Fair Value Measurements (Assumptions for Mortgage Servicing Rights) (Details) $ in Thousands	Jun. 30, 2018 USD ($) Loans	Mar. 31, 2018 USD ($) Loans
Fair Value Disclosures [Abstract]
Number of loans serviced with MSRs \| Loans	4,399	4,346
Weighted average servicing fee (basis points)	0.3205%	0.3203%
Capitalized servicing multiple	85.24%	84.76%
Capitalized servicing rate (basis points)	0.2732%	0.2715%
Serviced portfolio with MSRs	$ 528,206	$ 519,167
Mortgage servicing rights	$ 1,443	$ 1,410

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

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Balance Type:	debit
Period Type:	instant