Derivative Instruments and Hedging Activities - Interest Rate Swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Amount of (gain)/loss recognized in OCI on derivative for the year ended December 31,	$ (1,613)	$ (869)	$ 813
Other assets, net
Derivative [Line Items]
Interest Rate Swap - 2017	2,299	942
Cash Flow Hedging | Interest Rate Swap | Interest Expense
Derivative [Line Items]
Amount of (gain)/loss reclassified from accumulated OCI into income for the year ended December 31,	$ (256)	$ 300	$ 1,139