Available-for-Sale and Held-to-Maturity Securities (Schedule of Amortized Cost and Fair Values of Debt Securities by Contractual Maturity) (Details) (USD $) In Thousands	Sep. 30, 2011	Jun. 30, 2011
Debt securities, Available-for-sale, Amortized cost, Within one year		$ 30,183
Debt securities, Available-for-sale, Amortized cost, After one year through three years	233,280
Debt securities, Available-for-sale, Amortized cost, After three years through five years	153,110
Debt securities, Available-for-sale, Amortized cost, After five years through ten years	10,529
Debt securities, Available-for-sale, Amortized cost, After ten years	92,627
Debt securities, Available-for-sale, Amortized cost, Total	1,301,021
Debt securities, Available-for-sale, Estimated fair value, Within one year		30,579
Debt securities, Available-for-sale, Estimated fair value, After one year through three years		232,661
Debt securities, Available-for-sale, Estimated fair value, After three years through five years	150,672
Debt securities, Available-for-sale, Estimated fair value, After five years through ten years	11,169
Debt securities, Available-for-sale, Estimated fair value, After ten years	96,754
Debt securities, Available-for-sale, Estimated fair value, Total	1,312,784
Debt securities, Held-to-maturity, Amortized cost, Within one year	0
Debt securities, Held-to-maturity, Amortized cost, After one year through three years	0
Debt securities, Held-to-maturity, Amortized cost, After three years through five years	15,118
Debt securities, Held-to-maturity, Amortized cost, After five years through ten years	66,203
Debt securities, Held-to-maturity, Amortized cost, After ten years	77,811
Debt securities, Held-to-maturity, Amortized cost, Total	159,132
Debt securities, Held-to-maturity, Estimated fair value, Within one year	0
Debt securities, Held-to-maturity, Estimated fair value, After one year through three years	0
Debt securities, Held-to-maturity, Estimated fair value, After three years through five years		14,301
Debt securities, Held-to-maturity, Estimated fair value, After five years through ten years	64,441
Debt securities, Held-to-maturity, Estimated fair value, After ten years	78,343
Debt securities, Held-to-maturity, Estimated fair value, Total	157,085
Mortgage-backed securities [Member]
Debt securities, Available-for-sale, Amortized cost, After three years through five years		9,641
Debt securities, Available-for-sale, Amortized cost, After five years through ten years	13,825
Debt securities, Available-for-sale, Amortized cost, After ten years	757,826
Debt securities, Available-for-sale, Estimated fair value, After three years through five years	10,020
Debt securities, Available-for-sale, Estimated fair value, After five years through ten years	13,971
Debt securities, Available-for-sale, Estimated fair value, After ten years	766,958
Debt securities, Held-to-maturity, Amortized cost, After three years through five years	0
Debt securities, Held-to-maturity, Amortized cost, After five years through ten years	0
Debt securities, Held-to-maturity, Amortized cost, After ten years	0
Debt securities, Held-to-maturity, Estimated fair value, After three years through five years	0
Debt securities, Held-to-maturity, Estimated fair value, After five years through ten years	0
Debt securities, Held-to-maturity, Estimated fair value, After ten years	$ 0