Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 22,956	$ 18,126
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	27,066	29,651
Amortization of intangibles	8,413	7,842
Amortization of deferred grants	(181)	(344)
Impairment losses	1,711	8,701
Unrealized foreign currency transaction (gains) losses, net	(603)	(370)
Stock-based compensation expense	4,090	3,750
Deferred income tax provision (benefit)	325	1,070
Unrealized (gains) losses and premiums on financial instruments, net	(304)	625
Amortization of deferred loan fees	140	134
Other	417	(90)
Changes in assets and liabilities, net of acquisitions:
Receivables, net	(1,214)	(8,370)
Prepaid expenses	(1,122)	(1,611)
Other current assets	(896)	(2,016)
Deferred charges and other assets	(3,196)	(2,186)
Accounts payable	(2,824)	(5,499)
Income taxes receivable / payable	(5,225)	(6,526)
Accrued employee compensation and benefits	6,489	(2,349)
Other accrued expenses and current liabilities	1,228	5,079
Deferred revenue and customer liabilities	(2,435)	(155)
Other long-term liabilities	1,086	1,922
Operating lease assets and liabilities	415
Net cash provided by operating activities	56,336	47,384
Cash flows from investing activities:
Capital expenditures	(16,390)	(26,232)
Purchase of intangible assets		(7,606)
Other	284	484
Net cash (used for) investing activities	(16,106)	(33,354)
Cash flows from financing activities:
Payments of long-term debt	(18,000)	(190,000)
Proceeds from issuance of long-term debt	8,000	5,000
Cash paid for repurchase of common stock	(20,178)
Shares repurchased for tax withholding on equity awards	(1,269)	(3,682)
Cash paid for loan fees related to long-term debt	(1,098)
Other	(4)	38
Net cash (used for) financing activities	(32,549)	(188,644)
Effects of exchange rates on cash, cash equivalents and restricted cash	655	(6,748)
Net increase (decrease) in cash, cash equivalents and restricted cash	8,336	(181,362)
Cash, cash equivalents and restricted cash – beginning	130,231	344,805
Cash, cash equivalents and restricted cash – ending	138,567	163,443
Supplemental disclosures of cash flow information:
Cash paid during period for interest	1,874	1,975
Cash paid during period for income taxes	12,567	12,084
Non-cash transactions:
Property and equipment additions in accounts payable	2,663	2,637
Unrealized gain (loss) on postretirement obligation, net of taxes, in accumulated other comprehensive income (loss)	$ (10)	$ (20)