Loans and Leases - Narrative (Details)			3 Months Ended			9 Months Ended
	Mar. 31, 2018	Sep. 25, 2017 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($) property	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) property guarantors	Sep. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($) property
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired				$ 596,183,000		$ 596,183,000			$ 895,054,000
Carrying amount				1,622,000		1,622,000			7,352,000
Charge-offs				3,587,000	$ 2,189,000	6,002,000	$ 5,091,000
Nonaccrual Loans and Leases				15,949,000		15,949,000			17,916,000
Provision for loan losses				2,690,000	1,416,000	7,899,000	2,396,000
Impaired Financing Receivable, Related Allowance				88,000		88,000			235,000
Loans and Leases Receivable				2,890,981,000		2,890,981,000			2,390,832,000
Other accruing impaired loans				4,800,000		4,800,000			23,300,000
Specific reserves for other accruing impaired loans				73,000		73,000			$ 84,000
Impaired Financing Receivable, Recorded Investment				$ 30,560,000		$ 30,560,000
Maximum modification period on short-term basis						1 year
Restructured loan past due period						90 days
Foreclosed consumer residential real estate property | property				0		0			0
Software Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Charge-offs				$ 2,800,000
Nonaccrual Loans and Leases				5,000,000		$ 5,000,000
Provision for loan losses				1,900,000
Impaired Financing Receivable, Related Allowance								$ 886,000
Litigation Settlement, Number of Guarantors | guarantors						29
Litigation Settlement, Settlement Agreement Date		September 25, 2017
Litigation Settlement, Amount Awarded from Other Party		$ 1,000,000
Litigation Settlement, Subject to Election, Payment Per Guarantor						$ 43,000
Accounts receivable				2,300,000		2,300,000
Other Assets				1,000,000		1,000,000
Lease Financings [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired				0		0			$ 0
Charge-offs				3,097,000	176,000	3,681,000	541,000
Nonaccrual Loans and Leases				1,703,000		1,703,000			536,000
Provision for loan losses				2,654,000	$ 184,000	4,015,000	$ 505,000
Impaired Financing Receivable, Related Allowance				0		0
Loans and Leases Receivable				124,138,000		124,138,000			134,739,000
Impaired Financing Receivable, Recorded Investment				1,300,000		1,300,000			$ 0
Fox Chase Bank [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired				466,500,000		466,500,000
Carrying amount				832,000		832,000
Valley Green Bank [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired				129,700,000		129,700,000
Carrying amount				790,000		790,000
Minimum [Member] | Software Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Litigation Settlement, Not Subject to Election, Payment Per Guarantor						108,000
Maximum [Member] | Software Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Litigation Settlement, Amount Awarded from Other Party		$ 1,300,000
Litigation Settlement, Not Subject to Election, Payment Per Guarantor						228,000
Non-Accrual [Member] | Software Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable				$ 1,300,000		$ 1,300,000
Scenario, Forecast [Member]
Financing Receivable, Recorded Investment [Line Items]
Litigation Settlement, Amount Awarded from Other Party			$ 1,000,000
Scenario, Forecast [Member] | Software Lease [Member]
Financing Receivable, Recorded Investment [Line Items]
Litigation Settlement, Election Process Completion, Date	Mar. 31, 2018