Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities
Net income	$ 53,291	$ 44,478	$ 42,160
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization of property and equipment	28,542	26,686	23,228
Amortization of other intangible assets	1,713	822	141
Loss on asset disposals and impairments of property and equipment	2,123	3,011	2,088
Loss due to retirement plan settlements		1,222	1,803
Loss on impairment of investment	3,477
Deferred income taxes	(1,707)	6,147	(1,690)
Reduced tax benefits on share-based awards			(1,822)
Equity in net income of affiliate	(7,255)	(7,092)	(7,637)
Distributions from affiliate	7,250	7,425	9,000
Bad debt expense	2,234	1,375	2,723
Non-cash share-based compensation	8,020	6,478	10,031
Changes in operating assets and liabilities
Trade accounts receivable	(4,884)	(8,576)	(5,293)
Prepaid expenses and other assets	4,211	70	2,020
Accounts payable	1,340	(1,959)	(3,157)
Accrued expense and other current liabilities	2,817	(1,465)	312
Deferred revenue	601	(6,669)	(14,156)
Other noncurrent liabilities	2,825	(143)	(2,427)
Net cash provided by operating activities	104,598	71,810	57,324
Cash flows from investing activities
Additions to property and equipment	(31,967)	(30,425)	(31,681)
License of other intangible assets		(4,500)
Purchases of equity and other investments		(1,780)	(3,400)
Payments for business acquisitions, net of cash acquired	(10,553)	(2,500)
Net cash used in investing activities	(42,520)	(39,205)	(35,081)
Cash flows from financing activities
Proceeds from stock option exercises and stock purchase plan	3,775	7,560	988
Tax benefits realized from share-based awards	927	26
Payments for deferred financing costs	(998)
Dividends paid to stockholders	(10,849)	(10,667)	(10,584)
Change in bank overdraft payables		(3,833)	3,833
Debt borrowings	15,000	10,000	33,000
Debt repayments	(69,103)	(25,000)	(50,000)
Net cash used in financing activities	(61,248)	(21,914)	(22,763)
Effect of exchange rate changes on cash and cash equivalents	(40)	17	79
Net increase (decrease) in cash and cash equivalents	790	10,708	(441)
Cash and cash equivalents at beginning of year	18,925	8,217	8,658
Cash and cash equivalents at end of year	$ 19,715	$ 18,925	$ 8,217