Loans - Activity in Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	$ 77,444
Credit loss allowance at the end of the period	72,284
Activity in loan portfolio
Balance at the beginning of the period	12,139,908	$ 11,470,224
Acquisitions/origination/additional funding	2,671,394	1,898,905
Capitalized Interest	36,646	36,072
Basis of loans sold	(571,927)	(789,863)
Loan maturities/principal repayments	(1,092,984)	(796,323)
Discount accretion/premium amortization	16,745	12,080
Changes in fair value	(9,478)	(16,134)
Unrealized foreign currency translation (loss) gain	(14,263)	(87,319)
Credit loss provision, net	(2,597)	(43,332)
Transfer to/from other asset classifications	(7,320)
Balance at the end of the period	13,166,124	11,663,870
ASU 2016-13
Activity in loan portfolio
Loan maturities/principal repayments		(20,440)
Total loans held-for-investment
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	77,444
Credit loss allowance at the end of the period	72,284
Loans held-for-sale
Activity in loan portfolio
Balance at the beginning of the period	1,052,835	884,150
Acquisitions/origination/additional funding	375,270	646,160
Basis of loans sold	(571,927)	(789,259)
Loan maturities/principal repayments	(44,326)	(20,680)
Discount accretion/premium amortization		110
Changes in fair value	(9,188)	9,485
Unrealized foreign currency translation (loss) gain		(4,056)
Transfer to/from other asset classifications	41,967	449,024
Balance at the end of the period	844,631	1,174,934
Funded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	77,444
Credit loss provision (reversal), net	2,597
Charge-offs	(7,757)
Credit loss allowance at the end of the period	72,284
Unfunded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	6,070
Credit loss provision (reversal), net	(2,265)
Credit loss allowance at the end of the period	3,805
Unfunded commitments	1,357,095
Commercial Portfolio Segment | Total loans held-for-investment
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	69,611
Credit loss allowance at the end of the period	63,477
Activity in loan portfolio
Balance at the beginning of the period	9,583,949	8,517,054
Acquisitions/origination/additional funding	2,196,813	1,089,096
Capitalized Interest	36,646	36,072
Loan maturities/principal repayments	(1,021,393)	(689,972)
Discount accretion/premium amortization	15,824	11,559
Unrealized foreign currency translation (loss) gain	(14,082)	(83,263)
Credit loss provision, net	(1,880)	(37,527)
Transfer to/from other asset classifications	(211,904)
Balance at the end of the period	10,583,973	8,832,907
Commercial Portfolio Segment | Total loans held-for-investment | ASU 2016-13
Activity in loan portfolio
Loan maturities/principal repayments		(10,112)
Commercial Portfolio Segment | Funded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	69,611
Credit loss provision (reversal), net	1,880
Charge-offs	(7,757)
Transfers	(257)
Credit loss allowance at the end of the period	63,477
Commercial Portfolio Segment | Unfunded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	5,258
Credit loss provision (reversal), net	(2,122)
Credit loss allowance at the end of the period	3,136
Unfunded commitments	1,291,304
Infrastructure Portfolio Segment | Total loans held-for-investment
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	7,833
Credit loss allowance at the end of the period	8,807
Activity in loan portfolio
Balance at the beginning of the period	1,412,440	1,397,448
Acquisitions/origination/additional funding	99,311	62,929
Loan maturities/principal repayments	(18,055)	(37,051)
Discount accretion/premium amortization	921	411
Unrealized foreign currency translation (loss) gain	(181)
Credit loss provision, net	(717)	(5,805)
Transfer to/from other asset classifications	93,089	(26,333)
Balance at the end of the period	1,586,808	1,381,271
Infrastructure Portfolio Segment | Total loans held-for-investment | ASU 2016-13
Activity in loan portfolio
Loan maturities/principal repayments		(10,328)
Infrastructure Portfolio Segment | Funded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	7,833
Credit loss provision (reversal), net	717
Transfers	257
Credit loss allowance at the end of the period	8,807
Infrastructure Portfolio Segment | Unfunded commitments
Activity in allowance for loan losses
Credit loss allowance at the beginning of the period	812
Credit loss provision (reversal), net	(143)
Credit loss allowance at the end of the period	669
Unfunded commitments	65,791
Residential Portfolio Segment | Total loans held-for-investment
Activity in loan portfolio
Balance at the beginning of the period	90,684	671,572
Acquisitions/origination/additional funding		100,720
Basis of loans sold		(604)
Loan maturities/principal repayments	(9,210)	(48,620)
Changes in fair value	(290)	(25,619)
Transfer to/from other asset classifications	69,528	(422,691)
Balance at the end of the period	$ 150,712	$ 274,758