Note Transfers of financial assets and servicing rights (Changes in MSRs measured using the fair value method) (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Transfers and Servicing of Financial Assets
Fair value at beginning of period		$ 168,031	$ 196,889
Additions		2,557	2,763
Changes due to payments of loans	[1]	(3,335)	(4,587)
Reduction due to loan repurchases		(972)	(644)
Changes in fair value due to changes in valuation model inputs or assumptions		0	(723)
Fair value at end of period		$ 166,281	$ 193,698

[1] Represents changes due to collection / realization of expected cash flows over time.