Capital Transactions Capital Transactions - Summary of Shares Repurchased (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Payable for shares repurchased	$ 223,738			$ 223,738	$ 0
Shares repurchased (in shares)	8,344	12,400	11,389
Total consideration	$ 223,738	$ 337,156	$ 308,038	$ 868,932
Price paid per share (in dollars per share)	$ 26.82	$ 27.19	$ 27.05
Class I
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)	4,703		4,745
Total consideration	$ 127,066		$ 127,680
Price paid per share (in dollars per share)	$ 27.02		$ 26.91
Class FA
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)	400	12,400	6,400
Total consideration	$ 10,991	$ 337,156	$ 173,824
Price paid per share (in dollars per share)	$ 27.48	$ 27.19	$ 27.16
Class A
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)	56		244
Total consideration	$ 1,506		$ 6,534
Price paid per share (in dollars per share)	$ 26.79		$ 26.75
Class D
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)	3,185
Total consideration	$ 84,175
Price paid per share (in dollars per share)	$ 26.43