Derivatives - Additional Information (Detail) $ in Thousands	Mar. 31, 2017 USD ($) derivative
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Estimated amount of unrealized gains or losses expected to be reclassified as interest expense in next fiscal year	$ 4,209
Number of derivative financial instruments | derivative	28
Combined notional amount	$ 2,052,010
Credit risk derivative, fair value of derivatives in a net liability position	1,361
Estimated termination value on settlement	$ 1,361