Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities
Net income	$ 23,343	$ 27,770
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization of property and equipment	12,242	14,137
Amortization of other intangible assets	1,224	1,220
Loss on asset disposals and impairments of property and equipment	956	733
Deferred income taxes	513	(1,687)
Equity in net income of affiliate	(3,108)	(3,035)
Distributions from affiliate	1,675	4,300
Bad debt expense	557	860
Non-cash share-based compensation	3,903	4,377
Changes in operating assets and liabilities
Trade accounts receivable	(3,308)	722
Prepaid expenses and other assets	(4,604)	(548)
Accounts payable	3,428	(1,319)
Accrued expenses and other current liabilities	(15,015)	(10,770)
Deferred revenue	12,499	15,227
Noncurrent liabilities	420	1,667
Net cash provided by operating activities	34,725	53,654
Cash flows from investing activities
Additions to property and equipment	(9,790)	(10,627)
Net cash used in investing activities	(9,790)	(10,627)
Cash flows from financing activities
Proceeds from stock option exercises and stock purchase plan	5,187	3,311
Stock repurchases		(50,025)
Dividends paid to stockholders	(2,676)	(5,454)
Excess tax benefits realized from share-based awards	1,261	554
Net cash provided by (used in) financing activities	3,772	(51,614)
Effect of exchange rate changes on cash and cash equivalents	(111)	(55)
Net change in cash and cash equivalents	28,596	(8,642)
Cash and cash equivalents at beginning of period	66,469	19,715
Cash and cash equivalents at end of period	$ 95,065	$ 11,073