Junior Subordinated Debentures Issued to Affiliated Trusts (Details) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Mar. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Jun. 30, 2015 USD ($) derivative item $ / shares	Jun. 30, 2014 USD ($)	Jun. 30, 2010 USD ($)
Wholesale Repurchase Agreements
Carrying Amount of Junior Subordinated Debentures issued to affiliated trusts			$ 8,626	$ 8,440
Notional amount			$ 31,000	31,000
Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Number of derivative instruments | derivative			2
Notional amount	$ 10,000	$ 6,000			$ 6,000
NBN Capital Trust II Debenture maturing March 30, 2034 | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Maturity term		5 years
NBN Capital Trust IV Debenture maturing February 23, 2035
Wholesale Repurchase Agreements
Variable interest rate basis			three month LIBOR
Spread on variable rate basis (as a percent)			1.89%
NBN Capital Trust IV Debenture maturing February 23, 2035 | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Notional amount			$ 10,000
NBN Capital Trust IV Debenture maturing February 23, 2035 | Interest rate swaps | Cash flow hedge
Wholesale Repurchase Agreements
Notional amount					$ 10,000
NBN Capital Trust II and III Debentures maturing March 30, 2034
Wholesale Repurchase Agreements
Variable interest rate basis			three month LIBOR
Spread on variable rate basis (as a percent)			2.80%
NBN Capital Trust II and III Debentures maturing March 30, 2034 | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Notional amount			$ 6,000
NBN Capital Trusts | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Strike Rate (as a percent)			2.50%
Percentage increase in three-month LIBOR for recognition of higher interest expense			200.00%
Trust preferred securities
Wholesale Repurchase Agreements
Number of private placement offerings in which securities are sold | item			2
Unpaid Principal Balance of Private Trust Securities issued			$ 16,496	16,496
Trust preferred securities | Junior Subordinated Debentures
Wholesale Repurchase Agreements
Carrying Amount of Junior Subordinated Debentures issued to affiliated trusts			8,626	8,440
Trust preferred securities | NBN Capital Trust II Debenture maturing March 30, 2034
Wholesale Repurchase Agreements
Carrying Amount of Junior Subordinated Debentures issued to affiliated trusts			1,835	1,804
Trust preferred securities | NBN Capital Trust III Debenture maturing March 30, 2034
Wholesale Repurchase Agreements
Carrying Amount of Junior Subordinated Debentures issued to affiliated trusts			1,835	1,804
Trust preferred securities | NBN Capital Trust IV Debenture maturing February 23, 2035
Wholesale Repurchase Agreements
Carrying Amount of Junior Subordinated Debentures issued to affiliated trusts			4,956	4,832
NBN Capital Trust II
Wholesale Repurchase Agreements
Common securities of trust			93
NBN Capital Trust II | Trust preferred securities
Wholesale Repurchase Agreements
Unpaid Principal Balance of Private Trust Securities issued			$ 3,093	3,093
Contractual Rate of Private Trust Securities issued (as a percent)			3.26%
Liquidation amount per Preferred Security | $ / shares			$ 1,000
NBN Capital Trust III
Wholesale Repurchase Agreements
Common securities of trust			$ 93
NBN Capital Trust III | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Maturity term	5 years
NBN Capital Trust III | Trust preferred securities
Wholesale Repurchase Agreements
Unpaid Principal Balance of Private Trust Securities issued			$ 3,093	3,093
Liquidation amount per Preferred Security | $ / shares			$ 1,000
NBN Capital Trust IV
Wholesale Repurchase Agreements
Common securities of trust			$ 310
NBN Capital Trust IV | Trust preferred securities
Wholesale Repurchase Agreements
Unpaid Principal Balance of Private Trust Securities issued			$ 10,310	$ 10,310
Contractual Rate of Private Trust Securities issued (as a percent)			2.36%
Liquidation amount per Preferred Security | $ / shares			$ 1,000
NBN Capital Trust II and III | NBN Capital Trusts | Interest rate caps | Cash flow hedge
Wholesale Repurchase Agreements
Strike Rate (as a percent)			2.50%