Fair Value - Measurement Basis, Nonrecurring (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Notes Payable	$ 1,294,949		$ 1,294,949		$ 1,294,070
Nonrecurring basis
Financial statement items measured at fair value on a nonrecurring basis
Real estate acquired in settlement of loans	8,838		8,838		9,850
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Real estate acquired in settlement of loans	(1,001)	$ 105	(2,283)	$ 111
Nonrecurring basis | Level 3
Financial statement items measured at fair value on a nonrecurring basis
Real estate acquired in settlement of loans	8,838		8,838		9,850
Fair Values
Total gains (losses) on assets measured at estimated fair values on a nonrecurring basis
Notes Payable	$ 1,255,719		$ 1,255,719		$ 1,303,047