Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Activity in Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Activity in Allowance for Unfunded Commitments [Abstract]
Allowance for unfunded credit commitments, beginning balance	$ 51,770	$ 45,265	$ 34,415
Provision for unfunded credit commitments	3,578	6,365	10,982
Foreign currency translation adjustments	(165)	140	(132)
Allowance for unfunded credit commitments, ending balance	$ 55,183	$ 51,770	$ 45,265

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