Bank subsidiary (Details 9) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Credit risk profile based on payment activity for loans
30-59 days past due	$ 7,241	$ 5,781
60-89 days past due	7,161	1,752
Greater than 90 days	23,791	26,227
Total past due	38,193	33,760
Current	4,158,176	4,125,193
Total financing receivables	4,196,369	4,158,953	3,855,835
Recorded Investment greater than 90 days and accruing	52	0
Residential 1-4 family
Credit risk profile based on payment activity for loans
30-59 days past due	4,209	2,728
60-89 days past due	1,635	622
Greater than 90 days	14,321	15,411
Total past due	20,165	18,761
Current	1,965,647	1,987,246
Total financing receivables	1,985,812	2,006,007	1,915,207
Commercial real estate
Credit risk profile based on payment activity for loans
30-59 days past due	71	0
Greater than 90 days	3,750	3,770
Total past due	3,821	3,770
Current	448,482	436,673
Total financing receivables	452,303	440,443	391,679
Home equity line of credit
Credit risk profile based on payment activity for loans
30-59 days past due	640	765
60-89 days past due	98	312
Greater than 90 days	928	960
Total past due	1,666	2,037
Current	762,817	737,294
Total financing receivables	764,483	739,331	648,904
Residential land
Credit risk profile based on payment activity for loans
30-59 days past due	96	184
60-89 days past due	191	48
Greater than 90 days	2,223	2,756
Total past due	2,510	2,988
Current	13,396	13,188
Total financing receivables	15,906	16,176	23,894
Recorded Investment greater than 90 days and accruing	52
Commercial construction
Credit risk profile based on payment activity for loans
Current	66,578	52,112
Total financing receivables	66,578	52,112	40,698
Residential construction
Credit risk profile based on payment activity for loans
Current	16,474	12,774
Total financing receivables	16,474	12,774	8,275
Commercial loans
Credit risk profile based on payment activity for loans
30-59 days past due	1,794	1,668
60-89 days past due	5,050	612
Greater than 90 days	2,406	3,026
Total past due	9,250	5,306
Current	777,361	778,082
Total financing receivables	786,611	783,388	699,918
Recorded Investment greater than 90 days and accruing		0
Consumer loans
Credit risk profile based on payment activity for loans
30-59 days past due	431	436
60-89 days past due	187	158
Greater than 90 days	163	304
Total past due	781	898
Current	107,421	107,824
Total financing receivables	108,202	108,722	127,260
Recorded Investment greater than 90 days and accruing		$ 0