Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2012
Comprehensive Income [Abstract]
Available-for-sale Securities, Gross Unrealized Gain (Loss)	$ 2,784		$ 2,926
Deferred Tax Assets, Unrealized Losses on Trading Securities	179		175
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	2,963		3,101
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent	(142)	2,046
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent	4	(119)
Other comprehensive (loss) income	$ (138)	$ 1,927