Segment Information - Total Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Document Period End Date	Sep. 30, 2019
Assets	$ 7,338,732	$ 6,934,394
Operating Segments
Segment Reporting Information [Line Items]
Assets	6,701,430	6,737,720
Operating Segments | Other
Segment Reporting Information [Line Items]
Assets	1,062,447	1,153,518
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets	637,302	196,674
North America | Operating Segments | Carolinas/Richmond
Segment Reporting Information [Line Items]
Assets	516,811	525,041
North America | Operating Segments | Chicago/Minneapolis
Segment Reporting Information [Line Items]
Assets	597,557	591,792
North America | Operating Segments | Cincinnati/Columbus/Indianapolis
Segment Reporting Information [Line Items]
Assets	134,111	131,400
North America | Operating Segments | Dallas
Segment Reporting Information [Line Items]
Assets	306,463	261,538
North America | Operating Segments | Florida
Segment Reporting Information [Line Items]
Assets	550,623	547,232
North America | Operating Segments | Houston
Segment Reporting Information [Line Items]
Assets	608,761	568,756
North America | Operating Segments | Lehigh/Central PA
Segment Reporting Information [Line Items]
Assets	1,225,016	1,210,220
North America | Operating Segments | Philadelphia
Segment Reporting Information [Line Items]
Assets	540,972	624,373
North America | Operating Segments | Southern California
Segment Reporting Information [Line Items]
Assets	766,578	660,688
United Kingdom | Operating Segments | United Kingdom
Segment Reporting Information [Line Items]
Assets	$ 392,091	$ 463,162