Income Taxes - Summary of Tax Effects of Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowances for losses	$ 36,084	$ 41,924
Compensation and benefits (principally pension and other postretirement benefit plans)	40,759	40,072
Mortgage loans (principally deferred loan origination costs)	2,871	2,548
Net unrealized loss on securities available-for-sale	577	194
State and local net operating loss carryforwards	13,467	16,341
Other deductible temporary differences	4,320	4,568
Total gross deferred tax assets	98,078	105,647
Less valuation allowance	0	0
Deferred tax assets, net of valuation allowance	98,078	105,647
Deferred tax liabilities:
Premises and equipment	(3,465)	(3,665)
MSR	(1,534)	(438)
Total gross deferred tax liabilities	(4,999)	(4,103)
Net deferred tax assets (included in other assets)	$ 93,079	$ 101,544