Fair Value Measurement (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Unrealized gains (losses) arising during the period	$ 6,564	$ (1,683)
Change in unrealized gains on junior subordinated debentures carried at fair value, net of taxes	4,920	(1,253)
Net gain (loss) representing the change in fair value in earnings	$ 2,800	$ (306)

Amount, after tax, before reclassification adjustment, of unrealized gain (loss) from increase (decrease) in instrument-specific credit risk of financial liability measured under fair value option.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=75026489&loc=SL75136633-108610

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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