Loans (Schedule of the Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	$ 78,268	$ 73,328	$ 75,683
Provision (benefit) for loan losses	23,300	14,875	6,500
Charge-offs	(16,867)	(15,302)	(13,501)
Recoveries	7,186	5,367	4,646
Ending balance	91,887	78,268	73,328
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses				$ 8,002	$ 9,392
Loans collectively evaluated for impairment related to allowance for loan losses				83,885	68,876
Total	78,268	73,328	75,683	91,887	78,268
Loans individually evaluated for impairment related to recorded investment (loan balance)				111,877	106,869
Loans collectively evaluated for impairment related to recorded investment (loan balance)				9,635,552	7,351,532
Total loans				14,155,267	12,990,779
Commercial Loan Portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	51,201	47,234	44,156
Provision (benefit) for loan losses	19,007	9,788	7,275
Charge-offs	(8,570)	(8,906)	(6,385)
Recoveries	4,495	3,085	2,188
Ending balance	66,133	51,201	47,234
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses				5,537	5,234
Loans collectively evaluated for impairment related to allowance for loan losses				60,596	45,967
Total	51,201	47,234	44,156	66,133	51,201
Loans individually evaluated for impairment related to recorded investment (loan balance)				83,797	78,523
Loans collectively evaluated for impairment related to recorded investment (loan balance)				5,573,389	4,026,526
Total loans				8,460,527	7,594,212
Consumer Loan Portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	27,067	26,094	28,803
Provision (benefit) for loan losses	4,293	5,087	1,949
Charge-offs	(8,297)	(6,396)	(7,116)
Recoveries	2,691	2,282	2,458
Ending balance	25,754	27,067	26,094
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses				2,465	4,158
Loans collectively evaluated for impairment related to allowance for loan losses				23,289	22,909
Total	27,067	26,094	28,803	25,754	27,067
Loans individually evaluated for impairment related to recorded investment (loan balance)				28,080	28,346
Loans collectively evaluated for impairment related to recorded investment (loan balance)				4,062,163	3,325,006
Total loans				5,694,740	5,396,567
Unallocated
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	0	0	2,724
Provision (benefit) for loan losses	0	0	(2,724)
Charge-offs	0	0	0
Recoveries	0	0	0
Ending balance	0	0	0
Allowance for loan losses
Total	$ 0	$ 0	$ 2,724	0	0
Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses
Allowance for loan losses related to loans acquired with deteriorated credit quality				0	0
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)				4,407,838	5,532,378
Receivables Acquired with Deteriorated Credit Quality \| Commercial Loan Portfolio
Allowance for loan losses
Allowance for loan losses related to loans acquired with deteriorated credit quality				0	0
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)				2,803,341	3,489,163
Receivables Acquired with Deteriorated Credit Quality \| Consumer Loan Portfolio
Allowance for loan losses
Allowance for loan losses related to loans acquired with deteriorated credit quality				0	0
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)				$ 1,604,497	$ 2,043,215

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A valuation allowance for financing receivables that are expected to be uncollectible.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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