Securities - Realized Gains (Losses) for Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2018
Marketable Securities [Abstract]
Net gains (losses) recognized during the period on equity securities	$ 2	$ (6)
Less: Net gains (losses) recognized during the period on equity securities sold during the period	0	0
Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting date	$ 2	$ (6)

Amount of unrealized holding gain (loss) recognized in the income statement for investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

No definition available.

Name:	us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration