Acquisitions (Allocation of the Fair Value of Assets Acquired and Liabilities Assumed as of the Acquisition Date) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Land	$ 9,363		$ 7,602		$ 3,030
Buildings and improvements	14,341		80,975		80,818
Construction in Progress	103,334		62,884		12,127
Deferred costs			4,414
Other assets			309		633
Capital lease and lease financing obligations					$ 43,832
Fort Worth Facility
Business Acquisition [Line Items]
Land	136
Buildings and improvements	610
Construction in Progress	48,987
Acquired intangibles	237
Deferred costs	23
Other assets	7
Net working capital	86
Net identifiable assets acquired	50,086
Fort Worth Facility | Preliminary Allocation Reported
Business Acquisition [Line Items]
Land			136
Buildings and improvements			610
Construction in Progress			48,984
Acquired intangibles			240
Deferred costs			23
Other assets			7
Net working capital			86
Net identifiable assets acquired			$ 50,086
Fort Worth Facility | Adjustment
Business Acquisition [Line Items]
Construction in Progress	3
Acquired intangibles	(3)
Piscataway Facility
Business Acquisition [Line Items]
Land		$ 7,466
Buildings and improvements		80,366
Construction in Progress		13,900
Acquired intangibles		19,581
Deferred costs		4,390
Other assets		106
Total identifiable assets acquired		125,809
Acquired above market lease		809
Net working capital		2,019
Total liabilities assumed		2,828
Net identifiable assets acquired		$ 122,981
Measurement period adjustments	0
Piscataway Facility | Preliminary Allocation Reported
Business Acquisition [Line Items]
Land				$ 7,440
Buildings and improvements				78,370
Construction in Progress				13,900
Acquired intangibles				21,668
Deferred costs				4,084
Other assets				106
Total identifiable assets acquired				125,568
Acquired above market lease				568
Net working capital				2,019
Total liabilities assumed				2,587
Net identifiable assets acquired				$ 122,981
Piscataway Facility | Adjustment
Business Acquisition [Line Items]
Land	26
Buildings and improvements	1,996
Acquired intangibles	(2,087)
Deferred costs	306
Total identifiable assets acquired	241
Acquired above market lease	241
Total liabilities assumed	$ 241