v3.8.0.1

Deposits - Summary of Outstanding Balance of Deposits and Average Rates (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Deposits [Abstract] |  |
Demand deposits, Noninterest-bearing | $ 1,097,196 | $ 661,781
Demand deposits, Interest-bearing | 235,294 | 194,274
Money market and savings | 1,210,240 | 941,344
Certificates of deposits | 900,797 | 629,396
Total | $ 3,443,527 | $ 2,426,795
Demand deposits, Interest-bearing, Weighted Average Rate | 0.411% | 0.471%
Money market and savings, Weighted Average Rate | 0.84% | 0.677%
Certificates of deposits, Weighted Average Rate | 1.189% | 0.589%
Total, Weighted Average Rate | 0.634% | 0.453%

X
- Definition Certificates of deposit liabilities. + References No definition available. + Details
Name: | ffwm_CertificatesOfDepositLiabilities
Namespace Prefix: | ffwm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Interest-bearing demand deposits weighted average rate. + References No definition available. + Details
Name: | ffwm_InterestBearingDemandDepositsWeightedAverageRate
Namespace Prefix: | ffwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average rate of certificates of deposits. + References No definition available. + Details
Name: | ffwm_WeightedAverageRateOfCertificatesOfDeposits
Namespace Prefix: | ffwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average rate of deposits. + References No definition available. + Details
Name: | ffwm_WeightedAverageRateOfDeposits
Namespace Prefix: | ffwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average rate of money market and savings deposits. + References No definition available. + Details
Name: | ffwm_WeightedAverageRateOfMoneyMarketAndSavingsDeposits
Namespace Prefix: | ffwm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_Deposits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DepositsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts. Also includes amount of deposits in interest-bearing transaction accounts at banks or savings and loans, that are restricted in regard to ownership and can usually only be held by individuals, nonprofit entities and governments. Negotiable order of withdrawal accounts differ from money market demand accounts as they typically have higher reserve requirements and no limit on the number of checks that can be written. + References No definition available. + Details
Name: | us-gaap_DepositsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNOW
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The aggregate of all domestic and foreign interest-bearing deposit liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_InterestBearingDepositLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.12) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_NoninterestBearingDepositLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant