Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016
Cash flows from operating activities:
Net income	$ 17,120	$ 24,467
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation of property and equipment	38,077	31,345
Amortization of intangible assets	6,327	6,892
Amortization of loan costs	3,075	2,946
Asset impairment	1,000	52
Deferred income tax expense	8,922	15,901
Non-cash stock option compensation	3,140	3,308
Non-cash inventory adjustments	4,695	1,228
Debt issuance costs	2,702	0
Other	388	529
Changes in operating assets and liabilities:
Accounts receivable, net	(4,741)	569
Inventories	(7,001)	(8,007)
Other assets	2,487	(1,223)
Accounts payable	(5,838)	(8,738)
Other liabilities	25,898	21,807
Net cash provided by operating activities	96,251	91,076
Cash flows from investing activities:
Purchase of property and equipment	(67,135)	(66,771)
Purchase of investments	(1,500)	(1,000)
Other	(113)	(734)
Net cash used for investing activities	(68,748)	(68,505)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	173,712	0
Proceeds from issuance of common stock	1,004	0
Principal payments on long-term debt	(6,236)	(4,886)
Proceeds from exercise of stock options	1,088	884
Payments on capital lease obligations	(710)	(426)
Debt issuance costs	(2,702)	0
Dividend to stockholders	(170,983)	0
Net cash used for financing activities	(4,827)	(4,428)
Net change in cash and cash equivalents	22,676	18,143
Cash and cash equivalents, beginning of year	4,945	5,595
Cash and cash equivalents, end of period	27,621	23,738
Non-cash financing activities:
Deferred offering costs accrued at the end of period	$ 2,694	$ 0