Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

Interest Rate Swaps (Details) - USD ($) $ in Thousands				3 Months Ended		6 Months Ended		12 Months Ended
Interest Rate Swaps (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2016	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Derivative, Fair Value, Net	$ 8,404			$ 8,404	$ 3,049	$ 8,404	$ 3,049	$ 5,152
Accumulated Other Comprehensive Income (Loss), Net of Tax	5,742			5,742	1,521	5,742	1,521	3,358
Fair Value, Option, Changes in Fair Value, Gain (Loss)						2,384	129	1,371
Prior Period Reclassification Adjustment						0	0	595
Other Comprehensive Income (Loss), Net of Tax				552	(152)	2,384	129	1,966
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred	2,500
Derivative Instruments, Gain Recognized in Other Comprehensive Income (Loss), Effective Portion				737		3,205	211
Derivative Instruments, Loss Recognized in Other Comprehensive Income (Loss), Effective Portion					250
Derivative Instruments, Loss Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing				19	15	47	21
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax				185	(98)	821	82
Assets Needed for Immediate Settlement, Aggregate Fair Value	0			0		0
Interest Rate Swap Long Term Portion [Member]
Derivative [Line Items]
Derivative Asset	5,871			5,871	3,105	5,871	3,105	4,252
Interest Rate Swap Short Term Portion [Member]
Derivative [Line Items]
Derivative Asset	$ 2,533			2,533		2,533		900
Derivative Liability					$ (56)		$ (56)
Beginning Balance [Member]
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax								$ 3,358	$ 1,392
Term Loan 1 [Member]
Derivative [Line Items]
Interest Rate Swap Inception Date			Mar. 31, 2016
Interest Rate Swap Maturity Date	Feb. 19, 2021
Derivative Liability, Notional Amount	$ 170,000		$ 197,500	170,000		170,000
Term Loan 2 [Member]
Derivative [Line Items]
Interest Rate Swap Inception Date		Jun. 30, 2017
Interest Rate Swap Maturity Date	Jun. 15, 2022
Derivative Liability, Notional Amount	$ 95,000	$ 100,000		$ 95,000		$ 95,000