Loans Receivable and Allowance for Credit Losses (Summary of Activities in Allowance for Unfunded Credit Reserves) (Details) - Allowance for Unfunded Credit Reserve - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for unfunded credit reserves
Beginning balance	$ 13,318	$ 16,121	$ 20,360
(Reversal of) provision for unfunded credit reserves	(752)	(2,803)	(4,239)
Ending balance	$ 12,566	$ 13,318	$ 16,121

Amount of expense related to credit loss from transactions other than loan and lease transactions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(11))
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

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