Fair Value of Financial Instruments - Assets Measured at Fair Value on a Noncrecurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Level 1
Fair Value Disclosures
Individually evaluated loans/Impaired loans	$ 0	$ 0
Level 2
Fair Value Disclosures
Individually evaluated loans/Impaired loans	0	0
Level 3
Fair Value Disclosures
Individually evaluated loans/Impaired loans	13,351,092	8,691,019
Fair Value, Nonrecurring
Fair Value Disclosures
Individually evaluated loans/Impaired loans	4,077	2,257
Fair Value, Nonrecurring | Level 1
Fair Value Disclosures
Individually evaluated loans/Impaired loans	0	0
Fair Value, Nonrecurring | Level 2
Fair Value Disclosures
Individually evaluated loans/Impaired loans	0	0
Fair Value, Nonrecurring | Level 3
Fair Value Disclosures
Individually evaluated loans/Impaired loans	$ 4,077	$ 2,257