ALLL Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Allowance for loan and lease losses
Balance at beginning of period	$ 130,519	$ 130,636	$ 129,753	$ 130,351
Provision for loan losses	826	360	1,873	1,721
Charge-offs	(2,073)	(2,243)	(4,671)	(5,567)
Recoveries	1,496	1,879	3,813	4,127
Balance at end of period	130,768	130,632	130,768	130,632
Residential Real Estate
Allowance for loan and lease losses
Balance at beginning of period	14,850	14,624	14,680	14,067
Provision for loan losses	854	374	1,036	1,111
Charge-offs	(20)	0	(78)	(413)
Recoveries	24	42	70	275
Balance at end of period	15,708	15,040	15,708	15,040
Commercial Real Estate
Allowance for loan and lease losses
Balance at beginning of period	68,697	68,929	67,799	70,332
Provision for loan losses	(657)	(1,072)	(452)	(3,261)
Charge-offs	(921)	(944)	(1,669)	(1,208)
Recoveries	907	650	2,348	1,700
Balance at end of period	68,026	67,563	68,026	67,563
Other Commercial
Allowance for loan and lease losses
Balance at beginning of period	31,483	29,589	30,891	28,630
Provision for loan losses	195	758	1,839	3,025
Charge-offs	(367)	(579)	(1,736)	(2,328)
Recoveries	290	997	607	1,438
Balance at end of period	31,601	30,765	31,601	30,765
Home Equity
Allowance for loan and lease losses
Balance at beginning of period	8,946	9,725	9,963	9,299
Provision for loan losses	397	900	(621)	1,411
Charge-offs	(433)	(607)	(586)	(906)
Recoveries	136	86	290	300
Balance at end of period	9,046	10,104	9,046	10,104
Other Consumer
Allowance for loan and lease losses
Balance at beginning of period	6,543	7,769	6,420	8,023
Provision for loan losses	37	(600)	71	(565)
Charge-offs	(332)	(113)	(602)	(712)
Recoveries	139	104	498	414
Balance at end of period	$ 6,387	$ 7,160	$ 6,387	$ 7,160