Loans (Schedule of the Allowance for Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	$ 77,793	$ 82,184	$ 79,072	$ 84,491
Provision for loan losses	1,500	3,000	4,600	9,000
Charge-offs	(3,622)	(4,430)	(10,469)	(15,265)
Recoveries	1,335	778	3,803	3,306
Ending balance	77,006	81,532	77,006	81,532
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	1,503	4,223	1,503	4,223	1,591
Loans collectively evaluated for impairment related to allowance for loan losses	75,003	76,809	75,003	76,809	76,981
Loans acquired with deteriorated credit quality related to allowance for loan losses	500	500	500	500	500
Total	77,006	81,532	77,006	81,532
Loans individually evaluated for impairment related to recorded investment (loan balance)	103,732	96,513	103,732	96,513	107,313
Loans collectively evaluated for impairment related to recorded investment (loan balance)	4,673,882	4,117,215	4,673,882	4,117,215	4,245,611
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	263,306	308,943	263,306	308,943	294,697
Total loans	5,040,920	4,522,671	5,040,920	4,522,671	4,647,621
Commercial Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	44,224	47,780	44,482	49,975
Provision for loan losses	715	2,810	2,114	5,815
Charge-offs	(1,733)	(2,637)	(4,756)	(9,374)
Recoveries	789	374	2,155	1,911
Ending balance	43,995	48,327	43,995	48,327
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	1,175	3,638	1,175	3,638	1,081
Loans collectively evaluated for impairment related to allowance for loan losses	42,820	44,689	42,820	44,689	43,401
Loans acquired with deteriorated credit quality related to allowance for loan losses	0	0	0	0	0
Total	43,995	48,327	43,995	48,327
Loans individually evaluated for impairment related to recorded investment (loan balance)	84,103	78,782	84,103	78,782	89,905
Loans collectively evaluated for impairment related to recorded investment (loan balance)	2,388,586	2,105,006	2,388,586	2,105,006	2,178,714
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	226,119	261,999	226,119	261,999	250,207
Total loans	2,698,808	2,445,787	2,698,808	2,445,787	2,518,826
Consumer Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	29,565	28,745	30,145	29,333
Provision for loan losses	834	2,165	2,976	4,684
Charge-offs	(1,889)	(1,793)	(5,713)	(5,891)
Recoveries	546	404	1,648	1,395
Ending balance	29,056	29,521	29,056	29,521
Allowance for loan losses
Loans individually evaluated for impairment related to allowance for loan losses	328	585	328	585	510
Loans collectively evaluated for impairment related to allowance for loan losses	28,228	28,436	28,228	28,436	29,135
Loans acquired with deteriorated credit quality related to allowance for loan losses	500	500	500	500	500
Total	29,056	29,521	29,056	29,521
Loans individually evaluated for impairment related to recorded investment (loan balance)	19,629	17,731	19,629	17,731	17,408
Loans collectively evaluated for impairment related to recorded investment (loan balance)	2,285,296	2,012,209	2,285,296	2,012,209	2,066,897
Loans acquired with deteriorated credit quality related to recorded investment (loan balance)	37,187	46,944	37,187	46,944	44,490
Total loans	2,342,112	2,076,884	2,342,112	2,076,884	2,128,795
Unallocated [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	4,004	5,659	4,445	5,183
Provision for loan losses	(49)	(1,975)	(490)	(1,499)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	3,955	3,684	3,955	3,684
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	3,955	3,684	3,955	3,684	4,445
Loans acquired with deteriorated credit quality related to allowance for loan losses	0	0	0	0	0
Total	3,955	3,684	3,955	3,684
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