Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net income	$ 20,035	$ 21,303
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,363	13,170
Amortization of contract acquisition costs	281	358
Amortization of debt issuance costs	178	170
Imputed interest expense and fair value adjustments to contingent consideration	209	200
Provision for doubtful accounts	53	113
Gain on disposal of assets	(35)	0
Deferred income taxes	(1,479)	990
Excess tax benefit from equity-based awards	(409)	(788)
Equity-based compensation expense	2,690	3,160
Gain on foreign currency derivatives	87	(634)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(24,821)	(8,092)
Prepaids and other assets	1,849	1,618
Accounts payable and accrued expenses	(7,583)	(10,817)
Deferred revenue and other liabilities	(2,598)	(7,214)
Net cash provided by operating activities	3,820	13,537
Cash flows from investing activities
Proceeds from sale of long lived assets	0	135
Purchases of property, plant and equipment, net of acquisitions	(13,038)	(15,095)
Investment in securities	(9,000)	0
Acquisitions, net of cash acquired of zero and $812, respectively	(102)	(8,160)
Net cash used in investing activities	(22,140)	(23,120)
Cash flows from financing activities
Proceeds from line of credit	573,800	632,900
Payments on line of credit	(547,800)	(632,900)
Payments on other debt	(778)	(1,525)
Payments of contingent consideration related to acquisitions	(1,000)	(2,189)
Dividends to shareholders	8,710	0
Dividends distributed to noncontrolling interest	(990)	(990)
Proceeds from exercise of stock options	234	12
Excess tax benefit from equity-based awards	409	788
Purchase of treasury stock	(5,915)	(20,466)
Net cash used in financing activities	9,250	(24,370)
Effect of exchange rate changes on cash and cash equivalents	(2,532)	(3,687)
(Decrease) increase in cash and cash equivalents	(11,602)	(37,640)
Cash and cash equivalents, beginning of period	77,316	158,017
Cash and cash equivalents, end of period	65,714	120,377
Supplemental disclosures
Cash paid for interest	1,340	982
Cash paid for income taxes	2,803	2,834
Non-cash investing and financing activities
Acquisition of equipment through increase in accounts payable	1,704	941
Contract acquisition costs credited to accounts receivable	$ 0	$ 1,000