Segment Information (Total Assets by Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Assets	$ 5,992,813	$ 6,557,629
Operating Segments [Member]
Segment Reporting Information [Line Items]
Assets	5,889,764	6,493,176
Operating Segments [Member] | Carolinas Richmond [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	503,920	467,098
Operating Segments [Member] | Chicago Milwaukee [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	423,889	429,390
Operating Segments [Member] | Florida [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	514,431	874,352
Operating Segments [Member] | Houston [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	530,438	522,285
Operating Segments [Member] | Lehigh Central PA [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	1,311,815	1,157,468
Operating Segments [Member] | Minnesota [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	192,409	346,840
Operating Segments [Member] | Philadelphia [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	557,510	444,889
Operating Segments [Member] | Southeastern PA [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	262,155	448,523
Operating Segments [Member] | United Kingdom [Member] | United Kingdom [Member]
Segment Reporting Information [Line Items]
Assets	189,766	215,850
Operating Segments [Member] | Other Segments [Member] | North America [Member]
Segment Reporting Information [Line Items]
Assets	1,403,431	1,586,481
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Assets	$ 103,049	$ 64,453