Carrying Amount and Estimated Fair Value of Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Carrying Amount
Financial assets
Cash and cash equivalents	$ 547,610	$ 330,961
Debt securities, held-to-maturity	203,275	224,611
Loans receivable, net of ACL	11,290,869	9,388,320
Total financial assets	12,041,754	9,943,892
Financial liabilities
Term deposits	1,063,821	1,011,798
FHLB advances	37,963	38,611
Repurchase agreements and other borrowed funds	913,773	598,644
Subordinated debentures	139,917	139,914
Total financial liabilities	2,155,474	1,788,967
Estimated Fair Value | Level 1
Financial assets
Cash and cash equivalents	547,610	330,961
Debt securities, held-to-maturity	0	0
Loans receivable, net of ACL	0	0
Total financial assets	547,610	330,961
Financial liabilities
Term deposits	0	0
FHLB advances	0	0
Repurchase agreements and other borrowed funds	0	0
Subordinated debentures	0	0
Total financial liabilities	0	0
Estimated Fair Value | Level 2
Financial assets
Cash and cash equivalents	0	0
Debt securities, held-to-maturity	215,883	234,396
Loans receivable, net of ACL	0	0
Total financial assets	215,883	234,396
Financial liabilities
Term deposits	1,069,748	1,017,505
FHLB advances	38,219	38,787
Repurchase agreements and other borrowed funds	913,773	598,644
Subordinated debentures	100,750	124,094
Total financial liabilities	2,122,490	1,779,030
Estimated Fair Value | Level 3
Financial assets
Cash and cash equivalents	0	0
Debt securities, held-to-maturity	0	0
Loans receivable, net of ACL	11,444,388	9,438,121
Total financial assets	11,444,388	9,438,121
Financial liabilities
Term deposits	0	0
FHLB advances	0	0
Repurchase agreements and other borrowed funds	0	0
Subordinated debentures	0	0
Total financial liabilities	$ 0	$ 0