CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
OPERATING ACTIVITIES:
Net income	$ 17,230	$ 26,173
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	41,312	36,267
Deferred income tax	(1,138)	(642)
Amortization of debt issuance costs	784	1,236
Non-cash interest expense	0	4,168
Realized loss on sale of short-term investment	2,287	0
Loss on disposal of property and equipment	452	1,184
Change in fair value of contingent consideration and other	(1,995)	251
Share-based compensation	11,050	7,897
Changes in assets and liabilities, net of business acquisitions:
Accounts receivable	(11,303)	(13,525)
Inventories	(5,464)	(7,362)
Prepaid expenses and other current assets	(9,236)	4,362
Other non-current assets	(1,811)	(571)
Accounts payable, accrued expenses and other current liabilities	20,287	2,237
Deferred revenue	2,083	2,510
Other non-current liabilities	(6,785)	(1,076)
Net cash provided by operating activities	57,753	63,109
INVESTING ACTIVITIES:
Purchases of property and equipment	(22,010)	(19,162)
Proceeds from sale of property and equipment	143	0
Cash used in business acquisition, net of cash acquired	(225,744)	0
Cash received from business acquisition purchase price adjustment	0	224
Change in restricted cash	0	4,165
Proceeds from sale of short-term investments	16,951	0
Net cash used in investing activities	(230,660)	(14,773)
FINANCING ACTIVITIES:
Borrowings under senior credit facility	245,000	15,000
Repayments under senior credit facility	(30,000)	(28,750)
Net cash received for contingent consideration	87	0
Principal payments under capital lease obligations	0	(323)
Proceeds from exercised stock options	9,774	9,260
Cash taxes paid in net equity settlement	(6,498)	(4,269)
Net cash provided by (used in) financing activities	218,363	(9,082)
Effect of exchange rate changes on cash and cash equivalents	7,089	(583)
Net increase in cash and cash equivalents	52,545	38,671
Cash and cash equivalents at beginning of period	102,055	48,132
Cash and cash equivalents at end of period	$ 154,600	$ 86,803