cash and cash equivalents	(364,000)	(1,583,000)
Cash and cash equivalents at beginning of period	167,795,000	134,177,000
Cash and cash equivalents at end of period	$ 244,392,000	$ 161,138,000