Derivatives and Hedging Activities (Details) - USD ($) $ in Thousands			12 Months Ended
	Apr. 09, 2015	Feb. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative instruments and hedging activities disclosures
Interest rate as of reporting date (as a percent)	2.93%	3.23%
Term of loan facility	5 years	5 years
Amount of gain (loss) recorded in accumulated other comprehensive income				$ (2,426)	$ (1,409)
Earnings related to derivatives due to hedge ineffectiveness				0	0	$ 0
Interest Rate Swap | Designated as Hedging Instrument
Derivative instruments and hedging activities disclosures
Amount borrowed under term loan or revolving credit facility	$ 75,000	$ 100,000
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging
Derivative instruments and hedging activities disclosures
Amount of loss recorded in accumulated other comprehensive income				2,400	1,400	0
Amount reclassified to interest expense				1,900	1,100	$ 0
Amount recognized in unearned revenue, prepaid rent and other liabilities				$ 800	$ 300
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			$ 1,400
Interest Rate Swap | LIBOR | Designated as Hedging Instrument
Derivative instruments and hedging activities disclosures
Reference rate	one month LIBOR