Derivatives and Hedging (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Interest Rate Derivatives
Notional value	$ 1,674,000,000		$ 1,674,000,000		$ 2,083,250,000
Unrealized Gain (Loss) on Cash Flow Hedging Instruments			(402,000)	$ 0
Unrealized gains (losses) included in accumulated other comprehensive loss	(27,500,000)		(27,500,000)		16,200,000
Amount of hedge ineffectiveness	0	$ 0	0	0
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	0	0	(2,250,000)	0
Net unrealized gains in accumulated other comprehensive income expected to be reclassified into interest expense within the next 12 months	(3,100,000)		(3,100,000)
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(27,515,000)		(27,515,000)		16,195,000
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Ten [Member]
Interest Rate Derivatives
Notional value	0		0		125,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		148,000
Interest rate	2.02%		2.02%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Eleven [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		100,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		136,000
Interest rate	1.94%		1.94%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twelve [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		125,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		447,000
Interest rate	1.27%		1.27%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		100,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		153,000
Interest rate	1.96%		1.96%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Fourteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		50,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		93,000
Interest rate	1.85%		1.85%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Fifteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		50,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		99,000
Interest rate	1.81%		1.81%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Sixteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		25,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		54,000
Interest rate	1.74%		1.74%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Seventeen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		30,855,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		370,000
Interest rate	1.80%		1.80%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Eighteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		76,670,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		919,000
Interest rate	1.80%		1.80%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Nineteen [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		32,725,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		392,000
Interest rate	1.80%		1.80%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty [Member]
Interest Rate Derivatives
Notional value	$ 0		$ 0		143,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 0		$ 0		1,808,000
Interest rate	1.81%		1.81%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Four [Member]
Interest Rate Derivatives
Notional value	$ 100,000,000		$ 100,000,000		100,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 674,000		$ 674,000		3,072,000
Interest rate	1.15%		1.15%
Designated as Hedging Instrument | interest Rate, Swap Hedge, Type Twenty Five [Member]
Interest Rate Derivatives
Notional value	$ 100,000,000		$ 100,000,000		100,000,000
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 590,000		$ 590,000		2,955,000
Interest rate	1.20%		1.20%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Six [Member]
Interest Rate Derivatives
Notional value	$ 75,000,000		$ 75,000,000		75,000,000
Interest rate swap liability	$ (725,000)		$ (725,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					539,000
Interest rate	2.15%		2.15%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Seven [Member]
Interest Rate Derivatives
Notional value	$ 75,000,000		$ 75,000,000		75,000,000
Interest rate swap liability	$ (427,000)		$ (427,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					967,000
Interest rate	1.91%		1.91%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty-One [Member]
Interest Rate Derivatives
Notional value	$ 50,000,000		$ 50,000,000		50,000,000
Interest rate swap liability	$ (76,000)		$ (76,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					1,057,000
Interest rate	1.61%		1.61%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Two [Member]
Interest Rate Derivatives
Notional value	$ 50,000,000		$ 50,000,000		50,000,000
Interest rate swap liability	$ (24,000)		$ (24,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					1,129,000
Interest rate	1.56%		1.56%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Three [Member]
Interest Rate Derivatives
Notional value	$ 50,000,000		$ 50,000,000		50,000,000
Interest rate swap liability	$ (165,000)		$ (165,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					934,000
Interest rate	1.71%		1.71%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Eight [Member]
Interest Rate Derivatives
Notional value	$ 200,000,000		$ 200,000,000		200,000,000
Interest rate swap liability	$ (5,779,000)		$ (5,779,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					938,000
Interest rate	2.29%		2.29%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Twenty Nine [Member]
Interest Rate Derivatives
Notional value	$ 125,000,000		$ 125,000,000		125,000,000
Interest rate swap liability	$ (3,603,000)		$ (3,603,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					607,000
Interest rate	2.29%		2.29%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty [Member]
Interest Rate Derivatives
Notional value	$ 200,000,000		$ 200,000,000		200,000,000
Interest rate swap liability	$ (6,392,000)		$ (6,392,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					259,000
Interest rate	2.38%		2.38%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty One [Member]
Interest Rate Derivatives
Notional value	$ 100,000,000		$ 100,000,000		100,000,000
Interest rate swap liability	$ (3,193,000)		$ (3,193,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					139,000
Interest rate	2.38%		2.38%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Two [Member]
Interest Rate Derivatives
Notional value	$ 100,000,000		$ 100,000,000		100,000,000
Interest rate swap liability	$ (4,307,000)		$ (4,307,000)		(1,020,000)
Interest rate	2.75%		2.75%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Three [Member]
Interest Rate Derivatives
Notional value	$ 75,000,000		$ 75,000,000		0
Interest rate swap liability	$ (2,680,000)		$ (2,680,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					0
Interest rate	2.51%		2.51%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Four [Member]
Interest Rate Derivatives
Notional value	$ 75,000,000		$ 75,000,000		0
Interest rate swap liability	$ (2,417,000)		$ (2,417,000)
Interest Rate Cash Flow Hedge Asset at Fair Value					0
Interest rate	2.39%		2.39%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Five [Member]
Interest Rate Derivatives
Notional value	$ 49,000,000		$ 49,000,000		0
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 155,000		$ 155,000		0
Interest rate	1.35%		1.35%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Six [Member]
Interest Rate Derivatives
Notional value	$ 100,000,000		$ 100,000,000		0
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 426,000		$ 426,000		0
Interest rate	1.28%		1.28%
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type Thirty Seven [Member]
Interest Rate Derivatives
Notional value	$ 150,000,000		$ 150,000,000		0
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 428,000		$ 428,000		0
Interest rate	1.24%		1.24%
Not Designated as Hedging Instrument
Interest Rate Derivatives
Notional value	$ 281,000,000		$ 281,000,000		0
Interest Rate Derivative Instruments Not Designated as Heding Instruments, Liability at Fair Value	(402,000)		(402,000)		0
Not Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type One [Member]
Interest Rate Derivatives
Notional value	$ 30,360,000		$ 30,360,000		0
Interest rate	1.80%		1.80%
Interest Rate Derivative Instruments Not Designated as Heding Instruments, Liability at Fair Value	$ (34,000)		$ (34,000)		0
Not Designated as Hedging Instrument | Swap-cash flow, hedge type two
Interest Rate Derivatives
Notional value	$ 75,440,000		$ 75,440,000		0
Interest rate	1.80%		1.80%
Interest Rate Derivative Instruments Not Designated as Heding Instruments, Liability at Fair Value	$ (85,000)		$ (85,000)		0
Not Designated as Hedging Instrument | Swap-cash flow, hedge type three
Interest Rate Derivatives
Notional value	$ 32,200,000		$ 32,200,000		0
Interest rate	1.80%		1.80%
Interest Rate Derivative Instruments Not Designated as Heding Instruments, Liability at Fair Value	$ (36,000)		$ (36,000)		0
Not Designated as Hedging Instrument | Swap-cash flow, hedge type four
Interest Rate Derivatives
Notional value	$ 143,000,000		$ 143,000,000		0
Interest rate	1.81%		1.81%
Interest Rate Derivative Instruments Not Designated as Heding Instruments, Liability at Fair Value	$ (247,000)		$ (247,000)		0
Interest Expense
Interest Rate Derivatives
Unrealized Gain (Loss) on Cash Flow Hedging Instruments			2,300,000
Reclassification of unrealized gain on discontinued cash flow hedges to interest expense	1,100,000	$ 1,400,000	5,600,000	$ 1,700,000
Accounts payable and other liabilities | Interest rate swap
Interest Rate Derivatives
Interest rate swap liability	(30,200,000)		(30,200,000)		(1,000,000.0)
Prepaid expenses and other assets | Interest rate swap
Interest Rate Derivatives
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 2,300,000		$ 2,300,000		$ 17,200,000