Condensed Consolidating Statement Of Cash Flows (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	$ (15,835,000)	$ 5,264,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(6,804,000)	(3,015,000)
Proceeds from sales of assets	1,592,000	8,703,000
Equity method investments	(1,921,000)	(3,379,000)
Purchases of investments, employee benefit plans	(1,089,000)	(890,000)
Proceeds from sales of investments, employee benefit plans	925,000	281,000
Issuance of mezzanine and other notes receivable	0	(587,000)
Collections of mezzanine and other notes receivable	105,000	68,000
Other items, net	(77,000)	(154,000)
Net cash provided (used) by investing activities	(7,269,000)	1,027,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	20,700,000	15,000,000
Principal payments on long-term debt	(3,082,000)	(2,052,000)
Purchases of treasury stock	(6,227,000)	(4,530,000)
Dividends paid	(11,710,000)	(10,784,000)
Excess tax benefits from stock-based compensation	4,473,000	1,024,000
Proceeds from exercise of stock options	5,619,000	1,547,000
Net cash provided (used) by financing activities	9,773,000	205,000
Net change in cash and cash equivalents	(13,331,000)	6,496,000
Effect of foreign exchange rate changes on cash and cash equivalents	(1,004,000)	587,000
Cash and cash equivalents at beginning of period	214,879,000	167,795,000
Cash and cash equivalents at end of period	200,544,000	174,878,000
Parent [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	(20,715,000)	4,252,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(4,712,000)	(1,359,000)
Proceeds from sales of assets	0	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		(587,000)
Collections of mezzanine and other notes receivable	105,000	68,000
Advances to and investments in affiliates	0	(1,000,000)
Proceeds from Sale of Other Assets, Investing Activities	0
Other items, net	(77,000)	(154,000)
Net cash provided (used) by investing activities	(4,684,000)	(3,032,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	20,700,000	15,000,000
Principal payments on long-term debt	(2,813,000)	(1,875,000)
Proceeds from contributions from affiliates	0	0
Distributions to affiliates	0
Purchases of treasury stock	(6,227,000)	(4,530,000)
Dividends paid	(11,710,000)	(10,784,000)
Excess tax benefits from stock-based compensation	0	0
Proceeds from exercise of stock options	5,619,000	1,547,000
Net cash provided (used) by financing activities	5,569,000	(642,000)
Net change in cash and cash equivalents	(19,830,000)	578,000
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	25,290,000	9,785,000
Cash and cash equivalents at end of period	5,460,000	10,363,000
Guarantor Subsidiaries [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	(2,457,000)	(5,359,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(2,060,000)	(1,444,000)
Proceeds from sales of assets	0	8,703,000
Equity method investments	(1,177,000)	(98,000)
Purchases of investments, employee benefit plans	(1,089,000)	(890,000)
Proceeds from sales of investments, employee benefit plans	925,000	281,000
Issuance of mezzanine and other notes receivable		0
Collections of mezzanine and other notes receivable	0	0
Advances to and investments in affiliates	(35,000)	(2,314,000)
Proceeds from Sale of Other Assets, Investing Activities	1,592,000
Other items, net	0	0
Net cash provided (used) by investing activities	(1,844,000)	4,238,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	0	0
Principal payments on long-term debt	(177,000)	(174,000)
Proceeds from contributions from affiliates	0	0
Distributions to affiliates	0
Purchases of treasury stock	0	0
Dividends paid	0	0
Excess tax benefits from stock-based compensation	4,473,000	1,024,000
Proceeds from exercise of stock options	0	0
Net cash provided (used) by financing activities	4,296,000	850,000
Net change in cash and cash equivalents	(5,000)	(271,000)
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	25,000	569,000
Cash and cash equivalents at end of period	20,000	298,000
Non-Guarantor Subsidiaries [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	7,337,000	6,371,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(32,000)	(212,000)
Proceeds from sales of assets	1,592,000	0
Equity method investments	(744,000)	(3,281,000)
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
Proceeds from Sale of Other Assets, Investing Activities	0
Other items, net	0	0
Net cash provided (used) by investing activities	816,000	(3,493,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	0	0
Principal payments on long-term debt	(92,000)	(3,000)
Proceeds from contributions from affiliates	35,000	3,314,000
Distributions to affiliates	(1,592,000)
Purchases of treasury stock	0	0
Dividends paid	0	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	(1,649,000)	3,311,000
Net change in cash and cash equivalents	6,504,000	6,189,000
Effect of foreign exchange rate changes on cash and cash equivalents	(1,004,000)	587,000
Cash and cash equivalents at beginning of period	189,564,000	157,441,000
Cash and cash equivalents at end of period	195,064,000	164,217,000
Eliminations [Member]
Condensed Consolidating Financial Statements [Line Items]
Net cash provided (used) by operating activities	0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	0	0
Proceeds from sales of assets	0	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	35,000	3,314,000
Proceeds from Sale of Other Assets, Investing Activities	(1,592,000)
Other items, net	0	0
Net cash provided (used) by investing activities	(1,557,000)	3,314,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	0	0
Principal payments on long-term debt	0	0
Proceeds from contributions from affiliates	(35,000)	(3,314,000)
Distributions to affiliates	1,592,000
Purchases of treasury stock	0	0
Dividends paid	0	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	1,557,000	(3,314,000)
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	(15,835,000)	5,264,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Investment in property and equipment	(6,804,000)	(3,015,000)
Proceeds from sales of assets	1,592,000	8,703,000
Equity method investments	(1,921,000)	(3,379,000)
Purchases of investments, employee benefit plans	(1,089,000)	(890,000)
Proceeds from sales of investments, employee benefit plans	925,000	281,000
Issuance of mezzanine and other notes receivable		(587,000)
Collections of mezzanine and other notes receivable	105,000	68,000
Advances to and investments in affiliates	0	0
Proceeds from Sale of Other Assets, Investing Activities	0
Other items, net	(77,000)	(154,000)
Net cash provided (used) by investing activities	(7,269,000)	1,027,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Net borrowings pursuant to revolving credit facility	20,700,000	15,000,000
Principal payments on long-term debt	(3,082,000)	(2,052,000)
Proceeds from contributions from affiliates	0	0
Distributions to affiliates	0
Purchases of treasury stock	(6,227,000)	(4,530,000)
Dividends paid	(11,710,000)	(10,784,000)
Excess tax benefits from stock-based compensation	4,473,000	1,024,000
Proceeds from exercise of stock options	5,619,000	1,547,000
Net cash provided (used) by financing activities	9,773,000	205,000
Net change in cash and cash equivalents	(13,331,000)	6,496,000
Effect of foreign exchange rate changes on cash and cash equivalents	(1,004,000)	587,000
Cash and cash equivalents at beginning of period	214,879,000	167,795,000
Cash and cash equivalents at end of period	$ 200,544,000	$ 174,878,000