Debt and Capital Lease Obligations - Narrative (Details) - USD ($) $ in Thousands				12 Months Ended
		Dec. 06, 2017	Dec. 22, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 28, 2016
Line of Credit Facility [Line Items]
Leverage ratio				145.00%
Fixed charge coverage ratio				310.00%
Total debt and capital lease obligations				$ 209,192	$ 249,211
Revolving Credit Facility, Balance Outstanding	[1]			207,322	212,750
Capital lease obligations, total				2,854	1,469
Remaining borrowing capacity on line of credit				41,400
Letters of credit outstanding				1,300
Unamortized debt issuance cost				984	1,464
Maximum potential amount of future payments				$ 19,300
Guarantees relate to facilities leased by the company				2027-10
Recourse provisions				There are no recourse provisions that would enable us to recover from third parties any payments made under the guarantees
Accumulated Amortization				$ 31,320	$ 18,264
Debt, Weighted Average Interest Rate				3.70%	3.10%	3.20%
Fair value of debt				$ 203,200	$ 252,800
Cash paid for interest on debt				$ 7,700	5,500	$ 4,200
Revolving Credit Facility
Line of Credit Facility [Line Items]
Commitment fee percentage on line of credit				0.30%
Revolving Credit Facility, Balance Outstanding				$ 132,300
Collateral on line of credit				Furthermore, there are no collateral or similar arrangements whereby we could recover payments
Term Loan
Line of Credit Facility [Line Items]
Revolving Credit Facility, Balance Outstanding				$ 75,000
Brewster Revolver
Line of Credit Facility [Line Items]
Borrowing capacity on line of credit		$ 20,000					$ 38,000
Maturity date		Dec. 28, 2018
Commitment fee percentage on line of credit				0.20%
Revolving Credit Facility, Balance Outstanding	[1]				36,456
Remaining borrowing capacity on line of credit				$ 20,000
Capital Leases
Line of Credit Facility [Line Items]
Gross amount of assets recorded under capital leases				4,800	3,300
Accumulated Amortization				$ 2,000	$ 1,700
Amended and Restated Credit Agreement
Line of Credit Facility [Line Items]
Maturity date			Dec. 22, 2019
Amended and Restated Credit Agreement | Senior Credit Facility
Line of Credit Facility [Line Items]
Borrowing capacity on line of credit			$ 300,000
Amended and Restated Credit Agreement | Revolving Credit Facility
Line of Credit Facility [Line Items]
Borrowing capacity on line of credit			175,000
Additional borrowing capacity on line of credit			100,000
Line of Credit borrowings used to support letter of credit			40,000
Amended and Restated Credit Agreement | Term Loan
Line of Credit Facility [Line Items]
Borrowing capacity on line of credit			$ 125,000
Amendment No. 1
Line of Credit Facility [Line Items]
Maximum leverage ratio for acquisition				300.00%
Leverage ratio required for dividend or share activity				250.00%
Maximum leverage ratio for unsecured debt				300.00%
Annual share repurchase limit on leverage ratio basis				$ 20,000
Amendment No. 1 | Maximum
Line of Credit Facility [Line Items]
Leverage ratio				350.00%
Amendment No. 1 | Minimum
Line of Credit Facility [Line Items]
Fixed charge coverage ratio				175.00%
Top Tier Foreign Subsidiaries | Amended and Restated Credit Agreement
Line of Credit Facility [Line Items]
Percent of lenders security interest on capital stock foreign subsidiary			65.00%

[1] Represents the weighted-average interest rate in effect at the respective periods for the revolving credit facilities and term loan borrowings, including any applicable margin. The interest rates do not include amortization of debt issuance costs or commitment fees.