Consolidated Statements of Comprehensive Income Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Change in derivatives qualifying as hedges, taxes	$ (30)	$ 182	$ 55	$ (108)	$ 44	$ (522)	$ 206	$ (734)
Unrealized holding (loss) gain arising during the period, taxes	0	0	0	(44)	(49)	(25)	0	(145)
Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, before Tax	$ (30)	$ (9)	$ (211)	$ (2,713)	$ 63	$ 279	$ (249)	$ (1,995)

Amount of tax expense (benefit), after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for transition asset (obligation) of defined benefit plan.

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Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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