Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities
Net income	$ 18,603	$ 16,817
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,555	10,116
Amortization of contract acquisition costs	255	256
Amortization of debt issuance costs	175	153
Imputed interest expense	346	64
Provision for doubtful accounts	76	40
Loss (gain) on disposal of assets	(107)	110
Impairment losses	0	1,800
Deferred income taxes	3,975	(1,222)
Excess tax benefit from equity-based awards	(800)	(462)
Equity-based compensation expense	3,191	3,388
(Gain) loss on foreign currency derivatives	(433)	(299)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	5,012	3,031
Prepaids and other assets	(7,630)	(7,826)
Accounts payable and accrued expenses	(19,399)	(15,526)
Deferred revenue and other liabilities	(7,325)	4,224
Net cash provided by operating activities	6,494	14,664
Cash flows from investing activities
Proceeds from grant for property, plant and equipment	0	110
Purchases of property, plant and equipment, net of acquisitions	(4,105)	(6,484)
Acquisitions, net of cash acquired of $0 and $1,373, respectively	0	(4,627)
Net cash used in investing activities	(4,105)	(11,001)
Cash flows from financing activities
Proceeds from line of credit	366,950	248,550
Payments on line of credit	(359,950)	(227,550)
Proceeds from other debt	3,709	6,821
Payments on other debt	(1,338)	(655)
Dividends distributed to noncontrolling interest	(1,109)	(720)
Proceeds from exercise of stock options	539	342
Excess tax benefit from equity-based awards	800	462
Purchase of treasury stock	(9,850)	(22,656)
Payments of debt issuance costs	0	(419)
Net cash provided by (used in) financing activities	(249)	4,175
Effect of exchange rate changes on cash and cash equivalents	3,926	8,552
Increase in cash and cash equivalents	6,066	16,390
Cash and cash equivalents, beginning of period	164,485	156,371
Cash and cash equivalents, end of period	170,551	172,761
Supplemental disclosures
Cash paid for interest	1,048	873
Cash paid for income taxes	1,751	1,887
Non-cash investing and financing activities
Landlord incentives credited to deferred rent	$ 0	$ 604