Financial Instruments and Fair Values - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Interest rate swap agreements liability	$ 13,330,000	$ 5,243,000
Loss from derivative financial instruments	0	0	$ 289,000
Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements liability	14,500,000
Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Unrealized loss on valuation of interest rate swap agreements	20,600,000	900,000
Loss expected to be reclassified within twelve months	4,100,000
Loss from derivative financial instruments			$ 300,000
Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Notional amount	390,000,000.0	515,000,000.0
Accounts payable and accrued expenses | Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements liability	$ 13,300,000	5,200,000
Prepaid expenses and other assets | Designated as Hedging Instrument | Cash Flow Hedging | Interest rate swaps
Derivative [Line Items]
Interest rate swap agreements asset		$ 2,500,000