Fair Value Measurement - Additional Information (Details) - Fair Value on a Nonrecurring Basis [Member]	3 Months Ended
Mar. 31, 2019 USD ($)
Level 3 [Member]
Financial Assets Recorded on a Nonrecurring Basis [Abstract]
Minimum age of appraisal of real estate property for fair value to be considered Level 3	1 year
Mortgage Loans Held for Sale [Member]
Financial Assets Recorded on a Nonrecurring Basis [Abstract]
Nonrecurring fair value adjustments	$ 0

Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

No definition available.

Name:	us-gaap_AssetsFairValueAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration