Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 30, 2018
Current assets:
Cash and cash equivalents	$ 24,597	$ 48,651
Restricted cash	4,054	4,119
Accounts receivable, net of allowance for doubtful accounts of $8,259 and $8,042 at March 31, 2019 and December 30, 2018, respectively	153,222	174,274
Inventory	24,972	25,022
Prepaid expenses	30,155	23,935
Other current assets	21,149	21,608
Total current assets	258,149	297,609
Property, plant, and equipment, net of accumulated depreciation of $229,268 and $219,256 at March 31, 2019 and December 30, 2018, respectively	347,766	339,608
Operating lease right-of-use assets	102,583	0
Goodwill	316,208	310,737
Intangible assets, net of accumulated amortization of $110,877 and $101,543 at March 31, 2019 and December 30, 2018, respectively	485,026	486,054
Other assets	10,936	9,856
Total assets	1,520,668	1,443,864
Current liabilities:
Current portion of long-term debt	11,296	12,395
Current portion of operating lease liabilities	13,415	0
Accounts payable	28,219	16,612
Accrued expenses	90,290	113,650
Deferred revenue	116,521	105,187
Total current liabilities	259,741	247,844
Long-term liabilities:
Long-term debt	435,426	428,180
Long-term operating lease liabilities	96,248	0
Deferred income taxes	7,665	8,282
Pension and other postretirement benefit obligations	24,094	24,326
Other long-term liabilities	10,498	16,462
Total liabilities	833,672	725,094
Redeemable noncontrolling interests	1,298	1,547
Stockholders’ equity:
Common stock, $0.01 par value, 2,000,000,000 shares authorized; 60,806,451 shares issued and 60,529,861 shares outstanding at March 31, 2019; 60,508,249 shares issued and 60,306,286 shares outstanding at December 30, 2018	608	605
Additional paid-in capital	699,787	721,605
Accumulated other comprehensive loss	(6,911)	(6,881)
(Accumulated deficit) retained earnings	(5,224)	3,767
Treasury stock, at cost, 276,590 and 201,963 shares at March 31, 2019 and December 30, 2018, respectively	(2,562)	(1,873)
Total stockholders’ equity	685,698	717,223
Total liabilities, redeemable noncontrolling interests and stockholders’ equity	$ 1,520,668	$ 1,443,864