Condensed Consolidating Financial Statements Condensed Consolidating Statement Of Cash Flows (Details) (USD $)	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Net cash provided (used) from operating activities	$ 105,893,000	$ 108,239,000
Investment in property and equipment	(8,129,000)	(17,673,000)
Equity method investments	(3,600,000)	0
Acquisitions, net of cash acquired	0	(466,000)
Issuance of notes receivable	(4,320,000)	(8,901,000)
Collections of notes receivable	15,000	5,055,000
Purchases of investments, employee benefit plans	(1,051,000)	(1,396,000)
Proceeds from sale of investments, employee benefit plans	566,000	1,018,000
Other items, net	(312,000)	(296,000)
Net cash used in investing activities	(16,831,000)	(22,659,000)
Net borrowings pursuant to revolving credit facilities	(200,000)	(271,100,000)
Proceeds from issuance of long-term debt	75,000	247,733,000
Repayments of long-term debt	(74,000)	(20,000)
Settlement of forward starting interest rate swap agreement	0	(8,663,000)
Purchase of treasury stock	(24,796,000)	(11,171,000)
Debt issuance costs	(2,356,000)	(804,000)
Excess tax benefits from stock-based compensation	1,108,000	331,000
Dividends paid	(32,923,000)	(32,884,000)
Proceeds from exercise of stock options	3,726,000	1,321,000
Net cash used in financing activities	(55,440,000)	(75,257,000)
Net change in cash and cash equivalents	33,622,000	10,323,000
Effect of foreign exchange rate changes on cash and cash equivalents	(147,000)	1,355,000
Cash and cash equivalents at beginning of period	91,259,000	67,870,000
Cash and cash equivalents at end of period	124,734,000	79,548,000
Parent [Member]
Net cash provided (used) from operating activities	96,333,000	79,156,000
Investment in property and equipment	(2,460,000)	(1,409,000)
Equity method investments	0
Acquisitions, net of cash acquired		0
Issuance of notes receivable	(1,404,000)	(7,906,000)
Collections of notes receivable	0	5,000,000
Purchases of investments, employee benefit plans	0
Proceeds from sale of investments, employee benefit plans	0	0
Other items, net	(289,000)	(351,000)
Net cash used in investing activities	(4,153,000)	(4,666,000)
Net borrowings pursuant to revolving credit facilities	(200,000)	(271,100,000)
Proceeds from issuance of long-term debt	0	247,733,000
Repayments of long-term debt	0	0
Settlement of forward starting interest rate swap agreement		(8,663,000)
Purchase of treasury stock	(24,796,000)	(11,171,000)
Debt issuance costs	(2,356,000)
Excess tax benefits from stock-based compensation	38,000
Dividends paid	(32,923,000)	(32,884,000)
Proceeds from exercise of stock options	3,726,000	512,000
Net cash used in financing activities	(56,511,000)	(75,573,000)
Net change in cash and cash equivalents	35,669,000	(1,083,000)
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	4,849,000	4,281,000
Cash and cash equivalents at end of period	40,518,000	3,198,000
Guarantor Subsidiaries [Member]
Net cash provided (used) from operating activities	(10,502,000)	17,001,000
Investment in property and equipment	(5,395,000)	(15,993,000)
Equity method investments	0
Acquisitions, net of cash acquired		0
Issuance of notes receivable	(2,916,000)	(995,000)
Collections of notes receivable	15,000	55,000
Purchases of investments, employee benefit plans	(1,051,000)	(1,396,000)
Proceeds from sale of investments, employee benefit plans	566,000	1,018,000
Other items, net	(5,000)	23,000
Net cash used in investing activities	(8,786,000)	(17,288,000)
Net borrowings pursuant to revolving credit facilities	0	0
Proceeds from issuance of long-term debt	0	0
Repayments of long-term debt	(55,000)	0
Settlement of forward starting interest rate swap agreement		0
Purchase of treasury stock	0	0
Debt issuance costs	0
Excess tax benefits from stock-based compensation	1,070,000
Dividends paid	0	0
Proceeds from exercise of stock options	0	336,000
Net cash used in financing activities	1,015,000	336,000
Net change in cash and cash equivalents	(18,273,000)	49,000
Effect of foreign exchange rate changes on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	18,659,000	303,000
Cash and cash equivalents at end of period	386,000	352,000
Non-Guarantor Subsidiaries [Member]
Net cash provided (used) from operating activities	20,062,000	12,082,000
Investment in property and equipment	(274,000)	(271,000)
Equity method investments	(3,600,000)
Acquisitions, net of cash acquired		(466,000)
Issuance of notes receivable	0	0
Collections of notes receivable	0	0
Purchases of investments, employee benefit plans	0	0
Proceeds from sale of investments, employee benefit plans	0	0
Other items, net	(18,000)	32,000
Net cash used in investing activities	(3,892,000)	(705,000)
Net borrowings pursuant to revolving credit facilities	0	0
Proceeds from issuance of long-term debt	75,000	0
Repayments of long-term debt	(19,000)	(20,000)
Settlement of forward starting interest rate swap agreement		0
Purchase of treasury stock	0	0
Debt issuance costs	0
Excess tax benefits from stock-based compensation	0
Dividends paid	0	0
Proceeds from exercise of stock options	0	0
Net cash used in financing activities	56,000	(20,000)
Net change in cash and cash equivalents	16,226,000	11,357,000
Effect of foreign exchange rate changes on cash and cash equivalents	(147,000)	1,355,000
Cash and cash equivalents at beginning of period	67,751,000	63,286,000
Cash and cash equivalents at end of period	83,830,000	75,998,000
Eliminations [Member]
Net cash provided (used) from operating activities	0	0
Investment in property and equipment	0	0
Equity method investments	0
Acquisitions, net of cash acquired		0
Issuance of notes receivable	0	0
Collections of notes receivable	0	0
Purchases of investments, employee benefit plans	0	0
Proceeds from sale of investments, employee benefit plans	0	0
Other items, net	0	0
Net cash used in investing activities	0	0
Net borrowings pursuant to revolving credit facilities	0	0
Proceeds from issuance of long-term debt	0	0
Repayments of long-term debt	0	0
Settlement of forward starting interest rate swap agreement		0
Purchase of treasury stock	0	0
Debt issuance costs	0
Excess tax benefits from stock-based compensation	0
Dividends paid	0	0
Proceeds from exercise of stock options	0	0
Net cash used in financing activities	0	0
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]
Net cash provided (used) from operating activities	105,893,000	108,239,000
Investment in property and equipment	(8,129,000)	(17,673,000)
Equity method investments	(3,600,000)
Acquisitions, net of cash acquired		(466,000)
Issuance of notes receivable	(4,320,000)	(8,901,000)
Collections of notes receivable	15,000	5,055,000
Purchases of investments, employee benefit plans	(1,051,000)	(1,396,000)
Proceeds from sale of investments, employee benefit plans	566,000	1,018,000
Other items, net	(312,000)	(296,000)
Net cash used in investing activities	(16,831,000)	(22,659,000)
Net borrowings pursuant to revolving credit facilities	(200,000)	(271,100,000)
Proceeds from issuance of long-term debt	75,000	247,733,000
Repayments of long-term debt	(74,000)	(20,000)
Settlement of forward starting interest rate swap agreement		(8,663,000)
Purchase of treasury stock	(24,796,000)	(11,171,000)
Debt issuance costs	(2,356,000)
Excess tax benefits from stock-based compensation	1,108,000
Dividends paid	(32,923,000)	(32,884,000)
Proceeds from exercise of stock options	3,726,000	848,000
Net cash used in financing activities	(55,440,000)	(75,257,000)
Net change in cash and cash equivalents	33,622,000	10,323,000
Effect of foreign exchange rate changes on cash and cash equivalents	(147,000)	1,355,000
Cash and cash equivalents at beginning of period	91,259,000	67,870,000
Cash and cash equivalents at end of period	$ 124,734,000	$ 79,548,000