Income Taxes - Summary of Temporary Tax Differences Causing Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Allowances for losses	$ 41,924	$ 48,243
Compensation and benefits (principally pension and other postretirement benefit plans)	40,072	45,849
Mortgage loans (principally deferred loan origination costs)	2,548	981
Net unrealized loss on securities available-for-sale	194	0
State and local net operating loss carryforwards	16,341	16,122
Other deductible temporary differences	4,568	4,540
Total gross deferred tax assets	105,647	115,735
Less valuation allowance	0	(7,220)
Deferred tax assets, net of valuation allowance	105,647	108,515
Deferred tax liabilities:
Premises and equipment	(3,665)	(3,102)
Net unrealized gain on securities available-for-sale	0	(1,035)
MSR	(438)	(910)
Total gross deferred tax liabilities	(4,103)	(5,047)
Net deferred tax assets (included in other assets)	$ 101,544	$ 103,468