Debt - Cash Pool (Details) $ in Thousands	Jun. 30, 2021 USD ($) cash_pool	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Number of cash pools | cash_pool	2
QRS Cash Pool
Debt Instrument [Line Items]
Number of cash pools | cash_pool	1
GROSS CASH POSITION	$ 441,100	$ 448,700
OUTSTANDING DEBIT BALANCES	(435,200)	(447,400)
NET CASH POSITION	$ 5,900	1,300
TRS Cash Pool
Debt Instrument [Line Items]
Number of cash pools | cash_pool	1
GROSS CASH POSITION	$ 575,900	555,500
OUTSTANDING DEBIT BALANCES	(570,900)	(553,500)
NET CASH POSITION	$ 5,000	$ 2,000