Commitments and Contingent Liabilities (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Within one year	$ 6,061,231
One to three years	226,211
Three to five years	31,283
Over five years	242,088
Total	6,560,813
Deposits Without a Stated Maturity [Member]
Within one year	5,024,475	[1]
Total	5,024,475	[1]
Time Deposits [Member]
Within one year	617,526	[1]
One to three years	193,199	[1]
Three to five years	18,784	[1]
Total	829,509	[1]
Borrowed Funds [Member]
Within one year	401,561	[2]
Over five years	220,000	[2]
Total	621,561	[2]
Operating Lease Obligations [Member]
Within one year	7,604
One to three years	14,198
Three to five years	10,776
Over five years	12,138
Total	44,716
Outside Data Processing [Member]
Within one year	5,036	[3]
One to three years	9,570	[3]
Total	14,606	[3]
George Mason Sponsorship [Member]
Within one year	650	[4]
One to three years	1,300	[4]
Three to five years	1,350	[4]
Over five years	9,150	[4]
Total	12,450	[4]
Non-compete Agreement [Member]
Within one year	335	[5]
Total	335	[5]
LIHTC Investments [Member]
Within one year	4,044	[6]
One to three years	7,944	[6]
Three to five years	373	[6]
Over five years	800	[6]
Total	$ 13,161	[6]

[1] Excludes accrued interest payable at December 31, 2017.

[2] Borrowed funds include customer repurchase agreements, and other short-term and long-term borrowings.

[3] The Bank has outstanding obligations under its current core data processing contract that expire in May 2020 and two other vendor arrangements that relate to network infrastructure and data center services, one expires in July 2020 and the other expires in December 2018.

[4] The Bank has the option of terminating the George Mason agreement at the end of contract years 10 and 15 (that is, effective June 30, 2025 or June 30, 2030). Should the Bank elect to exercise its right to terminate the George Mason contract, contractual obligations would decrease $3.5 million and $3.6 million for the first option period (years 11-15) and the second option period (16-20), respectively.

[5] Non-compete agreement with a retired Director.

[6] Low Income Housing Tax Credits ("LIHTC") expected payments for unfunded affordable housing commitments.