Summary of Significant Accounting Policies - Derivative Financial Instruments (Details)	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Feb. 28, 2019 USD ($) derivative
Derivative Instruments, Gain (Loss) [Line Items]
Loss on interest rate swaps	$ (23,489,000)	$ (14,917,000)	$ 0
Interest Rate Swap Agreements
Derivative Instruments, Gain (Loss) [Line Items]
Number of derivative agreements | derivative				4
Weighted average fixed interest rate on notional amounts				2.48%
Notional amount				$ 400,000,000.0