Goodwill and Other Intangibles - Goodwill Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill
Balance - beginning of period	$ 934,688	$ 920,944	$ 643,960
Acquisition of CPA:17 – Global (Note 3)			280,306
CPA:17 Merger measurement period adjustments (Note 3)		15,802
Foreign currency translation adjustments	10,403	(2,058)	(3,322)
Allocation of goodwill based on portion of Investment Management business sold (Note 4)	(34,273)
Balance - end of period	910,818	934,688	920,944
Real Estate
Goodwill
Balance - beginning of period	871,081	857,337	580,353
Acquisition of CPA:17 – Global (Note 3)			280,306
CPA:17 Merger measurement period adjustments (Note 3)		15,802
Foreign currency translation adjustments	10,403	(2,058)	(3,322)
Allocation of goodwill based on portion of Investment Management business sold (Note 4)	0
Balance - end of period	881,484	871,081	857,337
Investment Management
Goodwill
Balance - beginning of period	63,607	63,607	63,607
Acquisition of CPA:17 – Global (Note 3)			0
CPA:17 Merger measurement period adjustments (Note 3)		0
Foreign currency translation adjustments	0	0	0
Allocation of goodwill based on portion of Investment Management business sold (Note 4)	(34,273)
Balance - end of period	$ 29,334	$ 63,607	$ 63,607

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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