Stockholders' Equity - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense	$ 13,464	$ 14,107	$ 39,202	$ 42,694
NET INCOME	$ 6,548	$ 3,173	53,456	$ 60,243
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
NET INCOME			369
Amounts reclassified from accumulated other comprehensive income (loss) related to settled interest rate swaps | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense			126
Amounts reclassified from accumulated other comprehensive income (loss) related to current interest rate swaps | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense			$ 243