Derivatives and Hedging Activities (Details) - USD ($) $ in Thousands				12 Months Ended
	Jan. 01, 2017	Apr. 09, 2015	Feb. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative instruments and hedging activities disclosures
Amount of gain (loss) recorded in accumulated other comprehensive income				$ (1,112)	$ (2,426)	$ (1,409)
Cash Flow Hedging
Derivative instruments and hedging activities disclosures
Earnings related to derivatives due to hedge ineffectiveness				0	0	0
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging
Derivative instruments and hedging activities disclosures
Amount borrowed under term loan or revolving credit facility		$ 75,000	$ 100,000
Term of loan facility		5 years	5 years
Derivative, Fixed Interest Rate		2.93%	3.23%
Amount of gain (loss) recorded in accumulated other comprehensive income				1,100	2,400	1,400
Amount reclassified to interest expense				1,700	1,900	$ 1,100
Amount recognized in unearned revenue, prepaid rent and other liabilities				400	800
Derivative asset recognized in other assets				$ 300	$ 0
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging | Forecast
Derivative instruments and hedging activities disclosures
Amount estimated to be reclassified as an increase to interest expense	$ 900
LIBOR | Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging
Derivative instruments and hedging activities disclosures
Reference rate		one-month LIBOR