Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income	$ 50,494	$ 52,785
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	33,281	31,040
Amortization of contract acquisition costs	753	763
Amortization of debt issuance costs	488	531
Imputed interest expense	933	600
Provision for doubtful accounts	412	490
(Gain) loss on disposal of assets	(94)	180
Impairment losses	1,205	2,958
Deferred income taxes	5,467	2,134
Excess tax benefit from equity-based awards	(1,074)	(1,005)
Equity-based compensation expense	9,842	10,310
Gain on foreign currency derivatives	(75)	(574)
Loss on deconsolidation of subsidiary, net of cash of $897 and zero, respectively	2,758	0
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	709	1,091
Prepaids and other assets	(11,241)	(30,893)
Accounts payable and accrued expenses	(14,020)	(15,696)
Deferred revenue and other liabilities	(3,225)	8,697
Net cash provided by operating activities	76,613	63,411
Cash flows from investing activities
Proceeds from grant for property, plant and equipment	0	110
Proceeds from sale of long-lived assets	0	450
Purchases of property, plant and equipment, net of acquisitions	(31,832)	(33,259)
Acquisitions, net of cash acquired of $6,423 and $1,373, respectively	(8,956)	(4,809)
Net cash used in investing activities	(40,788)	(37,508)
Cash flows from financing activities
Proceeds from line of credit	1,114,050	857,650
Payments on line of credit	(1,104,050)	(833,650)
Proceeds from other debt	3,709	8,014
Payments on other debt	(4,293)	(2,783)
Dividends distributed to noncontrolling interest	(3,420)	(1,440)
Proceeds from exercise of stock options	856	1,135
Excess tax benefit from equity-based awards	1,074	1,005
Purchase of treasury stock	(51,627)	(55,211)
Payments of debt issuance costs	(1,800)	(432)
Net cash used in financing activities	(45,501)	(25,712)
Effect of exchange rate changes on cash and cash equivalents	(9,906)	13,815
(Decrease) increase in cash and cash equivalents	(19,582)	14,006
Cash and cash equivalents, beginning of period	164,485	156,371
Cash and cash equivalents, end of period	144,903	170,377
Supplemental disclosures
Cash paid for interest	3,271	3,168
Cash paid for income taxes	12,329	13,213
Non-cash investing and financing activities
Purchases of equipment through financing arrangements	0	6,100
Acquisition of equipment through increase in accounts payable	3,803	396
Landlord incentives credited to deferred rent	1,016	1,723
Contract acquisition costs credited to accounts receivable	$ 1,000	$ 0