Subordinated Debentures - Summary of Trust Preferred Securities and Debentures (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Subordinated Borrowing [Line Items]
Subordinated debentures, net	$ 103,035	$ 101,929
Nara Capital Trust III
Subordinated Borrowing [Line Items]
Initial Rate	5.04%
Nara Statutory Trust IV
Subordinated Borrowing [Line Items]
Initial Rate	4.84%
Nara Statutory Trust V
Subordinated Borrowing [Line Items]
Initial Rate	4.85%
Nara Statutory Trust VI
Subordinated Borrowing [Line Items]
Initial Rate	3.54%
Center Capital Trust I
Subordinated Borrowing [Line Items]
Initial Rate	4.84%
Wilshire Statutory Trust II [Member]
Subordinated Borrowing [Line Items]
Initial Rate	3.69%
Wilshire Statutory Trust III [Member]
Subordinated Borrowing [Line Items]
Initial Rate	3.29%
Wilshire Statutory Trust IV [Member]
Subordinated Borrowing [Line Items]
Initial Rate	3.27%
Saehan Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Initial Rate	3.58%
Trust Preferred Security Amount
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	$ 126,000
Trust Preferred Security Amount | Nara Capital Trust III
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	5,000
Trust Preferred Security Amount | Nara Statutory Trust IV
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	5,000
Trust Preferred Security Amount | Nara Statutory Trust V
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	10,000
Trust Preferred Security Amount | Nara Statutory Trust VI
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	8,000
Trust Preferred Security Amount | Center Capital Trust I
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	18,000
Trust Preferred Security Amount | Wilshire Statutory Trust II [Member]
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	20,000
Trust Preferred Security Amount | Wilshire Statutory Trust III [Member]
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	15,000
Trust Preferred Security Amount | Wilshire Statutory Trust IV [Member]
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	25,000
Trust Preferred Security Amount | Saehan Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Trust Preferred Security Amount	20,000
Subordinated Debentures Amount
Subordinated Borrowing [Line Items]
Subordinated debentures, net	103,035	$ 101,900
Subordinated Debentures Amount | Nara Capital Trust III
Subordinated Borrowing [Line Items]
Subordinated debentures, net	5,155
Subordinated Debentures Amount | Nara Statutory Trust IV
Subordinated Borrowing [Line Items]
Subordinated debentures, net	5,155
Subordinated Debentures Amount | Nara Statutory Trust V
Subordinated Borrowing [Line Items]
Subordinated debentures, net	10,310
Subordinated Debentures Amount | Nara Statutory Trust VI
Subordinated Borrowing [Line Items]
Subordinated debentures, net	8,248
Subordinated Debentures Amount | Center Capital Trust I
Subordinated Borrowing [Line Items]
Subordinated debentures, net	14,235
Subordinated Debentures Amount | Wilshire Statutory Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures, net	15,743
Subordinated Debentures Amount | Wilshire Statutory Trust III [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures, net	11,134
Subordinated Debentures Amount | Wilshire Statutory Trust IV [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures, net	18,042
Subordinated Debentures Amount | Saehan Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures, net	$ 15,013