Derivatives and Hedging (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Derivatives and Hedging
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	$ 2,250,000	$ 0
Interest Rate Derivatives
Notional value	1,375,000,000		$ 2,083,250,000
Unrealized gains (losses) included in accumulated other comprehensive loss	(200,000)		16,200,000
Amount of hedge ineffectiveness	0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(2,250,000)	0
Net unrealized gains in accumulated other comprehensive income expected to be reclassified into interest expense within the next 12 months	6,400,000
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(191,000)		(16,195,000)
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type ten
Derivatives and Hedging
Interest rate swap asset	0
Interest rate swap liability			148,000
Interest Rate Derivatives
Notional value	$ 0		125,000,000
Interest rate	2.018%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type eleven
Derivatives and Hedging
Interest rate swap asset	$ 0
Interest rate swap liability			136,000
Interest Rate Derivatives
Notional value	$ 0		100,000,000
Interest rate	1.944%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twelve
Derivatives and Hedging
Interest rate swap asset	$ 0		(447,000)
Interest Rate Derivatives
Notional value	$ 0		125,000,000
Interest rate	1.2715%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type thirteen
Derivatives and Hedging
Interest rate swap asset	$ 0
Interest rate swap liability			153,000
Interest Rate Derivatives
Notional value	$ 0		100,000,000
Interest rate	1.9615%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type fourteen
Derivatives and Hedging
Interest rate swap asset	$ 0
Interest rate swap liability			93,000
Interest Rate Derivatives
Notional value	$ 0		50,000,000
Interest rate	1.85%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type fifteen
Derivatives and Hedging
Interest rate swap asset	$ 0
Interest rate swap liability			99,000
Interest Rate Derivatives
Notional value	$ 0		50,000,000
Interest rate	1.8115%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type sixteen
Derivatives and Hedging
Interest rate swap asset	$ 0		(54,000)
Interest Rate Derivatives
Notional value	$ 0		25,000,000
Interest rate	1.7445%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type seventeen
Derivatives and Hedging
Interest rate swap asset	$ 0		(370,000)
Interest Rate Derivatives
Notional value	$ 0		30,855,000
Interest rate	1.80%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type eighteen
Derivatives and Hedging
Interest rate swap asset	$ 0		(919,000)
Interest Rate Derivatives
Notional value	$ 0		76,670,000
Interest rate	1.80%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type nineteen
Derivatives and Hedging
Interest rate swap asset	$ 0		(392,000)
Interest Rate Derivatives
Notional value	$ 0		32,725,000
Interest rate	1.80%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty
Derivatives and Hedging
Interest rate swap asset	$ 0		(1,808,000)
Interest Rate Derivatives
Notional value	$ 0		143,000,000
Interest rate	1.80816%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty one
Derivatives and Hedging
Interest rate swap asset	$ (707,000)		(1,057,000)
Interest Rate Derivatives
Notional value	$ 50,000,000		50,000,000
Interest rate	1.6125%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty two
Derivatives and Hedging
Interest rate swap asset	$ (772,000)		(1,129,000)
Interest Rate Derivatives
Notional value	$ 50,000,000		50,000,000
Interest rate	1.5555%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty three
Derivatives and Hedging
Interest rate swap asset	$ (595,000)		(934,000)
Interest Rate Derivatives
Notional value	$ 50,000,000		50,000,000
Interest rate	1.7095%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty four
Derivatives and Hedging
Interest rate swap asset	$ (2,322,000)		(3,072,000)
Interest Rate Derivatives
Notional value	$ 100,000,000		100,000,000
Interest rate	1.15%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty five
Derivatives and Hedging
Interest rate swap asset	$ (2,215,000)		(2,955,000)
Interest Rate Derivatives
Notional value	$ 100,000,000		100,000,000
Interest rate	1.20%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty six
Derivatives and Hedging
Interest rate swap asset	$ (147,000)
Interest rate swap liability			539,000
Interest Rate Derivatives
Notional value	$ 75,000,000		75,000,000
Interest rate	2.15%
Designated as Hedging Instrument [Member] | Swap-cash flow, hedge type twenty seven
Derivatives and Hedging
Interest rate swap asset	$ (534,000)		(967,000)
Interest Rate Derivatives
Notional value	$ 75,000,000		75,000,000
Interest rate	1.91%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Twenty Eight [Member]
Derivatives and Hedging
Interest rate swap asset	$ (970,000)
Interest rate swap liability			938,000
Interest Rate Derivatives
Notional value	$ 200,000,000		200,000,000
Interest rate	2.29%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Twenty Nine [Member]
Derivatives and Hedging
Interest rate swap asset	$ (588,000)
Interest rate swap liability			607,000
Interest Rate Derivatives
Notional value	$ 125,000,000		125,000,000
Interest rate	2.29%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Thirty [Member]
Derivatives and Hedging
Interest rate swap asset	$ (1,656,000)		(259,000)
Interest Rate Derivatives
Notional value	$ 200,000,000		200,000,000
Interest rate	2.38%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Thirty One [Member]
Derivatives and Hedging
Interest rate swap asset	$ (820,000)		(139,000)
Interest Rate Derivatives
Notional value	$ 100,000,000		100,000,000
Interest rate	2.38%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Thirty Two [Member]
Derivatives and Hedging
Interest rate swap asset	$ (1,920,000)		(1,020,000)
Interest Rate Derivatives
Notional value	$ 100,000,000		100,000,000
Interest rate	2.75%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Thirty Three [Member]
Derivatives and Hedging
Interest rate swap asset	$ (891,000)		0
Interest Rate Derivatives
Notional value	$ 75,000,000		0
Interest rate	2.51%
Designated as Hedging Instrument [Member] | Interest Rate, Swap Hedge, Type Thirty Four [Member]
Derivatives and Hedging
Interest rate swap asset	$ (638,000)		0
Interest Rate Derivatives
Notional value	$ 75,000,000		0
Interest rate	2.39%
Designated as Hedging Instrument
Interest Rate Derivatives
Notional value	$ 282,500,000		0
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net	(2,250,000)		0
Designated as Hedging Instrument | Interest Rate, Swap Hedge, Type One [Member]
Derivatives and Hedging
Interest rate swap asset	(240,000)		0
Interest Rate Derivatives
Notional value	$ 30,690,000		0
Interest rate	1.80%
Designated as Hedging Instrument | Swap-cash flow, hedge type two
Derivatives and Hedging
Interest rate swap asset	$ (597,000)		0
Interest Rate Derivatives
Notional value	$ 76,260,000		0
Interest rate	1.80%
Designated as Hedging Instrument | Swap-cash flow, hedge type three
Derivatives and Hedging
Interest rate swap asset	$ (255,000)		0
Interest Rate Derivatives
Notional value	$ 32,550,000		0
Interest rate	1.80%
Designated as Hedging Instrument | Swap-cash flow, hedge type four
Derivatives and Hedging
Interest rate swap asset	$ (1,158,000)		0
Interest Rate Derivatives
Notional value	$ 143,000,000		0
Interest rate	1.81%
Interest Expense
Derivatives and Hedging
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	$ 2,300,000
Interest Rate Derivatives
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2,600,000	$ (400,000)
Accounts payable and other liabilities | Interest rate swap
Derivatives and Hedging
Interest rate swap liability	7,500,000		1,000,000
Prepaid expenses and other assets | Interest rate swap
Derivatives and Hedging
Interest rate swap asset	$ (9,500,000)		$ (17,200,000)