Allowance for Loan Losses Allowance Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2015		Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014	[1]	Jun. 30, 2014	[1]	Mar. 31, 2014		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								$ 75,838								$ 76,371		$ 75,838		$ 76,371		$ 84,057
Provision/ (credit) for loan losses		$ (1,655)	[1]	$ 2,600		$ 0		(2,500)	[1]	$ 2,400	[1]	$ (2,600)		$ (5,000)		(1,200)	[1]	(1,555)		(6,400)		(10,000)
Loans charged-off																		(2,036)		(5,296)		(5,417)
Financing Receivable, Allowance for Credit Losses, Recovery																		6,253		11,163		7,731
Loans and Leases Receivable, Allowance, End of Period		78,500								75,838								78,500		75,838		76,371
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								14,114								12,837		14,114		12,837		11,825
Provision/ (credit) for loan losses																		(518)		(237)		11
Loans charged-off																		(253)		(717)		(218)
Financing Receivable, Allowance for Credit Losses, Recovery																		2,471		2,231		1,219
Loans and Leases Receivable, Allowance, End of Period		15,814								14,114								15,814		14,114		12,837
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								43,854								44,979		43,854		44,979		52,497
Provision/ (credit) for loan losses																		(721)		(1,940)		(10,024)
Loans charged-off																		(1,400)		(3,160)		(2,712)
Financing Receivable, Allowance for Credit Losses, Recovery																		2,482		3,975		5,218
Loans and Leases Receivable, Allowance, End of Period		44,215								43,854								44,215		43,854		44,979
Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								4,041								4,465		4,041		4,465		5,016
Provision/ (credit) for loan losses																		1,123		(1,905)		(1,683)
Loans charged-off																		0		(1,100)		(100)
Financing Receivable, Allowance for Credit Losses, Recovery																		1,158		2,581		1,232
Loans and Leases Receivable, Allowance, End of Period		6,322								4,041								6,322		4,041		4,465
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								10,374								10,732		10,374		10,732		10,892
Provision/ (credit) for loan losses																		342		(2,247)		1,824
Loans charged-off																		(313)		(263)		(2,008)
Financing Receivable, Allowance for Credit Losses, Recovery																		141		2,152		24
Loans and Leases Receivable, Allowance, End of Period		10,544								10,374								10,544		10,374		10,732
Home Equity Line of Credit [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								1,003								1,020		1,003		1,020		1,085
Provision/ (credit) for loan losses																		82		(32)		271
Loans charged-off																		0		0		(360)
Financing Receivable, Allowance for Credit Losses, Recovery																		0		15		24
Loans and Leases Receivable, Allowance, End of Period		1,085								1,003								1,085		1,003		1,020
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								382								322		382		322		540
Provision/ (credit) for loan losses																		207		(93)		(213)
Loans charged-off																		(70)		(56)		(19)
Financing Receivable, Allowance for Credit Losses, Recovery																		1		209		14
Loans and Leases Receivable, Allowance, End of Period		520								382								520		382		322
Unallocated Financing Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning of Period								$ 2,070	[2]							$ 2,016	[2]	2,070	[2]	2,016	[2]	2,202
Provision/ (credit) for loan losses	[2]																	(2,070)		54		(186)
Loans and Leases Receivable, Allowance, End of Period	[2]	$ 0								$ 2,070								$ 0		$ 2,070		$ 2,016

[1] Due to rounding, the sum of the four quarters may not add to the year to date total.

[2] As of December 31, 2015, the unallocated reserve was allocated to the qualitative factors as part of the general reserves (ASC 450). The allocation had no effect on the 2015 provision/ (credit) for loan losses.