Loans (Schedule of the Allowance for Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	$ 78,473	$ 82,834	$ 79,072	$ 84,491
Provision for loan losses	1,500	3,000	3,100	6,000
Charge-offs	(3,375)	(5,361)	(6,847)	(10,835)
Recoveries	1,195	1,711	2,468	2,528
Ending balance	77,793	82,184	77,793	82,184
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	1,719	4,434	1,719	4,434	1,591
Loans collectively evaluated for impairment related to allowance for loan losses	75,574	77,250	75,574	77,250	76,981
Loans acquired with deteriorated credit quality related to allowance for loan losses	500	500	500	500	500
Total	77,793	82,184	77,793	82,184
Loans individually evaluated for impairment related to recorded investment (loan balance)	107,176	98,210	107,176	98,210	107,313
Loans collectively evaluated for impairment related to recorded investment (loan balance)	4,517,233	3,892,423	4,517,233	3,892,423	4,245,611
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	274,395	345,238	274,395	345,238	294,697
Total loans	4,898,804	4,335,871	4,898,804	4,335,871	4,647,621
Commercial Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	45,010	49,107	44,482	49,975
Provision for loan losses	439	568	1,399	3,005
Charge-offs	(1,814)	(3,221)	(3,023)	(6,737)
Recoveries	589	1,326	1,366	1,537
Ending balance	44,224	47,780	44,224	47,780
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	1,340	3,852	1,340	3,852	1,081
Loans collectively evaluated for impairment related to allowance for loan losses	42,884	43,928	42,884	43,928	43,401
Loans acquired with deteriorated credit quality related to allowance for loan losses	0	0	0	0	0
Total	44,224	47,780	44,224	47,780
Loans individually evaluated for impairment related to recorded investment (loan balance)	86,823	80,804	86,823	80,804	89,905
Loans collectively evaluated for impairment related to recorded investment (loan balance)	2,301,480	1,989,486	2,301,480	1,989,486	2,178,714
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	234,569	294,580	234,569	294,580	250,207
Total loans	2,622,872	2,364,870	2,622,872	2,364,870	2,518,826
Consumer Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	29,233	28,852	30,145	29,333
Provision for loan losses	1,287	1,648	2,142	2,519
Charge-offs	(1,561)	(2,140)	(3,824)	(4,098)
Recoveries	606	385	1,102	991
Ending balance	29,565	28,745	29,565	28,745
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	379	582	379	582	510
Loans collectively evaluated for impairment related to allowance for loan losses	28,686	27,663	28,686	27,663	29,135
Loans acquired with deteriorated credit quality related to allowance for loan losses	500	500	500	500	500
Total	29,565	28,745	29,565	28,745
Loans individually evaluated for impairment related to recorded investment (loan balance)	20,353	17,406	20,353	17,406	17,408
Loans collectively evaluated for impairment related to recorded investment (loan balance)	2,215,753	1,902,937	2,215,753	1,902,937	2,066,897
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	39,826	50,658	39,826	50,658	44,490
Total loans	2,275,932	1,971,001	2,275,932	1,971,001	2,128,795
Unallocated [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	4,230	4,875	4,445	5,183
Provision for loan losses	(226)	784	(441)	476
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	4,004	5,659	4,004	5,659
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	0	0	0	0	0
Loans collectively evaluated for impairment related to allowance for loan losses	4,004	5,659	4,004	5,659	4,445
Loans acquired with deteriorated credit quality related to allowance for loan losses	0	0	0	0	0
Total	4,004	5,659	4,004	5,659
Loans individually evaluated for impairment related to recorded investment (loan balance)	0	0	0	0	0
Loans collectively evaluated for impairment related to recorded investment (loan balance)	0	0	0	0	0
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	0	0	0	0	0
Total loans	$ 0	$ 0	$ 0	$ 0	$ 0