Investment Securities Investment Securities: Investments with Unrealized Loss Positions (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Principal payments from investment securities available for sale	$ 5,800	$ 3,200	$ 11,722	$ 7,296
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	71,893		71,893		$ 28,722
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	437				77
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	0				0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	71,893		71,893		28,722
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	437				77
U.S. government sponsored enterprise MBS
Payments to Acquire Mortgage Backed Securities (MBS) categorized as Held-to-maturity	28,400	$ 0	38,500	$ 0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	71,893		71,893		28,722
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	71,893		71,893		28,722
Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss	437		437		77
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	437		437		77
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0		$ 0		$ 0

Amount of unrealized loss on securities classified as available-for-sale that have been in a loss position for twelve months or longer.

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Amount of unrealized loss on investments in available-for-sale securities that have been in a loss position for less than twelve months.

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This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity that have been in a continuous loss position for twelve months or longer.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity in a continuous loss position.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity that have been in a continuous loss position for less than twelve months.

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The cash outflow for the purchase of securities issued by a governmental agency or corporation (for example, GNMA or FHLMC) or by private issuers (for example, banks and mortgage banking enterprises) secured by and repaid from underlying mortgages, which were designated as held to maturity when acquired.

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The cash inflow from the maturity (principal due), prepayment and call (request of early payment) of a loan financed by home mortgage payments classified as held to maturity.

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