Fair Value - Measurement Basis, Nonrecurring (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Notes Payable	$ 1,294,514		$ 1,294,070
Nonrecurring basis
Financial statement items measured at fair value on a nonrecurring basis
Real estate acquired in settlement of loans	11,104		9,850
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Real estate acquired in settlement of loans	(3,980)	$ 21
Nonrecurring basis | Level 3
Financial statement items measured at fair value on a nonrecurring basis
Real estate acquired in settlement of loans	11,104		9,850
Fair Values
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Notes Payable	$ 978,250		$ 1,303,047