Bank segment - Credit risk profile - assigned grades (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Credit risk profile by internally assigned grade for loans
Commercial real estate	$ 561,262	$ 531,917
Commercial construction	62,444	96,438
Commercial	821,636	791,757
Pass
Credit risk profile by internally assigned grade for loans
Commercial real estate	507,904	493,105
Commercial construction	58,356	79,312
Commercial	763,238	743,334
Special mention
Credit risk profile by internally assigned grade for loans
Commercial real estate	7,232	5,209
Commercial construction	4,088	0
Commercial	10,313	16,095
Substandard
Credit risk profile by internally assigned grade for loans
Commercial real estate	46,126	33,603
Commercial construction	0	17,126
Commercial	47,492	31,665
Doubtful
Credit risk profile by internally assigned grade for loans
Commercial	$ 593	$ 663